research on animals examples

Research using animals: an overview

Around half the diseases in the world have no treatment. Understanding how the body works and how diseases progress, and finding cures, vaccines or treatments, can take many years of painstaking work using a wide range of research techniques. There is overwhelming scientific consensus worldwide that some research using animals is still essential for medical progress.

Animal research in the UK is strictly regulated. For more details on the regulations governing research using animals, go to the UK regulations page .

Why is animal research necessary?

There is overwhelming scientific consensus worldwide that some animals are still needed in order to make medical progress.

Where animals are used in research projects, they are used as part of a range of scientific techniques. These might include human trials, computer modelling, cell culture, statistical techniques, and others. Animals are only used for parts of research where no other techniques can deliver the answer.

A living body is an extraordinarily complex system. You cannot reproduce a beating heart in a test tube or a stroke on a computer. While we know a lot about how a living body works, there is an enormous amount we simply don’t know: the interaction between all the different parts of a living system, from molecules to cells to systems like respiration and circulation, is incredibly complex. Even if we knew how every element worked and interacted with every other element, which we are a long way from understanding, a computer hasn’t been invented that has the power to reproduce all of those complex interactions - while clearly you cannot reproduce them all in a test tube.

While humans are used extensively in Oxford research, there are some things which it is ethically unacceptable to use humans for. There are also variables which you can control in a mouse (like diet, housing, clean air, humidity, temperature, and genetic makeup) that you could not control in human subjects.

Is it morally right to use animals for research?

Most people believe that in order to achieve medical progress that will save and improve lives, perhaps millions of lives, limited and very strictly regulated animal use is justified. That belief is reflected in the law, which allows for animal research only under specific circumstances, and which sets out strict regulations on the use and care of animals. It is right that this continues to be something society discusses and debates, but there has to be an understanding that without animals we can only make very limited progress against diseases like cancer, heart attack, stroke, diabetes, and HIV.

It’s worth noting that animal research benefits animals too: more than half the drugs used by vets were developed originally for human medicine. 

Aren’t animals too different from humans to tell us anything useful?

No. Just by being very complex living, moving organisms they share a huge amount of similarities with humans. Humans and other animals have much more in common than they have differences. Mice share over 90% of their genes with humans. A mouse has the same organs as a human, in the same places, doing the same things. Most of their basic chemistry, cell structure and bodily organisation are the same as ours. Fish and tadpoles share enough characteristics with humans to make them very useful in research. Even flies and worms are used in research extensively and have led to research breakthroughs (though these species are not regulated by the Home Office and are not in the Biomedical Sciences Building).

What does research using animals actually involve?

The sorts of procedures research animals undergo vary, depending on the research. Breeding a genetically modified mouse counts as a procedure and this represents a large proportion of all procedures carried out. So does having an MRI (magnetic resonance imaging) scan, something which is painless and which humans undergo for health checks. In some circumstances, being trained to go through a maze or being trained at a computer game also counts as a procedure. Taking blood or receiving medication are minor procedures that many species of animal can be trained to do voluntarily for a food reward. Surgery accounts for only a small minority of procedures. All of these are examples of procedures that go on in Oxford's Biomedical Sciences Building. 

How many animals are used?

Figures for 2023 show numbers of animals that completed procedures, as declared to the Home Office using their five categories for the severity of the procedure.

# NHPs - Non Human Primates

Oxford also maintains breeding colonies to provide animals for use in experiments, reducing the need for unnecessary transportation of animals.

Figures for 2017 show numbers of animals bred for procedures that were killed or died without being used in procedures:

Why must primates be used?

Primates account for under half of one per cent (0.5%) of all animals housed in the Biomedical Sciences Building. They are only used where no other species can deliver the research answer, and we continually seek ways to replace primates with lower orders of animal, to reduce numbers used, and to refine their housing conditions and research procedures to maximise welfare.

However, there are elements of research that can only be carried out using primates because their brains are closer to human brains than mice or rats. They are used at Oxford in vital research into brain diseases like Alzheimer’s and Parkinson’s. Some are used in studies to develop vaccines for HIV and other major infections.

What is done to primates?

The primates at Oxford spend most of their time in their housing. They are housed in groups with access to play areas where they can groom, forage for food, climb and swing.

Primates at Oxford involved in neuroscience studies would typically spend a couple of hours a day doing behavioural work. This is sitting in front of a computer screen doing learning and memory games for food rewards. No suffering is involved and indeed many of the primates appear to find the games stimulating. They come into the transport cage that takes them to the computer room entirely voluntarily.

After some time (a period of months) demonstrating normal learning and memory through the games, a primate would have surgery to remove a very small amount of brain tissue under anaesthetic. A full course of painkillers is given under veterinary guidance in the same way as any human surgical procedure, and the animals are up and about again within hours, and back with their group within a day. The brain damage is minor and unnoticeable in normal behaviour: the animal interacts normally with its group and exhibits the usual natural behaviours. In order to find out about how a disease affects the brain it is not necessary to induce the equivalent of full-blown disease. Indeed, the more specific and minor the brain area affected, the more focussed and valuable the research findings are.

The primate goes back to behavioural testing with the computers and differences in performance, which become apparent through these carefully designed games, are monitored.

At the end of its life the animal is humanely killed and its brain is studied and compared directly with the brains of deceased human patients. 

Primates at Oxford involved in vaccine studies would simply have a vaccination and then have monthly blood samples taken.

How many primates does Oxford hold?

* From 2014 the Home Office changed the way in which animals/ procedures were counted. Figures up to and including 2013 were recorded when procedures began. Figures from 2014 are recorded when procedures end.

What’s the difference between ‘total held’ and ‘on procedure’?

Primates (macaques) at Oxford would typically spend a couple of hours a day doing behavioural work, sitting in front of a computer screen doing learning and memory games for food rewards. This is non-invasive and done voluntarily for food rewards and does not count as a procedure. After some time (a period of months) demonstrating normal learning and memory through the games, a primate would have surgery under anaesthetic to remove a very small amount of brain tissue. The primate quickly returns to behavioural testing with the computers, and differences in performance, which become apparent through these carefully designed puzzles, are monitored. A primate which has had this surgery is counted as ‘on procedure’. Both stages are essential for research into understanding brain function which is necessary to develop treatments for conditions including Alzheimer’s, Parkinson’s and schizophrenia.

Why has the overall number held gone down?

Numbers vary year on year depending on the research that is currently undertaken. In general, the University is committed to reducing, replacing and refining animal research.

You say primates account for under 0.5% of animals, so that means you have at least 16,000 animals in the Biomedical Sciences Building in total - is that right?

Numbers change daily so we cannot give a fixed figure, but it is in that order.

Aren’t there alternative research methods?

There are very many non-animal research methods, all of which are used at the University of Oxford and many of which were pioneered here. These include research using humans; computer models and simulations; cell cultures and other in vitro work; statistical modelling; and large-scale epidemiology. Every research project which uses animals will also use other research methods in addition. Wherever possible non-animal research methods are used. For many projects, of course, this will mean no animals are needed at all. For others, there will be an element of the research which is essential for medical progress and for which there is no alternative means of getting the relevant information.

How have humans benefited from research using animals?

As the Department of Health states, research on animals has contributed to almost every medical advance of the last century.

Without animal research, medicine as we know it today wouldn't exist. It has enabled us to find treatments for cancer, antibiotics for infections (which were developed in Oxford laboratories), vaccines to prevent some of the most deadly and debilitating viruses, and surgery for injuries, illnesses and deformities.

Life expectancy in this country has increased, on average, by almost three months for every year of the past century. Within the living memory of many people diseases such as polio, tuberculosis, leukaemia and diphtheria killed or crippled thousands every year. But now, doctors are able to prevent or treat many more diseases or carry out life-saving operations - all thanks to research which at some stage involved animals.

Each year, millions of people in the UK benefit from treatments that have been developed and tested on animals. Animals have been used for the development of blood transfusions, insulin for diabetes, anaesthetics, anticoagulants, antibiotics, heart and lung machines for open heart surgery, hip replacement surgery, transplantation, high blood pressure medication, replacement heart valves, chemotherapy for leukaemia and life support systems for premature babies. More than 50 million prescriptions are written annually for antibiotics. 

We may have used animals in the past to develop medical treatments, but are they really needed in the 21st century?

Yes. While we are committed to reducing, replacing and refining animal research as new techniques make it possible to reduce the number of animals needed, there is overwhelming scientific consensus worldwide that some research using animals is still essential for medical progress. It only forms one element of a whole research programme which will use a range of other techniques to find out whatever possible without animals. Animals would be used for a specific element of the research that cannot be conducted in any alternative way.

How will humans benefit in future?

The development of drugs and medical technologies that help to reduce suffering among humans and animals depends on the carefully regulated use of animals for research. In the 21st century scientists are continuing to work on treatments for cancer, stroke, heart disease, HIV, malaria, tuberculosis, diabetes, neurodegenerative diseases like Alzheimer's and Parkinson’s, and very many more diseases that cause suffering and death. Genetically modified mice play a crucial role in future medical progress as understanding of how genes are involved in illness is constantly increasing. 

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Computer model: a computer program designed to predict what might happen based off of collected data.

Ethical: relating to a person's moral principles.

Morals: a person's beliefs concerning what is right and wrong.

Zoologist: a person who studies animals.

Scientists learn a lot about snakes and other animals through basic research. Image by the Virginia State Park staff.

“Don’t worry, they aren’t dangerous” you hear the zoologist say as she leads you and a group of others toward an area with a number of different snakes. She removes a long snake from a larger glass enclosure and asks who would like to hold it. You take a step back, certain that holding a snake is the last thing you’d like to do.

"But how do you know they aren’t dangerous?” you ask. The zoologist looks up and smiles. She explains that scientists have studied this type of snake, and so we actually know quite a bit about it. This type of snake rarely bites and does not produce venom, so it isn’t dangerous to people. You nod along as she talks about the snakes, their natural habitats, and other details like what they eat.

Animals in the Research Process

How do we know so much about snakes or other animals? Animals are all unique, and scientists study them to learn more about them. For example, by studying snakes we have learned that they stick their tongues out because they are trying to pick up odors around them. This helps them sense food, predators, and other things that may be nearby. When research is performed to expand our understanding of something, like an animal, we call it basic research .

Scientists study animals for other reasons too. What we learn about animals can actually help us find solutions to other problems or to help people. For example, studying snakes helps us understand which ones are venomous so that humans know what kinds of snakes they shouldn't touch. Scientists also study animals to find new treatments to diseases and other ailments that affect both people and animals. If we learn what is in snake venom, we can create a medicine to give to people that have been bitten as a treatment to help them feel better. Using what we know about an animal or thing to help us solve problems or treat disease is called  applied research .

Scientists use many other tools, such as computer models, in addition to animals to study different topics. Image by Andreas Horn.

No matter what type of research is being performed, scientists must consider many things when they study animals.  

Do Scientists Need to Study Animals?

Of course we can learn a lot from using animals for research, but are there alternative options? Sometimes there are. For example, scientists could use some other method, like cells or computer models, to study a particular topic instead of using animals. However, for a number of reasons , scientists have found that using animals is sometimes the best way to study certain topics.

What If Scientists Harm Animals for Research?

Some research using animals only requires scientists to watch behavior or to take a few samples (like blood or saliva) from the animal. These activities may cause the animals some stress, but they are unlikely to harm the animals in any long-term way. Studies of the behavior or physiology of an animal in its natural environment is an example of such research.

In other cases, scientists may need to harm or kill an animal in order to answer a research question. For example, a study could involve removing a brain to study it more closely or giving an animal a treatment without knowing what effects it may have. While the intention is never to purposely harm animals, harm can be necessary to answer a research question.

How Do Scientists Decide When It’s OK to Study Animals?

Many animals are used in research. But there is still debate on whether they should be used for this purpose. Image by the United States Department of Agriculture.

There are  many guidelines  for when it’s ok to use animals in research. Scientists must write a detailed plan of why and how they plan to use animals for a research project. This information is then reviewed by other scientists and members of the public to make sure that the research animals will be used for has an important purpose. Whatever the animals are used for, the scientists also make sure to take care of animal research subjects as best as they can.

Even with rules in place about using animals for research, many people (both scientists and non-scientists) continue to debate whether animals should be used in research. This is an ethical question, or one that depends on a person's morals. Because the way each person feels about both research and animals may be different, there is a range of views on this matter.

• Some people argue that it doesn’t matter that there are rules in place to protect animals. Animals should never be used for research at all, for any reason. 
• Others say we should be able to use animals for any kind of research because moving science forward is more important than the rights or well-being of animals. 
• Lastly, there are people whose opinions sit somewhere in the middle. They might argue that it’s ok to use animals for research, but only in some cases. For example, if the results of the research are very likely to help treat something that affects people, then it may be okay to use animals.

Along with this debate, there are many advantages and disadvantages of doing animal research . Scientists must weigh these options when performing their research.

Additional Images via Wikimedia Commons. White rat image by Alexandroff Pogrebnoj.

Read more about: Using Animals in Research

View citation, bibliographic details:.

• Article: Using Animals in Research
• Author(s): Patrick McGurrin and Christian Ross
• Publisher: Arizona State University School of Life Sciences Ask A Biologist
• Site name: ASU - Ask A Biologist
• Date published: December 4, 2016
• Date accessed: May 21, 2024
• Link: https://askabiologist.asu.edu/explore/Animal-use-in-Research

Patrick McGurrin and Christian Ross. (2016, December 04). Using Animals in Research. ASU - Ask A Biologist. Retrieved May 21, 2024 from https://askabiologist.asu.edu/explore/Animal-use-in-Research

Chicago Manual of Style

Patrick McGurrin and Christian Ross. "Using Animals in Research". ASU - Ask A Biologist. 04 December, 2016. https://askabiologist.asu.edu/explore/Animal-use-in-Research

MLA 2017 Style

Patrick McGurrin and Christian Ross. "Using Animals in Research". ASU - Ask A Biologist. 04 Dec 2016. ASU - Ask A Biologist, Web. 21 May 2024. https://askabiologist.asu.edu/explore/Animal-use-in-Research

Animals are an important part of research. But many argue about whether it's ethical to use animals to help advance scientific progress.

Using Animals in Research

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Ethical care for research animals

WHY ANIMAL RESEARCH?

The use of animals in some forms of biomedical research remains essential to the discovery of the causes, diagnoses, and treatment of disease and suffering in humans and in animals., stanford shares the public's concern for laboratory research animals..

Many people have questions about animal testing ethics and the animal testing debate. We take our responsibility for the ethical treatment of animals in medical research very seriously. At Stanford, we emphasize that the humane care of laboratory animals is essential, both ethically and scientifically.  Poor animal care is not good science. If animals are not well-treated, the science and knowledge they produce is not trustworthy and cannot be replicated, an important hallmark of the scientific method .

There are several reasons why the use of animals is critical for biomedical research: 

••  Animals are biologically very similar to humans. In fact, mice share more than 98% DNA with us!

••  Animals are susceptible to many of the same health problems as humans – cancer, diabetes, heart disease, etc.

••  With a shorter life cycle than humans, animal models can be studied throughout their whole life span and across several generations, a critical element in understanding how a disease processes and how it interacts with a whole, living biological system.

The ethics of animal experimentation

Nothing so far has been discovered that can be a substitute for the complex functions of a living, breathing, whole-organ system with pulmonary and circulatory structures like those in humans. Until such a discovery, animals must continue to play a critical role in helping researchers test potential new drugs and medical treatments for effectiveness and safety, and in identifying any undesired or dangerous side effects, such as infertility, birth defects, liver damage, toxicity, or cancer-causing potential.

U.S. federal laws require that non-human animal research occur to show the safety and efficacy of new treatments before any human research will be allowed to be conducted.  Not only do we humans benefit from this research and testing, but hundreds of drugs and treatments developed for human use are now routinely used in veterinary clinics as well, helping animals live longer, healthier lives.

It is important to stress that 95% of all animals necessary for biomedical research in the United States are rodents – rats and mice especially bred for laboratory use – and that animals are only one part of the larger process of biomedical research.

Our researchers are strong supporters of animal welfare and view their work with animals in biomedical research as a privilege.

Stanford researchers are obligated to ensure the well-being of all animals in their care..

Stanford researchers are obligated to ensure the well-being of animals in their care, in strict adherence to the highest standards, and in accordance with federal and state laws, regulatory guidelines, and humane principles. They are also obligated to continuously update their animal-care practices based on the newest information and findings in the fields of laboratory animal care and husbandry.  

Researchers requesting use of animal models at Stanford must have their research proposals reviewed by a federally mandated committee that includes two independent community members.  It is only with this committee’s approval that research can begin. We at Stanford are dedicated to refining, reducing, and replacing animals in research whenever possible, and to using alternative methods (cell and tissue cultures, computer simulations, etc.) instead of or before animal studies are ever conducted.

Organizations and Resources

There are many outreach and advocacy organizations in the field of biomedical research.

• Learn more about outreach and advocacy organizations

Stanford Discoveries

What are the benefits of using animals in research? Stanford researchers have made many important human and animal life-saving discoveries through their work. 

• Learn more about research discoveries at Stanford

Using animals for scientific research is still indispensable for society as we know it

Senior Advisor Animal Ethics and Outreach, Donders Centre for Neuroscience, Radboud University

Professor, Radboud University

Associate Professor in Neuroinformatics, Radboud University

Disclosure statement

The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.

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Kenya’s national airline – Kenya Airways – made headlines when it announced it would stop transporting monkeys for animal research. This followed an accidental highway crash in Pennsylvania , in the US, which involved a truck transporting monkeys that had been bred in Mauritius for laboratory experiments in the US.

Following the accident, the People for the Ethical Treatment of Animals (PETA) US, an animal rights group, contacted Kenya Airways urging them to reconsider transporting the animals, putting forward their view that animal experimentation is a cruel industry.

Read more: The macaque monkeys of Mauritius: an invasive alien species, and a major export for research

Such an incident is indeed tragic. But if we consider the number of people who would have died without the existence of medication and novel medical technologies developed thanks to animal research, then ending animal research could lead to a more tragic outcome in the longer term.

Most countries do animal research, perhaps not very tiny countries or very poor countries. There is a nationwide ban on animal testing for cosmetics throughout the European Union, Israel, Norway, as well as in India. But animal testing for other reasons is still widely accepted.

Most of the animals used come from commercial breeders – one is Jackson Laboratory in the US. Other sources include specialist breeders and large breeding centres which can provide genetically modified animals for specific research. The animal testing facilities themselves may also rear animals.

In general, all over the world, policymakers do aim to move towards animal-free methods of scientific research and have introduced very strict regulations for animal research.

Scientists and policymakers share the long-term goal of reducing animal use in scientific research and where possible eventually even stopping it. It’s an ambitious goal. For this to happen, animal-free methods need to be developed and validated before they can become a new standard.

Animal-free innovations have been developed for some areas of biomedical research, such as toxicology . However, most parties recognise that at present, not all research questions can be answered using only animal-free methods.

Based on decades of doing research on the human brain, which involves using animals, to us it’s clear that – for the foreseeable future – there remains a crucial need for animal models to understand health and disease and to develop medicines.

Unique knowledge

It is animal research that provides researchers with unique knowledge about how humans and animals function. Perhaps more than in any other field of biomedical research, complete living animals are needed to understand brain function, behaviour and cognition.

Behaviour and cognition, the final outputs of a brain organ, cannot be mimicked using any existing animal-free technologies. We currently simply do not understand the brain well enough to make animal-free solutions.

Another striking, very recent example that showed the current need for animal research is the COVID-19 pandemic . The way out of the pandemic required the development of a functioning vaccine. Researchers amazed the world when they made targeted vaccines available within one year. This, however, has relied greatly on the use of animals for testing the efficacy and safety of the vaccine.

A key fact that remains often invisible is that the rules and regulations for conducting animal research are, in comparison, perhaps even stricter and more regulated, by for example the Animal Welfare act in the US and the European Convention for the Protection of Vertebrate Animals used for Experimental and other Scientific Purposes in Europe. Than, for example, in the food and entertainment industry, although regulations are in place here too such as governmental rules for the treatment of animals in order to protect their health and wellbeing.

Should it be banned?

In the world as we know it today, animal research is still generally accepted as part of society. There are many important reasons why laboratory animal research is still needed:

To learn about biological processes in animals and humans.

To learn about the cause of diseases.

To develop new treatments and vaccines and evaluate their effects.

To develop methods that can prevent disease both in animals and humans.

To develop methods for the management of animals such as pests but also for the conservation of endangered species.

Of course many, animal researchers included, are hopeful that one day animal experiments will no longer be necessary to achieve the much needed scientific outcomes. However, the situation is that for many research questions related to human and animal health we still need animals.

As long as we cannot replace animals, there should be more focus on transparency and animal welfare, to benefit the animals as well as science. Awareness and financial support of this at the governmental level is key to enable animal researchers to always strive for the highest level of animal welfare possible.

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An Introduction to Animal Research

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• James Kinross 3 &
• Lord Ara Darzi 4  

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Despite advances in computer modelling and bioinformatics, animal models remain a vital component of biomedical research. The growth in this area of work is in part due to the evolution next generation of biotechnologies, which more than ever necessitate the need for in vivo experimentation. An understanding of the principals of animal research therefore remains a necessity for medical researchers as it permits scientific analysis to be interpreted in a more critical and meaningful manner. Initiating and designing an animal experiment can be a daunting process, particularly as the law and legislation governing animal research is complex and new specialist skills must be acquired. This chapter reviews the principles of animal research and provides a practical resource for those researchers seeking to create robust animal experiments that ensure minimal suffering and maximal scientific validity.

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Alternatives of Animal Models for Biomedical Research: a Comprehensive Review of Modern Approaches

Research: Animals

Abbreviations

The American College of Laboratory Animal Medicine

Animal and Plant Health Inspection Service

Animal Welfare Act

Control of substances hazardous to health

European Coalition for Biomedical Research

The Food and Drug Agency

Health and Safety Executive

The Human Fertilisation and Embryology Authority

Institutional Animal Care and Use Committee

Individually ventilated cage

In vitro fertilisation

Laboratory animal allergy

Named animal care and welfare officer

National Institute for Clinical Excellence

Named veterinary surgeon

The Office of Laboratory Animal Welfare

Public Health Service

Personal License under the Scientific (Animal Procedures) Act 1986

Project License under the Scientific (Animal Procedures) Act 1986

Royal Society for the Prevention of Cruelty to Animals

Specified pathogen free

The United States Department of Agriculture

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Kinross, J., Darzi, L.A. (2010). An Introduction to Animal Research. In: Athanasiou, T., Debas, H., Darzi, A. (eds) Key Topics in Surgical Research and Methodology. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-71915-1_17

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Science, Medicine, and Animals (1991)

Chapter: how have animals contributed to improving human health, how have animals contributed to improving human health.

A hundred years ago, good health was much rarer than it is today. In 1870, the leading cause of death in the United States was tuberculosis. 12 Of all the people born in developed countries like the United States, a quarter were dead by the age of 25, and about half had died by the age of 50. Those fortunate enough to have survived to old age had probably experienced several bouts with diseases like typhoid fever, dysentery, or scarlet fever. 13

Today, the leading causes of death in the United States are heart disease and cancer—diseases of old age rather than infancy and childhood. Fully 97 percent of Americans live past their 25th birthday, and over 90 percent live to be more than 50.

Better nutrition and sanitation did much to reduce the toll from infectious diseases. But these diseases could not have been eliminated as significant causes of death and illness without animal research. Animal research has also made people healthier, since it has contributed to virtually eliminating many infectious diseases like polio or rheumatic fever that can be debilitating without causing death. Animal research has even contributed to better nutrition and sanitation, since it has helped to identify the agents that contribute to good or bad health.

Because of a genetic defect, nude mice such as the one shown here have no thymus and cannot make certain cells essential for various immune responses. This characteristic makes them extremely helpful to scientists working in immunology research.

Methods to combat infectious diseases have not been the only dividends of animal research. Surgical procedures, pain relievers, psychoactive drugs, medications for blood pressure, insulin, pacemakers, nutrition supplements, organ transplants, treatments for shock trauma and blood diseases—all have been developed and tested in animals before being used in humans. 14 In fact, according to the American Medical Association, “Virtually every advance in medical science in the 20th century, from antibiotics and vaccines to antidepressant drugs and organ transplants, has been achieved either directly or indirectly through the use of animals in laboratory experiments.” 15

Animals will continue to be essential in combatting human illness. Though human health has improved greatly over the last 100 years, much remains to be done. Many of today's leading killers, such as cancer, atherosclerosis, diabetes, Alzheimer's disease, and AIDS, remain inadequately understood. Furthermore, debilitating conditions such as traumatic injury, strokes, arthritis, and a variety of mental disorders continue to exact a severe toll on human well-being.

Animal research will be no less important in the future than it has been in the past. Indeed, it may be even more important, because the questions remaining to be answered generally involve complex diseases and injuries that require whole organisms to be studied.

A scientist compares similarities in baboon virus and HIV-1. This is one of the studies being conducted to help discover the proper sequence of the AIDS virus.

The necessity for animal use in biomedical research is a hotly debated topic in classrooms throughout the country. Frequently teachers and students do not have access to balanced, factual material to foster an informed discussion on the topic. This colorful, 50-page booklet is designed to educate teenagers about the role of animal research in combating disease, past and present; the perspective of animal use within the whole spectrum of biomedical research; the regulations and oversight that govern animal research; and the continuing efforts to use animals more efficiently and humanely.

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Research Animals

This comprehensive resource looks at the animals most commonly used in research and dissection, examining issues like the Animal Welfare Act, breeding and transport, research alternatives and more.

On this Page

Research on animals costs many millions of lives each year. And millions more animals are kept confined in laboratories and cages, awaiting their turn for experimentation. Biomedical research using animals is a largely secretive process and the public knows little about what goes on in research labs. This exclusive Faunalytics Fundamental examines the use of animals in research, estimating the scope and nature of the problem based on the best available data. We hope you find the information useful in your advocacy for research animals. Please see all the sources here.

Meet the Animals

Animals live rich and complex lives. Primates exhibit deep thought and intricate social structures; their similarity to humans has made using other primates unthinkable for most purposes other than experimentation (and “entertainment”). Dogs like beagles are docile, friendly, and cooperative – traits that make them easier to manage as test subjects. Guinea pigs, which have become synonymous with animal research, are gentle and even purr like cats when they’re happy. Mice and rats are empathetic and studies have shown that they will risk themselves to rescue cage-mates in captivity. There is no doubt that the animals we use for research and dissection are capable of thinking, feeling, and suffering just like we are. Check out the interactive graphics below to explore facts about some of the animals most commonly used in research. Of course, we’re only scratching the surface of what makes these animals unique, sentient, and deserving of their own rights to life and freedom.

Rats & Mice

Show empathy in different forms to other rats and mice in trouble.

• Sentient & Smart – Remember sources of pain and have a long-lasting aversion to them
• Cage Boredom – Can quickly become bored unless provided with enrichment
• Have A Heart – Have gregarious personalities and live in cohesive social groups

Guinea Pigs

Need companionship and enjoy cuddling and sleeping together.

• Active Animals – Love to play and need “boredom breakers” to stay stimulated
• Happy Pop – Known to jump in the air—called “popcorning”—when excited
• A Balancing Act – Have complex and delicately balanced social structures

Used in research because they are gentle, sweet, and curious.

• Mother’s Intinct – Are highly protective of their own puppies and even human babies
• Strength In Numbers – Have a deep pack instinct and struggle with separation anxiety
• Led By The Nose – Have an extraordinary sense of smell and a strong urge to investigate scents

Often become bored, depressed, and aggressive in captivity.

• Healing Touch – Groom each other after conflicts to repair damaged relationships
• Getting Their Point Across – Communicate through vocalizations, facial expressions, and gestures
• Cool Tools – Use a variety of objects as tools to help solve problems

Opinions about the use of animals for research are complicated and often divided when it comes to different purposes or types of research. For instance, a clear majority of people are against the use of animals for testing cosmetics and personal care products . However, if the research is claimed to save or improve human lives, then opinions shift, even if those claims are hypothetical or baseless. Attitudes regarding the use of animals for student dissection are less clear given there are fewer surveys of those audiences. However, the limited research shows that many students and teachers prefer non-animal alternatives to dissection – see our “In The Classroom” section below for a detailed breakdown.

What about trends over time? The Gallup figures shown in the graphic above have shown a consistent decline in the perceived moral acceptability of testing on animals. From 65% saying “acceptable” in 2001 to 51% saying “acceptable” in 2017 (a record low). Through our Animal Tracker survey, Faunalytics has monitored attitudes about animals used for research since 2008. In the selection of Animal Tracker charts below, you can see that feelings about the protection of animals in laboratories has fluctuated since 2008/2009, but only slightly. In summary, belief in the importance of research animal welfare has stayed strong, most people continue to question the adequacy of laws protecting laboratory animals, and belief in the necessity of animal research and dissection appears to be dropping in recent years.

Breeding and Transport

Before they arrive at the laboratory, animals used for research are most often born and housed in large breeding facilities found throughout the world. Some research animals may come from relatively regulated companies such as Charles River or Interfauna, based in countries like the United States, England, or Spain. Other animals, such as monkeys, more often come from international suppliers that operate in Southeast Asia, parts of Africa, and China. Below, we connect some of the dots of the global breeding and transport of research animals, with Southeast Asia as an example.

In the Laboratory

How many animals are bred for research, kept in laboratories, and used in experiments? Unfortunately, under current regulations in virtually any country, it’s impossible to know the exact answer. Estimates for the total number of animals used in research worldwide hover around 115 million to 127 million, while estimates for the U.S. specifically hover around 25 million. In the U.S., researchers are not required to report the numbers of rats, mice, and birds used in experiments, and these species combined make up an estimated 95% of all animals used in research. The chart below provides the best estimates for the numbers of mice, rats, and birds used in the United States in 2015, as well as the other species whose use is covered by the Animal Welfare Act.

Immediately, we can see that the Animal Welfare Act is inadequate and ignores the big picture. Not only does the act not cover these animals, it also does not mandate that researchers maintain any statistics for these species. Therefore, we can only make educated estimates on the numbers of animals being used. Secondly, we see that researchers, who already keep hidden from public view, have very few official controls or oversight for most of the work they do. For animal advocates, it is important to spotlight these facilities and the often egregious suffering that they house.

The above map shows animal experimentation labs and breeding facilities in the U.S. You can look up the animal research facilities in your state using this tool put together by HSUS . The prevalence of such operations throughout the country may be shocking to see. Unlike the farms and feedlots that we often see while driving through the countryside, animal research and breeding facilities are much more hidden from view. Likewise, the laws that govern and regulate experimentation in the U.S. (and many other places in the world) do their part to obscure both the scope and the nature of animal research.

In the Classroom

Conventional wisdom says that the best way for students to learn about biology is through hands-on methods, usually involving the dissection of dead animals. Dissection has been used as a learning tool for many decades, and it’s estimated that 6-12 million animals are used each year – though that is a very loose estimate and no official statistics are kept. Thankfully, scientific advancements and public opinion are starting to help turn the tide. Recently, a study by Faunalytics on behalf of the National Anti-Vivisection Society found that only half of students are interested in dissecting animals and more than a third (37%) of students would prefer to use alternatives to animal dissection. What’s more, a study by the American Anti-Vivisection Society found that 75% of U.S. adults agree that “students taking biology courses should be allowed to choose alternative methods of learning that do not involve dissecting animals.”

Support for dissection isn’t just dwindling. Students are actively demanding alternatives to the use of animals in grade school classrooms. In response, many schools have created what are called “student choice policies,” which allow students to opt-out of dissection for ethical reasons. Unfortunately, such policies are not ubiquitous yet; in the U.S., only 18 states and the District of Columbia allow students to choose alternatives. Even when such policies exist, teachers and students may not be aware of them. The Faunalytics/NAVS study mentioned earlier showed that only 53% of educators in states with student choice policies knew about those policies. The same study found that 38% of students didn’t know if alternatives were available to them. Thanks to the work of anti-vivisection groups, this is changing.

Alternatives

If you aren’t swayed by the ethical arguments against animal research, perhaps this will change your mind: Approximately 100 vaccines have shown effectiveness against HIV-like animal viruses, but none prevent HIV in humans. Up to 1,000 drugs have shown effectiveness for neuroprotection in animals, but none for humans. While the biomedical research industry is quick to claim victories, the reality is less glamourous: nine out of ten drugs fail in clinical studies because they cannot predict how they will behave in people; only 8% of drugs tested on animals are deemed fit for human use; one meta-study found that animal trials overestimate the likelihood that a treatment works by 30% because negative results often go unpublished. Fortunately, using animals in scientific research is not a foregone conclusion. On the contrary, there is a burgeoning field of alternatives to animal research, and many such alternatives are already in use today.

The above graphic shows a small selection of some of the most exciting and promising alternatives to animal research that exist today. There are many others that are available, and even more are on the way. Among the many organizations and institutions working on better alternatives are FRAME , INTERNICHE , and Animalearn who are leading the way in promoting clinical and educational alternatives.

This Faunalytics Fundamental has provided a visual overview of the use of animals in research. The result is a complex picture: public opinion is mixed and context-specific; the number of animals used is a guesstimate due to lack of reporting for certain species; and laws are not keeping pace with students’ interest in dissection alternatives. The scientific establishment has a lot of inertia in favor of continuing the use of animals in research, but is slowly shifting towards alternatives.

Meanwhile, millions of animals are trapped in labs, waiting for us to help them. The data presented here raise many questions for how to invest limited advocacy resources:

• How can advocates galvanize the majority of the public that believes research animal welfare is important and guide them towards supporting elimination and alternatives? Looking a public opinion research such as this and this can help advocates to target different public audiences on a case by case basis.
• What can animal advocates – and members of the public – do to contribute to the development of research alternatives? Education about alternatives and their effectiveness is key.
• Public opinion for various animal research issues is somewhat contradictory and confused. What are the most effective ways that advocates can clarify the issues? First, animal advocates needs to educate themselves on the science , and then communicate that effectively.
• As animal research regulations become more stringent in some parts of the world, “outsourcing” to laboratories in other parts of the world becomes a bigger issue. How can advocates anticipate and prevent this trend?

These are questions advocates should think about and possibly research further.

We hope you find the above information useful in your advocacy for animals used in research. Check out all the sources here.

There is so much more work to be done to give advocates the insight they need to choose the most effective ways to help animals. Please donate generously now to help us bring you and other advocates this crucial information.

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Animal Research

Animal research case studies

UCL is a leading centre for biomedical research in the UK. Scientific research is conducted not by shadowy figures in ivory towers, but by human beings working earnestly to address major issues facing society today.

Dr Clare Stanford: using mice to find treatments for ADHD

Dr Clare Stanford is a Reader in Experimental Psychopharmacology at UCL. Despite the intimidating title, Clare is a down-to-earth, compassionate researcher with a real commitment to animal welfare. She is chair of the Bloomsbury AWERB and does not hold back from questioning the ethics of research objectives , as well as the way it is carried out.

Clare is currently working on a mouse model for Attention Deficit Hyperactivity Disorder (ADHD). This is a strongly inherited psychiatric disorder, which causes problems for patients by making them hyperactive, excessively impulsive and inattentive. ADHD is often regarded as a childhood issue, but about 65% of people carry it through to adulthood where the associated problems are far worse. It has been associated with alcohol and drug misuse in later life, and an estimated 25% of the prison population have ADHD . There is also an increased risk of other health complications, including asthma and epilepsy.

Dr Simon Waddington and Rajvinder Karda: reducing mouse use with glowing firefly genes

Although animal research remains a necessary part of modern research, current methods are far from perfect. By injecting the genes that fireflies use to emit light into newborn mice, UCL scientists have developed a way to drastically reduce the numbers of mice needed for research into disease and development.

At the moment, researchers often need to cull and perform autopsies on animals to see how diseases develop on a molecular level. This means that an animal needs to be killed for every data point recorded, so some studies might use dozens of mice to get reliable data on disease progression.

The new technique could allow researchers to get molecular-level data by simply taking a picture with specialist equipment rather than killing an animal, allowing them to get data more regularly and ethically. An experiment that previously need 60 mice can be done with around 15, and the results are more reliable.

Dr Karin Tuschl: Using zebrafish to treat a rare form of childhood Parkinsonism

Using genetically modified zebrafish, UCL scientists have identified a novel gene affected in a devastating disorder with childhood-onset Parkinsonism. Indeed, when a drug that worked in the fish was given to one of the children, she regained the ability to walk.

The research studied a group of nine children who suffered from severely disabling neurological symptoms including difficulties in walking and talking. Dr Karin Tuschl and her team at the UCL Great Ormond Street Institute of Child Health and UCL Department of Cell and Developmental Biology used state of the art genome editing in zebrafish to validate the identity of the gene affected in these children.

The scientists disrupted a gene known as slc39a14 in the fish, which is important for transporting metals in the body. Disrupting the transporter in fish led to a build up of manganese in the brain and impaired motor behaviour. As similar symptoms were seen in the patients, this confirmed that slc39A14 is required to clear manganese from the body and protect it from manganese toxicity. It also confirmed that the scientists had found the gene causing the disease in the patients.

• Open access
• Published: 01 July 2022

Role of animal models in biomedical research: a review

• P. Mukherjee 1   na1 ,
• S. Roy 1   na1 ,
• D. Ghosh 2 &
• S. K. Nandi   ORCID: orcid.org/0000-0002-6487-4546 2  

Laboratory Animal Research volume  38 , Article number:  18 ( 2022 ) Cite this article

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The animal model deals with the species other than the human, as it can imitate the disease progression, its’ diagnosis as well as a treatment similar to human. Discovery of a drug and/or component, equipment, their toxicological studies, dose, side effects are in vivo studied for future use in humans considering its’ ethical issues. Here lies the importance of the animal model for its enormous use in biomedical research. Animal models have many facets that mimic various disease conditions in humans like systemic autoimmune diseases, rheumatoid arthritis, epilepsy, Alzheimer’s disease, cardiovascular diseases, Atherosclerosis, diabetes, etc., and many more. Besides, the model has tremendous importance in drug development, development of medical devices, tissue engineering, wound healing, and bone and cartilage regeneration studies, as a model in vascular surgeries as well as the model for vertebral disc regeneration surgery. Though, all the models have some advantages as well as challenges, but, present review has emphasized the importance of various small and large animal models in pharmaceutical drug development, transgenic animal models, models for medical device developments, studies for various human diseases, bone and cartilage regeneration model, diabetic and burn wound model as well as surgical models like vascular surgeries and surgeries for intervertebral disc degeneration considering all the ethical issues of that specific animal model. Despite, the process of using the animal model has facilitated researchers to carry out the researches that would have been impossible to accomplish in human considering the ethical prohibitions.

The animals used in various studies and investigations are related to the evolution of human history. Though there are many shreds of evidence that Aristotle in ancient Greece successfully used animals in understanding the human body, the main breakthrough in animal models happened in the eighteenth and nineteenth centuries with the scientists like Jean Baptiste Van Helmont, Francesco Redi, John Needham, Lazzaro Spallanzani, Lavoisier and Pasteur who studied the origin of life using animal models [ 1 ]. At the same time, human physiology, anatomy, pathology as well as pharmacology were also studied using animal models. With the remarkable advancements in drug development, biomedicine and pre-clinical trials, the importance of animal models has increased many folds in the last decades, as the therapeutic outcome and drug safety are the foremost important criteria for a drug and medical device considered to be used in the human model [ 2 ]. The scientific apply of animal models in the arena of biological research and drug development is an age-old practice because of the notable resemblance in physiology and anatomy between humans and animals, especially mammals [ 3 ]. One must consider that the physiological processes of humans, as well as mammals, are complex in terms of circulatory factors, hormones, cellular structures, and tissue systems. Hence, investigation of various aspects such as molecular structures, cellular and organ functions in physiological and pathological conditions must be taken into consideration.

The process of selection of an animal model for biomedical research is a very intricate part, as all models are not acceptable due to various limitations. Many factors should be taken into consideration during the selection of an ideal animal model for biomedical trials. The most important criteria are the proper selection of models in terms of resemblance between animal species and humans in terms of physiological and/or pathophysiological aspects. Detailed evaluation during the application of certain drugs/molecules/devices and their capacity to reproduce the disease or pathology at the same level as that of humans. Availability and the size of animal species under consideration. Long life duration of the animal species under study. A Large animal population in a model facilitates the availability of multiple sub-species.

Many animal species such as  Drosophila  (insects),  Danio rerio , or zebrafish (fish),  Caenorhabditis elegans  (nematodes),  Xenopus  (frogs), and mammals such as mice, rabbits, rats, cats, dogs, pigs, and monkeys have been accepted worldwide for their phylogenetic resemblance to humans [ 4 ].

Choice of an appropriate animal model is most of the time a tedious job and sometimes depends on assumptions and convenience of the study and researchers without considering whether the model will be appropriate or not. Irrational selection of an inappropriate animal model for scientific investigations will yield incorrect findings, as well as fetch misusage of resources and lives. Moreover, it results in erroneous, duplicative, and inappropriate experiments [ 5 ]. To minimize these problems, recently researchers have advanced their researches to produce animal models that are very specific to the research under consideration. They produced custom-made transgenic animal models by incorporating genetic information directly into the embryo either by injecting foreign DNA or through retroviral vectors [ 6 ]. Through the incorporation of human cells into the recipient animals, researchers can study the effects of pathogens similar to the way in the human body [ 7 ]. Proper selection of animal models is mainly related to the nature of the drug or medical devices under study. In many instances, a single animal model is not able to signify a human disease alone, in that case, the combination of several models can potentially signify the procedure [ 8 ].

The significance and challenges of animals in biomedical research

There has always been a debate among the researchers about the significance of animal models, as many experiments yield promising results, whereas, others couldn’t produce desired outcomes, so, that model could be translated to humans too. Owing to their close phylogenetic closeness to humans, non-human primates are proved to be the most potential candidate. They have genetic, biochemical, and psychological activities similar to humans. In this context, the necessity of non-human primates continues to grow in several areas of research of human diseases viz. AIDS, Parkinson’s disease, hepatitis, dentistry, orthopaedic surgical techniques, cardiovascular surgeries, psychological disorders, toxicological studies, drug development, toxicological studies as well as vaccine development [ 4 ]. The discovery of vaccines and diagnostic modalities with the animal model does not only benefit humans but also enhances the lifespan of animals and prevents many zoonotic diseases, with the production of many vaccines and drugs like rabies, tetanus, parvo virus, feline leukemia, etc (Table 1 ).

Ethical matters on the use of animals

Animal research adheres to a few dimensions like government legislation, public opinion, moral stand, and search for appropriate alternatives for the research. Mahatma Gandhi opined that to judge the greatness and moral progress of a nation, one should judge the way its animals are being treated. Government legislation restricts the researchers and institutes from likely injury, pain, or suffering that may arise during animal research [ 33 ]. On the contrary, many modern countries ruled that before human administration, vaccine testing, lethal dose testing should be done on animals [ 34 ]. Social acceptance has also an influential role in animal experiments as it utilizes public money [ 33 ]. In their moral view, many people think that dog has more moral impact than pig, rat, fishes, mouse, etc.

Ethical issues on animal experimentation started in 1959, where the emphasis has been given on principles of 3Rs, reduction, refinement, and replacement of animal use [ 35 ]. According to this principle, minimum necessary numbers of animals are to be used for scientific experiments i.e. reduction. Pain or distress of the animals during experiments has to be minimized, i.e. refinement. Wherever applicable replacements of the animals are to be done with other non-animal alternatives, i.e. replacement. Though these principles are considered as the cornerstone of animal experimentations, but there are questions regarding the implementation of these regulations [ 36 ].

Laboratory (small) and large animal models for human diseases

The importance of rat and mouse models has proved their outstanding importance in biomedical research. Besides, other mammalian and non-mammalian small domestic animals like the guinea pig, hamster, rabbit, ferrets, birds, amphibians, fishes, flies, worms have equal importance in terms of anatomical and physiological resemblance with humans. Large animal models also proved their uniqueness due to specific anatomical and physiological characteristics pertinent to those specific researches (Table 2 ).

Transgenic animal models in biomedical research

The gene rule and role in the biological system of human diseases has improved many folds with the introduction of the transgenic animal model in biomedical research within the last three decades. The early example of most unique biological research started, when structural gene coding for the human growth hormone (GH) was initiated into mice after fusion with the regulatory region of mouse metallothionein-I gene, as a result, transgenic mouse produced and showed excess GH production [ 157 ].

Linking of the genotype with disease phenotype has been expedited with the genome editing with the introduction of the CRISPR–Cas9 system by which disease-causing mutations are done in animal models [ 158 ]. Moreover, the production of transgenic animals has been radically changed by the introduction of the CRISPR–Cas9 system. Through the successful use of this model accurate human disease models in animals have been produced and possible therapies have been potentiated. Recapitulation of various disease-causing single nucleotide polymorphisms (SNPs) in animal models is achieved by the introduction of gRNA with the combination of Cas9 and donor template DNA [ 159 ], viz. mouse model has enormous importance in carrying human genetic traits, developmental similarities as well as disease translation [ 158 , 160 , 161 , 162 ]. Zhang and Sharp labs at MIT/Broad Institute used CRISPR–Cas9 through AAV and lentivirus [ 163 ] both in vivo and ex vivo in neurons as well as endothelial cells of mice for the production of lung cancer model in mice where lung causing genes namely Kras, Tp53, and Lkb1 were mutated. On the other hand, an MIT-Harvard team [ 164 ] disrupted the tumor suppressor genes Pten and Tp53, and consequently liver cancer was produced in mice.

Animal models in pharmaceutical drug development

In recent advancements, animal models are the most practical tools for pre-clinical drug screening before application into clinical trials. Animal models are considered as most important in vivo models in terms of basic pharmacokinetic parameters like drug efficiency, safety, toxicological studies, as these pre-clinical data are required before translating into humans. Toxicological tests are performed on a large number of animals like general toxicity, mutagenicity, carcinogenicity, and teratogenicity and to evaluate whether the drugs are irritant to eyes and skin. In most instances, both in vitro and in vivo models are corroborated before proceeding to medical trials. In vivo models are mostly conducted in mice, rats, and rabbits [ 2 ]. Certain stages are involved in pre-clinical trials with animal models: firstly, if the trial drug shows desirable efficacy then only further studies are carried out; secondly, if a drug in pre-clinical trials on animals proved to be safe, then it is administered in small human volunteer groups, at the same time, the animal trial will go on to evaluate the effect of the drug when administered for an extended period [ 8 , 165 ]. Mostly, rodents are used for these trials as they have similar biological properties to humans and are easy to handle and rear in laboratories. In new regulations, it is mandatory to carry on the trials on non-rodents such as rabbits, dogs, cats, or primates simultaneously with rodents [ 166 ].

Animal models in orthopedic research

There are many conditions involving bone pathologies such as osteomyelitis, osteosarcoma, osteoporosis, etc. Being a complex organ, the treatment of bone needs special care and extensive researches that involves specialized techniques as well as specific animal models for the studies of specific diseases. Herein, the animal models emphasize mostly related to fracture healing (critical size defect), osteoporosis, osteomyelitis, and osteosarcoma (Table 3 ).

Animal models in diabetic and burn wound healing

Type 2 diabetes and associated foot ulcer have turned into an epidemic worldwide in recent years causing severe socio-economic trouble to the patients as well as the health care system of the nation as a whole [ 208 ]. Various researches depicted that chance of developing an ulcer in diabetic patients varies between 15–25% [ 209 , 210 ] and the chance of recurrence is about 20–58% among the patients within a year after recovery [ 211 ]. Hence, many researchers studied different materials or drugs to treat diabetic wounds. Similarly, burn wounds occur due to exposure to flames, hot surfaces, liquids, chemicals, or even cold exposure [ 212 ]. Though with the recent modalities like skin grafting prognosis has improved however, the mortality rate is high [ 213 , 214 , 215 ].

Diabetic wound rat model

For developing this model, clinically healthy male Wistar rats (150 ~ 250 g body weight) are used. To induce hyperglycemia, injection nicotinamide (NAD)@ 150 mg/kg BW intraperitoneally, after 15 min injection Streptozotocin (STZ) @ 65 mg/kg BW intraperitoneally [ 216 ] are to be injected. The same procedure has to be repeated after 24 h. Blood is to be collected from the tail after 72 h to check hyperglycemia. Rats having high blood glucose levels (≥ 10 mmol/L) are considered to be diabetic [ 217 ]. For wound creation, rats are to be anesthetized with a combination of xylazine @10 mg/kg (intramuscular injection) and ketamine @90 mg/kg (intramuscular injection) [ 218 ]. After marking the dorsal back area with methylene blue, the site is to be prepared aseptically after shaving [ 219 ]. Full-thickness wound creation is to be done with a sterile 6 mm biopsy punch measuring 6 mm diameter and 2 mm depth and left open [ 218 ] (Fig.  1 c).

a . Bone defect model and implantation of implant b . Vascular graft mode c . Diabetic wound model d . Osteomyelitis model development e . Creation of burn wound model f . Cartilage graft model—All in rabbit

Burn wound models

Because of the severity and types of cause, the management of burn injuries poses a significant challenge to plastic surgeons in humans. In general, primary and secondary burn wounds heal by the primary healing process, but, third-degree burn injuries with the destruction of all the skin layers are resistant to the normal healing process and necessitate the added surgical procedures, such as skin grafting, and the relevance of advanced wound dressing [ 220 ]. Several researchers used the albino Winstar male rats ( Rattus norvegicus ) model weighing 250 ± 50 g for the study of burn wounds. Anesthesia was achieved with intramuscular administration of atropine sulfate (0.04 mg/kg BW) and after 10 min a combination of 10% ketamine (90 mg/kg) and 2% xylazine (10 mg/kg) intramuscularly produced adequate anesthesia [ 221 ]. After aseptic preparation of the dorsal back area, thermal injury has to be made with a 10 mm aluminium rod previously heated with 100 °C boiling water. The aluminium rod has to be kept in situ for 15 s. Immediately after the procedure analgesic is to be provided and to be continued for at least 3 days [ 222 , 223 , 224 ]. A hot air blower has been used to produce a 6% third-degree burn injury in a mouse model [ 225 ]. In pig, a partial-thickness burn model in the skin was produced by placing a glass bottle having heated water at 92 °C for 14 s [ 226 ] In other studies, a homemade heating device was placed over the skin for 35 s to create burn wound [ 227 ]. In rabbits, it was demonstrated to use a dry-heated brass rod for 10 and 20 s at 90 °C to create a deep partial-thickness burn wound in the ear [ 228 ]. In mice, a full-thickness burn was created under 3–5% isoflurane anesthesia and intraperitoneal caprofen 5 mg/kg as analgesia. Here, a 4 cm 2 brass rod attached to a temperature probe was first heated to 260 °C and then cool to 230 °C and finally placed on the dorsum skin for 9 s [ 229 ] (Fig.  1 e).

Animal models in cartilage repair

Animal models have enormous importance in the study of cartilage repair. Though in vitro models have been reported, it could not replace the necessity of using animal models prior to clinical implementation [ 230 , 231 , 232 , 233 , 234 , 235 , 236 ] (Table 4 ).

Animal models in vascular grafting

With the increase of cardiovascular complications, there is a need for surgical intervention using vascular grafts. Vascular grafting and cardiac valve repair have become important issues to the clinicians for the replacement of damaged vessels [ 249 , 250 ], hence there is an increased demand for tissue-engineered blood vessel substitute [ 250 , 251 ]. The main prosthetic options are synthetic grafts such as polytetrafluoroethylene, polyethylene terephthalate, and polyurethane [ 252 ], and autologous conduits. Although these types of synthetic grafts provide reasonable outcomes in large-diameter vascular applications, long-term patency is questionable as compared to autologous conduits in small-diameter (< 6 mm) applications due to their inclination to various complications [ 253 ]. Despite the superior outcome of autologous grafts, it has some disadvantages such as limited availability and prior use. Moreover, the determination of a suitable animal model needs considerations of various factors. The factors for the selection of animal species depend on diameter and length of conduits, period of implantation, anastomotic site, price, accessibility, reaction to anesthesia and surgery, and flow of blood at sites of graft implantation. Animal applications of these tissue-engineered vessels are, therefore, an utmost necessity as pre-clinical studies before use in humans (Fig.  1 b, Table 5 ).

Animal models in disc degeneration

Intervertebral disc degeneration (IVDD) and herniation manifested as lower back pain cause a massive socio-economic burden to the patient and society as a whole [ 264 , 265 , 266 , 267 ]. But there is a lack of treatment modalities to cure mildly to moderate degeneration as well as complications associated with surgical interventions associated with the advanced stage; hence, researchers are enormously trying to reinforce regenerative strategies and to lower the suffering by controlling the pain with the injection of stem cells, growth factors hydrogels for replacement of the disc [ 268 ]. Diverse animal models have been reported as a pre-clinical trial to translate the procedure in humans (Table 6 ).

Conclusions

The importance of animal models is unquestionable in terms of in vivo study for the implementation of any biomedical research to humans. It serves not only the human race but also well being of veterinary patients. Animal models have not only important roles in drug development, toxicity studies, pharmacokinetic studies of a drug, but also the pre-clinical study of medical and tissue engineering devices that are intended to be used in humans. Laboratory animal models are more cost-effective and agreeable to high throughput testing as compared to large animal models. Yet, to obtain preclinical data and to ascertain the clinical potential of vascular graft as well as orthopedic bone plates and implants, large animal models that mimic human anatomy and physiology are to be developed. Whatever may be the modes of using animal models for biomedical researches, it should abide by the principles of 3Rs, i.e., reduction, refinement, and replacement of animals.

Availability of data and materials

The data in the present manuscript were collected by searching of literatures as well as involving authors own materials.

Abbreviations

Body weight

Colony forming unit

Embryonic stem cell

Intervertebral disc degeneration

Polycaprolactone

Streptozotocin

Vascular endothelial growth factor

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Social Sciences | 7.25.2019

From the Archives: Animal Research

Every year, scientists use millions of animals—mostly mice and rats—in experiments. the practice provokes passionate debates over the morality and efficacy of such research—and how to make it more humane..

Click image to see full cover: The original January-February 1999 issue that this article appeared in

Read the original article as it appeared in 1999.

The volume of biomedical research, and of trials of new therapies, has increased dramatically in recent decades, fueled by advances in understanding of the genome and how to manipulate it, methods of processing huge data sets, and fundamental discoveries such as targeted and immunological approaches to attacking cancer (see “Targeting Cancer,” May-June 2018). Greater Boston, and Harvard, are major participants in academic biomedical research, in close proximity to the biotech and pharmaceutical industries, which have set up shop locally to tap into the wealth of talent and ideas. Along the way, new research techniques that are driven by more sophisticated imaging, bioinformatics (see “Toward Precision Medicine,” May-June 2015), and “organ-on-a-chip” technology have made it possible to conduct science with less reliance on various kinds of animal-testing. Given rising social concern for and interest in animal welfare (see “Are Animals ‘Things’?” March-April 2016), these converging trends make rereading this in-depth 1999 report by John F. Lauerman on the use of animals in biomedical research still timely and important. ~The Editors

“What is man without the beasts? If the beasts were gone, man would die from a great loneliness of spirit. For whatever happens to the beasts soon happens to man.”

~ Chief Seattle

Frederick Banting would never have begun his research without access to research animals. Before he had even spoken of his ideas, his first note to himself on the subject read: "Ligate the pancreatic ducts of dogs." The quiet Ontario doctor envisioned that severing the connection between the pancreas and the digestive system in a living animal would allow him to isolate the mysterious substance that would control diabetes.

During the first week in the laboratory, Banting and his assistant, Charles Best, operated on 10 dogs; all 10 died. Finally, in 1921, after months of experimentation, Banting and his colleagues isolated a material that kept a depancreatized dog named Marjorie alive for about 70 days. Exactly what information was gained from using dogs, and how many dogs were absolutely needed, is not clear. Work previous to Banting and Best’s, some of it in humans, had indicated the presence and importance of a hormone involved in glucose transport. Many more experienced scientists in the diabetes-research community believed that Marjorie had never been fully depancreatized, and thus may have never been diabetic. More likely, they said, the dog died of infection caused by her pancreatectomy. It’s possible that even the death of the famous Marjorie was unnecessary for the great discovery.

But the two Toronto researchers had isolated insulin, providing the first step toward producing it from pig and cow pancreas, available in bulk from slaughterhouses. The result—that Banting and Best "saw insulin"—appears to have justified all sacrifices. What’s the life of a dog, 10 dogs, a hundred? Before Banting and Best operated on dogs, we had no insulin; afterwards, we did.

Stories such as these are the reason our society and the vast majority of societies in the world accept the use of animals as a vital component of medical research.

Deeply entrenched traditions support the notion that animal welfare must bow to the best interests of humans. Animal domestication was among the first labor-saving devices. Humans have experimented with animal breeding, feeding, and disease control for thousands of years—not to benefit the animals themselves, but to insure that the owners obtained a maximum yield.

Today, those traditional practices have evolved into a scientific institution, the appropriateness of which is subject to perennial debate. In the United States alone, there are an estimated 17 million to 22 million animals in laboratory research facilities. To many people, animal research represents a doorway to the medical treatment of tomorrow. But to animal protectionists, and a growing number of other Americans, animal experimentation is a barbaric, outdated practice that—on the basis of a few notable past successes—has somehow retained its vestigial acceptability.

"Let’s say that it’s true, that animals were indispensable to the discovery of insulin," says Neal Barnard, M.D., of the Physicians Committee for Responsible Medicine, an animal-protection group. "That was a long time ago. I think to say, ‘It was done this way and there’s no other way it could have been done’ is a bit of a leap of faith, but let’s say that at the time there was no other way. You could also say that you couldn’t have settled the South without slavery. Would you still do it that way today? Just because something seemed necessary or acceptable at the time is not to say that we should do it in our time."

The Animal Debate

The legitimation of the animal-research debate challenges one of the most important and widely used scientific approaches to discovery about the human body and its diseases. Animal experimentation is often considered as much of a sine qua non to research as the Bunsen burner. But animal protectionists reply that the importance of animals to research is overrated, and that their pressure has exposed profligacy among experimenters.

In February 1997, a highly controversial collection of articles appeared in  Scientific American  on the subject of laboratory-animal research. The first, written by Barnard and Stephen Kaufman, M.D., of the Medical Research Modernization Committee, another protectionist group, advanced the view that data collected from animal experimentation are almost always redundant and unnecessary, frequently misleading, and by their very nature unlikely to provide reliable information about humans and their diseases. "Animal ‘models’ are, at best, analagous to human conditions," the authors wrote, "but no theory can be refuted or proved by analogy. Thus, it makes no logical sense to test a theory about humans using animals."

A rebuttal in support of animal research followed, by Jack Botting, Ph.D., former scientific adviser to the Research Defense Society in London, and Adrian Morrison, Ph.D., D.V.M., of the University of Pennsylvania School of Veterinary Medicine. Their reply cited examples of scientists from Louis Pasteur to John Gibbon, a twentieth-century pioneer in open-heart surgery, who made important breakthroughs in the treatment of human disease through animal research.

Many scientists—both supporters of animal research and advocates for its diminution—simply refused to discuss the difficult topic, recalls Madhusree Mukerjee, the editor who proposed that  Scientific American  explore the controversy and who wrote a third article, reporting on the overall state of animal research in the sciences. (Similar difficulties were encountered in researching the present article.) Mukerjee suspects that possible interviewees feared the criticism of their colleagues.

Reader response, on the other hand, was overwhelming, both pro and con. "We got a huge amount of flak for dealing with the subject at all," recalls Mukerjee. "Some of it was fairly frightening." To many animal-research supporters, it was as though the floodgates had been opened. "I am simply stunned that  Scientific American,  a paragon of promotion of scientific research, would actually offer up for debate whether animal research should occur," wrote one reader. "Please leave this question of animal research to animal-rights activists, and stop yourselves from turning into scientific wimps." "A lot of the scientific community felt [ Scientific American’ s editors] had overstepped their bounds and compromised their values by printing the Barnard-Kaufman article," says Joanne Zurlo, associate director of the Johns Hopkins School of Public Health Center for Alternatives to Animal Testing and a specialist in chemical carcinogenesis.

Those researchers who supported animal use and wrote in said the animal-protectionists’ side of the  Scientific American  debate was fraught with misstatements and scientific errors, although Mukerjee maintains that all the articles were painstakingly fact-checked. "We annoyed a lot of influential scientists," she says. "Our publication has spent more than a century describing advances in medical research, including some by fairly controversial figures. We’d never addressed the question of research on animals before, and in a sense it was a necessary thing to do. We probably lost some subscriptions because of it. But we are a bridge between the researchers who write for us and the public who read us, and we decided to let our readers decide for themselves."

Animal Welfare

Animal protectionists date their movement back to the times of Leonardo da Vinci and even Pythagoras, who are alleged to have been vegetarians. Numerous essayists and animal lovers have detailed their objections to the misuse of animals. Yet not long ago, virtually anyone who wanted to could conduct experiments on animals. In the 1960s, it was not uncommon to walk into a laboratory and find mice, dogs, cats, even monkeys, housed on the premises in whatever conditions researchers saw fit to provide. Banting himself frequently bought pound dogs and may even have caught dogs on his own; his collaborators recalled that he once arrived at the lab with a dog he had leashed with his tie.

Only in the nineteenth century did animal research begin to draw explicit objections from protectionists. A pivotal event occurred in England in 1874, when a lecturer at the University of Norwich demonstrated how to induce epileptic symptoms in a dog through the administration of absinthe. Objections were raised by students in the audience, and the dog was set free. Later, charges were filed against the lecturer under Dick Martin’s Act, an 1822 law that called for a fine of 10 shillings from anyone committing acts of cruelty against animals. Two years later, in 1876, Parliament passed the Cruelty to Animals Act, requiring a license for animal experimentation and placing restrictions on some painful forms of experimentation.

In the United States, minimal restrictions on animal experimentation prevailed until 1966, when the first federal Laboratory Animal Welfare Act (now known as the Animal Welfare Act, or AWA) was passed by Congress. In 1970 the AWA was broadened to require the use of appropriate pain-relieving drugs, and to include commercially bred and exhibited animals. Six years later, provisions were added covering animal transport and prohibiting animal-fighting contests. In 1985, Congress passed the Improved Standards for Laboratory Animals Act, which again strengthened the AWA by providing laboratory-animal-care standards, enforced by U.S. Department of Agriculture (USDA) inspectors, and also aimed to reduce unnecessarily duplicative animal-research experimentation.

In 1976, however, the AWA was amended in a rather curious way: rats, mice, birds, horses, and farm animals were specifically excluded from its purview for reasons that are not fully clear, although the USDA’s limited resources—along with political pressure from interested parties—are likely to be among them. Since rats and mice make up more than 95 percent of all research animals in this country, the amendment effectively put the vast majority of laboratory animals outside the reach of the USDA. Since then, at least one court has ruled the 1976 amendment "arbitrary and capricious."

The Mouse Warehouse

As associate professor of surgery Arthur Lage, D.V.M., walks through the doors of Harvard Medical School’s Alpert Building, people recognize him, smile, and let us pass without showing identification. He is director of the Center for Animal Resources and Comparative Medicine and the Center for Minimally Invasive Surgery at the medical school and director of the Office of Animal Resources for the Faculty of Arts and Sciences as well. We take an elevator down to a basement, where Lage swipes a card through a reader, unlocking a door to a hallway, where he speaks into a phone. A minute later, a young man clad in blue scrubs opens the door. Lage explains that he’s bringing a reporter in for a tour and that we’ll need keys to see certain rooms. The young man hands over the keys and closes the door.

At the other end of the short hallway are two doors, each leading to a sanitary changing room. When you turn the lights on in the changing rooms, the doors at either end lock automatically. After we’ve pulled blue scrubs over our clothes, Lage douses the lights and we step out of the room into another brightly lit hallway.

We’re in one of Harvard’s 16 animal facilities now, a moderately "clean" facility—meaning that it requires only minimal preparations for entry. Some laboratories would require us to remove our clothes and shower before entering; others don’t even stock scrubs. But this facility is full of mice—transgenic mice. A stray pathogen in one of the animal rooms could wipe out millions of dollars’ worth of experiments or, just as disastrous, infect a colony of mice with viruses or bacteria that might confound the results of a study.

Of course, the security isn’t intended only to repel microbes. Perhaps in frustration with perceived shortcomings in the oversight of animal experimentation, some animal-protection groups have gained a reputation for tactics that are rash and often destructive. On several occasions, animals have been "liberated" from laboratories, erasing potential results and sometimes careers. In 1989, the Animal Liberation Front took credit for the release of more than 1,200 laboratory animals, some of them infected with cryptosporidium, which can be harmful to infants and immunocompromised people. The total damage was estimated at $250,000. In 1987, a laboratory under construction at the University of California at Davis was burned; the loss was estimated at $3 million.

Although there is little evidence of violence toward animal researchers here in the United States, in Europe, where the animal- protection movement is more firmly entrenched, activists have taken aim at individuals, sometimes with disastrous results. In 1990, the infant daughter of a researcher was injured by a car bomb believed to have been set by animal protectionists. In separate, related incidents, a furrier and a breeder of cats used in experimentation were injured by letter bombs. Responsibility for the mail bombs was assumed by "The Justice Department," a militant, underground, animal-protection organization.

Even today, animal-protection groups find ways to gain access to research and testing facilities. In 1997, Michelle Rokke of People for the Ethical Treatment of Animals (PETA) infiltrated Huntingdon Life Sciences, a drug- and cosmetic-testing firm in East Millstone, New Jersey. Using a surveillance camera embedded in her eyeglasses, Rokke took hours of films that PETA claimed showed animals being slammed into cages and roughly handled. PETA president and co-founder Ingrid Newkirk said their investigation also revealed that young beagles’ legs were broken for another study at Huntingdon. Movie star Kim Basinger gave a press conference on Huntingdon’s lawn. In April 1998, the USDA fined Huntingdon $50,000 for AWA violations.

In the basement of the Alpert building, there is no evidence of such fury. Each room holds literally hundreds of mice in shoebox-sized cages, and there are so many of them it looks like a shoe warehouse. There are about 55,000 mice involved in research at Harvard at any one time, but that number is growing constantly. In 1997 it was closer to 50,000; by the end of 1998 it approached 58,000. By comparison, the numbers of other animals are almost negligible: about 1,300 rats, 145 rabbits, 115 hamsters, 70 guinea pigs, 67 primates, 35 pigs, 30 gerbils, 25 chicks, 20 dogs, 18 sheep, 6 cats, and 1 ferret. In addition, the New England Regional Primate Research Center in Southborough, Massachusetts, houses another 1,500 monkeys and other primates. Established at Harvard in 1966 with a grant from the National Institutes of Health, the NERPRC is one of seven such centers created by Congress in the early 1960s to serve as regional resources for scientists.

Surprisingly, there is no hint of animal smell within the basement facility. Temple Grandin of Colorado State University, a specialist in the behavior of captive animals, says that what mice really crave is some form of bedding—wood chips, paper, or shavings—which not all these animals have. Still, these laboratory animals, born and bred under fluorescent lights, are comfortable enough to live out lifespans they would never approach in the wild and, of course, to reproduce. And since almost all of them are involved in genetic studies, making sure they’re happy and healthy enough to reproduce is of vital importance. Keeping these buildings clean and free of infection is a triumph of research design. All the soiled animal cages are shuttled to one end of the laboratory where, before they re-enter, they pass through an enormous autoclaving machine that sanitizes the cages as well as the carts they sit on.

Amid the towers and technology of the medical area, animals one normally associates with a farm are a jarring sight. But Lage (pronounced lah-gee) led me through animal laboratories in the basement of the Seeley Mudd Building where we saw pigs, sheep, and rabbits held in small, clean pens. At one point, we watched eight sheep slated for experimental surgery frisk around a room that looked almost exactly like an office. If the straw were swept away, one could easily have moved in a desk and gone to work.

"We care for all these animals just as though they were covered by the [Animal Welfare] Act," Lage says proudly. "I think most of us believe that the act should cover rats and mice."

Although the Association for Assessment and Accreditation of Laboratory Animal Care (AAALAC), like the USDA, inspects laboratory-animal facilities, including those of rats and mice, AAALAC accreditation isn’t legally required to conduct animal research. "AAALAC conducts something like a ‘peer review’ assessment," Lage says. "It’s a voluntary process, subscribed to by many, many research organizations. If you decide not to go through accreditation, you have to describe your entire program every time you apply to the government for funding for animal research."

Many laboratories and commercial drug-testing companies that receive no funding from federal sources and use only rats and mice proceed with only minimal oversight from their own institutional animal care and use committees (IACUCs). But restrictions on animal research are, if anything, increasing, not abating. Not content with the level of state and federal regulation, for example, the city of Cambridge in 1989 passed its own law creating an inspector’s office with the power to make USDA-type inspections of all research facilities housing vertebrate animals, including rats and mice.

Cambridge’s current commissioner of laboratory animals, Julie Medley, D.V.M., annually inspects 34 laboratories, makes follow-up visits to some facilities (sometimes unannounced), and reviews "hundreds and hundreds" of research protocols to ensure that all experiments meet federal standards for pain control. Investigators readily comply with Medley’s suggestions for better animal care and pain control, she says, but she perceives an undercurrent among some researchers who chafe under what they perceive as excessive government intervention in their work. "I’m sure some of the principal investigators resent these regulations," she says. "It doesn’t happen that often, but there are rare occasions when I run into resistance from an investigator."

Still, for animal protectionists, the intentions of the Animal Welfare Act, AAALAC, and state inspectors are not enough. Sandi Larson, a scientific adviser to the New England Anti-Vivisection Society, who has a master’s degree in microbiology, concedes that "not all researchers are Dr. Frankensteins. But," she adds, "they have been trained to look at animals as tools. It’s ingrained in them to shut off their compassion and act like scientists. They think there’s no room for emotions." A significant portion of the animal-protection movement believes that most experimentation on animals is without merit. If animals are different enough from humans that we can dismiss their suffering as inconsequential, isn’t it just a little too convenient that they resemble us enough to be considered a source of reliable information about human physiology?

Animal Liberation 

Peter Singer was an Oxford philosophy student who had little interest in animals, domesticated or otherwise, until he had lunch with a vegetarian friend one day and they began talking about the use and abuse of animals. Singer was quickly converted to the cause, and within a few years became its champion. One of the pivotal events in the treatment of laboratory animals in this country and throughout the world was the publication of his manifesto,  Animal Liberation,  in 1975.

Just 25 years ago, some proponents of animal experimentation still held that animals’ intellectual inferiority to humans meant that they could not be accorded the same rights as humans. Some argued that animals had no consciousness or memory, that they did not think as humans did. The quality and intensity of the pain felt by animals was still subject to debate. Singer, recently appointed DeCamp professor of bioethics at Princeton University’s Center for Human Values, refuted the assertion of animals’ inequality, pointing out that our society grants equal rights to all humans without regard to IQ or ability to function. "If the demand for equality were based on the actual equality of all human beings, we would have to stop demanding equality," he wrote. "...[T]he claim to equality does not depend on intelligence, moral capacity, physical strength, or similar matters of fact."

As for consciousness and the ability to feel pain, Singer pointed out that we have no reason to believe animals lack either one. Some of the experiments he recounts make their emotional vulnerability all too clear. In the late 1950s, for instance, psychologist Harry Harlow of the University of Wisconsin embarked on a series of experiments in which he deprived young rhesus monkeys of contact with their mothers. Young monkeys who were most completely deprived of parental contact developed very bizarre behavior, and would cling to objects that supplied the most minimal comfort, such as a scrap of terrycloth. Many of his fellow researchers considered Harlow a genius for having established the importance of interpersonal contact to normal childhood development. Singer, on the other hand, pointed out that the experiments demonstrated just how much like us monkeys really are, and he condemned the inhumanity of torturing them to obtain information that could have been elucidated in many other ways, perhaps through epidemiological studies of children who had been separated from their mothers at critical periods of development.

"You can’t have it both ways," says biochemist Karin Zupko ’77, an animal-rights advocate formerly with the New England Anti-Vivisection Society. "You can’t say that animals are different enough from people so that it’s acceptable to experiment on them, but enough like people so that the results of the experiments are valid."

Models for Medicine

Scientists, however, counter that you can, in fact, gather useful information about humans from animals that seem vastly different from us. They point to the many surgical experiments performed on pigs, dogs, and monkeys that have led to advances in transplantation, heart-valve replacement, and coronary artery bypass graft surgery.

"Research on live organisms is essential for medical advance," asserts Francis D. Moore ’35, M.D. ’39, S.D. ’82, Moseley professor and surgeon-in-chief emeritus at Harvard Medical School and Brigham and Women’s Hospital, respectively. As Moore has pointed out in testimony to the Massachusetts legislature and in his autobiographical book,  A Miracle and A Privilege,  the first successful human kidney transplant, in which Moore played a pivotal role in 1963, would not have been possible at that time without an understanding of immunology based on experiments in rats and mice. Important aspects of the surgery were developed in larger animals. "There’s no substitute for it," says Moore. "Some people say you can set up a computer program to act like a dog. Well, forget it. All animals have responses that we don’t understand, and there’s no way to set that up on a computer."

A great deal of our understanding of basic human physiology comes from experiments in large animals, like dogs and chimpanzees. Harvard physiologist Walter B. Cannon, A.B. 1896, M.D. ’00, S.D. ’37, for example, performed experiments on dogs for many years to understand the basic dynamics of digestion. Different animals may be selected for different purposes. A dog’s prostate differs from that of a human in having only two lobes, yet dogs, like humans, can develop benign prostatic hyperplasia.

"Not all animal models are ideal, but some cases are a perfect fit," says Arthur Lage. "Mice are certainly a very good model for studying human genes. Much of the genetic makeup of the mouse is very similar to that of a human; there are large regions of shared identity." That’s why, Lage explains, Harvard will probably double its use of mice over the next five years—to about 100,000 mice annually. The chief reason for this is transgenic-mouse technology—which allows the insertion and deletion of key disease genes into the mouse genome. These techniques allow researchers to study the impact of both subtle and drastic changes in the genome, and to make key predictions about how similar changes would affect humans. Mice can be bred, for example, with varying ability to express the  p53  gene, which has been implicated in a wide variety of cancers. Understanding how the activity of such genes affects cancer development promises to vastly increase our knowledge of treatment and prevention.

Philip Leder ’56, M.D. ’60, Andrus professor of genetics and head of the medical school’s department of genetics, who pioneered the technology, points out that transgenic mice have been used to test the safety and efficacy of new therapeutics; to detect biohazards; and to advance our knowledge of cancer. Yet he concedes this widely embraced methodology has yet to produce new therapies itself. "It’s impossible as yet to bring it home to lives of patients," he says, "because the development of diagnostics and therapeutics takes time."

There are many areas, however, where a direct connection between animal research and patient welfare can be argued. In the field of AIDS, for instance, research on animals has been making important contributions to the basic understanding, prevention, and treatment of this life-threatening disease.

In 1981, Norman Letvin ’71, M.D. ’75, received a call that would change his life. It concerned an epidemic of mysterious deaths, all caused by unusual pathogens and cancers, such as pneumocystis carinii pneumonia, cytomegalovirus, and rare lymphomas. But the patients suffering from these infections were not humans, but laboratory monkeys.

We now recognize these so-called "opportunistic infections" as signals of the presence of the human immunodeficiency virus (HIV) that causes AIDS. But at that time, the disease was just being recognized in humans, the term "AIDS" itself was unknown, and the cause of all these infections was still a frightening mystery.

Letvin, now professor of medicine at Harvard, says HIV probably began as a relatively harmless virus that infected some species of African monkeys. When it crossed species lines, it did so in several directions, spreading simultaneously into both human and additional non-human primate populations. In these new populations, the infection had much more serious consequences than in the African monkeys: it was lethal. But to Letvin, the realization that a parallel syndrome was occurring in man and monkeys was a tremendous opportunity.

"A great deal of effort has been expended on trying to find rodent and rabbit models for studying HIV infections, but they have not proven terribly useful," Letvin notes. "The only way we can see what happens in the first few minutes, hours, and days after infections—questions that are essential to answer in order to develop an HIV vaccine—is by working in animal models. We are forced to work in these models if we want to answer these questions." (The number of monkeys needed for such an experiment, he hastens to point out, is relatively small: usually about six.)

In Letvin’s experiments, monkeys are inoculated with candidate vaccines against HIV. After a brief period during which the vaccine draws a response from the host monkeys’ immune system, the animals are inoculated with a strain of immunodeficiency virus that brings on an AIDS-like disease. Periodic blood samples are taken to monitor their white blood cell counts and viral replication. An experimental model that causes the monkeys to get sick is more informative, Letvin explains, because even if the vaccine doesn’t prevent infection, it may slow the course of the disease enough to be useful.

"There’s little question that exciting animal data is a major drive for the initiation of human studies," Letvin says. "It’s not a gatekeeper, but an important piece of a complex puzzle we use to determine whether to go forward with the long march into humans. There are hundreds of approaches one could take. If a strategy does look promising, an animal trial makes it easier to determine whether it’s worth spending millions of dollars to measure its safety and efficacy in humans."

Letvin points out that an AIDS vaccine would save millions of human lives, particularly in populations where expensive treatment is not available. Thus the use of animals in research on diseases such as AIDS seems fated to continue for years to come. If the past is any indication, it will probably yield a rich crop of new medical information.

Perhaps the more accurate question then—under the circumstances—is, how much do we care about animal suffering? Is it worthwhile to consider that issue in our quest for better treatment for diseases?

The Three R’s

Since Peter Singer formulated his ideas, the animal-protection movement has gone from a series of staccato eruptions to a steady influence on the course of medical research. Everyone involved in the animal-research debate admits that the situation has changed considerably during the last 25 years. Ernie Prentice, a nationally recognized expert in the regulation and ethics of animal research and a member of the institutional animal care and use committee at the University of Nebraska Medical Center, can remember a time when animals were routinely subjected to painful measures without pain control. In one well-publicized experiment, pigs were burned without anesthetic; in another long-running research project, monkeys were subjected to traumatic blows to the head without analgesics. Animals progressed to the end stages of artificially induced malignancies, renal failure, and heart disease, all without any form of pain control.

"Those kinds of projects would not be permitted now. They would be unacceptable for at least two reasons," says Prentice. "One is that we now have regulations that clearly ban this kind of experimentation, and those regulations are adequately enforced to make sure that they’re followed. At the same time, there is heightened ethical sensitivity among both researchers and IACUCs. If you had sat in on a meeting of an IACUC in 1985 and were able to compare the level of discussion back then with what goes on today, you would see a tremendous difference."

Increasingly, members of the protection community are taking legal steps to gain input into animal-treatment guidelines, and have found more conventional ways to exert pressure. Marc Jurnove, a member of the Animal Legal Defense Fund (ALDF), is suing the USDA for "aesthetic and recreational injuries" that he suffered when seeing the living conditions of chimpanzees and apes at a Long Island zoo. Jurnove charged that the USDA failed to adopt and enforce adequate standards for the animals’ well-being, as is required by the AWA. This past September, the U.S. Court of Appeals for the District of Columbia Circuit, the nation’s most influential circuit court, upheld Jurnove’s right to sue. Recently, the ALDF also led animal-rights groups in successfully suing the National Academy of Sciences for access to records and to committee meetings pertaining to a guide on the care and use of laboratory animals.

Some major funding organizations have also embraced the animal-rights movement. The Doris Duke Charitable Foundation, with assets of $1.25 billion, is one of the 25 wealthiest philanthropies in the country. Although it funds medical research, one of its restrictions is that animals not be used as subjects. This creates a sticky situation for the board, which hopes to fund research on AIDS, cancer, heart disease, and sickle-cell anemia, areas heavily dependent on animal research in the past.

But the effort to occupy a middle ground, supporting the principles of reduction, replacement, and refinement of animal research while acknowledging its necessity, has been extremely frustrating.

Several research institutions have established centers of animal-rights advocacy. The Center for Animals and Public Policy at Tufts University and the Center for Alternatives to Animal Testing at Johns Hopkins University, for example, have tried to establish liaisons with both protectionists and researchers. "I wasn’t running around throwing bombs," says Andrew Rowan, Ph.D., former director of the Tufts Center and now senior vice president of the Humane Society of the United States. "I was engaging colleagues in scientific debate without being obstreperous. People were shouting past each other." Veterinarian Peter Theran, vice president of the health and hospitals division of the Massachusetts Society for the Prevention of Cruelty to Animals and director of the MSPCA’s Center for Laboratory Animal Welfare, says that his group has had to walk a fine line. "We try to maintain a rapport with both sides," he stresses. "I have to say that we often don’t agree with some of the more aggressive groups, like PETA. But there’s a tendency to paint the animal-welfare community with a broad brush. And that makes dialogue extremely difficult."

"When you say you’re for animal welfare, you’re perceived as rabid," says Joanne Zurlo of the Johns Hopkins center. "At the same time, we can’t deal with groups like PETA because they believe in abolition of animal use. When we organized the first World Congress on Alternatives and Animal Use in the Life Sciences in 1993, we invited representatives from every organization to sit at the table. PETA would not join. Even the American AntiVivisection Society sent a representative, but members of the hard-line groups who were picketing outside hounded her and called her a murderer."

Human Lives, Humane Experiments

The growth of the animal-protection debate has been fraught with acrimony. The results, however, go beyond the additional credibility that has been afforded animal protectionists. Scientists, too, find that they can be more open about the feelings they have or may have had for the creatures in their care, and are more free to explore alternative methods of experimentation.

"All of us, whether we’re doing research on animals or not, recognize that this is something that is not optimal," Andrew Rowan says. "If society didn’t feel that we needed the information, we wouldn’t do research on animals. But society feels we do, and so do scientists. There’s a tension between our concern about causing pain and distress and killing animals and our need for new knowledge. No one would say that the animals in research benefit from it, and in a world that was perfect we wouldn’t be doing this. We’re engaged in encouraging people to make animal welfare a higher priority without compromising their ability to gather information."

Neal Barnard, of the Physicians Committee for Responsible Medicine, argues that the route away from animal research should carry us toward population-based efforts like the Framingham Heart Study, in which heart researchers have closely followed the health habits and outcomes of 5,000 adults for just over 50 years. That study was a key factor in galvanizing current national efforts to lower cholesterol, combat hypertension, and encourage proper diet and exercise to reduce mortality from heart disease.

"Those areas where we struggle the most, clinically, are those where we haven’t exploited good clinical research and are relying on animal models," Barnard says. "Look at cardiac defects. We don’t know how they’re caused because no one has done the equivalent of the Framingham study for heart defects, even though it’s quite feasible. The Centers for Disease Control and organizations study these congenital abnormalities only in a very haphazard way.

"Of course," he continues, "there have been some brilliant exceptions, such as the research on neural tube defects. It was found through observation of humans that these defects were associated with deficiencies in folic acid, and that by taking vitamin supplements you can reduce the risk. The same with fetal alcohol syndrome: the breakthroughs came in studying humans, not animals."

Politics frequently obscures our view of research bias, Barnard says. He has called for a Framingham-style study of the health implications of cow’s milk consumption, which has been implicated in some studies as a possible cause of Type 1 diabetes in children. Barnard believes that the political strength of the dairy industry has kept such a study from becoming a reality even though some 700,000 Americans suffer from Type 1 diabetes.

Even within the scientific community, there is an increasing willingness to admit that current research methods can be improved upon. A wide variety of in vitro tests have been proposed (among them, the use of human tissue culture and in vitro cell-culture assays), as well as increased reliance on computer modeling and the creative application of human epidemiological studies. Both government and industry experts agree that if new techniques eliminate or reduce the use of animals, so much the better. "[T]he current rodent bioassay for assessing carcinogenicity costs $1 million to $3 million and requires at least 3 years to complete," reads the summary of a January 1997 meeting of the Scientific Group on Methodologies for the Safety Evaluation of Chemicals. The main topic of the meeting was the development of alternatives to animal research, and the report continues, "More efficient testing methods may reduce the time required to bring new products to the marketplace and increase the amount of useful information that can be obtained."

Most researchers recognize that the humane treatment of animals isn’t only compassionate—it’s also good science. Imagine trying to measure the effect of blood-pressure medication on a dog that hasn’t been walked in days. We now know that animals’ feelings, behavior, and emotions have a profound effect on their physiological functioning—as is the case with humans. Consequently, after strong initial opposition to the Animal Welfare Act, most researchers have come to support it.

The Humane Society of the United States represents one example of how animal protectionists can set reasonably limited goals that promote animal welfare in ways that better serve both animals and humans. "We’ve contacted animal care and use committees and asked them to work with us to identify techniques that cause pain and distress and figure out ways to share ways to eliminate that in research," says HSUS’s Andrew Rowan. "Some of the committees are rather suspicious; they see a hidden attempt to stop all animal research. The response has been slight so far. But we think that most researchers are bright people and will understand that our primary goal is just to eliminate animal suffering wherever possible."

Norman Letvin, who frequently debates animal protectionists, knows that there are many who would like to end the practice of animal research for good. Although he is ready and willing to discuss the morality and ethics of his work, he thinks that calling an end to the practice would hurt society enormously.

"It is very easy to take an absolutist position and say it is wrong to cause the death of another living animal," Letvin says. "The difficulty in what [researchers] do comes in saying, ‘I understand that what I’m doing is causing the death of a limited number of animals, but I’m making a judgment that the information gained from this limited, focused experiment will yield results that will justify doing the study.’ Many humans infected with viruses or suffering from cancer or heart disease enter into studies that allow the development of new therapeutics. Every day, thousands of humans say, ‘It is worth it for me to be involved in those studies because, even though I probably won’t benefit, others will.’ In the end, the decisions I’m making with respect to experimental animals are not dissimilar."

As we walked to a new facility on Longwood Avenue, Arthur Lage reminded me that it was the former site of Angell Memorial Animal Hospital, which has since moved to Huntington Avenue in Jamaica Plain. He points out where horses were tethered in the courtyard as they waited to be seen by a veterinarian. He indicates a barely visible tower protruding from the rear roof where distempered dogs were once quarantined. "It was hard work," he recalls, somewhat wistfully, of the internship and residency he served at Angell. "But it was rewarding. You might sit up all night with a sick dog or cat, trying to save its life."

Today, Lage cannot devote as much time to saving animals’ lives. Instead, as he says, he’s helping save human lives through animal research, while ensuring that animals are used humanely. Embodied in his work are many of the contradictions that many of us feel when we consider the millions of animals—from mice to monkeys—that annually give their lives for human health. The use of animals in research will not end today, nor tomorrow, but opinions on the matter appear to be evolving, perhaps toward a better life for animals in the laboratory, and toward better science.

John Lauerman used to write the magazine’s " Harvard Health " column. He is coauthor of a book on diabetes and, with Thomas Perls, M.P.H. ’93, M.D., and Margery H. Silver, Ed.D. ’82, of  Living to 100,  forthcoming from Basic Books in March.

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Basic research

Fundamental (or basic) research in medicine and biology is done  to try to find out more about what keeps humans and animals alive and healthy. It is important to understand exactly how the different tissues and organs of the body work when healthy, and to find out what goes wrong when disease strikes. In the past, animal research was vital for discoveries such as how the kidneys work, or how hormones control different parts of the body. Today, basic research in many areas of biology and medicine still needs to use animals. A good example is the brain: there is still a lot we do not know about how it works and if we are to find answers to these important questions, fundamental research must continue. Fundamental research is to medicine as the foundations are to a house: if you haven't laid the foundations properly then the house will either fall down or be impossible to build in the first place. The understanding gained by fundamental research often feeds into the more applied medical research that ultimately leads to new medicines. Basic research accounts for just over a quarter of all animal procedures carried out in the UK. Here is more information on numbers of animals used in the UK , including the latest statistics.

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• Published: 11 May 2024

Exploration of the creative processes in animals, robots, and AI: who holds the authorship?

• Cédric Sueur 1 , 2 , 3 ,
• Jessica Lombard 4 ,
• Olivier Capra 3 ,
• Benjamin Beltzung 1 &
• Marie Pelé   ORCID: orcid.org/0000-0003-2297-5522 3  

Humanities and Social Sciences Communications volume  11 , Article number:  611 ( 2024 ) Cite this article

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Picture a simple scenario: a worm, in its modest way, traces a trail of paint as it moves across a sheet of paper. Now shift your imagination to a more complex scene, where a chimpanzee paints on another sheet of paper. A simple question arises: Do you perceive an identical creative process in these two animals? Can both of these animals be designated as authors of their creation? If only one, which one? This paper delves into the complexities of authorship, consciousness, and agency, unpacking the nuanced distinctions between such scenarios and exploring the underlying principles that define creative authorship across different forms of life. It becomes evident that attributing authorship to an animal hinges on its intention to create, an aspect intertwined with its agency and awareness of the creative act. These concepts are far from straightforward, as they traverse the complex landscapes of animal ethics and law. But our exploration does not stop there. Now imagine a robot, endowed with artificial intelligence, producing music. This prompts us to question how we should evaluate and perceive such creations. Is the creative process of a machine fundamentally different from that of an animal or a human? As we venture further into this realm of human-made intelligence, we confront an array of ethical, philosophical, and legal quandaries. This paper provides a platform for a reflective discussion: ethologists, neuroscientists, philosophers, and bioinformaticians converge in a multidisciplinary dialogue. Their insights provide valuable perspectives for establishing a foundation upon which to discuss the intricate concepts of authorship and appropriation concerning artistic works generated by non-human entities.

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In titling this article, we utilised the AI capabilities of ChatGPT, drawing upon our summary for guidance. This decision prompts a consideration of whether this AI ought to be acknowledged as one of the authors. Artistic authorship involves the recognition of an entity as the originator of a work that possesses aesthetic, cultural, or intellectual value. This concept is deeply rooted in philosophical debates about expression, identity, and the nature of art itself, while also engaging in legal discussions about copyright and ownership. The issues addressed in this context are poised to spark extensive debate in the future, bridging both artistic and scientific communities. This paper focuses on our research into the artistic output of non-human animals and machines, examining the extent to which their creations–ranging from pictures and paintings to music–are not acknowledged as their own work. Despite the evident capacity of these entities to produce what can be described as art, authorship is often not attributed to them. Instead, their creations are appropriated and monetised by humans, raising significant questions about the recognition of authorship and ownership in the context of non-human and artificial creators. For instance, in 2016, in Indonesia, a wild-crested macaque (later named Naruto) took a selfie with the camera of a professional photographer. This ‘selfie’ went viral worldwide and was quickly seen as a financial opportunity by the camera owner, who claimed the copyright. PETA (People for the Ethical Treatment of Animals) filed a lawsuit and initiated legal proceedings against the camera owner, seeking recognition of the sole monkey as the author of the photograph and demanding that copyright royalties be paid to Naruto if the image were to be used for commercial purposes. However, the legal vacuum surrounding non-human copyright and the fact that Naruto was not recognised as a legal person led the judge to reject PETA’s request (Guadamuz, 2016 ; Rosati, 2017 ).

This paper is the collaborative effort of a diverse team of researchers, including two ethologists, a neuroscientist, a philosopher, and a computer scientist. Our interdisciplinary approach is deliberate, reflecting our belief that the complex questions surrounding non-human authorship and rights in the context of animals, robots, and AI necessitate insights from multiple disciplines. Each author brings a unique perspective to the discussion, from the nuanced behaviours and cognitive abilities of animals to the ethical implications of emerging technologies and the philosophical underpinnings of creativity Footnote 1 and intelligence. Our collective expertise enables a comprehensive exploration of the subject matter, though it also means that our discussion flows through a wide range of arguments and disciplines. Recognising the importance of situatedness and positionality in scholarly work, we aim to locate our argumentation within the intersections of our respective fields, thereby providing a multifaceted view that enriches the debate on non-human entities’ potential for creativity and authorship. By clarifying our backgrounds and the intentional breadth of our perspectives, we hope to make explicit the relevance and intention behind our scholarly argumentation, ensuring our readers understand the foundation upon which our analysis is built.

Introduction

Just as toolmaking, sense of humour, or mathematics have been considered uniquely human activities, art has long been regarded as a distinctly human endeavour. However, without claiming to be Picasso or Mozart, some animals exhibit graphic or musical behaviours that we might classify as artistic (Watanabe, 2012 ). In Oceania, male bowerbirds build intricate structures from branches to attract females and secure opportunities for mating (Diamond, 1986 ). Pebbles, seeds, or leaves, often coloured, are placed by the birds at the entrance of the bower to master its symmetry, aesthetics, and perspective. Birds even adhere to a gradation of these different elements, from larger to smaller or from darker to lighter, to refine their decor. Also, in an effort to court females, male pufferfish sculpt rosettes in the sand with their mouths (Kawase et al., 2013 ). These sandy structures are likened to the lines and geoglyphs of Nazca, located in southern Peru and associated with the pre-Inca Nazca culture (Mujica, 2000 ). Another example of complex graphic compositions in animals that we could appreciate as art is undoubtedly the structure of spider webs (Krink and Vollrath, 1997 ). On the musical side, it would be difficult not to mention the complexity of the songs of the animals around us. In many bird species, males use their most beautiful songs to attract females for reproduction. Others have mastered the art of imitation, such as the lyrebird (Menura sp.) (Dalziell and Magrath, 2012 ). Among primates, the communication of gibbons (Hylobates sp.) is entirely based on their vocalisations which even allow them to recognise each other individually (Terleph et al., 2015 ; Oyakawa et al., 2007 ; Geissmann, 2000 ). The same is true for cetaceans like whales and dolphins (Janik, 2014 ). The creation of these complex graphic or vocal compositions involves both elaborate learning processes and simple rules that enhance the desired effectiveness of the produced structure. Like with computational algorithms, natural selection and sexual selection have shaped the processes behind these animal creations, which sometimes emotionally touch us and move us. The creative aspect of these examples lies in the animals’ ability to produce and modify sounds in ways that serve both functional and expressive purposes. The complexity of the songs, the individual recognition through vocalisation, and their structured, evolving nature, all point to a process that involves learning, innovation, and even cultural transmission among these animals. Such behaviours mirror the human capacity for creating, involving not just the application of simple rules but also the expression of complex emotions, social connections, and cultural identities. This complexity and depth of animal vocalisations underscore their value as creative productions, inviting us to broaden our understanding of creativity beyond human artistic endeavours. Eventually, it is not uncommon for some of these animal productions to become sources of artistic inspiration for humans. The French Olivier Messiaen, for example, was one of the first contemporary music composers to incorporate bird songs into his works. Our focus on music and paintings stems from their prominence in both human and non-human artistic expression, as well as their significant development within machine and AI-generated art. These art forms are not only the most extensively studied in animal behaviour research but also represent the forefront of technological advancements in creative AI applications. By concentrating on music and paintings, we aim to explore the complexities of authorship in areas where the intersection of biological and technological creativity is most evident and advanced. This deliberate choice allows us to delve deeply into the implications of authorship across these two major domains of artistic expression, providing insights that are directly relevant to ongoing discussions in both animal studies and AI research.

The definition of art frequently hinges on the concept of the creator’s intentionality, such as the formation of a goal to be realised (Beardsley, 1970 ; Levinson, 1979 ; Bloom, 1996 ). A simple question then arises: do the above animal creations fall within the realm of art? Do these animal-creators become authors of their creations or even artists? The definition of art is often introduced by the notion of intentionality of its creator, e.g., the conception of a goal to be achieved. We can thus question the levels of intentionality and consciousness of action in these animals. This reflection can also extend to machines and artificial intelligences (AIs Footnote 2 ) (Mikalonytė and Kneer, 2022 ) whose creations, sometimes indistinguishable from human ones, now fetch several hundred thousand euros (Doherty, 2019 ). In 2005, a captive chimpanzee named Barney was observed playing percussion on a plastic barrel (Dufour et al., 2015 ). An in-depth analysis of the recorded sound demonstrated rhythmicity, decontextualisation, and control of the gesture by this chimpanzee (Dufour et al., 2015 ). Prior to Barney, the bonobo Kanzi, trained in sign language, had also been observed playing percussion rhythmically (Kugler and Savage-Rumbaugh, 2002 ). Unfortunately, observations of such behaviours are extremely rare, and data are lacking.

Simultaneously, other primates and great apes draw and paint when given the opportunity (Fig. 1A ; for a review among non-human primates, see Martinet and Pelé, 2021 ). Their creations, often compared to children’s scribbles (Fig. 1B ), are exhibited, sold, or printed on accessories (Applegate and Grupper, 2013 ; Matsuzawa, 2017 ) without questioning their authorship as given to artists (Fig. 1C ). Ownership of a scarf adorned with patterns by the female chimpanzee Ai, or a painting by the male chimpanzee Congo from the 1960s, introduces a dilemma regarding authorship. If a chimpanzee can be acknowledged as the creator of its work, the question extends to why a young child’s scribbles, a worm’s paint trail, or a machine’s programmed drawing (Fig. 1D ) should not receive similar recognition. This prompts a broader enquiry into how creation is defined across early, non-human, or even non-biological contexts. It also brings the concept of intelligence into the discussion, ranging from the cognitive capabilities necessary for the intention behind creation to those required for recognising a creation as such. From this concept of ‘creative’ intelligence, arise other ethical and legal concepts, notably at the origin of the question of legal personality. This paper will address these different notions in order to discuss authorship, considered as the act of characterising a full-fledged author and recognising them as such, and the appropriation of creation, whether it is auditory or graphic, created by an animal or a machine.

This figure presents a diverse array of drawings originating from varied sources: A an adult chimpanzee, illustrating non-human animal creativity that challenges traditional notions of artistic authorship (drawing previously collected by Cédric Sueur in 2019 and extracted from Martinet et al. ( 2023 ) dataset, with the courtesy of Tetsuro Matsuzawa); B a 2-year-old human toddler, representing the nascent stages of human creativity and expression (drawing anonymously and previously collected by Marie Pelé in 2018 and extracted from Martinet et al. ( 2021 ) dataset); C an adult human professional artist (drawing anonymously and previously collected by Cédric Sueur in 2018 and extracted from Martinet et al. ( 2021 ) dataset); and D a visualisation generated by a simple random walk (Sueur, 2011 ) algorithm developed in NetLogo (Tissue and Wilensky, 2004 ), demonstrating how artificial intelligence can create patterns that mimic certain aspects of artistic creativity. Netlogo model available on Netlogo Community platform © Cédric Sueur.

Of the intention to create…

Picture an earthworm traversing a sheet of paper, trailing paint in its wake, contrasted with a chimpanzee applying paint to paper with a brush. This juxtaposition raises the issue of whether the creative processes of these two animals are comparable and if both can be deemed authors of their creations. Furthermore, it questions whether they should be regarded as equals in terms of authorship and what is behind this term. In the context of art and creativity, indexicality refers to the way in which a piece of art can act as a direct indicator or physical trace of its creator’s actions or intentions. This concept is deeply intertwined with intentionality, especially when considering the creative outputs of animals like chimpanzees and the products of artificial intelligence (AI). In animal drawings, for example, the indexicality of a chimpanzee’s artwork can be seen in the brush strokes, patterns, and choices of colour that directly relate to the animal’s physical movements and decision-making processes at the moment of creation (Martinet et al., 2021 , 2023 ). Similarly, in the realm of AI-generated art, indexicality manifests in the output of algorithms designed to create visual or auditory artworks. The ethics of virtue discussed by Aristotle or Kant (Betzler, 2008 ) focuses on the character and motivations of the individual, known as the agent, while consequentialism focuses on the consequences of the actions taken, without regard for the means employed and potential intentionality. Thus, virtue ethics allows us to consider art as the only intentional process, regardless of the final outcome. In contrast, consequentialism views art as a finished product, without considering the process of creation. Therefore, the intentionality of an animal artist or musician emerges as a key point in defining whether they are truly the author of their graphic production or musical composition. For some authors, intentionality even characterises art and the artist (Beardsley, 1970 ; Levinson, 1979 ; Bloom, 1996 ). For others, intentionality is defined by five elements: (i) a desire for a result, (ii) a belief about the action leading to that result, (iii) an intention to carry out the action, (iv) awareness of the accomplishment of the intention while executing the action, and (v) the ability to execute the action (Malle and Knobe, 1997 ).

In cognitive ethology, studies have shown that individuals of animal species such as pigeons, rats, or non-human primates are capable of anticipating their actions (Le Neindre et al., 2018 ). Individuals of most of these species are also aware of their decision-making and the consequences of these decisions. These degrees of action anticipation correspond to elements (i) and (ii) as defined by Malle and Knobe ( 1997 ), while the level of consciousness in these animals relates to elements (iii) and (iv) that define intentionality, again according to Malle and Knobe ( 1997 ). By applying these two capacities (anticipation and consciousness) to behaviours such as drawing, for example, consequentialism would qualify both the ape and the earthworm as authors of their drawings, while virtue ethics would consider the ape as the sole author, conscious of its actions. Consciousness is conceptualised as the awareness of oneself and one’s surroundings, a state that encompasses the ability to experience sensations, thoughts, and emotions. From a neuroscientific perspective, consciousness is associated with specific patterns of brain activity and connectivity that denote an awareness of internal and external states. Ethological studies further validate these concepts by demonstrating instances of self-awareness and environmental responsiveness in non-human animals, indicating levels of consciousness that challenge the boundaries traditionally reserved for humans. Philosophically, this definition is accepted as it resonates with discussions on the nature of mind, self, and agency, bridging empirical observations with theoretical inquiries into the essence of sentient life.

Nevertheless, it is necessary to determine whether these capacities are genuinely underlying animal drawing. Some researchers argue that animal drawings are induced by experimenters who invite them to draw or even encourage them to do so (see Tomasello and Call, 2004 for cognitive tasks in general). For example, in Thailand, Asian elephants ( Elephas maximus ) create shapes that closely resemble self-portraits or bouquets of flowers, but the conditioning and latent mistreatment behind such productions lead researchers to doubt the pachyderm’s understanding of its drawing (OneGreenPlanet, 2020 ). Moreover, in the wild, no spontaneous drawing behaviour has been reported to date in elephants or great apes. However, it is common for captive hominids to manipulate pencils and brushes on sheets of paper or even draw with their fingers on touchscreens (Martinet and Pelé, 2021 ). Thus, some chimpanzees maintain their graphic activity without any food reinforcement, indicating their interest in the action (Boysen et al., 1987 ). Beyond the sensation directly related to locomotor movement, visual feedback would also serve as reinforcement. Indeed, the drawing behaviour on a touchscreen decreases when the chimpanzee’s trace becomes invisible (Tanaka et al., 2003 ). The various studies on chimpanzees, therefore, support the argument that the act of drawing itself has a reinforcing property for these animals. While drawings are not spontaneous in chimpanzees, the simple act of drawing and the properties of the drawing modify the subjects’ future actions. However, if the earthworm leaves no trace behind, this absence of a trace will not impact its movements on the paper, unlike the hominid. Schiller ( 1951 ) went further and presented a young female chimpanzee named Alpha with blank sheets featuring geometric figures. She marked the sheets differently based on the stimuli presented, thus raising the question of intentionality behind these seemingly ‘simplistic’ ‘scribbles’ by animals. However, despite numerous studies on great apes, especially chimpanzees, no representative drawings have ever been observed, and researchers generally compare their productions to those of young human children (Martinet and Pelé, 2021 ). Using fractal mathematical indices to assess the representativeness of a drawing, Martinet et al. ( 2021 ) demonstrated that chimpanzee drawings, while not as proficient as those of children, are not random either. The most common way to determine if a drawing is representative or not is to ask its author about its meaning. The question was posed to another sign-language-proficient female chimpanzee, and her response was ‘bird’ (Gardner and Gardner, 1978 ). However, this response does not prove the presence of intentionality in this individual; it could have been a random response, influenced by experimenters, or the sign may have been misinterpreted. All of these elements suggest that some individuals of certain species, especially great apes, appear to interact with their production (graphic or auditory) in the sense that what is created influences what will be. The concept of agency (McFarland and Hediger, 2009 ; Blattner et al., 2020 ; Sueur et al., 2023 ) can thus be attributed to these animals from a psychological perspective, for example, as actors in the world affecting their environment. It can also be attributed to a philosophical and ethological perspective if we consider great apes as capable of recognising themselves as individuals and having a certain sense of morality if these capacities define the very essence of personhood. Legal personhood refers to the recognition by the legal system of an entity as a subject that can bear rights and duties. Traditionally reserved for human beings, the concept’s boundaries are being tested by advancements in AI and growing awareness of animal cognition and social complexity. This general definition of agency is accepted by biologists, psychologists as researchers in law and philosophers. In contemporary fields of art history, theory, and creative practices, the term ‘agency’ is employed to denote the capacity of individuals or entities to act autonomously and make independent choices within the creative process. Agency emphasises the role of the creator not just as a passive conduit for external influences but as an active participant with the power to shape the creative outcome. This perspective acknowledges the complexity of creative acts, recognising them as the result of deliberate choices, influences, and interactions between the creator’s intentions and the medium’s possibilities. A cross-disciplinary approach to agency enriches our understanding of art and creativity by challenging anthropocentric views and expanding the notion of who or what can be considered a creator. It encourages a re-evaluation of the criteria for authorship and creativity, pushing us to consider the ethical, philosophical, and practical implications of recognising agency in a broader spectrum of creative entities.

… to author recognition

Mylène Ferrand Lointier’s doctoral thesis ( 2022 ) in Arts ‘Le Tournant animal dans l’art contemporain (de 1960 à nos jours), approche écoféministe,’ [The Animal Turn in Contemporary Art (from 1960 to today), an Ecofeminist Approach] delves into the increasingly significant role of the animal question in contemporary discourse, driven by evolving anthro-zoological relationships. Highlighting a shift in the portrayal of animals in art from mere objects or symbols to subjects with intrinsic value, this research examines a diverse international corpus of artworks and artists deeply engaged with animal issues from the 1960s to the present: lEija-Liisa Ahtila, Julie Andreyev, Banksy, Joseph Beuys, Sue Coe, Minerva Cuevas, Terike Haapoja, Jonathan Horowitz, Joan Jonas, Jenny Kendler, EvaMarie Lindahl, Isabella & Tiziana Pers, Araya Rasdjarmrearnsook, Rachel Rosenthal, Saeborg, Lin May Saeed, Sin Kabeza Productions, Bryndís Snæbjörnsdóttir & Mark Wilson, Diana Thater, and Robert Zhao Renhui. Through an ecofeminist lens, incorporating ethics of care and intersectionality, Ferrand explores an ecocritical territory intertwining art, emotion, animal ethics, and posthumanism. This thesis aims to chart a new eco- and zoo-poetic/political path towards an era termed the ‘Ecocene’, advocating for a revaluation of human–animal relations within art as with The Compassion Manifesto: An Ethics for Art + Design and Animals (Andreyev, 2016 ).

There is currently no research on the abilities of great apes to claim ownership of their creations, whether they are graphic or musical. Nevertheless, it becomes evident that consciousness and morality emerge as pivotal concepts in the realm of authorship. Morality is understood as a set of principles or guidelines that govern the behaviour of individuals within a social context, reflecting notions of right and wrong, justice, empathy, and welfare. Ethologically, the roots of moral behaviour are observed in the social interactions of non-human animals (e.g., great apes, elephants or even rats), where acts of altruism, cooperation, and fairness are not uncommon and serve to maintain social cohesion and mutual benefit (De Waal, 2016 ). Such behaviours suggest a biological underpinning for moral conduct, further supported by neuroscience, which identifies neural circuits and processes involved in empathetic responses, decision-making, and the evaluation of fairness and harm. Philosophically, these empirical findings are incorporated into broader discussions about the nature of morality as well as consciousness, their origin, and their applicability across different forms of life. By acknowledging the evidence of moral-like behaviours and consciousness in non-human animals, philosophy expands its enquiry into the moral agency, questioning the exclusivity of moral consideration and rights to humans and opening the door to a more inclusive understanding of moral subjects. These concepts enable individuals to achieve the status of a ‘person’, nothing more and nothing less, and subsequently, to acquire legal rights through their recognised personhood. Historically, this term ‘person’ has been exclusively applied to humans and is defined as ‘an intelligent, thinking being, capable of reason and reflection, who can recognise themselves as the same thinking entity across different times and places’ (Locke and Perry, 1975 ). Self-awareness and moral cognition thus play a significant role in the authorisation and appropriation of creative works, attributes currently ascribed solely to humans, who are deemed to possess ‘a soul and consciousness’ (Schrecker, 1938 ; Engels, 2009 ).

It is indeed in the field of metaphysics that are often grounded the basis for the attribution of rights for living beings, and more precisely in the question of the difference between humans and animals. Pivotal moments in philosophy engage in a significant debate regarding the anthropological question and the specific traits that distinguish humans from animals. A crucial argument for this discussion revolves around whether the differentiation is grounded in ontological terms, suggesting a fundamental disparity in nature or condition between humans and animals, or if it hinges on ontic qualities, indicating inherent, distinct characteristics between the two. Through the lens of an ontological distinction, numerous philosophers have constructed a recognised hierarchy within the spectrum of living beings, often based on universals (such as soul, conscience or reason). As an example, Aristotle considers that the human soul is the only one to demonstrate the dianoetic faculty, which means the ‘power of thinking’ (Aristotle, 1987 , Book II, Chapter I, 412a) or the ability to exercise and apply reason. Descartes, by qualifying human beings as the only ones that possess the cogitatio , discloses a theory where animals are constituted as mere biological machines (Descartes, 1637/ 1937 , p. 164), providing a landing mark for later theories on the mechanism and animal environment (Loeb, 1918 ). Malebranche ( 1997 , book VI, part 2, chapter vii) argues that ‘in animals, there is neither intelligence nor souls as ordinary meant’. And later, Marx ( 2022 /1845, MEGA I, 5, p. 10; CW 5, p. 31) elaborates that ‘men can be distinguished from animals by consciousness, by religion or anything else you like’.

By those few examples, we highlight that major authors in the philosophical tradition have influenced current interdisciplinary discussions on animal rights, and the ethical and political treatment of non-human entities. Ontological attributes such as consciousness, morality, reason, intelligence and self-recognition have traditionally been used as a way to distinguish human beings from animals. The anthropological distinction between humans and animals ensues the possibility to acknowledge ontic differences and to ground them in a metaphysical perspective, giving them an axiological weight that easily leads to a hierarchy of living beings. Even though we will not tackle this issue in our article, this metaphysical debate is still widely discussed today and of major importance. But one of its many consequences is noteworthy: it impacted our ability to ground animal agency over a robust ontological status, which led to the denial of several categories of rights for animals, including the right to be acknowledged as authors (since, by definition, authorship has been attributed to individuals and people).

Even if ontological hierarchies have often been used as the groundwork on which are based distinct rights for human beings and animals, several contemporary debates explore the possibility that the possession of specific ontic, cognitive, or emotional attributes might entail the entitlement to certain rights, regardless of the inherent nature, status or condition of the subject. In short, the question of animal rights could be distinguished from the ontological question of the essence of animality, and more empirical ethological, bio-semiotical or zoological studies could lead to a better understanding of animal cognition, sociality and behaviour, leading to the establishment of grounded animal rights. From then on, numerous researchers, including Charles Darwin, who ascribed consciousness to individuals within social species, have probed the presence of intellect, self-awareness or autonomy in animals. Donald Griffin ( 2013 ) proposes that it is through the realms of communication, encompassing dialogues and negotiations, that we should investigate intentional behaviours and processes governed by consciousness. Research on great apes capable of using sign language or symbols has shown that they can speak about others and themselves as distinct and autonomous entities. Autobiographical self-awareness (Le Neindre et al., 2018 ) has also been found in many animal species (primates, cetaceans, birds) through the mirror test, demonstrating that subjects can identify and recognise themselves in it (Gallup et al., 2002 ). Likewise, metacognition, the ability by which an individual acquires knowledge of their own mental processes, or their ability to evaluate the state of what they know, has been verified in several animal species through tests assessing certainty or confidence (Le Neindre et al., 2018 ). Additionally, some social animals also display theory of mind, i.e., the capacity to impute a mental self to conspecifics or to understand what they are looking at, what they intend to do, or even to know their beliefs (Tomasello and Call, 1997 ). Finally, observations of chimpanzees and elephants, as well as experiments with rats, have shown that these animals possess a certain degree of empathy and morality (De Waal, 2006 ). From these new findings, the qualification of ‘person’ could be attributed to animals capable of self-recognition and demonstrating morality. By assigning legal personality, they could be granted ownership of their creations and recognised as genuine authors.

Legal personality

Therefore, some rights could be attributed to animals who possess capacities or qualities similar to those of human beings, beyond the ontological question of their essence, nature or condition. As highlighted by the example of marginal cases by Peter Singer and discussed by DeGrazia ( 1990 ), several categories of individuals—such as infants, adults with severe mental disabilities, or those in a coma—do not possess the cognitive, locomotor, or emotional faculties usually attributed to an ideal type of human being. Nevertheless, these individuals do have legal personality. According to Peter Singer, if these individuals have legal personality, it could also be attributed to animals who have equal or sometimes more developed capabilities than these individuals. The young child or disabled adult who scribbles or drums has rights and will be recognised as the author of the drawing or sound they produce, regardless of the levels of intentionality and consciousness they put in their creation (in the process and towards its finality). By considering the complex philosophical question of the nature of the subject as a separate discussion from the legal rules that apply to them, animals could be granted legal personality based on certain faculties they possess, allowing them to hold rights and duties. This question entails difficult debates, and several actions that aim to grant rights to animals have already been initiated by animal protection associations. In particular, in the United States of America, the Non-Human Rights Project led by Steven Wise (Wise, 2010 ) relies on the legal concept of Habeas corpus, which states the fundamental freedom not to be imprisoned without trial, and aims to free several wild animals that are held captive despite possessing enough cognitive abilities to be aware of their deplorable living conditions.

As shown with the macaque Naruto (Guadamuz, 2016 ; Rosati, 2017 ), recognising animals with consciousness as legal persons appears to be a prerequisite for them to be truly and fully recognised as authors of their creations. In 2019, the Toulon Declaration reiterated the Cambridge Declaration on Consciousness ( 2012 ), stating that most animals with neurological substrates of consciousness should have legal personality (Regad and Riot, 2019 ). The theory of animal rights is increasingly discussed and formalised, allowing animals, depending on their species, agency, and interactions with humans, to have recognised rights (Donaldson and Kymlicka, 2011 ). The authorisation of animal artistic creations fits seamlessly into this theory.

What about artificial intelligence (AI)?

When highlighting the argument of authorship for non-human beings, an important discussion arises from the question of non-living or non-organic beings, such as machines, robots and AI. The philosophical considerations surrounding the attribution of rights to animals and machines or AI overlap in significant ways. By examining these questions in parallel, we gain insights into the principles that currently guide our interactions with non-human entities, whether biological or artificial. It helps us to reconsider our relationship with non-human entities and to reassess the values and norms that underpin our social and legal systems.

As such, our demonstration will mostly focus on the question regarding AI. Indeed, a proposition would be to consider that there could be a major distinction for authorship between machines themselves because the embodiment of a robot Footnote 3 would have a huge impact on its perceived authorship compared to a non-embodied AI system. As such, a robot would be perceived as more susceptible to have rights than a non-embodied AI. In this case, embodiment itself would have a significant impact on whether or not something possesses rights and whether or not people believe that those rights are acceptable Footnote 4 . However, this thought experiment would be confronted with the fact that, currently, authorship is not attributed depending on their embodiment to living beings such as animals (which are by definition embodied). When determining authorship, embodiment appears to matter less than the legal personality we usually ascribe a being, and their status—be it human, animal, or machine, but also depending on if it is an adult or a child, or the degree of agency we ascribe to the animal in question. Therefore, we chose to mostly focus this line of questioning on IA algorithms that could or could not be embodied.

In 2018, an AI-created painting was auctioned for $432,500, signed with a mathematical formula, developed by the Obvious research collective (Doherty, 2019 ; Vernier et al., 2020a , 2020b ). This event raises the question of whether artificial intelligence could be acknowledged as the creator of its works and entitled to copyright rights. Additionally, platforms like Playform by Artrendex Inc. offer algorithms that replicate the style of renowned painters on any image. This situation poses a dilemma regarding the true authorship of the resulting artwork: Is it the AI (Davies, 2011 ; Abbott, 2016 ; Christie, 2018 ), the developers of the algorithm, or the original artists whose styles were emulated (Bridy, 2012 ; Hristov, 2016 ; McCormack et al., 2019 ), or another entity? The methodologies and debates surrounding animal intelligence and authorship could similarly be extended to the realm of artificial intelligence (Nguyen, 2019 ). In the case of the Obvious creation, the produced algorithm is not intelligent in the sense described above. It should be noted that the model used to create this painting was trained on existing paintings, which can be likened to the learning process present in humans. Capable of producing a specific act, this model is not, however, able to solve any problem, has no intentional acts, and is not self-aware. However, more complex robots capable of recognising themselves in a mirror could well be self-aware (Hart and Scassellati, 2012 ; Schneider et al., 2014 ; Meyer et al., 2020 ). New fields of research are thus created and developed to better understand the behaviour of machines and their emerging capabilities (Rahwan et al., 2019 ; Dorigo et al., 2020 ). Specific tests such as the Turing Test (Copeland, 2000 ) exist to precisely determine the capabilities of machines, especially in relation to artistic creation (Bishop and Boden, 2010 ). However, these tests are often criticised. On the one hand, because many humans do not pass them, and on the other hand, because they are conceptualised by humans with all the anthropomorphic biases that this presupposes (Sueur and Pelé, 2017 ; Sueur et al., 2020 ). However, even if some do not wish to recognise machines as artists, it is important to note the difficulty for a human to distinguish computer-generated creations from human creations (Mikalonytė and Kneer, 2022 ).

Consequently, the question of authorship and AI plays a key role in better understanding the issues of authorship and agency themselves. As regarding animals, this very specific issue depends on many factors such as the nature of the agents involved (weak AI or strong AI Footnote 5 ), the degree of intentionality of the creation (intentional or accidental), and the content or nature of the graphical creation itself (abstract or representational) (Mikalonytė and Kneer, 2022 ). However, as the attribution of agency and personhood are a crucial issue both for AI and animals, the question of authorship for machines often ends with a much clearer conclusion than that of animal authorship. Indeed, as a machine is created by humans, it is usually considered devoid of all rights in favour of its creator or user. For instance, the authorship of an AI-generated artwork is commonly attributed to the human artist behind the machine (when there is no copyrights issues…), whereas it is much more complicated to consider that the human who gave a pencil to an animal is the author of the resulting canvas. Therefore, by considering through an experiment of thought that authorship for a machine or AI is a real issue, and as it may indeed soon become a crucial one, we may better uncover what is usually the basis for authorship in a broader sense.

Photons be free

To tackle this complicated issue, we decided to incorporate and decipher a science fictional case study in our analysis. It serves as a valuable methodological tool allowing us to explore the potential futures shaped by current technological advancements and ethical considerations. Science fiction, often regarded as a form of speculative methodology, enables us to envision the societal, legal, and ethical implications of technology before they fully manifest in reality. This approach is particularly relevant when discussing the rights and authorship of non-human entities, as it provides a narrative framework to examine complex issues that might not yet be fully realised or understood within our current legal and ethical systems. To further ground our use of sci-fi examples, we draw upon the concept of technological imaginaries (Sartori and Bocca, 2023 ; Jasanoff and Kim, 2015 ), which is extensively used to describe modern societies in which technology plays a key role in shaping both our understanding of them and our way to envision their evolution. This critical theoretical framework investigates how collective visions of technological futures influence current technological development and societal norms. Technological imaginaries help us understand how our expectations, fears, and hopes for technology shape the way we interact with and conceptualise emerging technologies. By examining these imaginaries, we aim to unpack the cultural and social underpinnings of our assumptions about non-human authorship and the rights of artificial entities, offering insights that are accessible to readers from a broad range of disciplinary backgrounds. In the scope of this article, engaging with fictional narratives urges us to envision new possibilities and challenge conventional thinking about the role of machines in creative processes and intellectual endeavours, and the evolving concept of authorship in the digital age.

In this context, a specific example issued from science fiction helps us better understand this evolving aspect of our technological imaginaries and the various dimensions of authorisation that can apply to artificial or non-human entities. The episode ‘Author, Author’ ( 2001 , Season 7, Episode 20) of the series Star Trek: Voyager questions the situation of the Doctor, a hologram (with a strong AI 5 ) that has exceeded its initial programming’s limits over the years, and developed behavioural and emotional characteristics usually seen only in living beings. The Doctor is confronted with the controversial question of his own copyright when he writes a holoprogram and sells the rights to a publishing house. The editor published it without his consent while he still had major modifications to make. The stakes that this episode highlights mirror the famous debate about the rights of the android Data in the well-known episode ‘Measure of a Man’ (1989, Season 2, Episode 9) of Star Trek: The Next Generation . In both episodes, the question aims to determine to what extent Data and the Doctor are individuals because a certain number of rights will depend on their identity, status, and the legal personality that will be granted to them. If Data is not a person, then he is the property of Starfleet, much like any toaster or computer. If the Doctor is not a person, then he cannot be considered an artist and has as many rights over his holoprogram as a coffee machine has over the coffee it produces.

For the Doctor, as Data before, this debate unfolds in the legal framework of a trial whose decision will be a legal action: ‘A Federation Arbitrator has been assigned to determine whether the Doctor has the right to control his artistic creation.’ (‘Author, Author’, 00:32:13). The first session aims to outline the scope of the debate and raises the question of the Doctor’s personhood, rather than his rights as an artist. Indeed, Starfleet defines an artist as ‘a person who creates an original artistic work.’ (‘Author, Author’, 00:34:36). While the Doctor has indeed created an original artistic work, he is not considered a full person and, therefore, cannot claim authorship of his work of art.

This episode delves into a crucial aspect of our discussion: the notion that an individual must belong to a specific category to access certain rights, such as those allowing humans exclusively to be recognised as authors or artists. It proposes an alternative perspective where rights could be allocated with respect to the subject’s category, enabling entities–whether human, non-human, animal, or artificial–to be acknowledged as authors or artists. This perspective raises the possibility of recognising an animal or an AI as an artist without necessarily classifying them as persons. However, it also suggests that affirming an entity’s status as an artist might require expanding the definition of personhood. Legal decisions and efforts to establish precedents are currently addressing these considerations, bringing theoretical debates into the realm of practical applications. Last year, the United States Copyright Office (USPTO) reversed its decision to grant copyright protection to a comic book whose images were generated by AI (Ostrow and Dengel, 2022 ). The fundamental element in this latter case is that the USPTO’s revocation is based on the ‘Human Authorship Requirement’, Footnote 6 which means the necessity for the author of a work to be … a human being. Here, we find thirty years later the stake that was raised by Star Trek about the relevance of encompassing authorship in a category: be it a strictly human definition for the USPTO’s Human Authorship Requirement or, more broadly, the status of personhood or individual, in Star Trek series.

By trying to avoid the strict question of copyright and to focus on the legal personality of the Doctor, the episode ‘Author, Author’ explicitly reminds us that the question still exists today for other individuals within the human species. For example, the tendency to invisibilize female authors in artistic fields is still a contemporary issue (Rollet, 2007 ; Nochlin, 1971 / 2021 ), which questions the way we structure our understanding of creation by highlighting mechanisms that delegitimise certain individuals based on their gender or origin. This example illustrates the painstaking evolution of authorisation norms even within the human species. In this regard, the question of the right to be called an ‘author’ still arises from identity premises (the subject’s status—male or female, human or non-human, etc.) rather than from the artistic production itself. If an animal cannot be an artist, it is not because it has not created a work of art, but because it is not considered as an operating subject. And it is not the work of the non-human artificial entity that is judged, but the AI’s status within humanity, as demonstrated by the USPTO, when it first recognised the artistic value of an AI work before retracting its decision.

In the series episode ‘Author, Author’, as it is the question of personhood that is at stake through the issue of authorisation, the trial’s witnesses emphasise the importance of the Doctor’s experiences, by highlighting his ability to evolve beyond his programming, to think for himself, and even, to disobey orders. However, when he returns with his decision, the Arbitrator instructs a judgement similar to the one that granted the android Data free will in ‘Measure of a Man’, but without changing his status. The Arbitrator is not willing to declare the Doctor a ‘person’ per se. However, the legal definition of the term ‘artist’ can and will be expanded to include his creations. Therefore, the Doctor holds the copyright on his artwork and can intervene in the distribution of his holoprogram. This conclusion underlines that the status of an artist is generally deemed more flexible than the definition of personhood; and that expanding the sphere of authorship and its associated rights raises fewer challenges than to extend the concept of personhood. As such, it is easier to imagine that the USPTO could remove the Human Authorship Requirement to include non-human individuals like AI or animals in copyright protection, rather than to extend the human status to animals or AI. In other words, the legal personality is more flexible and plastic than the natural personality, understood as the nature or condition of the subject (human, non-human).

That being said, Star Trek highlights the important point that the definition of what constitutes a person itself has continued to evolve. The episode presents the important issue that conceding certain rights to certain entities (such as copyright and artistic authorship to an AI or an animal) implies, in fact, an evolution of their natural status. Moreover, these legal changes could lead to changes in ethical frameworks. In essence, granting copyright to the Doctor, then other rights to other holograms, and so on, brings closer to a legal decision in which a hologram’s personhood could no longer be questioned. To consider that personhood alone grants access to certain rights may imply that gaining these rights is the first step towards the modification of a non-human entity’s status. Star Trek offers us the following alternative: perhaps the access to certain rights should not depend on the subject’s status. Perhaps human imaginaries must reconcile with emerging realities, driven by the evolution of our technological landscapes, and acknowledge the necessity of granting rights and protections to non-human entities. In fact, it is no coincidence that the Doctor’s holoprogram, duly entitled ‘Photons Be Free’, revolves around the struggle for equality of hologram populations.

What about digital tools in musical creations?

Science fiction is often considered as a literature of ideas that allows for thought experiments in hypothetical or speculative scenarios that may not yet have real-world manifestations, but will or could have important implications for our societies. Consequently, it is now of major importance to apply the questioning that arose from this example to a more grounded debate regarding AI-generated artworks and the use of machines and algorithms in artistic practices.

Nowadays, with technological advancements and the rise of digital equipment, the issue of authorship is increasingly relevant in live performances, particularly in music (see seminal works of Reeves et al., 2005 ; Berthaut, 2015 ; Capra et al., 2020 ). The intense experience of creation ‘in the making’ can be disrupted by the presence of machines if the audience begins to believe that the machines, rather than the artists, are producing the artistic work. Unless the contributions are shared? For the artists themselves, there may be a challenge in distinguishing what is produced by their exclusive actions from what is produced by the accompanying machines (Rimoldi and Manzolli, 2016 ). Here, the question is no longer about determining whether the artist is an author or not, but to what extent, and from which perspective, that of the author or the audience.

In music, the sophistication and apparent autonomy of digital instruments raise questions that are nearly absent in the case of analogue instruments such as the violin or drums. When a machine is capable of playing autonomously—whether in a rudimentary manner, as with an MP3 player, or more adaptively, through generative algorithms and artificial intelligence–the role of the artist-author in music production no longer appears as evident, at least not exclusively. From a cognitive perspective, this dilution of the artist’s contribution due to digital assistance is partly explained by the close connection between movement and perception (Rizzolatti et al., 1996 ; Jeannerod, 2001 ). In traditional music performances where instruments have almost no autonomy, the perception of the link between the musicians’ gestures and the produced sounds is clear (these are referred to as ‘transparent instruments’ Fels et al., 2002 ). The brain’s constant simulation of perceived gestures to predict their consequences is the basis for integrating this link (Zatorre et al., 2007 ; Salimpour et al., 2015 ). From this simulation emerges the sense of understanding what is happening, perceiving what the artist controls, their intention, and virtuosity, all of which are components of authorship.

In electronic music, a single gesture can generate a multitude of different sounds depending on machine settings. AI and digital technology blur the traditional link between a musician’s actions and the resulting sounds, raising questions about authorship. The causal link between gesture and sound can thus disappear, leading to a loss of interest for the audience and doubt regarding the artist’s involvement (Schloss, 2003 ; Stuart, 2003; Huron, 2008 ). Indeed, the audience may struggle to attribute authorship due to the obscured causal relationship between gesture and sound. As AI plays a significant role in generating music, it necessitates re-evaluating how we define and recognise the creative contributions of human artists and the extent to which AI systems can be considered co-creators in the artistic process.

Towards shared authorship: from human–machine interaction to human–animal–machine collaboration?

Recent studies (Capra et al., 2020 ) have shown that the audience’s sense of understanding a digital music interaction leads them to consider the artist as more contributory than the machine in performances with digital instruments or computers. These findings not only emphasise the crucial role of the sense of understanding in the judgement of authorship but also highlight the gradual nature of this judgement. Furthermore, the ‘evidence’ of a machine’s involvement in the artistic process is not always obvious; computers can be hidden backstage, and artists can pretend to play live while everything is pre-recorded. One might have images of musicians with their hands in the air, clapping while the music continues, or, conversely, focused on their instruments without it is possible to see what they are doing or even distinguish which sound they are working on. This perceptual deficiency and its consequences on the audience’s experience have led the Human–Computer Interaction (HCI) community to propose new evaluation criteria for digital devices (Berthaut et al., 2013 ; Berthaut et al., 2015 ; Bin 2018 ; see an extended review in Capra, 2020 ), including the Association (Capra et al., 2020 ), which designates the capacity of a device to expose to the audience the respective contributions of artists and machines in electronic performances. This human–machine collaboration in artistic creation can also occur in other disciplines, such as cinema, again in various and graduated forms. In the film Attack the Sun by Gwendal Sartre and Fabien Zocco ( 2019 ), the dialogues are generated by processing content from social networks and communicated to the actors by an artificial intelligence. The artists remain in control of the overall framework and many production elements, but by letting an AI drive something as structurally significant as the dialogues, are we witnessing a strictly human production or a human–machine collaboration with a shared degree of authorship?

Thus, authorship in digital creation can be refined with more gradual notions of the level of control by the artist and the varying degree of their contribution to artistic production compared to that of machines. Additionally, as we have seen, authorship can be understood here from a dual perspective: that of the artist and their agency, and that attributed to them by the audience, referred to as attributed agency (Berthaut, 2015 ; Capra, 2020 ). This dual consideration highlights technology not only as a medium for creation but also for its mediation to make digital interactions perceptible and to reveal them (Berthaut et al., 2013 ), thus allowing authors to assert their desired level of authorship.

Delving deeper into the realm of human–animal–machine collaboration, we explore an innovative paradigm of authorship that transcends traditional species boundaries. This interdisciplinary nexus is exemplified by initiatives such as the Interspecies Internet (Dolgin, 2019 ; Jones, 2019 ) and the use of environmental sensing technologies (Gabrys and Pritchard, 2018 ), which are pioneering the way for a new form of artistic expression and communication across species and technologies. This blending of human creativity, animal behaviour, and technological intervention serves as a powerful testament to the potential of collective intelligence and creativity (Bonnet et al., 2019 ; Wang et al., 2023 ). It suggests that authorship can extend beyond the confines of human endeavour, encompassing the contributions of non-human participants whose interactions with technology provide a unique perspective to transcend creativity. The exchange of learning and behaviours between humans and animals (Sueur and Huffman, 2024 ), becomes a fundamental element of this co-creative process. This mutual adaptation and shared understanding facilitate a form of artistic creation that is truly collaborative, allowing for the emergence of novel expressions.

The outcomes of such partnerships—be it in the form of music that incorporates animal sounds interpreted through AI algorithms, or visual art that visualises the migratory patterns of birds captured via satellite technology, shapes of ants or termite colonies to co-create sculptures—enrich our artistic vocabulary.

In a mesmerising fusion of human movement and natural spectacle, choreographer Sadeck Berrabah’s Murmuration Footnote 7 stands as a profound example of interspecies inspiration in contemporary art. Drawing from the breathtaking phenomenon of murmuration—where thousands of birds, typically starlings, move in unison through the sky, creating fluid, dynamic shapes–Sadeck Berrabah captures the essence of this natural wonder through human bodies in motion. This performance blurs the lines between human and animal realms, redefining artistic authorship as a shared, interspecies endeavour.

Björk, through her innovative use of technology and nature in music, exemplifies shared authorship by integrating animal sounds and digital manipulation, blurring the lines between human, non-human, and technological creativity. Her project Biophilia Footnote 8 showcases this symbiosis, treating natural sounds not merely as inspirations but as co-creators, challenging traditional notions of creative agency. Björk’s approach, where machines serve as bridges between human creativity and the natural world, contributes to redefining authorship as a collective effort that transcends species boundaries. This perspective enriches discussions on the creative participation of non-human entities, urging a broader recognition of diverse contributions within the creative process.

Chris Jordan, Oliver Beer and Richard Mankin each uniquely engage with the natural world through their art, exploring the interplay between human activity, wildlife, and the environment. Jordan’s digital photography, especially in Midway: Message from the Gyre Footnote 9 , reveals the dire effects of plastic pollution on seabirds, offering a stark visual commentary on environmental degradation. Beer merges art with ecology, using animal sounds in installations to examine space’s acoustic qualities, connecting architectural and natural harmonies. Mankin, blending entomology with artistry, transforms insect acoustics into music, highlighting their ecological significance and challenging our perceptions of natural soundscapes. Together, these artists contribute to a broader dialogue on environmental awareness and interspecies relationships through innovative artistic practices.

In conclusion

We acknowledge the complexity inherent in discussing authorship across a spectrum of entities, ranging from animals to various forms of technology such as machines, robots, computers, and artificial intelligence (AI). We recognise that each of these entities possesses distinct levels of consciousness, intentionality, and embodiment, which significantly impact their perceived and potential authorship. To clarify, our argument is rooted in the notion that authorship should not be considered a binary attribute but rather as existing on a continuum that reflects the degree of consciousness and intentionality of the creator, whether animal or artificial. This approach allows us to critically examine the prevailing norms of personhood and human-centric authorship, while also addressing the significant impact of embodiment on the perception of authorship. Specifically, the physical presence or absence of a robot, as opposed to the disembodied nature of an AI system, influences how authorship is ascribed and perceived. We have to embrace a nuanced understanding of these differences and propose a framework for degrees of authorship, based on the capacities of both biological and technological entities. This stance not only enriches the dialogue around the intersection of ethics, law, and technology but also ensures that our discussion remains relevant and adaptable to the evolving landscape of intelligent and creative beings.

The concepts related to authorship and ownership of creation are those that define a person: a conscious entity with rights. The scientific approach to applying copyright involves various steps to assess the intentionality of an act and its awareness of it. Therefore, machines cannot currently be recognised as authors of their creations. However, if one considers that an artist is less of an author when accompanied by a machine whose contribution to the work is evident, or even superior, this illustrates the gradual nature of authorship. From the artist’s perspective, in a context where they are both the public performer and the programmer of the software used to create, they have a legitimate claim to authorship to a higher degree than if they were using prebuilt algorithms. This is a higher level of authorship than that perceived by a novice audience incapable of distinguishing the artist-computer scientist’s contribution from the presence of machines. It results in a subjective notion, nonetheless linked to objective technical knowledge of the attributed agency. In the context of collaboration between human artists and machines, and from the perspective of spectators, the notion of authorship would not necessarily imply the existence of consciousness.

However, this conclusion appears different regarding conscious animals. In the case of great apes, even though only captive individuals seem to enjoy drawing, this enculturation (Tomasello and Call, 2004 ) should not prevent us from recognising their authorship and ownership of their creations, since a similar learning process is observed in humans. Drawing or playing an instrument is a skill that develops through observation and learning in Homo sapiens , similar to other hominids, including young children who undergo a lengthy process to acquire these abilities. Mozart’s composition of musical works at the age of six illustrates that age or species does not constrain creativity. Some primatologists recognise the primates they study as co-authors in their research, publications, or productions, acknowledging their contributions (Savage-Rumbaugh et al., 2007 ; Applegate and Grupper, 2013 ; Matsuzawa, 2017 ). However, granting authorship to animals raises concerns about potentially undermining their agency (McFarland and Hediger, 2009 ; Blattner et al., 2020 ). Similarly, this article’s title, derived from the AI of ChatGPT, prompts a reflection on its authorship status. These considerations are likely to spark extensive debate within both the artistic and scientific communities in the future.

Furthermore, our exploration into the realms of authorship and creativity among non-human entities prompts a consideration of the concepts of transhumanism and transanimalism, especially in relation to the use of assisted technologies and robotics within contemporary art (Burgat, 2015 ; Delfin, 2019 ; Grundmann, 2007 ; Someşan, 2022 ; Vita‐More, 2013 ). Transhumanist and metahumanist (Sorgner and Deretic, 2015 ) movements that advocate for the evolution of the human condition through advanced technologies, offer compelling lenses through which to view the integration of AI and robotics in artistic creation. These movements question the plasticity of the human condition and envision political and practical possibilities where the boundaries between human and machine, organic and artificial, are increasingly blurred, suggesting a new paradigm of creativity that is collaborative, hybrid, and expansive in its potential. Additionally, the concept of transanimalism (Cayol et al., 2024 )—extending transhumanist ideas to include non-human animals in the technological enhancement narrative—further enriches this discourse. It invites us to reimagine the creative capacities of animals when augmented by technology, thus opening up new avenues for artistic expression that transcend traditional species boundaries. By integrating these considerations into our discussion, we acknowledge the evolving landscape of contemporary art, where assisted technologies not only redefine the parameters of human creativity but also challenge us to envisage a future where diverse forms of intelligence, both human and non-human, contribute to the tapestry of artistic expression in unprecedented ways.

Data availability

Data sharing is not applicable to this article as no datasets were generated or analysed during the current study.

From an ethological perspective, creativity may be observed in animal behaviour that solves new problems or adapts in novel ways. In AI research, creativity is often demonstrated through the ability to produce work that is indistinguishable from or surpasses human-created art, challenging our understanding of creativity’s origins and manifestations. Philosophically, creativity involves the exploration of the bounds of imagination and the capacity for conceptual expansion, inviting a re-evaluation of creative agency across different forms of consciousness.

Just as there are multiple forms and instances of intelligence across different animal species, with varied structures and supports for intelligence, the same reasoning can apply to AI. The term ‘artificial intelligences’ acknowledges the diversity and multiplicity of AI systems, frameworks, and applications. Each AI system can be designed with unique capabilities, purposes, and underlying algorithms, thus representing distinct ‘intelligences’ in the artificial realm. This pluralisation can emphasise the variety and specificity of AI entities, recognising their individual characteristics and contributions to the broader landscape of technology and society.

A robot is typically defined as a machine that is capable of carrying out complex actions automatically, especially when programmed to do so by a computer. Not all robots necessarily incorporate AI technologies and some robots may operate based on pre-programmed instructions or simple rule-based systems without the need for sophisticated AI algorithms. But many robots can be considered embodiments of AI because they incorporate AI algorithms to interact with the physical world through sensors and actuators, process sensory information and make decisions about how to act in their environment.

The question regarding agency and IA embodiment itself is an important discussion that is notably addressed by phenomenology and cognitive phenomenology (Buongiorno, 2023 ; Corti, 2022 ; Turner, 2020 ).

Strong AI, also known as Artificial General Intelligence (AGI), refers to a type of artificial intelligence that has the ability to understand, learn, and apply its intelligence to solve any problem, similarly to how a human would. It possesses the capacity for conscious thought, understanding, judgement and self-awareness, allowing it to perform tasks requiring human-like cognitive abilities and to adapt to new situations without human intervention. Strong AI aims to replicate the multifaceted intelligence of human beings but is still a theoretical object that only exists in cultural items such as movies or video games, with famous characters such as Data ( Star Trek: The Next Generation ). Weak AI, also known as Narrow AI, is designed and trained for a specific task as or a simple computer, an articulated robot or a machine. Unlike Strong AI, it operates under a limited pre-defined range or context and does not possess consciousness or self-awareness. Weak AI is focused on executing specific applications such as voice recognition, image analysis, or executing specific functions within a software environment. Examples include virtual assistants, chatbots, and recommendation systems. While it can exhibit some level of learning and adaptation within its narrow domain, it does not have the capability to generalise its intelligence to the broad spectrum of tasks that a human or Strong AI can perform.

The U.S. Copyright Office will register an original work of authorship, provided that the work was created by a human being." (U.S. Copyright, 2021 , Compendium (Third) § 306) This regulation was renewed in March 2023 in the legal text Copyright Registration Guidance: Works Containing Material Generated by Artificial Intelligence (U.S. Copyright, 2023 , Copyright Registration Guidance).

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Acknowledgements

This work was financially supported by the Région Hauts-de-France (Protocole FUPL-HDF). The authors also thank DeepL software and ChatGPT AI for helping with English language corrections.

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Sueur, C., Lombard, J., Capra, O. et al. Exploration of the creative processes in animals, robots, and AI: who holds the authorship?. Humanit Soc Sci Commun 11 , 611 (2024). https://doi.org/10.1057/s41599-024-03125-y

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How to write an animal report

Your teacher wants a written report on the beluga whale . Not to worry. Use these organizational tools from the Nat Geo Kids Almanac so you can stay afloat while writing a report.

STEPS TO SUCCESS:

Your report will follow the format of a descriptive or expository essay and should consist of a main idea, followed by supporting details and a conclusion. Use this basic structure for each paragraph as well as the whole report, and you’ll be on the right track.

Introduction

State your main idea .

The beluga whale is a common and important species of whale.

Provide supporting points for your main idea.

1. The beluga whale is one of the smallest whale species.

2. It is also known as the “white whale” because of its distinctive coloring.

3. These whales are common in the Arctic Ocean’s coastal waters.

Then expand on those points with further description, explanation, or discussion.

1a. Belugas range in size from 13 to 20 feet (4 to 6.1 m) in length.

2a. Belugas are born gray or brown. They fade to white at around five years old.

3a. Some Arctic belugas migrate south in large herds when sea ice freezes over.

Wrap it up with a summary of your whole paper.

Because of its unique coloring and unusual features, belugas are among the most familiar and easily distinguishable of all the whales.

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Here are some things you should consider including in your report:

What does your animal look like? To what other species is it related? How does it move? Where does it live? What does it eat? What are its predators? How long does it live? Is it endangered? Why do you find it interesting?

SEPARATE FACT FROM FICTION: Your animal may have been featured in a movie or in myths and legends. Compare and contrast how the animal has been portrayed with how it behaves in reality. For example, penguins can’t dance the way they do in Happy Feet.

PROOFREAD AND REVISE: As with any essay, when you’re finished, check for misspellings, grammatical mistakes, and punctuation errors. It often helps to have someone else proofread your work, too, as he or she may catch things you have missed. Also, look for ways to make your sentences and paragraphs even better. Add more descriptive language, choosing just the right verbs, adverbs, and adjectives to make your writing come alive.

BE CREATIVE: Use visual aids to make your report come to life. Include an animal photo file with interesting images found in magazines or printed from websites. Or draw your own! You can also build a miniature animal habitat diorama. Use creativity to help communicate your passion for the subject.

THE FINAL RESULT: Put it all together in one final, polished draft. Make it neat and clean, and remember to cite your references.

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One Health is an approach that recognizes that the health of people is closely connected to the health of animals and our shared environment. One Health is not new, but it has become more important in recent years. This is because many factors have changed interactions between people, animals, plants, and our environment.

• Human populations are growing and expanding into new geographic areas. As a result, more people live in close contact with wild and domestic animals, both livestock and pets. Animals play an important role in our lives, whether for food, fiber, livelihoods, travel, sport, education, or companionship. Close contact with animals and their environments provides more opportunities for diseases to pass between animals and people.
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One Health is gaining recognition in the United States and globally as an effective way to fight health issues at the human-animal-environment interface, including zoonotic diseases. CDC uses a One Health approach by involving experts in human, animal, environmental health, and other relevant disciplines and sectors in monitoring and controlling public health threats and to learn about how diseases spread among people, animals, plants, and the environment.

Successful public health interventions require the cooperation of human, animal, and environmental health partners. Professionals in human health (doctors, nurses, public health practitioners, epidemiologists), animal health (veterinarians, paraprofessionals, agricultural workers), environment (ecologists, wildlife experts), and other areas of expertise need to communicate, collaborate on, and coordinate activities. Other relevant players in a One Health approach could include law enforcement, policymakers, agriculture, communities, and even pet owners. No one person, organization, or sector can address issues at the animal-human-environment interface alone.

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Experts say coral reef bleaching near record level globally because of ‘crazy’ ocean heat

FILE - Bleached coral is visible at the Flower Garden Banks National Marine Sanctuary, off the coast of Galveston, Texas, in the Gulf of Mexico, Sept. 16, 2023. Ocean temperatures that have gone “crazy haywire” hot, especially in the Atlantic, are close to making the current global coral bleaching event the worst in history. It’s so bad that scientists are hoping for a few hurricanes to cool things off. (AP Photo/LM Otero, File)

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Ocean temperatures that have gone “crazy haywire” hot, especially in the Atlantic , are close to making the current global coral bleaching event the worst in history. It’s so bad that scientists are hoping for a few hurricanes to cool things off.

More than three-fifths — 62.9% — of the world’s coral reefs are badly hurting from a bleaching event that began last year and is continuing. That’s nearing the record of 65.7% in 2017, when from 2009 to 2017 about one-seventh of the world’s coral died, said Derek Manzello, coordinator of the National Oceanic and Atmospheric Administration Coral Reef Watch Program .

When water gets too hot, coral, which are living creatures, bleach and sometimes die.

In the Atlantic, off the Florida coast and in the Caribbean, about 99.7% of the coral reefs have been hit with “very very severe’’ losses in staghorn and elkhorn species, Manzello said Thursday in NOAA’s monthly climate briefing. Sixty-two countries are seeing damaged coral, with Thailand shutting off a tourist-laden island to try to save the coral there.

Meteorologists say a La Nina — a natural cooling of parts of the Pacific that changes the weather worldwide — is forecast to develop soon and perhaps cool oceans a bit, but Manzello said it may be too little and too late.

“I still am very worried about the state of the world’s coral reefs just because we’re seeing things play out right now that are just very unexpected and extreme,” Manzello said.

“This wouldn’t be happening without climate change. That’s basically the cornerstone of all the ocean warming we’re seeing,” Manzello said. But on top of that are changes in El Nino, the reverse of La Nina and a natural warming of ocean waters; reduced sulfur pollution from ships and an undersea volcano eruption.

Former top NASA climate scientist James Hansen said “acceleration of global warming is now hard to deny” in a new analysis and statement Thursday.

For coral, it comes down to how hot the water is and “things have just gone crazy haywire with ocean temperatures in the last year,” Manzello said. He said hurricanes bring up cool water from deep and benefit coral reefs if they don’t hit them directly.

“Hurricanes can be devastating for reefs,” Manzello. “But in the grand scheme of things and given the current situation we are in on planet Earth, they’re now a good thing essentially, which is kind of mind-blowing.”

On Wednesday, parts of the Atlantic where hurricanes often develop had an ocean heat content — which measures water warmth at depths — equivalent to mid-August , said hurricane researchers Brian McNoldy at the University of Miami and Phil Klotzbach at Colorado State University.

The world’s oceans last month broke a record for the hottest April on record. It was the 13th straight month global seas broke records, and because the oceans are slow to cool or warm, more records are likely, said Karin Gleason, NOAA’s climate monitoring chief.

Coral reefs are key to seafood production and tourism worldwide. Scientific reports have long said loss of coral is one of the big tipping points of future warming as the world nears 1.5 degrees Celsius (2.7 degrees Fahrenheit) of warming since pre-industrial time. That’s a limit that countries agreed to try to hold to in the 2015 Paris climate agreement.

“This is one of the most biodiverse ecosystems on the planet,” said Andrew Pershing, a biological oceanographer who is vice president for science of Climate Central. “It’s an ecosystem that we’re literally going to watch disappear in our lifetimes.”

Read more of AP’s climate coverage at http://www.apnews.com/climate-and-environment

Follow Seth Borenstein on X at @borenbears

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Protein is an essential macronutrient, but not all food sources of protein are created equal, and you may not need as much as you think. Learn the basics about protein and shaping your diet with healthy protein foods.

Jump to: – What is protein? – How much protein do I need? – It’s all about the protein “package” – Research on protein and human health – Protein foods and the planet – The bottom line: choosing healthy protein foods – [Quiz] Test your protein knowledge!

What Is Protein?

Protein is found throughout the body—in muscle, bone, skin, hair, and virtually every other body part or tissue. It makes up the enzymes that power many chemical reactions and the hemoglobin that carries oxygen in your blood. At least 10,000 different proteins make you what you are and keep you that way.

Protein is made from twenty-plus basic building blocks called amino acids. Because we don’t store amino acids, our bodies make them in two different ways: either from scratch, or by modifying others. Nine amino acids—histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine—known as the essential amino acids, must come from food.

How Much Protein Do I Need?

The National Academy of Medicine recommends that adults get a minimum of 0.8 grams of protein for every kilogram of body weight per day, or just over 7 grams for every 20 pounds of body weight . [1]

• For a 140-pound person, that means about 50 grams of protein each day.
• For a 200-pound person, that means about 70 grams of protein each day.

The National Academy of Medicine also sets a wide range for acceptable protein intake—anywhere from 10% to 35% of calories each day. Beyond that, there’s relatively little solid information on the ideal amount of protein in the diet or the healthiest target for calories contributed by protein. In an analysis conducted at Harvard among more than 130,000 men and women who were followed for up to 32 years, the percentage of calories from total protein intake was not related to overall mortality or to specific causes of death. [2] However, the source of protein was important.

“Pure” protein, whether derived from plant or animal foods, probably has similar effects on health, although the mix of amino acids can have health implications. Some proteins found in food are “complete,” meaning they contain all twenty-plus types of amino acids needed to make new protein in the body. Others are incomplete, lacking one or more of the nine essential amino acids, which our bodies can’t make from scratch or from other amino acids. Animal-based foods (meat, poultry, fish, eggs, and dairy foods) tend to be good sources of complete protein, while plant-based foods (fruits, vegetables, grains, nuts, and seeds) often lack one or more essential amino acid. Those who abstain from eating animal-based foods can eat a variety of protein-containing plant foods each day in order to get all the amino acids needed to make new protein, and also choose to incorporate complete plant proteins like quinoa and chia seeds .

It’s important to note that millions of people worldwide, especially young children, don’t get enough protein due to food insecurity. The effects of protein deficiency and malnutrition range in severity from growth failure and loss of muscle mass to decreased immunity , weakening of the heart and respiratory system, and death.

However, it’s uncommon for healthy adults in the U.S. and most other developed countries to have a deficiency, because there’s an abundance of plant and animal-based foods full of protein. In fact, many in the U.S. are consuming more than enough protein, especially from animal-based foods. [3]

It’s All About the Protein “Package”

When we eat foods for protein, we also eat everything that comes alongside it: the different fats, fiber, sodium, and more. It’s this protein “package” that’s likely to make a difference for health.

The table below shows a sample of food “packages” sorted by protein content, alongside a range of components that come with it.

To call out a few examples:

• A 4-ounce broiled sirloin steak is a great source of protein—about 33 grams worth. But it also delivers about 5 grams of saturated fat .
• A 4-ounce ham steak with 22 grams of protein has only 1.6 grams of saturated fat, but it’s loaded with 1,500 milligrams worth of sodium .
• 4 ounces of grilled sockeye salmon has about 30 grams of protein, naturally low in sodium, and contains just over 1 gram of saturated fat. Salmon and other fatty fish are also excellent sources of omega-3 fats , a type of fat that’s especially good for the heart.
• A cup of cooked lentils provides about 18 grams of protein and 15 grams of fiber , and it has virtually no saturated fat or sodium.

What about protein powders?

Research on protein and health.

Available evidence indicates that it’s the source of protein (or, the protein “package”), rather than the amount of protein, that likely makes a difference for our health. You can explore the research related to each disease in the tabs below, but here’s the evidence-based takeaway: eating healthy protein sources like beans, nuts, fish, or poultry in place of red meat and processed meat can lower the risk of several diseases and premature death.

Research conducted at the Harvard Chan School of Public Health has found that eating even small amounts of red meat—especially processed red meat—on a regular basis is linked to an increased risk of heart disease and stroke , and the risk of dying from cardiovascular disease or any other cause. [4-6] Conversely, replacing red and processed red meat with healthy protein sources such as beans, soy foods, nuts, fish, or poultry seems to reduce these risks. One of the reasons why plant sources of protein are related to lower risk of cardiovascular disease compared to protein from red meat and dairy is because of the different types of fat in these protein packages. Plant-based protein sources are more unsaturated, which lowers LDL cholesterol—an established risk factor for heart disease. Also, plant sources contain no cholesterol . Other factors are likely to contribute to the lower risk, but this is a key factor.

• Processed red meat was even more strongly linked to dying from cardiovascular disease—and in smaller amounts: every additional 1.5 ounce serving of processed red meat consumed each day (equivalent to one hot dog or two strips of bacon) was linked to a 20% increase in the risk of cardiovascular disease death.
• Cutting back on red meat could save lives: the researchers estimated that if all the men and women in the study had reduced their total red and processed red meat intake to less than half a serving a day, one in ten cardiovascular disease deaths would have been prevented.
• In another study of 43,000 men that looked at both amount and sources of protein found that intake of total protein was minimally associated with heart disease risk, but intake of protein from red meat was associated with higher risk. [7]
• The study included data from 36 randomized controlled trials involving 1,803 participants. The researchers compared people who ate diets with red meat with people who ate more of other types of foods (i.e. chicken, fish, carbohydrates, or plant proteins such as legumes, soy, or nuts), looking at blood concentrations of cholesterol, triglycerides, lipoproteins, and blood pressure—all risk factors for cardiovascular disease.
• Researchers found that when diets with red meat were compared with all other types of diets combined, there were no significant differences in total cholesterol, lipoproteins, or blood pressure, although diets higher in red meat did lead to higher triglyceride concentrations than the comparison diets.
• However, researchers found that diets higher in high-quality plant protein sources such as legumes, soy, and nuts resulted in lower levels of both total and LDL (“bad”) cholesterol compared to diets with red meat.

In terms of the  amount of protein consumed, there’s evidence that eating a relatively high-protein diet may be beneficial for the heart, as long as the protein comes from a healthy source.

• A 20-year prospective study of over 80,000 women found that those who ate low-carbohydrate diets that were high in plant-based sources of fat and protein had a 30%lower risk of heart disease compared with women who ate high-carbohydrate, low-fat diets. [8] However, eating a low-carbohydrate diet high in animal fat or protein did not offer such protection.
• Further evidence of the heart benefits of eating healthy protein in place of carbohydrate comes from a randomized trial known as the Optimal Macronutrient Intake Trial for Heart Health (OmniHeart). A healthy diet that replaced some carbohydrate with healthy protein (or healthy fat) did a better job of lowering blood pressure and harmful low-density lipoprotein (LDL) cholesterol than a higher carbohydrate diet. [9]
• Similarly, the “EcoAtkins” weight loss trial compared a low-fat, high -carbohydrate, vegetarian diet to a low-carbohydrate vegan diet that was high in vegetable protein and fat. Though weight loss was similar on the two diets, study participants on the high protein diet saw improvements in blood lipids and blood pressure. [10]
• Of course, occasionally a study will generate headlines because it found the opposite result. For example, one study of Swedish women who ate low-carbohydrate, high-protein diets had higher rates of cardiovascular disease and death than those who ate lower-protein, higher-carbohydrate diets. [11] But the study, which assessed the women’s diets only once and then followed them for 15 years, did not look at what types of carbohydrates or what sources of protein these women ate. That was important because most of the women’s protein came from animal sources.

Again, the source of protein  matters more than protein quantity when it comes to diabetes risk. Eating more red meat predicts a higher risk of type 2 diabetes, while consuming nuts, legumes, and poultry is related to lower risk.

• A 2011 study found that people who ate diets high in red meat, especially processed red meat, had a higher risk of type 2 diabetes than those who rarely ate red or processed meat. [12] For each additional serving a day of red meat or processed red meat that study participants ate, their risk of diabetes rose 12% and 32%, respectively. Investigators also found that replacing a serving of red meat with one serving of nuts, low-fat dairy products, or whole grains each day was associated with an estimated 16% to 35% lower risk of type 2 diabetes.
• A related study also found that people who started eating more red meat than usual were had a 50% higher risk of developing type 2 diabetes during the next four years, and researchers also found that those who reduced red meat consumption had a 14% lower risk of type 2 diabetes over a 10-year follow-up period. [13]
• How meat is cooked may also affect type 2 diabetes risk . In a study that tracked the health of over 289,000 men and women, researchers found that individuals who most frequently ate red meats and chicken cooked at high temperatures were 1.5 times more likely to develop type 2 diabetes, compared to those who ate the least. There was also an increased risk of weight gain and developing obesity in the frequent users of high-temperature cooking methods, which may have contributed to the development of diabetes. Of note, this research demonstrated that cooking methods might contribute to diabetes risk beyond the effects of meat consumption alone. [14] Learn more about this study .
• More evidence that the source of protein matters comes from a 20-year study that looked at the relationship between low-carbohydrate diets and type 2 diabetes in women. Low-carbohydrate diets that were high in vegetable sources of fat and protein were associated with a lower risk of type 2 diabetes. [15] But low-carbohydrate diets that were high in animal sources of protein or fat did not show this benefit.
• For type 1 diabetes (formerly called juvenile or insulin-dependent diabetes), proteins found in cow’s milk have been implicated in the development of the disease in babies with a predisposition to the disease, but research remains inconclusive. [16,17]

When it comes to cancer, once again, the source of protein seems to matter more than quantity.

• In the Nurse’s Health Study and the Health Professionals Follow-Up Study, every additional serving per day of red meat or processed red meat was associated with a 10% and 16% higher risk of cancer death, respectively. [5]
• Conclusions were primarily based on the evidence for colorectal cancer . Data also showed positive associations between processed meat consumption and stomach cancer , and between red meat consumption and pancreatic and prostate cancer .
• A 2014 study also found a link between high consumption of red meat during adolescence and premenopausal breast cancer, while higher intakes of poultry, nuts, and legumes were associated with lower risk. Using data on the health of 89,000 women (aged 24 to 43) followed over a 20-year period, researchers found a 22% higher risk of breast cancer in those who ate 1.5 servings of red meat per day while in high school, compared to those who only had one serving per week. Each additional daily serving of red meat seemed to increase the risk of breast cancer by another 13%.  [19]
• How meat is cooked may also have implications for cancer risk. High-temperature grilling creates potentially cancer-causing compounds in meat, including polycyclic aromatic hydrocarbons and heterocyclic amines. Learn about tips for healthy grilling.
• In 2016, researchers reviewed protein intakes of more than 131,000 women and men from the Nurses’ Health Study and Health Professionals Follow-up Study. After tracking their diets for up to 32 years, the authors found that a higher intake of red meat, especially processed versions (sausage, bacon, hot dogs, salami), was linked to a modestly higher risk of death, while a higher protein intake from plant foods carried a lower risk. [2] Learn more about this study .
• Digesting protein releases acids into the bloodstream, which the body usually neutralizes with calcium and other buffering agents. As a result, early research theorized that eating lots of protein requires a lot more calcium – which may be pulled from bone. A 2009 systematic review found that this doesn’t appear to happen. [20]

The same healthy protein foods that are good choices for disease prevention may also help with weight control. Again, it’s the source of protein that matters.

• Those who ate more red and processed meat over the course of the study gained more weight, about one extra pound every four years, while those who ate more nuts over the course of the study gained less weight, about a half pound less every four years.
• A subsequent detailed analysis of this cohort also found that eating red meat, chicken with skin, and regular cheese was associated with greater weight gain. Yogurt, peanut butter, walnuts and other nuts, chicken without skin, low-fat cheese, and seafood was associated with less weight gain. [22]
• Another study showed that eating around one daily serving of beans, chickpeas , lentils or peas can increase fullness, which may lead to better weight management and weight loss. [23]

There’s no need to go overboard on protein. Though some studies show benefits of high-protein, low-carbohydrate diets in the short term (such as the paleo diet ), avoiding fruits and whole grains means missing out on healthful fiber, vitamins, minerals, and other phytonutrients.

• Specific proteins in food and the environment are involved in food allergies, which are overreactions of the immune system (take gluten and celiac disease , for example).
• Medical journals are also full of reports linking allergic responses to specific protein sources with a variety of conditions (breathing problems, chronic digestive issues, etc.). Eggs, fish, milk, peanuts, tree nuts, and soybeans cause allergic reactions in some people.
• Individuals diagnosed with certain diseases (such as kidney and liver disease) need to monitor their protein intake according to their physician’s guidelines.
• You may have also heard that the use of antibiotics in the production of animal-based foods has contributed to the emergence of “superbugs,” or strains of bacteria resistant to currently available antibiotics. In 2016, the FDA announced a voluntary program to limit the routine use of antibiotics in food production (such as giving antibiotics to healthy animals to help them grow faster). [24] As a consumer, you may want to find products “raised without antibiotics” if you plan on eating meat. Some companies feature this language on the packaging, others don’t.

New research highlight: Red meat and diabetes risk

Protein foods and the planet.

To give you an idea, this “scorecard” from the World Resources Institute illustrates the differing GHG emissions per gram of protein from both animal and plant-based protein foods. [25] Making just one pound (454 grams) of lamb generates five times more GHGs than making a pound of chicken and around 30 times more than making a pound of lentils. [26] In the U.S. alone, beef accounts for 36% of all food-related GHG emissions. [27] Beyond emissions, it’s also important to note that food production places an enormous demand upon our natural resources, as agriculture is a major contributor to deforestation, species extinction, and freshwater depletion and contamination.

Bottom Line

Protein is a key part of any diet. The average person needs about 7 grams of protein every day for every 20 pounds of body weight. Because protein is found in an abundance of foods, many people can easily meet this goal. However, not all protein “packages” are created equal. Because foods contain a lot more than protein, it’s important to pay attention to what else is coming with it. That’s why the Healthy Eating Plate encourages choosing healthy protein foods.

Building off this general guidance, here are some additional details and tips for shaping your diet with the best protein choices:

• Legumes: lentils , beans (adzuki, black, fava, chickpeas /garbanzo, kidney,  lima, mung, pinto etc.), peas (green, snow, snap, split, etc.), edamame/soybeans (and products made from soy : tofu, tempeh, etc.), peanuts.
• Nuts and Seeds: almonds , pistachios, cashews, walnuts, hazelnuts, pecans, hemp seeds, squash and pumpkin seeds, sunflower seeds, flax seeds, sesame seeds, chia seeds .
• Whole Grains: kamut, teff, wheat, quinoa , rice , wild rice, millet, oats , buckwheat,
• Other: while many vegetables and fruits contain some level of protein, it’s generally in smaller amounts than the other plant-based foods. Some examples with higher protein quantities include corn, broccoli, asparagus, brussels sprouts , and artichokes.

Prioritize hearty and savory plant-based preparations

• Generally, poultry (chicken, turkey, duck) and a variety of seafood ( fish , crustaceans, mollusks) are your best bet. Eggs can be a good choice, too.
• If you enjoy dairy foods , it’s best to do so in moderation (think closer to 1-2 servings a day; and incorporating yogurt is probably a better choice than getting all your servings from milk or cheese ).
• Red meat —which includes unprocessed beef, pork, lamb, veal, mutton, and goat meat—should be consumed on a more limited basis. If you enjoy red meat, consider eating it in small amounts or only on special occasions.
• Processed meats , such as bacon, hot dogs, sausages, and cold cuts should be avoided. Although these products are often made from red meats, processed meats also include items like turkey bacon, chicken sausage, and deli-sliced chicken and ham. (Processed meat refers to any meat that has been “transformed through salting, curing, fermentation, smoking, or other processes to enhance flavor or improve preservation.” [18])

Looking to reduce red and processed meats, but unsure where to start? Here are a few approaches to cutting-back while keeping your meals satiating and flavorful. Simply find your “starting point” and move forward with the strategies that work for you:

Eat a little less red meat, any way you can

Swap out red meat for healthier meats

Consume less meat, enjoy more variety

Test your protein knowledge.

Ready to see how much you know about protein and healthy protein foods? Try this 10 question quiz to find out:

• National Academies of Medicine.  Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients) .
• Song M, Fung TT, Hu FB, Willett WC, Longo VD, Chan AT, Giovannucci EL. Association of animal and plant protein intake with all-cause and cause-specific mortality. JAMA internal medicine . 2016 Oct 1;176(10):1453-63.
• Fehrenbach KS, Righter AC, Santo RE. A critical examination of the available data sources for estimating meat and protein consumption in the USA. Public health nutrition . 2016 Jun;19(8):1358-67.
• Bernstein AM, Sun Q, Hu FB, Stampfer MJ, Manson JE, Willett WC. Major dietary protein sources and risk of coronary heart disease in women. Circulation . 2010 Aug 31;122(9):876-83.
• Pan A, Sun Q, Bernstein AM, Schulze MB, Manson JE, Stampfer MJ, Willett WC, Hu FB. Red meat consumption and mortality: results from 2 prospective cohort studies. Archives of internal medicine . 2012 Apr 9;172(7):555-63.
• Bernstein AM, Pan A, Rexrode KM, Stampfer M, Hu FB, Mozaffarian D, Willett WC. Dietary protein sources and the risk of stroke in men and women. Stroke . 2011 Jan 1:STROKEAHA-111.
• Preis SR, Stampfer MJ, Spiegelman D, Willett WC, Rimm EB. Dietary protein and risk of ischemic heart disease in middle-aged men–. The American journal of clinical nutrition . 2010 Sep 29;92(5):1265-72.
• Halton TL, Willett WC, Liu S, Manson JE, Albert CM, Rexrode K, Hu FB. Low-carbohydrate-diet score and the risk of coronary heart disease in women. New England Journal of Medicine . 2006 Nov 9;355(19):1991-2002.
• Appel LJ, Sacks FM, Carey VJ, Obarzanek E, Swain JF, Miller ER, Conlin PR, Erlinger TP, Rosner BA, Laranjo NM, Charleston J. Effects of protein, monounsaturated fat, and carbohydrate intake on blood pressure and serum lipids: results of the OmniHeart randomized trial. JAMA . 2005 Nov 16;294(19):2455-64.
• Jenkins DJ, Wong JM, Kendall CW, Esfahani A, Ng VW, Leong TC, Faulkner DA, Vidgen E, Greaves KA, Paul G, Singer W. The effect of a plant-based low-carbohydrate (“Eco-Atkins”) diet on body weight and blood lipid concentrations in hyperlipidemic subjects. Archives of internal medicine . 2009 Jun 8;169(11):1046-54.
• Lagiou P, Sandin S, Lof M, Trichopoulos D, Adami HO, Weiderpass E. Low carbohydrate-high protein diet and incidence of cardiovascular diseases in Swedish women: prospective cohort study. BMJ . 2012 Jun 26;344:e4026.
• Pan A, Sun Q, Bernstein AM, Schulze MB, Manson JE, Willett WC, Hu FB. Red meat consumption and risk of type 2 diabetes: 3 cohorts of US adults and an updated meta-analysis–. The American journal of clinical nutrition . 2011 Aug 10;94(4):1088-96.
• Pan A, Sun Q, Bernstein AM, Manson JE, Willett WC, Hu FB. Changes in red meat consumption and subsequent risk of type 2 diabetes mellitus: three cohorts of US men and women. JAMA internal medicine . 2013 Jul 22;173(14):1328-35.
• Pan A, Sun Q, Bernstein AM, Manson JE, Willett WC, Hu FB. Changes in red meat consumption and subsequent risk of type 2 diabetes mellitus: three cohorts of US men and women. JAMA internal medicine . 2013 Jul 22;173(14):1328-35.
• Halton TL, Liu S, Manson JE, Hu FB. Low-carbohydrate-diet score and risk of type 2 diabetes in women–. The American journal of clinical nutrition . 2008 Feb 1;87(2):339-46.
• Åkerblom HK, Vaarala O, Hyöty H, Ilonen J, Knip M. Environmental factors in the etiology of type 1 diabetes. American journal of medical genetics . 2002 May 30;115(1):18-29.
• Vaarala O, Ilonen J, Ruohtula T, Pesola J, Virtanen SM, Härkönen T, Koski M, Kallioinen H, Tossavainen O, Poussa T, Järvenpää AL. Removal of bovine insulin from cow’s milk formula and early initiation of beta-cell autoimmunity in the FINDIA pilot study. Archives of pediatrics & adolescent medicine . 2012 Jul 1;166(7):608-14.
• Bouvard V, Loomis D, Guyton KZ, Grosse Y, El Ghissassi F, Benbrahim-Tallaa L, Guha N, Mattock H, Straif K. Carcinogenicity of consumption of red and processed meat. The Lancet Oncology . 2015 Dec 1;16(16):1599-600.
• Farvid MS, Cho E, Chen WY, Eliassen AH, Willett WC. Adolescent meat intake and breast cancer risk. International journal of cancer . 2015 Apr 15;136(8):1909-20.
• Darling AL, Millward DJ, Torgerson DJ, Hewitt CE, Lanham-New SA. Dietary protein and bone health: a systematic review and meta-analysis–. The American journal of clinical nutrition . 2009 Nov 4;90(6):1674-92.
• Mozaffarian D, Hao T, Rimm EB, Willett WC, Hu FB. Changes in diet and lifestyle and long-term weight gain in women and men. New England Journal of Medicine . 2011 Jun 23;364(25):2392-404.
• Smith JD, Hou T, Ludwig DS, Rimm EB, Willett W, Hu FB, Mozaffarian D. Changes in intake of protein foods, carbohydrate amount and quality, and long-term weight change: results from 3 prospective cohorts–. The American journal of clinical nutrition . 2015 Apr 8;101(6):1216-24.
• Li SS, Kendall CW, de Souza RJ, Jayalath VH, Cozma AI, Ha V, Mirrahimi A, Chiavaroli L, Augustin LS, Blanco Mejia S, Leiter LA. Dietary pulses, satiety and food intake: A systematic review and meta‐analysis of acute feeding trials. Obesity . 2014 Aug;22(8):1773-80.
• Food and Drug Administration. FDA’s Strategy on Antimicrobial Resistance – Questions and Answers.  https://www.fda.gov/animalveterinary/guidancecomplianceenforcement/guidanceforindustry/ucm216939.htm . Accessed on 11/6/2018.
• World Resources Institute.  Protein Scorecard.   https://www.wri.org/resources/data-visualizations/protein-scorecard . Accessed on 11/6/2018.
• Culinary Institute of America and Harvard T.H. Chan School of Public Health.  Menus of Change: 2016 Annual Report.   http://www.menusofchange.org/
• Heller MC, Keoleian GA. Greenhouse gas emission estimates of US dietary choices and food loss. Journal of Industrial Ecology . 2015 Jun;19(3):391-401.
• Guasch-Ferré M, Satija A, Blondin S, Janiszewski M, Emlen E, O’Connor L, Campbell W, Hu F, Willett W, Stampfer M. Meta-Analysis of Randomized Controlled Trials of Red Meat Consumption in Comparison With Various Comparison Diets on Cardiovascular Risk Factors. Circulation . 2019 Apr 1;139(15):1828-45. *Disclosures: Dr. Hu has received research support from the California Walnut Commission. Dr. Campbell reported receiving research support from the National Institutes of Health (T32 Fellowship for Lauren O’Connor), the American Egg Board – The Egg Nutrition Center, The Beef Checkoff Program, The National Dairy Council, The Pork Checkoff Program, and the Barilla Group. Dr. Campbell also reported serving on the 2015 Dietary Guidelines Advisory Committee. Dr. Satija is an employee of Analysis Group, Inc. The other authors declare no conflicts.

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• Front Vet Sci

Critical Problems for Research in Animal Sheltering, a Conceptual Analysis

Kevin horecka.

1 Research Department, Austin Pets Alive!, Austin, TX, United States

2 Arkansas State University, Department of Political Science, Jonesboro, AR, United States

Animal shelter research has seen significant increases in participation over the past several decades from academic organizations, private organizations, public entities, and even corporations that aims to improve shelter programs, processes, operations, and outcomes for the various stakeholders/participants involved in a shelter system (animals, humans, the community, wildlife, and the environment). These efforts are scattered through a huge variety of different research areas that are challenging to define and scope for organizations seeking to start new lines of research inquiry. This work aims to enumerate some of the most critical outstanding problems for research in animal sheltering in a conceptual framework that is intended to help direct research conversations toward the research topics of highest impact (with the highest quality outcomes possible). To this end, we define seven (7) key areas for research: animal behavior, adoptions and special needs populations, medical conditions, disease transmission, community, ecology, and wellness (one health), operations, and public-private-academic-corporate collaboration. Within each of these areas, we review specific problems and highlight examples of successes in each area in the past several decades. We close with a discussion of some of the topics that were not detailed in this manuscript but, nonetheless, deserve some mention. Through this enumeration, we hope to spur conversation around innovative methodologies, technologies, and concepts in both research and practice in animal sheltering.

Introduction

Animal Sheltering in Western society, in some form, has existed since the mid-1800's (with the creation of both the Royal Society for the Prevention of Cruelty to Animals and the American Society for the Prevention of Cruelty to Animals in 1824 and 1866, respectively) and has been a constantly evolving field to both the benefit ( 1 , 2 ) and detriment ( 3 , 4 ), of its stakeholders: animals, pet owners, communities, and the organizations that tie these groups together. In the past several decades, a cultural shift has been occurring in which animal welfare ( 5 , 6 ) has received more attention, resources, and scrutiny than in the decades before. Success in sheltering is commonly measured by the Live Release Rate (hereafter LRR) that is obtained by dividing the total number of live animal outcomes (such as adoptions and transfers) by the total number of live animal intakes ( 7 ). Many cities have been able to increase their LRR and those of surrounding counties above 90 and even 95% ( 8 ), yet shelters still struggle with having adequate resources ( 9 ) and rural shelters may be more likely to struggle ( 10 ). The number of conceptual problems in sheltering is enormous, and as awareness of the needs of shelters continues to rise, more and more groups—academic, corporate, non-profit, and private—are looking for ways to contribute to the wider movement of animal welfare using their unique skills and talents. One difficulty for these potential partners is in understanding what the needs of shelters are and what high-value unsolved problems exist in the field.

Some of these are knowledge problems, others, implementation problems, and even more, systemic, cultural, and societal problems. Almost all require some manner of research to elucidate best practices and truths and differentiate them from traditions and myths. To aid interested parties in contributing to these areas of animal sheltering, we seek to enumerate and explain many of the critical problems for research in animal sheltering so that those organizations and interested parties might find a place to contribute. The key areas for future research were developed through a combination of both empirical and a priori traditions. The empirical approach used included input from animal sheltering professionals, including the responses of over 10 working groups representing more than 300 shelter professionals associated with Human Animal Support Services project to the question of what research needs were to advance animal sheltering. A priori observation and reflection of the researchers and reviews of the existing literature also helped to inform a lengthy list of research needs. These research needs were then thematically grouped in to the 7 key areas. Each of the areas was then evaluated on two factors: the degree of potential impact to animal sheltering and the difficulty in studying the problem.

Table 1 presents the 7 key areas identified. It also presents the impact potential for research in these areas by identifying the top-level impacts that advances in each topic area could have on the field of animal sheltering. While not intended to be all encompassing, this list captures the main topics generated by the authors and the consulted professionals.

The 7 key problem areas identified in this work and their impact potential in the space of animal sheltering. While not intended to be all encompassing, this list captures the main topics generated by the authors and the consulted professionals.

Figure 1 provides an additional way of examining these topical areas. This figure provides examples of critical problems for research in animal sheltering and provides a way to compare and evaluate the areas in terms of the relative difficulty of studying the problems as well as the relative magnitude of the potential impact. In addition to evaluating these factors for the key research areas identified herein, this figures also shows a framework through which other researchers could evaluate the relative impacts and difficulty of other possible research topics.

A Force Directed Graph showing the various problems discussed in this article. The size of a node represents the relative impact a solution would have. The color represents the relative difficulty of studying the problem (with red being more difficult). Links relate the topics. An interactive version can be found here: https://codepen.io/kevroy314/pen/jONoXma . Click to isolate nodes and their neighbors. Drag to move around. Scroll to zoom.

Key Areas for Research

Animal behavior.

Animal behavior is one of the most challenging and complex topics in animal sheltering. Leaving aside controversies surrounding the ethics of adopting out animals with known behavior challenges or the ending of the life of an animal, whether for the protection of the public, retribution for an incident, quality of life, or any other justification related to behavioral issues, such as biting or inappropriate elimination, the practical need to better understand and modify animal behavior to improve the lives of animals and their caregivers to improve their chances of adoption and/or their probability of remaining in the home ( 11 ) is substantial. Here, we highlight 4 key areas in animal behavior that may have the biggest impact in a shelter setting and that may be underrepresented in the literature.

Efforts to form a typology of dog behaviors that may be problematic in the home, and, specifically, dog behavior that may be averse to a successful adoption and retention in a home ( 12 , 13 ) have been attempted in the past ( 14 – 16 ). Despite the interest in canine behavior in general rising sharply in the early 1990s and more recently ( 17 ), no consensus has been reached upon a singular behavioral classification and identification system that can be used to make decisions around best practices with dogs with histories of behavior problems or potential for behavior problems. Such a classification system should have the following properties [( 18 ) for a more detailed discussion of the difficulties surrounding some of these issues]:

• Objective measurability and reproducibility.
• Characterization of common temporal progressions.
• Understood correlations between related behaviors.
• Clinical relevance to predictability and intervention.

Somewhat recent attempts ( 18 , 19 ) at assessing the efficacy of behavioral evaluations have not been as promising as might be hoped given the 50+ year history of the field, and the impact of such a system, especially in establishing new interventions that can help these animals be successfully placed in homes, could be enormous given the extreme difficulty in achieving successful outcomes for dogs with behavior issues.

One key factor in negative animal behaviors, especially as pertaining to the adoptability of animals, is the stress they experience while in a shelter setting ( 20 – 22 ). Studies of animal stress date back to 1926 ( 23 ) with animals have often serving as a model for human stress ( 24 , 25 ). Practical tools are needed to assess the impact of shelter environmental improvements. Using Biomarkers to assess stress ( 26 ) across species ( 27 – 29 ) have shown significant success in recent years. Unfortunately, the practical measurement of such biomarkers in shelter settings remains unlikely due to resource and practical constraints. Non-invasive measures of stress are possible in many species [including thermographic ( 30 , 31 ), salivary ( 32 ), visual ( 33 ), and multimodal ( 34 ) systems], though their efficacy as an intervention target is unclear. A more thorough understanding of best practices around the reduction of stress for animals in shelters will allow for significant improvement in the quality of life of long-stay animals as well as the adoptability of animals that may show fewer behavioral issues once removed from a stressful environment, with some evidence showing changes in cortisol levels, a common biomarker for stress, with even a single night removed from the shelter environment in adult dogs ( 35 ).

A key element in the success of an animal with behavioral issues, post-adoption is not simply the cessation of negative behaviors, but also the match with an adopter who can maintain the environment necessary for permanent improvement in behavior as well as following up with those adopters to ensure continued success is achieved. Preparing adopters and proper matching is key given the frequency of post adoption behavioral issues among shelter animals ( 36 ). This problem comes down to two key sets of questions:

Given evidence suggesting choice of pet is often tied to factors like appearance more than behavioral considerations ( 37 ), how should shelters best match behavioral issues with potential adopters who can handle the maintenance surrounding those issues to reduce the chance of return ( 36 , 38 , 39 ) and adverse incidents such as bites or escape from a yard?

What risks (i.e., environment impact on biting) ( 40 ) exist in the home that might exacerbate issues surrounding behavior?

Finally, when it comes to animal behavior, especially canine behavior, one of the most critical incidents that can occur is a bite incident since these can result in serious injury to persons and potentially result in liability claims against the shelter ( 41 ). The previously mentioned issues all likely contribute to the probability of a bite incident occurring, but predictions of such events, even in aggregate across a city ( 42 ), are challenging at best. A successful bite prediction system would also pose ethical issues as individuals, shelters, and cities may choose to use such a system to decide which animal's lives should be preemptively ended, to avoid the potential risk and liability. It is critical, therefore, that the predictability of bite incidents increase at the same rate as our ability to reasonably intervene to prevent the incidents.

Adoptions and Special Needs Populations

The core problem with adoptions at shelters is always “how do we get as many animals out to good homes as quickly as possible?.” Of course, as with so many seemingly simple problems, the posing of the question in such a general manner means no obvious solutions present themselves. Properly reframing the question often begins to imply solutions. Preventing the surrender of animals to the shelter system is certainly a key component to assuring positive outcomes for animals and people alike. New programs, such as the Human Animal Support Services project, are focusing heavily on programs aimed at keeping animals out of the shelter altogether and in their original homes whenever possible. Further, this paradigm shift has the potential to profoundly impact positive outcomes for community cats, who may not be best served through adoption. Although adoption is not the only possible positive outcome for all animals that enter a shelter system, for many animals (and the humans who manage the systems of sheltering), it remains an important practical and ethical outcome. Here, we review 3 key areas in adoptions that remain complex and difficult despite extensive efforts in the sheltering community. For a more complete list of these challenge areas, see the American Pets Alive! Documentation on the topic (“American Pets Alive! Resources;” https://americanpetsalive.org/resources ) ( 43 ).

First and most critically, large dogs, often considered to be those weighing over approximately 35 pounds or 16 kilograms, consistently have more difficulty in being adopted ( 44 – 46 ). This can be due to factors such as the general public perception around larger breeds ( 47 , 48 ), city ordinances banning ownership of certain breeds ( 49 ), housing restrictions implemented at the facility level ( 50 ), or concerns around safety, behavior, and compatibility with other home residents ( 51 ). These issues are exacerbated by the difficulty in accurately identifying breed information in shelter animal populations ( 52 ). As a result of these complications around getting large breeds out of shelters, shelters often end up with a stagnant population of these animals that has less turnover than other, easier to adopt categories (puppies of any breed, for example). This can create a perception that the only populations present are these large breed animals. These factors result in many of these animals having long stays and, as mentioned in prior sections, increased stress and overall wellness difficulties that further worsen their adoptable potential. Moreover, animals in the shelter are less likely to behave the way they might otherwise in a home ( 53 ), further decreasing their chances for a positive outcome. A strategy around breaking this cycle and helping large dogs would alleviate significant amounts of trapped resources as site maintenance and housing can create substantial costs and reduce flexibility in serving other populations. The importance of providing an equal opportunity for these large breed dogs to stay in their home is one consideration beyond adoption in strategy design. For example, policies that disallow the use of size of a dog as criteria for access to housing (as discussed above) would help keep these animals out of the shelter system in the first place. Adequate access to resources to behavior training could be another community level intervention that could allow more of these animals to stay in their homes.

Other Special Populations

Beyond these major issues, there are numerous conditions of decreasing commonality that require increasingly complex adaptations of program and policy to accommodate. This article cannot enumerate all such conditions, but the following list, sorted roughly by difficulty, captures some of the most critical special needs populations that require specially trained homes to inhabit, making them more difficult to adopt out:

• Geriatric Animals.
• Animals with Chronic Allergies.
• Hospice Animals.
• Feline Leukemia Virus (FeLV) Cats.
• Kidney Failure Animals.
• Diabetic Animals.
• Behavior Animals.
• Animals with Paralysis and/or Incontinence.

Much of the care, maintenance, and treatment of these populations is well understood, but the problem of placing them in amenable homes is still a significant one. More research around interventions that can increase the likelihood of placement as well as the factors that impact the likelihood of special population placement may provide actionable insights [see ( 54 ) as an example in geriatric animals].

Finally, and significantly, a more thorough understanding of how to match adopters to animals ( 37 , 55 ), how to evaluate homes for safety and longevity of adoption outcomes ( 13 , 56 ), how to optimize placement of animals in homes ( 57 ), and what preferences exist when it comes to adoption practices around marketing, visitation, and engagement is desperately needed. This understanding will likely depend significantly on local cultural distinctions in populations ( 58 , 59 ) and is, therefore, difficult to examine systematically. More best practices around adoption matching and marketing would greatly simplify one of the most critical functions in animal shelters.

Unique Challenges of Cats

Another, potentially less obvious problem in sheltering is the difference in positive outcomes for cats vs. dogs. Best Friends, a national non-profit that provides the most comprehensive summary of annual shelter statistics reports that cats are still dying in shelters at a ratio of 2:1 when compared with dogs ( 60 ) despite approximately one-fourth of US households providing a home for cats ( 61 ). Many shelters consistently report difficulties in adopting out adult cats once they no longer have the appearance of a kitten ( 62 ). Further, shelter or municipal policies around the extermination of community cats ( 63 ) may also be a significant contributor to the numbers of cats not having successful outcomes in shelters.

Approaches to improving live outcomes for cats require shelters to explore ideas outside of the traditional intake to adoption framework. Some strategies that are specifically applicable to cats have been evaluated and shown to be effective such as trap-neuter-return and shelter-neuter-return, which could reduce the number of un-adoptable cats entering the shelter system ( 64 , 65 ), but more research into the social drivers and potential interventions for this issue are warranted. A development of the recognition of the ecology of community cats is an additional issue that is elaborated on in Section Operations.

Medical Conditions

In addition to its capacity as an adoption agency for unowned animals, animal shelters often perform a variety of medical services. These services depend on the location, resources, and risk tolerance each organization has, and it is often difficult for organizations to decide what to treat and what to not treat (whether euthanasia is then called for or not). One critical element of this that remains a challenge for all shelters is the effective, actionable diagnosis of disease [see, ( 66 )]. Many diseases have reliable tests (such as canine parvovirus) while others have a much more complicated history in the development of a reliable test [such as canine distemper, though many strongly claim RNA tests should be considered reliable; ( 67 – 69 )]. Cost is also a critical factor in shelter tests as even a relatively inexpensive (50 dollars) test in an outbreak scenario can be entirely impractical in a population of just a few dozen animals. Further research into low-cost testing is certainly needed for a wide variety of diseases.

Once the disease is identified, shelters often lack the resources for what would be considered “standard” care in a private practice. Some shelters opt to not offer reduced care and, instead, euthanize, while others choose to offer whatever care they can within their own ethical limitations of suffering and quality of life considerations. The need for significantly more research into evidence-based medical guidelines, and especially those that are specifically optimized for triage situations with limited resources and around medical conditions seen in shelters, is widely apparent. Some conditions, such as kitten diarrhea, may be somewhat understood in a general medical sense, but the treatments and time course do not scale appropriately for the model of a medium to large shelter.

Although many diseases could use additional scrutiny for the purposes outlined above, the following are of particular interest due to the costs, in either lives or resources, associated with typical treatment or management (T; indicates specific transmissible disease relevant to Section Disease Transmission):

• (T) Canine parvovirus ( 70 , 71 ).
• (T) Feline panleukemia ( 72 ).
• (T) Canine distemper ( 73 ).
• (T) Feline leukemia virus (FeLV) ( 74 ).
• (T) Feline immunodeficiency virus ( 75 – 78 ).
• Kitten diarrhea ( 79 ).
• Fracture and trauma management.

Disease Transmission

More so than the treatment of disease, the prevention of disease spread in the shelter environment is one of the most challenging, concretely measurable in the form of infection rates, yet ambiguous (difficult to diagnose in source) tasks a shelter may face. Shelters are examples of anthropogenic biological instability due to the housing of transient, displaced mixed-species of animals that may not have prior veterinary care or have been scavenging during times of homelessness ( 80 ). The disease transmission in shelters is further complicated by situation of overcrowding, poor levels of hygiene, and housing of multiple species which can add significant sources of stress for the animals and create a perfect environment for pathogen emergence and transmission ( 80 ). This transmission can quickly lead to a crisis in the shelter ( 81 ). Shelters that treat infectious disease like the canine parvovirus establish isolation areas in which only that disease is treated, but little is known about the ease with which these diseases spread under different quarantine practices.

Although there are many interesting diseases that are typically seen in shelters, some (such as those listed in Section Medical Conditions) are considered more impactful/deadly than others and, therefore, would make excellent targets for more detailed studies of disease spread.

While it is not officially recommended as a best practice ( 82 ), when shelters experience disease outbreaks, some may opt to depopulate, i.e., end the lives of their entire population, ( 83 ) rather than have it persist through many generations of animals flowing through the system. Better understanding of how to stem these outbreaks rapidly, efficiently, safely, in a resource-efficient manner, and given the constraints of a shelter environment (space, staffing, facility design, and the need to maintain normal operations) will allow shelters to avoid mass culling and take an approach that increases lifesaving with more confidence.

Community, Ecology, and Wellness (One Health)

Beyond the scope of the basic operations of a shelter in managing the conditions of individual animals and placing them in appropriate homes, shelters also serve a critical role in the community as providers of services that can enhance public perception and wellbeing ( 84 ). This collaboration requires an engaged community that recognizes the importance of animal welfare in the health and wellness of the larger, shared space. Best practices around establishing this type of engagement are not well identified in the existing body of knowledge. This is further confounded by variation in the distribution of resources and community attitudes in different geographic areas.

As animal shelters continue to evolve in response to societal shifts in attitudes toward animals, the focus of operations are changing from centering on adoptions to centering on the prevention of surrender of animals to the shelter in the first place [see ( 11 ) for a review]. This has already been discussed as it relates to community cats and behavior/health but there are many other human-centered reasons that animals are surrendered to shelters such as guardian health problems, housing insecurity, domestic violence, and many others ( 85 ). Our understanding of how human welfare intersects with animal welfare has the potential to have a dramatic impact on the way shelters operate in their communities. Some communities have hotlines, spay and neuter programs, and other medical/behavioral services that can potentially contribute to this issue, but the efficacy of such systems and the gaps they leave are not well understood. More significant study of the needs of local populations as they relate to shelter success is needed.

Local populations also differ in their perception and support of shelter policies, ethics, and the local system of laws that are intertwined with these efforts. No unified system of ethics is established in animal sheltering, and communities often do not understand the nuances of practices in shelters (especially regarding resource allocations and euthanasia practices). This makes galvanizing community support difficult, even in communities that have achieved remarkably high live release rates. Public perception, messaging, and ethical alignment will undoubtedly continue to be an ever-evolving socio-cultural landscape that is sorely in need of attention.

The mental health of volunteers, staff, and veterinarians ( 86 ) in animal shelters also requires much more attention than it often receives. Individuals that participate in euthanasia are reported to have higher work stress and lower job satisfaction than their counterparts ( 87 ). Suicide rates are significantly higher in the field of animal welfare than other high-stress fields ( 88 , 89 ), and more understanding and support is needing to help those working in these areas receive the help they need to continue to serve the community in a sustainable, healthy manner.

Access to Care

Access to veterinary care is emerging as a critical issue in animal welfare. Access to care is an aspect of the One Health approach to considering animal welfare due to the zoonotic potential of various diseases that can find reservoir in companion animals ( 90 ). In addition to being a risk to public health, lack of access to veterinary care can result in surrender of animals to shelters, stress to the caregiver/family ( 91 ) as well as stress to veterinarians who must counsel caregivers who cannot afford the recommended care ( 92 ). Shelters feel the impact of this as downstream recipients of animals when owners surrender due to an inability to access needed care. This can both drive surrender to shelters and result in a greater financial burden for shelters to meet medical needs that may be complicated by a historic lack of access to preventative or early intervention care. Further, shelters themselves compete in the market to employ veterinary professionals and support staff that may be further complicated by a shortage of veterinarians ( 93 , 94 ).

Access to care can be seen as a problem with multiple causes from cost to lack of transportation to the unequal distribution of veterinary resources across the landscape. Cost was identified as the most common barrier to accessing veterinary care in the Access to Veterinary Care Coalition report on this issue ( 91 ). In the past decade, costs for veterinary care have been outpacing increases in human health care ( 95 ). The average American spends 47% more on equivalent veterinary care today than a decade ago ( 96 ). The functional impact of this increasing cost is that fewer people are seeking care for their pets ( 97 ) resulting in what is considered the greatest current threat to companion animal welfare in the US ( 91 ). More research that identifies efficient, effective, and sustainable solutions to the cost of veterinary care will be key for animal shelters.

Key research questions in access to care can come down to three key areas:

Advances in areas like incremental care or spectrum of care, which are not equivalent but present different perspectives on the issue of cost-benefit analyses in treatment protocols, could reduce costs and prevent shelter surrenders but could also help shelters mitigate the increasing expense of medical treatment for animals in their care.

A deeper understanding of the number of animals surrendered for medical reasons, the types of these conditions and potential treatment routes pre-surrender would also add valuable knowledge to the animal sheltering and animal welfare communities.

Development of community-based solutions that focus on disease prevention when the cost is likely lower than when a disease process is more advanced. This includes the prevention of infectious disease transmission in the community and the development of effective education around other preventable conditions by pet guardians.

Ecology/Environment

The study of the ecology surrounding community cats has received significant attention over the past several years ( 63 , 64 , 98 – 102 ), and debates are likely to continue in this area to determine the most effective ways to ensure the health and safety of community cats and the organisms with which they interact. Additionally, ecological perspectives on the interaction between stray and roaming animals in general and the community are also of interest, but often only actively studied due to concerns over infectious disease spread such as the Rabies virus. Finally, the interaction of wildlife systems with domesticated animals may be of some interest both due to the spread of infectious disease and the more complex interactions these two animal groups may have with one another.

As animal welfare incorporates a One-health approach, further research that identifies strategies to reduce the environmental impact of shelter operations cannot be ignored. Effective ways of cleaning outdoor kennels without contributing to contaminate run-off, ecological disposal of animal waste and the evaluation of how large-scale animal transport can contribute to environmental degradation are just a few examples of the interaction of sheltering and the environment that are open for additional exploration.

In addition to the study of animal-centric, adoption-centric, and community-centric aspects of sheltering, the study of the operations that contribute to the ability of shelters to continually adapt, and advance is of critical importance if we are to have systems robust to disaster and capable of implementing our values and ethics on a global scale. Although blueprints do exist that can guide communities in setting up new shelters and enhancing existing shelters, significant problems remain in the space beyond the distribution of known solution resources. Here, we discuss 4 key operations problem areas with varying levels of complexity.

Data Problems

Shelters need to collect data to know how they are serving their animals, adopters, volunteers, staff, and community, and how to improve operations in all areas of the shelter. While the industry recognizes the need for quality data, significant barriers have been identified such as a lack of training and resources [( 103 ), additionally, see the Associate for Veterinary Informatics (AVI) for additional information on this topic; https://avinformatics.org/ ]. Solutions such as ShelterLuv, Chameleon, and PetPoint for database management go a long way to improving situations for shelters, but the ability to flexibly collect and curate all manner of useful data (including electronic medical records, location-based event history, and other meta-data about entities that comprise shelters) remains an open problem. It is also essential that the prioritization and understanding of the critical importance of data is shared by line staff as well as senior management. When line staff fail to understand the importance of complete data collection this action can be de-prioritized in fast paced shelter environment.

Beyond this, shelters need methods of protecting themselves in the sharing of data with the public, academic institutions, and each other. The public, which support shelters through taxes or donations, show widespread support, for example, for programs that reduce levels of shelter euthanasia shelters ( 104 ). The best practices around of performing data sharing and managing data access for shelters have yet to be established (though some progress has been made in recent months at the Municipal Shelter level). Over time, there have been attempts to create a single authoritative collection of sheltering data but to date, none have achieved high success. The current initiative that has achieved the most progress is Shelters Animals Count (SAC). SAC is a national database that relies on the voluntary participation by shelters and animal rescues to upload monthly sheltering summary statistics. Unfortunately, there is still relatively poor participation. For example, in 2020 there was participation by only 422 municipal shelters, 359 private shelters and 516 rescues ( 105 ). This can be contrasted with a 2014 estimate by the Humane Society of the United States of 3,500 municipal and non-profit shelters and over 10,000 rescue organizations ( 106 ). Despite the move toward increasing transparency in government, only a small handful of states and municipalities require reporting to their state and local governments, with even fewer providing enough clarity as to what should be reported for such reporting to be of use to the wider sheltering community. The result of this paucity and irregularity of data provides a significant challenge to researchers and policymakers in understanding what is happening across the nation regarding sheltering, though the contributions of states in which reporting is mandated effectively have provided a valuable starting point for these efforts.

KPI Problems

Once data is collected, linking that data down to trackable KPIs (Key Performance Indicators) that are useful to shelters in improving outcomes for animals is a challenge in and of itself. The standardization of KPIs and their strict definitions has suffered from some of the disagreement and difficulties surrounding data collection. The most marked attempt to create unified KPIs occurred in 2004 resulting in the Asilomar Accords. The Live Release Rate, and methods of fairly but consistently calculating it materialized as a critical outcome of the Accords ( 107 ). This measure has never been without controversy and is limited, in part, by the wide variance in the various ways in which animal shelters operate in their community and what their priority services are ( 108 ). As the operation of shelters have changed, with more innovative programs designed to prevent animals from ever entering the shelter system appearing, advancements in medical and behavioral interventions, and the geographically biased nature of animal population distributions ( 109 ), the use of a single KPI will likely remain a source of both conflict and difficulty for many shelters. A more diverse set of KPIs will allow for shelters to perform more nuanced comparisons of their successes and failures that will enable better sharing of solutions and resources. What this list of KPIs should entail remains an open problem [see ( 110 )].

Growth Problems

Finally, as some shelters begin to stabilize the animal welfare situation in their cities, adapting to the varying degrees and paces of growth in various organizations to ensure resources are being properly utilized to the benefit of animals and the community is a challenge, to say the least. The field of Health Economics in humans has a rich history ( 111 ), and a similar field in Animal Health Economics ( 112 , 113 ) will likely need to be expanded beyond its traditional focus on production animals so that organizations are not put in a position to blindly guess at the proper allocations or resources toward different intervention programs (such as a canine parvovirus treatment program, FeLV treatment program, behavior program, or kitten foster program).

One particularly challenging program area for shelters to understand in the context of growth, integration, and resource allocation is the management of foster programs. Foster programs have been fantastically successful as a method of expanding the effective capacity of shelters, increasing live outcomes ( 114 ), enhancing community engagement, increasing quality of life of animals in care ( 35 ), and providing special assistance for more difficult to adopt populations. However, a thorough understanding of how to best engage, utilize, and grow foster programs is lacking.

Diversity Equity and Inclusion

Researchers have evidenced that the oppression of non-human animals, disabled humans, and people of color are deeply interconnected ( 115 ). If animal shelters are to continue to function as key members of diverse communities it is essential that they pay increasing attention to issues of diversity, equity, and inclusion in their operations both internal and external. While the community of research in this space has assembled a basic understanding of some inequities that currently exist, many others have yet to be explored in a thorough way. For example, we know that African Americans are underrepresented in leadership positions ( 116 ). The homogeneity of animal shelters is not confined to the workforce alone. Two large survey-based studies found similar results in evaluating the demographics of animal welfare volunteers concluding that most volunteers were White females in the middle to upper middle class ( 117 , 118 ). Questions of why this lack of diversity persists and what successful strategies could be used to improve conditions would be of benefit as representation of communities within organizations that serve them allow those organizations to supply the appropriate services to maximize the community benefit and foster a highly participatory, engaged, fair, enthusiastic, and ethical social system.

Beyond direct engagement with shelters as volunteers or employees, there are fecund areas for research in the provisioning of shelter operations. As increases in public-private partnerships place more animal shelters in the business of providing animal control operations, the enforcement of ordinances becomes a key issue in balancing public demand for action and the ethics and priorities of animal welfare. A recently published commentary on the subject argues that there is inherent bias in the design and enforcement of public policy around animal welfare and urges a shift from enforcement to resource provision ( 119 ). Evaluating policies and enforcement and implementation of these policies and whether biases are leading to unequal burden are not well understood though it is difficult to not draw comparisons to the arena of policing and the long, complicated relationship between marginalized communities and law enforcement personnel. Additional challenges persist in understanding potential inequities between the surrender of animals and the adoption of animals and whether these differences enforce equity imbalances or are based on existing biases and structural inequities ( 120 ).

Public-Private-Academic-Corporate Collaborations

A less visible and virtually unstudied problem in animal sheltering is the ability for organizational entities of different types and with different incentives to collaborate to the benefit of animals, their owners, the community, and each other. The social network analysis of Reese and Ye ( 121 ) is a prime example of the complex collaborative relationships that can emerge between organizations to advance lifesaving in a community. Many questions in this space exist around the best ways for these organizations to interact (i.e., what roles are best served by what organizations, what incentives are best to ensure ethical treatment of all parties, and what restrictions should be put on various types of interactions). Legal restrictions around the use of shelter animals in research may be a barrier that exists to research collaborations between shelters and academic institutions. Dialogue, consensus, and potential legislative change may be needed between animal shelters, the veterinary community, and academia to address the negative consequences of legislation originally intended to protect animals from harm.

Public-private partnerships in other areas of medicine have become increasingly common and valuable ( 122 ), and corporate sponsorship of shelters has become increasingly common. Public-private shelter partnerships are also on the rise with some proposing this structure as the new standard in the field ( 123 ). Academic collaboration with animal shelters, where academic institutions take advantage of the wealth of available subjects and data in shelters, is still a relatively new concept. Though many potential pitfalls exist in these collaborations (including issues with credit attribution, resource allocation, and ethical alignment), the potential to accelerate the state of the art in animal sheltering via these collaborations is huge thanks to the varied strengths of each organizational type.

The seven key areas for research in animal sheltering outlined above are not the only areas that might be of interest to shelter practitioners and their partners. Some additional areas of interest were not mentioned specifically in this manuscript due to the well-researched nature of the topics, the lack of clear definition in the space, and/or their relative distance from the typical practices of an animal shelter. These areas, nonetheless, merit some mention due to their importance to the area of animal welfare research at large and potential intersection with some shelter practices (depending on specific shelter policy, philosophy, and operations).

A variety of interventions have been proposed that might address some of the problems mentioned in this manuscript. On the behavior side, playgroup services have been proposed that may aid in social development and lead to more positive behavioral outcomes for dogs ( 124 ). Moreover, foster programs that take advantage of these and other medical or behavioral services to accelerate positive outcomes for animals deserve significant attention ( 35 , 125 ). Foster programs can serve as an additional reservoir for animal populations, increase community engagement in the shelter system, and encourage positive outcomes for animals in the foster system through positive environmental enrichment in homes. In situations where foster homes are not available, additional environmental enrichment to achieve similar aims may be found through clever building and facility design at the shelter site ( 126 , 127 ). Finally, a variety of programmatic and procedural interventions around lost and found animals, self-service rehoming, and intake-to-placement optimization, and field services optimization that aim to prevent animals from entering the physical shelter facility can serve as systems optimizations that improve outcomes for all parties; though, more research is needed in these areas to examine their efficacy. Each of these intervention areas, and other innovations in sheltering, deserve significantly more attention than can be afforded in this outline, and future work should attempt to address them more directly.

In addition to a variety of community and ecology problems and interventions, ethical problems in the industry of animal sheltering are not specifically addressed in this work as these are not research topics per se , but more in the realm of philosophy. Future work should examine ethical questions surrounding the topics outlined in this manuscript and other sociological research questions related to the ethics of animal shelter practices.

In this work, we present a conceptual organization of topics for research in Animal Sheltering. These topics vary significantly in difficulty and impact but represent a large swath of needed scientific contributions in the literature. Many of these areas are being actively worked upon by various research institutions (i.e., significant work in animal diseases has occurred), but some have received little attention yet (i.e., operations research). Moreover, some of these areas are being examined, but due to resource and/or methodological constraints, progress is slow. By enumerating these problems, the community of researchers attempting to improve the function of shelters for animals, staff, volunteers, and the community can more carefully and wholistically consider the breadth of applicability of their ideas and investigations and hopefully, more productively contribute to the literature.

Author Contributions

The above document was drafted and originated by KH with review, added sections on community cats, DEI, and Access to Care and most edits provided by SN. Figures were generated by KH. Both authors contributed to the article and approved the submitted version.

Funding for publication was provided by the American Pets Alive! Organization, while funding for individual authors and the creation of the work herein was provided by their respective institutions or the authors themselves.

Conflict of Interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Publisher's Note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

Acknowledgments

The authors would like to thank the Human Animal Support Services organization for their support and encouragement. Additionally, we would like to especially thank Dr. Nipuni Ratnayaka for her contributions to and review of some of the ideas in this document, Dr. Elizabeth Davis for her support in the development of these ideas, Rory Adams for his thoughtful comments around the topics in this document, Steve Porter for his commentary around shelter operations, Dr. Ellen Jefferson for her leadership and support of this work, and all of the staff, volunteers, and communities that continue to advance the state of the art in animal sheltering around the world. This work originally appeared in large part in a blog post from November of 2019. The original blog post can be found at: https://medium.com/@amparesearch/critical-problems-for-research-in-animal-sheltering-404395127b35 .