Animals in Science / Research

Animals in Research: Overview

Animals in Research: Overview

Under the U.S. Department of Health and Human Services, the National Institutes of Health (NIH) is the primary federal agency that conducts and supports medical research and is “the largest source of funding for medical research in the world.” Part of NIH’s mission is to “enhance [human] health, lengthen life, and reduce the burdens of illness and disability.”1 To achieve this goal, all but six of the 30 Institutes and Centers that make up NIH use animals in their intramural research (research conducted by NIH), establishing the use of animals in all areas of research, training, and biological testing.2 For extramural research (research funded by NIH) in 2010, “about 40% of NIH-funded grants and contracts involve animal research.”3

Commonly used in biomedical research as “models” for human disease, animals are also used in basic biomedical research (research for general understanding); behavioral research such as psychology and addiction studies; military, space, and agricultural research; product development and drug testing; and science education. Historically, the concept of "animal models" of human health problems was formulated in response to concerns about infectious diseases. The basic assumption was that if animals used in laboratories experimentally contracted an infection and were cured, there was a high probability of stopping the same disease in humans. As originally conceived, to be a valid model of human health concerns, the animal disease must have the same biological mechanisms, symptoms, and responses to treatment as the theoretically similar human counterpart. In turn, failure to meet one or more of these criteria invalidates the animal model—we see this occur again and again in all areas of disease research.

There is demonstrated evidence of the failures of the animal model. For example: forcing dogs to inhale cigarette smoke did not show a link to lung cancer; Flosint, an arthritis medication, tested safe in monkeys but caused deaths in humans; and the recalled diet drug fen-phen caused no heart damage in animals, while it did in humans—just a small sampling of volumes of examples. Yet in spite of the fact that species differences between human and nonhuman animals have led to flawed science and incorrect conclusions, the practice of animal experimentation continues. An estimated 100 million animals, including rats, mice, and birds, are used yearly in the U.S. in all areas of research, testing, and education.

In an attempt to overcome the limitations of animal models, researchers are genetically engineering animals, by removing or adding genes they believe relate to specific human diseases. The underlying assumption here is that these new genetically constructed animals will be more human-like. This technology is commonly used in mice and rats and the number of genetically altered (transgenic) animals being produced for research has grown exponentially over the past ten years. Scientists also breed these animals to produce offspring whom they hope will express the desired traits or will be more susceptible to the disease or disorder they are studying.

The fact that existing animal models need to be genetically “improved” is further evidence of their original lack of biological and/or clinical relevance. Most noteworthy is the case of the chimpanzee, for whom it is scientifically substantiated that despite their natural genetic similarity to humans (we are more closely related to them and they to us than any other species); they still have failed in every major area of research to provide important or even helpful information for humans. The implications of this for the use of all other species in research meant to benefit humans are serious and likely insurmountable challenges for anyone who supports the use of animals for human biomedical research.


There is no doubt that non-animal alternatives are the future and that this can happen sooner rather than later. The development and use of replacement alternatives is limited only by the imagination of the investigators involved, and the unwillingness of both the NIH and individual researchers to abandon the old school mentality of using animal models with all of its limitations and dangers and associated costs to taxpayers. 

Proponents of animal research are varied and well funded. Their lobbying interest reflects concern for profit while throwing compassion and even human health to the wind. NEAVS’ principled actions and compassionate commitment have an impact on the public, science, and government because NEAVS understands the wisdom of intelligent and defined strategy to best respond to the urgent need of the animals now suffering in laboratories, and to the needs of every human who is or knows someone ill or injured. Our core ethical objection to the use of animals in research stands firmly on growing scientific evidence of how unnecessary, limited, and dangerous the use of other species is to study human disease. NEAVS shows that there is a better way to promote human and animal health and safety than the cruel, outdated, and counterproductive use of animals in research, testing, and education.

[1] National Institutes of Health. (n.d.). About NIH.

[2] Office of Animal Care and Use. (2012, July 25). Homepage.

[3] Robinson, B. (2010, November 2). Recognition of animal welfare in biomedical science takes center stage. NCI Cancer Bulletin, 7(21).