An estimated 26 million animals are used every year in the United States for scientific and commercial testing. Animals are used to develop medical treatments, determine the toxicity of medications, check the safety of products destined for human use, and other biomedical, commercial, and health care uses. Research on living animals has been practiced since at least 500 BC.
Proponents of animal testing say that it has enabled the development of many life-saving treatments for both humans and animals, that there is no alternative method for researching a complete living organism, and that strict regulations prevent the mistreatment of animals in laboratories.
Opponents of animal testing say that it is cruel and inhumane to experiment on animals, that alternative methods available to researchers can replace animal testing, and that animals are so different from human beings that research on animals often yields irrelevant results. Read more...
Animal Testing ProCon.org is a nonpartisan, nonprofit website that presents research, studies, and pro and con statements on whether or not animals should be used for scientific or commercial testing. The term animal testing is used here to refer to all research using animals, including "basic research" that does not involve the testing of a product.
95% of animals used in experiments are not protected by the federal Animal Welfare Act (AWA), which excludes birds, rats and mice bred for research, and cold-blooded animals such as reptiles and most fish. [1, 2, 3]
A 2011 poll of nearly 1,000 biomedical scientists conducted by the science journal Nature found that more than 90% "agreed that the use of animals in research is essential." 
Chimpanzees share 99% of their DNA with humans, and mice are 98% genetically similar to humans. The United States and Gabon are the only two countries that allow experimentation on chimpanzees. 
In 2010, Minnesota used more cats for testing than any other state (2,703), New Jersey used the most dogs (6,077), and Massachusetts used the most primates (7,458). 
In 1997, researchers Joseph and Charles Vacanti grew a human "ear" seeded from implanted cow cartilage cells on the back of a living mouse to explore the possibility of fabricating body parts for plastic and reconstructive surgery. 
Pro & Con Arguments: "Should Animals Be Used for Scientific or Commercial Testing?"
PRO Animal Testing
Animal testing has contributed to many life-saving cures and treatments. The California Biomedical Research Association states that nearly every medical breakthrough in the last 100 years has resulted directly from research using animals.  Experiments in which dogs had their pancreases removed led directly to the discovery of insulin, critical to saving the lives of diabetics.  The polio vaccine, tested on animals, reduced the global occurrence of the disease from 350,000 cases in 1988 to 223 cases in 2012. [112, 113] Animal research has also contributed to major advances in understanding and treating conditions such as breast cancer, brain injury, childhood leukemia, cystic fibrosis, malaria, multiple sclerosis, tuberculosis, and many others, and was instrumental in the development of pacemakers, cardiac valve substitutes, and anesthetics. [10, 11, 12, 13] Chris Abee, Director of the University of Texas M.D. Anderson Cancer Center's animal research facility, states that "we wouldn't have a vaccine for hepatitis B without chimpanzees," and says that the use of chimps is "our best hope" for finding a vaccine for Hepatitis C, a disease that kills 15,000 people every year in the United States. 
There is no adequate alternative to testing on a living, whole-body system. Living systems like human beings and animals are extremely complex. Studying cell cultures in a petri dish, while sometimes useful, does not provide the opportunity to study interrelated processes occurring in the central nervous system, endocrine system, and immune system.  Evaluating a drug for side effects requires a circulatory system to carry the medicine to different organs.  Also, conditions such as blindness and high blood pressure cannot be studied in tissue cultures.  Computer models can only be reliable if accurate information gleaned from animal research is used to build the models in the first place. Furthermore, even the most powerful supercomputers are unable to accurately simulate the workings of complex organs such as the brain. 
Animals are appropriate research subjects because they are similar to human beings in many ways. Chimpanzees share 99% of their DNA with humans, and mice are 98% genetically similar to humans.  All mammals, including humans, are descended from common ancestors, and all have the same set of organs (heart, kidneys, lungs, etc.) that function in essentially the same way with the help of a bloodstream and central nervous system.  Because animals and humans are so biologically similar, they are susceptible to many of the same conditions and illnesses, including heart disease, cancer, and diabetes. 
Animals must be used in cases when ethical considerations prevent the use of human subjects. When testing medicines for potential toxicity, the lives of human volunteers should not be put in danger unnecessarily. It would be unethical to perform invasive experimental procedures on human beings before the methods have been tested on animals, and some experiments involve genetic manipulation that would be unacceptable to impose on human subjects before animal testing.  The World Medical Association Declaration of Helsinki states that human trials should be preceded by tests on animals. 
Animals themselves benefit from the results of animal testing. If vaccines were not tested on animals, millions of animals would have died from rabies, distemper, feline leukemia, infectious hepatitis virus, tetanus, anthrax, and canine parvo virus. Treatments for animals developed using animal testing also include pacemakers for heart disease and remedies for glaucoma and hip dysplasia. [9, 21] Animal testing has also been instrumental in saving endangered species from extinction, including the black-footed ferret, the California condor and the tamarins of Brazil. [13, 9] Koalas, ravaged by an epidemic of sexually transmitted chlamydia and now classified as endangered in some regions of Australia, are being tested with new chlamydia vaccines that may stall the animal's disappearance. [22, 18] The American Veterinary Medical Association (AVMA) endorses animal testing.
Animal research is highly regulated, with laws in place to protect animals from mistreatment. In addition to local and state laws and guidelines, animal research has been regulated by the federal Animal Welfare Act (AWA) since 1966. As well as stipulating minimum housing standards for research animals (enclosure size, temperature, access to clean food and water, and others), the AWA also requires regular inspections by veterinarians.  All proposals to use animals for research must be approved by an Institutional Animal Care and Use Committee (IACUC) set up by each research facility. Humane treatment is enforced by each facility's IACUC, and most major research institutions' programs are voluntarily reviewed for humane practices by the Association for Assessment and Accreditation of Laboratory Animal Care International (AAALAC). [24, 25] All institutions receiving funding from the US Public Health Service (PHS) must comply with the PHS Policy on Humane Care and Use of Laboratory Animals. [3, 26, 27, 28]
Animals often make better research subjects than human beings because of their shorter life cycles. Laboratory mice, for example, live for only two to three years, so researchers can study the effects of treatments or genetic manipulation over a whole lifespan, or across several generations, which would be infeasible using human subjects. [29, 9] Mice and rats are particularly well-suited to long-term cancer research, partly because of their short lifespans. 
Animal researchers treat animals humanely, both for the animals' sake and to ensure reliable test results. Research animals are cared for by veterinarians, husbandry specialists, and animal health technicians to ensure their well-being and more accurate findings. According to the journal Nature Genetics, because "stressed or crowded animals produce unreliable research results, and many phenotypes are only accessible in contented animals in enriched environments, it is in the best interests of the researchers not to cut corners or to neglect welfare issues." At Cedars-Sinai Medical Center's animal research facility, for example, dogs are given exercise breaks twice daily, when they can socialize with their caretakers and other dogs, and a "toy rotation program" provides opportunities for play.
Animals do not have rights, therefore it is acceptable to experiment on them. Animals do not have the cognitive ability or moral judgment that humans do and because of this they have been treated differently than humans by nearly every culture throughout recorded history. If we granted animals rights, all humans would have to become vegetarians, and hunting would need to be outlawed. [33, 34]
The vast majority of biologists and several of the largest biomedical and health organizations in the United States endorse animal testing. A 2011 poll of nearly 1,000 biomedical scientists conducted by the science journal Nature found that more than 90% "agreed that the use of animals in research is essential."  The American Cancer Society, American Physiological Society, National Association for Biomedical Research, American Heart Association, and the Society of Toxicology all advocate the use of animals in scientific research. [36, 37, 38, 39, 40]
Some cosmetics and health care products must be tested on animals to ensure their safety. American women use an average of 12 personal care products per day, so product safety is of great importance.  The US Food and Drug Administration endorses the use of animal tests on cosmetics to "assure the safety of a product or ingredient." China requires that all cosmetics be tested on animals before they go on sale, so cosmetics companies must have their products tested on animals if they want distribution in China. Mosquito repellent, which helps protect people from malaria and other dangerous illnesses, must undergo toxicological testing (which involves animal testing) in order to be sold in the United States and Europe. 
Religious traditions allow for human dominion over animals. The Bible states in Genesis 1:26: "And God said... let them [human beings] have dominion over the fish of the sea, and over the fowl of the air, and over the cattle, and over all the earth, and over every creeping thing that creepeth upon the earth."  The BBC reports that Jewish, Christian, and Muslim teaching allows for animal experimentation as long as there is no unnecessary pain inflicted and there is a real possibility of benefit to human beings. 
The thalidomide disaster shows a need for more animal testing, not less.If thalidomide had been properly tested on pregnant animals, its potential for causing severe birth defects would have been discovered before the drug became legal for human use.  Testing on animals showed that the drug induced birth defects in mice, rats, hamsters, marmosets, baboons, and the New Zealand white rabbit. [110, 111]
Relatively few animals are used in research, which is a small price to pay for advancing medical progress. People in the United States eat 9 billion chickens and 150 million cattle, pigs and sheep annually, yet we only use around 26 million animals for research, 95% of which are rodents, birds and fish. [1, 2, 115] We eat more than 1,800 times the number of pigs than the number used in research, and we consume more than 340 chickens for every research animal. 
CON Animal Testing
Animal testing is cruel and inhumane. According to Humane Society International, animals used in experiments are commonly subjected to force feeding, forced inhalation, food and water deprivation, prolonged periods of physical restraint, the infliction of burns and other wounds to study the healing process, the infliction of pain to study its effects and remedies, and "killing by carbon dioxide asphyxiation, neck-breaking, decapitation, or other means."  The Draize eye test, used by cosmetics companies to evaluate irritation caused by shampoos and other products, involves rabbits being incapacitated in stocks with their eyelids held open by clips, sometimes for multiple days, so they cannot blink away the products being tested. [48, 49] The commonly used LD50 (lethal dose 50) test involves finding out which dose of a chemical will kill 50% of the animals being used in the experiment. [65, 102] The US Department of Agriculture (USDA) reported in 2010 that 97,123 animals suffered pain during experiments while being given no anesthesia for relief, including 1,395 primates, 5,996 rabbits, 33,652 guinea pigs, and 48,015 hamsters.
Alternative testing methods now exist that can replace the need for animals. In vitro (in glass) testing, such as studying cell cultures in a petri dish, can produce more relevant results than animal testing because human cells can be used.  Microdosing, the administering of doses too small to cause adverse reactions, can be used in human volunteers, whose blood is then analyzed. Artificial human skin, such as the commercially available products EpiDerm and ThinCert, is made from sheets of human skin cells grown in test tubes or plastic wells and can produce more useful results than testing chemicals on animal skin. [15, 50, 51] Microfluidic chips ("organs on a chip"), which are lined with human cells and recreate the functions of human organs, are in advanced stages of development. Computer models, such as virtual reconstructions of human molecular structures, can predict the toxicity of substances without invasive experiments on animals. 
Animals are very different from human beings and therefore make poor test subjects. The anatomic, metabolic, and cellular differences between animals and people make animals poor models for human beings.  Paul Furlong, Professor of Clinical Neuroimaging at Aston University (UK), states that "it's very hard to create an animal model that even equates closely to what we're trying to achieve in the human."  Thomas Hartung, Professor of evidence-based toxicology at Johns Hopkins University, argues for alternatives to animal testing because "we are not 70 kg rats." 
Drugs that pass animal tests are not necessarily safe. The 1950s sleeping pill thalidomide, which caused 10,000 babies to be born with severe deformities, was tested on animals prior to its commercial release.  Later tests on pregnant mice, rats, guinea pigs, cats, and hamsters did not result in birth defects unless the drug was administered at extremely high doses. [109,110] Animal tests on the arthritis drug Vioxx showed that it had a protective effect on the hearts of mice, yet the drug went on to cause more than 27,000 heart attacks and sudden cardiac deaths before being pulled from the market. [55, 56]
Animal tests may mislead researchers into ignoring potential cures and treatments.Some chemicals that are harmful to animals prove valuable when used by humans. Aspirin, for example, is dangerous for some animal species, and Fk-506 (tacrolimus), used to lower the risk of organ transplant rejection, was "almost shelved" because of animal test results, according to neurologist Aysha Akhtar, MD, MPH.  A June 1, 2006 report on Slate.com stated that a "source of human suffering may be the dozens of promising drugs that get shelved when they cause problems in animals that may not be relevant for humans." 
95% of animals used in experiments are not protected by the Animal Welfare Act.The AWA does not cover rats, mice, fish and birds, which comprise around 95% of the animals used in research. The AWA covered 1,134,693 animals used for testing in fiscal year 2010, which leaves around 25 million other animals that are not covered. These animals are especially vulnerable to mistreatment and abuse without the protection of the AWA. [1, 2, 26]
Animal tests do not reliably predict results in human beings. 94% of drugs that pass animal tests fail in human clinical trials.  According to neurologist Aysha Akhtar, MD, MPH, over 100 stroke drugs that were effective when tested on animals have failed in humans, and over 85 HIV vaccines failed in humans after working well in non-human primates.  A 2013 study published in Proceedings of the National Academy of Sciences of the United States of America (PNAS) found that nearly 150 clinical trials (human tests) of treatments to reduce inflammation in critically ill patients have been undertaken, and all of them failed, despite being successful in animal tests. [59, 58] A 2013 study in Archives of Toxicology stated that "The low predictivity of animal experiments in research areas allowing direct comparisons of mouse versus human data puts strong doubt on the usefulness of animal data as key technology to predict human safety." 
Animal tests are more expensive than alternative methods and are a waste of government research dollars.Humane Society International compared a variety of animal tests with their in vitro counterparts. An "unscheduled DNA synthesis" animal test costs $32,000, while the in vitro alternative costs $11,000. A "rat phototoxicity test" costs $11,500, whereas the non-animal equivalent costs $1,300. A "rat uterotrophic assay" costs $29,600, while the corresponding in vitro test costs $7,200. A two-species lifetime cancer study can cost from $2 million to $4 million, and the US National Institutes of Health (NIH) spends $14 billion of its $31 billion annual budget on animal research. [61, 62, 63]
Most experiments involving animals are flawed, wasting the lives of the animal subjects. A 2009 peer-reviewed study found serious flaws in the majority of publicly funded US and UK animal studies using rodents and primates. 87% of the studies failed to randomize the selection of animals (a technique used to reduce "selection bias") and 86% did not use "blinding" (another technique to reduce researcher bias). Also, "only 59% of the studies stated the hypothesis or objective of the study and the number and characteristics of the animals used."  Since the majority of animals used in biomedical research are killed during or after the experiments, and since many suffer during the studies, the lives and wellbeing of animals are routinely sacrificed for poor research. 
Animals can suffer like humans do, so it is speciesism to experiment on them while we refrain from experimenting on humans. All suffering is undesirable, whether it be in humans or animals. Discriminating against animals because they do not have the cognitive ability, language, or moral judgment that humans do is no more justifiable than discriminating against human beings with severe mental impairments. [66, 67] As English philosopher Jeremy Bentham wrote in the 1700s, "The question is not, Can they reason? nor, Can they talk? but, Can they suffer?" 
The Animal Welfare Act has not succeeded in preventing horrific cases of animal abuse in research laboratories. In Mar. 2009, the Humane Society of the United States (HSUS) found 338 possible violations of the Animal Welfare Act at the federally funded New Iberia Research Center (NIRC) in Louisiana. Some of the primates housed at NIRC were suffering such severe psychological stress that they engaged in self-mutilation, "tearing gaping wounds into their arms and legs." Video footage shows infant chimps screaming as they are forcibly removed from their mothers, infant primates awake and alert during painful experiments, and chimpanzees being intimidated and shot with a dart gun.  In a 2011 incident at the University of California at Davis Center for Neuroscience, "three baby mice were found sealed alive in a plastic baggie and left unattended" on a laboratory counter, according to the Sacramento Bee. 
Religious traditions tell us to be merciful to animals, so we should not cause them suffering by experimenting on them. In the Bible, Proverbs 12:10 states: "A righteous [man] regardeth the life of his beast..."  The Hindu doctrine of ahimsa teaches the principle of not doing harm to other living beings.  The Buddhist doctrine of right livelihood dissuades Buddhists from doing any harm to animals. 
Medical breakthroughs involving animal research may still have been made without the use of animals. There is no evidence that animal experiments were essential in making major medical advances, and if enough money and resources were devoted to animal-free alternatives, other solutions would be found. 
Background: "Should Animals Be Used for Scientific or Commercial Testing?"
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Marmoset monkeys used for testing being offered marshmallows in an animal research facility. Source: Ben Goldacre, "Animal Research Study Shows Many Tests Are Full of Flaws," theguardian.com, Jan. 22, 2010
An estimated 26 million animals are used every year in the United States for scientific and commercial testing.  Animals are used to develop medical treatments, determine the toxicity of medications, check the safety of products destined for human use, and other biomedical, commercial, and health care uses. Research on living animals has been practiced since at least 500 BC.
Proponents of animal testing say that it has enabled the development of numerous life-saving treatments for both humans and animals, that there is no alternative method for researching a complete living organism, and that strict regulations prevent the mistreatment of animals in laboratories.
Opponents of animal testing say that it is cruel and inhumane to experiment on animals, that alternative methods available to researchers can replace animal testing, and that animals are so different from human beings that research on animals often yields irrelevant results.
Animal testing in the United States is regulated by the federal Animal Welfare Act (AWA), passed in 1966 and amended in 1970, 1976, and 1985.  The AWA defines "animal" as "any live or dead dog, cat, monkey (nonhuman primate mammal), guinea pig, hamster, rabbit, or such other warm blooded animal." The AWA excludes birds, rats and mice bred for research, cold-blooded animals, and farm animals used for food and other purposes. 
The AWA requires that each research facility develop an internal Institutional Animal Committee (more commonly known as an Institutional Animal Care and Use Committee, or IACUC) to "represent society's concerns regarding the welfare of animal subjects." The Committee must be comprised of at least three members. One member must be a veterinarian and one must be unaffiliated with the institution.
While the AWA regulates the housing and transportation of animals used for research, it does not regulate the experiments themselves. The US Congress Conference Committee stated at the time of the bill's passage that it wanted "to provide protection for the researcher... by exempting from regulations all animals during actual research and experimentation... It is not the intention of the committee to interfere in any way with research or experimentation." 
Animal studies funded by US Public Health Service (PHS) agencies, including the National Institutes of Health (NIH), are further regulated by the Public Health Service Policy on Humane Care and Use of Laboratory Animals.  All PHS funded institutions must base their animal care standards on the AWA and the Guide for the Care and Use of Laboratory Animals (also known as the Guide), prepared by the Institute for Laboratory Animal Research at the National Research Council. Unlike the AWA, the Policy on Humane Care and Use of Laboratory Animals and the Guide cover all vertebrate animals used for research, including birds, rats and mice. The Guide "establishes the minimum ethical, practice, and care standards for researchers and their institutions," including environment and housing standards and required veterinary care. The Guide stipulates that "the avoidance or minimization of discomfort, distress, and pain when consistent with sound scientific practices, is imperative." 
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Undercover photo taken in 1981 by a PETA activist of a monkey at the Institute for Biological Research in Silver Spring, MD. Source: wikipedia.org (accessed Oct. 22, 2013)
The US Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) reports the number of animals used for research each year, though it excludes animals not covered by the AWA. For fiscal year 2010 (the latest year for which data are available as of Oct. 11, 2013), 1,134,693 animals were reported.  Since the data excludes cold-blooded animals, farm animals used for food, and birds, rats, and mice bred for use in research, the total number of animals used for testing is unknown.Estimates of the number of animals not counted by APHIS range from 85%-96% of the total of all animals used for testing. [2, 65, 72, 1]
The USDA breaks down its data by three categories of pain type: animals that experience pain during their use in research but are given drugs to alleviate it (339,769 animals in 2010); animals who experience pain and are not given drugs (97,123); and animals who do not experience pain and are not given drugs (697,801). 
The US Food and Drug Administration, which regulates the development of new medications, states that "At the preclinical stage, the FDA will generally ask, at a minimum, that sponsors... determine the acute toxicity of the drug in at least two species of animals..." 
A public outcry over animal testing and the treatment of animals in general broke out in the United States in the mid-1960s, leading to the passage of the AWA. An article in the November 29, 1965 issue of Sports Illustrated about Pepper, a farmer's pet Dalmation that was kidnapped and sold into experimentation, is believed to have been the initial catalyst for the rise in anti-testing sentiment.  Pepper died after researchers attempted to implant an experimental cardiac pacemaker in her body. 
A May 2013 Gallup poll found that 56% of Americans say medical testing on animals is morally acceptable (down from 65% in 2001), with 39% saying it is morally wrong.  Younger Americans are less likely to accept animal testing. 47% of people aged 18-34 say that animal testing is morally acceptable, whereas 60% of people aged 35-54 and 61% of people aged 55 and older say it is morally acceptable.  67% of registered voters in the US are opposed to using animals to test cosmetics and personal care products, according to a 2013 nationwide poll conducted by Lake Research Partners. The poll found that women are more likely to object, with 76% of women under 50 and 70% of women over 50 being opposed to animal testing, and 63% of men under and over 50 being opposed. 52% of voters said they feel safer using a product that was tested using non-animal methods, while 18% said they feel safer with products tested on animals. 
Descriptions of the dissection of live animals have been found in ancient Greek writings from as early as circa 500 BC. Physician-scientists such as Aristotle, Herophilus, and Erasistratus performed the experiments to discover the functions of living organisms. [79, 80] Vivisection (dissection of a living organism) was practiced on human criminals in ancient Rome and Alexandria, but prohibitions against mutilation of the human body in ancient Greece led to a reliance on animal subjects. Aristotle believed that animals lacked intelligence, and so the notions of justice and injustice did not apply to them. Theophrastus, a successor to Aristotle, disagreed, objecting to the vivisection of animals on the grounds that, like humans, they can feel pain, and causing pain to animals was an affront to the gods. 
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Vivisection performed on a dog, painted by Emile-Edouard Mouchy in 1832. Source: Lindsey Nield, "History: The Nature of the Beast," bluesci.org, Jan. 4, 2010
Roman physician and philosopher Galen (130-200 AD), whose theories of medicine were influential throughout Europe for fifteen centuries, engaged in the public dissection of animals (including an elephant), which was a popular form of entertainment at the time. [81, 80] Galen also engaged in animal vivisection in order to develop theories on human anatomy, physiology, pathology, and pharmacology.  In one of his experiments, he demonstrated that arteries, which were believed by earlier physicians to contain air, actually contained blood. Galen believed that animal physiology was very similar to that of human beings, but despite this similarity he had little sympathy for the animals on which he experimented. Galen recommended that his students vivisect animals "without pity or compassion" and warned that the "unpleasing expression of the ape when it is being vivisected" was to be expected. 
French philosopher René Descartes (1596-1650), who occasionally experimented on live animals, including at least one rabbit, as well as eels and fish, believed that animals were "automata" who could not experience pain or suffer the way that humans do.  Descartes recognized that animals could feel, but because they could not think, he argued, they were unable to consciously experience those feelings. 
English Physician William Harvey (1578-1657) discovered that the heart, and not the lungs, circulated blood throughout the body as a result of his experiments on living animals. [84, 85]
Animal Testing in the 1800s and Early 1900s
There was little public objection to animal experimentation until the 19th Century, when the increased adoption of domestic pets fueled interest in an anti-vivisection movement, primarily in England. This trend culminated in the founding of the Society for the Protection of Animals Liable to Vivisection in 1875, followed by the formation of similar groups. [79, 87]
One of the first proponents of animal testing to respond to the growing anti-testing movement was French physiologist Claude Bernard in his Introduction to the Study of Experimental Medicine (1865). Bernard argued that experimenting on animals was ethical because of the benefits to medicine and the extension of human life. 
Queen Victoria was an early opponent of animal testing in England, according to a letter written by her private secretary in 1875: "The Queen has been dreadfully shocked at the details of some of these [animal research] practices, and is most anxious to put a stop to them."  Soon the anti-vivisection campaign became strong enough to pressure lawmakers into establishing the first laws controlling the use of animals for research: Great Britain's Cruelty to Animals Act of 1876. 
Russian physiologist Ivan Pavlov (1849-1936) demonstrated the "conditioned reflex" by training dogs to salivate upon hearing the sound of a bell or electric buzzer. In order to measure "the intensity of the salivary reflex," wrote Pavlov, the dogs were subjected to a "minor operation, which consists in the transplantation of the opening of the salivary duct from its natural place on the mucous membrane of the mouth to the outside skin." A "small glass funnel" was then attached to the salivary duct opening with a "special cement." [86, 75]
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A mouse with an "ear" seeded from implanted cow cartilage cells growing on its back, the result of a 1997 experiment created by Joseph and Charles Vacanti to explore the possibility of fabricating body parts for plastic and reconstructive surgery. Source: thedailytouch.com, Mar. 20, 2013
In 1959, The Principles of Humane Experimental Technique by zoologist William Russell and microbiologist Rex Burch was published in England. The book laid out the principle of the "Three Rs" for using animals in research humanely: Replacement (replacing the use of animals with alternative research methods), Reduction (minimizing the use of animals whenever possible), and Refinement (reducing suffering and improving animals' living conditions).  The "Three Rs" were incorporated into the AWA and have formed the basis of many international animal welfare laws. [90, 91]
Animals in Space and the Military
Since as early as 1948, animals have been used by the US space program for testing such aspects of space travel as the effects of prolonged weightlessness. After several monkeys died in unmanned space flights carried out during the 1940s, the first monkey to survive a space flight was Yorick, recovered from an Aerobee missile flight on Sep. 20, 1951. However, Yorick died several hours after landing, possibly due to heat stress.   The first living creature to orbit the Earth was Laika, a stray dog sent into space on the Soviet spacecraft Sputnik 2 in Nov. 1957. Laika died of "overheating and panic" early in the mission, according to the BBC.  The record for the most animals sent into space was set Apr. 17, 1998, when more than two thousand animals, including rats, mice, fish, crickets, and snails, were launched into space on the shuttle Columbia (along with the seven-member human crew) for neurological testing. [7, 8]
Since the Vietnam war, animals have also been used by the US military. The US Department of Defense used 488,237 animals for research and combat trauma training ("live tissue training") in fiscal year 2007 (the latest year for which data are available), which included subjecting anesthetized goats and pigs to gunshot wounds, burns, and amputations for the training of military medics. [6, 93] In February 2013, after an escalation of opposition by animal rights groups such as People for the Ethical Treatments of Animals (PETA), Congress ordered the Pentagon to present a written plan to phase out live tissue training. The US Coast Guard, however, which was at the center of a 2012 scandal involving videotaped footage of goats being mutilated as part of its live tissue training program, said in May 2013 that the program will continue. [94, 95]
The Modern Debate
The 1975 publication of Animal Liberation by Australian philosopher Peter Singer galvanized the animal rights and anti-testing movements by popularizing the notion of "speciesism" as being analogous to racism, sexism, and other forms of prejudice. Addressing animal testing specifically, Singer predicted that "one day... our children's children, reading about what was done in laboratories in the twentieth century, will feel the same sense of horror and incredulity... that we now feel when we read about the atrocities of the Roman gladiatorial arenas or the eighteenth-century slave trade." 
In 1981, an early victory by then-fledgling animal rights group People for the Ethical Treatment of Animals (PETA) served to revitalize the anti-testing movement once again. A PETA activist working undercover at the Institute for Biological Research in Silver Spring, MD took photographs of monkeys in the facility that had engaged in self-mutilation due to stress. The laboratory's director, Edward Taub, was charged with more than a dozen animal cruelty offences, and an especially notorious photo of a monkey in a harness with all four limbs restrained became a symbolic image for the animal rights movement. 
In 2001, controversy erupted over animal experiments undertaken by a veterinarian at Ohio State University. Dr. Michael Podell infected cats with the feline AIDS virus in order to study why methamphetamine users deteriorate more quickly from the symptoms of AIDS. After receiving several death threats, Dr. Podell abandoned his academic career.  Over 60% of biomedical scientists polled by Nature magazine say "animal-rights activists present a real threat to essential biomedical research." 
A 2007 report by the National Research Council of the National Academy of Sciences called for a reduction in the use of animal testing, recommending instead the increased use of in vitro methods using human cells. Though the report touted new technologies that could eventually eliminate the need for animal testing altogether, the authors acknowledged that "For the foreseeable future... targeted tests in animals would need to be used to complement the in vitro tests, because current methods cannot yet adequately mirror the metabolism of a whole animal." 
In Mar. 2013, the European Union banned the import and sale of cosmetic products that use ingredients tested on animals. Some proponents of animal testing objected, arguing that some animal tests had no non-animal equivalents. A spokesman for the trade association Cosmetics Europe stated it is likely "that consumers in Europe won’t have access to new products because we can’t ensure that some ingredients will be safe without access to suitable and adequate testing."  India and Israel have also banned animal testing for cosmetic products, while the United States has no such ban in place.  China is the only major market where testing all cosmetics on animals is required by law, and foreign companies distributing their products to China must also have them tested on animals. [65, 43] China has announced that its animal testing requirement will be waived for shampoo, perfume, and other so-called "non-special use cosmetics" manufactured by Chinese
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Pro animal testing billboard posted by the Foundation for Biomedical Research. Source: Jane E. Allen, "Animal Rights: Scientists' Billboards Ask Whether You'd Save a Child or a Lab Rat," abcnews.go.com, Apr. 14, 2011
companies after June 2014. "Special use cosmetics," including hair regrowth, hair removal, dye and permanent wave products, antiperspirant, and sunscreen, will continue to warrant mandatory animal testing. 
After ceasing to breed chimpanzees for research in May 2007, the US National Institutes of Health announced in June 2013 that it will retire most of its chimpanzees (310 in total) over the next several years. While the decision was welcomed by animal rights groups, proponents said the decision would have a negative impact on the development of critical vaccines and treatments. The Texas Biomedical Research Institute released a statement claiming that the number of chimps to be retained (up to 50) was "not sufficient to enable the rapid development of better preventions and cures for hepatitis B and C, which kill a million people every year."  The United States and Gabon are the only two countries in the world that still experiment on chimpanzees. 
(If you have trouble viewing any of the videos below, you may need to get the latest free version of Adobe Flash at http://get.adobe.com/flashplayer/otherversions/)
Americans for Medical Progress video featuring a tour of Cedars-Sinai Medical Center's animal research facility. Source: Americans for Medical Progress, "Touring and Animal Research Facility," youtube.com (accessed Sep. 23, 2013)
Wyss Institute video promoting "organs on a chip" as an alternative to animal testing. Source: Wyss Institute, "Organs on Chips," youtube.com (accessed Sep. 23, 2013)
Warning: Video below contains graphic and potentially emotionally disturbing footage. Viewer discretion is advised.
Society for Neuroscience video hosted by neuroscientist Elizabeth Burnett, PhD, advocating the use of animal testing. Source: Society for Neuroscience, "Understanding Animal Research," brainfacts.org(accessed Aug. 11, 2014)
Humane Society of the United States video shot undercover at the New Iberia Research Center (NIRC) in Louisiana. Source: Humane Society of the United States (HSUS), "CHIMPS: Undercover Investigation at Research Lab," www.youtube.com (accessed Sep. 23, 2013)
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