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Animals in Scientific Experimentation


Science has made important inroads into fighting several major diseases with the aid of many different species of animals. It was all without the permission of the species, though, and it was not without significant costs to human lives, as well as the lives of millions of animals. This report will discuss scientific and ethical reasons against the use of animals in scientific experiments and will show that in the face of overwhelming evidence, such practices should be discontinued.

There are two main categories of animal experimentation. The first uses animals to test an enormous variety of shampoos, cosmetics, household cleaners, and other chemicals.  Such things are tested to make sure, for example, that they do not extensively irritate the skin.  The second category comprises medical research – the use of animals to research diseases which affect humans. This second category is obviously more difficult to argue against, since the object is to save human lives, and improve the quality of human life. However, I will show that this is at best a fallacious argument, because there is an increasingly wide array of alternatives to animal research, and because humanity cannot justify exploiting animals simply to make their own lives better.

Animal Experimentation is Exploitation

No animal has ever signed a form giving consent to have experiments performed on them. For this reason alone, animal experimentation is ethically irresponsible. It is generally accepted that it is morally and ethically wrong for humans to exploit, torture, or experiment on other humans. Unfortunately, humans are the only animal included in this category.

All animals should have the right to a life free from deliberate pain and suffering. Like humans, many animals are capable of both physical pain and psychological stress. They can experience fear, boredom, and depression. Deliberately harming animals in the home is a punishable offense – cruelty towards animals is illegal in most situations, yet it is allowed to continue in laboratories. Animals may be submitted to physical pain or psychological stress in the name of science, and it is perfectly legal.

Animals Suffer During Experimentation

In product testing, for example, animals may undergo intense prolonged pain. The Draize Test is used to test toxicity on household products. This test involves application of solutions directly to the animal test subjects ‘ eyes. Rabbits are commonly used because their tear ducts are such that they do not produce a lot of tears, which would have the effect of washing away the toxic substance from their eyes. Tests last for as long as seven hours, often damaging the animals’ eyes and causing severe pain. The animals are then killed to examine them for internal damage. (Miller 15) Another test, called the LD50 (lethal dose 50%) Test, measures the toxicity of a substance. The test measures the amount of substance required to kill half the animals in a group. The test may go on for days, and animals may be in extreme pain.  Again, when the test is over, the remaining animals are killed. (Miller 15)

Also Study: Pros and Cons of Animal Testing

Most of the animal species that are used in laboratory experiments feel a great deal of stress when they are locked up in cages. Dogs, cats, rabbits, and even rats and mice can become stressed as a result of being caged, and even more so when conditions are overcrowded. It is the primates, however, who are subjected to the worst indignities and undergo the most stress as a result of being caged. In the wild, chimpanzees for example roam miles and miles of territory, yet in laboratories they are often kept in cages as small as 5 x 5 x 7 feet. Many research chimpanzees, once locked up, are completely isolated from their own kind. They are never allowed outside again, and instead sit in isolation in these tiny cages, which causes immense stress to such social animals. (Chimpanzee Collaboratory 14) The psychological stress caused by such living conditions and by physical pain due to experimentation can produce misleading results.

The Threat of Extinction

In 2001, 2,567,713 animals were used in scientific experiments in the United Kingdom alone.  This includes 1.6 million mice, nearly 500,000 rats, 23,000 rabbits, and 3,300 primates.  While it is true that the majority of animals used in this way are bred for the purpose and therefore such use does not threaten the existence of the species, there are some specific cases where species are in danger of extinction partly because of ongoing use in experimentation.  Such an example is the use of chimpanzees in AIDS research.

As early as 1988, some people have feared that the use of chimpanzees in AIDS research could eventually lead to the extinction of the species, even though it was unclear that chimps were valuable in AIDS research. (Booth 777) Conservation of the species is becoming an increasingly important issue. Primates are the species which are most closely related to humans, and chimpanzees are the most closely related of all other species on earth. As well as this, chimpanzees are known to have been the original carriers of the virus that mutated into HIV; however they themselves do not get sick from the disease. For these reasons, they are the preferred animal to use in HIV/AIDS research – and for these and other reasons they are now in danger of extinction. (China Daily par. 2) One hundred years ago, two million chimpanzees lived in Africa – in this century, there are fewer than 150,000 remaining in the wild, and while experimentation is not the most significant cause of their depletion, it is a contributing factor. (Jane Goodall Institute par 6)

Animals are not the same as Humans

It cannot be denied that animal testing has aided in the development of successful vaccines and other treatments.  For example, vaccines for rabies, polio, measles, mumps, rubella, and TB were all developed using animals as test subjects. (BBC par 6) However, this is not conclusive proof that animal experimentation is safe and reliable. Many substances which are toxic to humans are not toxic to animals, and vice versa. For example, aspirin can be fatal to cats, penicillin kills guinea pigs, and insulin causes deformities in a number of animal species, including mice and rabbits. (BUAV, FAQ par 23) All of these animals are commonly used in scientific experiments, yet they are different enough from humans as to process chemicals in entirely different ways.

There are also many instances where animal experiments have led to unsafe drugs being marketed or have hindered rather than helped scientists gain knowledge about human diseases. Such an example is the animal experiments that delayed the development of drugs used in the treatment of AIDS.

Protease Inhibitors

Protease inhibitors are drugs which have in the past made a major contribution to slowing the progress of AIDS in infected individuals, enabling many people to live more normal lives. However, the initial development of protease inhibitors was significantly slowed by the use of animal testing. In the 1980s, the drug company Merck was in the process of developing protease inhibitors for use in AIDS treatment. The inhibitors were tested for toxicity in dogs and rats, and were found to be highly toxic to both species. For this reason, clinical trials of the new drugs were delayed by four years, because scientists felt that it would be unethical to test the drugs on humans when the effects on animals were so severe. (Tatchell par 6)

In 1993, Merck began clinical trials of a protease inhibitor based on results using in vitro experiments that examined interactions between HIV and human tissue cells. These experiments showed the drug was safe to use in humans. According to Bennett M. Shapiro, former Merck president of world-wide research, “animal tests were neither needed nor used to explore the ability of protease inhibitors to block the growth of the AIDS virus…the action could be evaluated before the clinical trials using computers, cell culture, and biochemical assays”. (Tatchell par 10)

In short, the very same drugs that cause liver failure in the dogs and rats used in these experiments proved to be safe and beneficial to use in humans with AIDS. It is obvious that animal experimentation has the ability to produce data which is misleading because animals are not enough like humans for experimental results to be accurate. In this case, reliance on animal experimentation delayed the release of a drug which increased the quality and duration of life for thousands of AIDS sufferers world-wide.

Alternatives to Animal Experimentation

There are several different methods of experimentation which can replace aspects of animal testing.  The biggest advantage of such techniques is that they are far more relevant to human biological systems than animals are. In addition to this, adopting alternative research practices can save the lives of millions of animals every year. Such practices include cell and tissue culture, and computer modeling. (BUAV, Replacing Animal Experiments 1)

As computer systems become increasingly sophisticated, computer models can be used to predict the way the human body behaves when it is infected with disease, or exposed to drugs. For example, computers can be programmed with data about new drugs that is obtained using cell studies. These computers can then predict how the drug will be absorbed and transported around the body, and how it will be metabolized by various different organs.  These types of studies can replace experiments that are commonly conducted on dogs or monkeys. (BUAV, Replacing Animal Experiments 1) This is the type of approach that led to the development of successful protease inhibitors after the delay caused by the use of animal studies.

Many animal experiment models may be replaced by the use of cell cultures. Almost every type of human cell can be grown in culture, and such systems have been important in research in cancers, kidney disease, and AIDS. Cell culture-based experiments are used in chemical safety testing and drug development. In addition, cell cultures can replace animal systems which were once used to produce large amounts of vaccines and other medical treatments such as monoclonal antibodies. (BUAV, Replacing Animal Experiments 2) These types of systems can also replace the LD50 test which measures substance toxicity, and are much more accurate than animal-based tests. For example, an evaluation of animal tests compared to cell-based tests found that LD50 tests using rats were only 59% accurate, but that tests using human cell cultures were 83% accurate in the prediction of human toxicity. (PCRM par 6)


The ethics of using animals in medical experiments is open to interpretation. The scientists who use animals in experiments day after day can justify it to themselves and others because they genuinely believe the research is beneficial enough to override the morally dubious concept of exploiting animals for human benefit. But science itself gives us two important reasons which fail to justify it for many people – medical experiments that use animals are often misleading, and there are increasingly sophisticated technological advances being made that can replace the use of animals in experiments.

Animal experimentation is an integral part of medical science. However, it seems to be that this is in part due to it being a scientific institution rather than something which is of great benefit. Medical research has relied on animals and animal models for such a long time that some scientists, perhaps, are unable to see the benefits of alternative means of experimentation. Animal models have been used for decades, and they are familiar, and even if they are not specifically accurate when it comes to modeling human disease, they are at least predictable and well-characterized.

It may be that many of the new techniques that have the potential to replace animal experimentation are simply not-well known enough to be considered acceptable replacements for animal models that are considered more reliable. Hopefully, as these new techniques are used more often, they will be considered more acceptable. The key is that people must start using them so that they can become more familiar and more popular. Banning animal experimentation outright may be the only way of introducing these new techniques on a wide scale.

The evidence against animal experimentation is almost overwhelming. It cannot be denied that there have been situations in history where it has helped advance medical knowledge.  However, there are far too many instances where animal experimentation has slowed the progress of science for it to be thought that it is truly beneficial to science. Even one such instance is one too many. At best, it could be said that sometime it is beneficial to use animals in medical experiments and this is simply not enough. It is too risky to use animals as models for human diseases when there are ever more advanced technologies available to replace animal use.


Considering all the evidence, it is truly impossible to see how an ethical use of animals can be considered in medical experiments. How can we justify the suffering and killing of millions of people when the results are so often misleading, sometimes to the point where harm is caused to humans, animals worldwide every year?

The simple answer is that we can’t. Animal testing is not adequately efficient or secure, it is morally and ethically unethical and the number of healthy, accurate and reliable alternatives to this practice is growing. Animal experimentation must and should stop.

  • Booth, William. (1988) Chimps and Research: Endangered? Science 4867: 241, p 777.
  • British Union for the Abolition of Vivisection (BUAV). (2005). Replacing Animal Experiments.  Retrieved May 3, 2006 from <https://www.buav.org/resources/documents/B1-ReplacingAnimalExperiments.pdf>.
  • British Union for the Abolition of Vivisection (BUAV) FAQ. (2006). Retrieved May 3, 2006 from <https://www.buav.org/faqs.html>.
  • BBC. (2004) Does Animal Testing Work? Retrieved May 3, 2006 from <https://www.bbc.co.uk/science/hottopics/animalexperiments/index.shtml#for_against1>.
  • Jane Goodall Institute FAQ. Retreived May 3, 2006 from <https://www.janegoodall.org/about-jgi/faqs.asp#chimps3>.
  • Miller, S.R. (200.), Animal Research  The Humanist Sept. 2001: 15
  • Physicians Committee for Responsible Medicine (PCRM). (2005). Research Without Animals. Retrieved May 3, 2006 from <https://www.humaneseal.org/research.html>.
  • Tatchell. P, (2004) Why Animal Research Is Bad Science. New Statesman 9 Aug. 2004
  • The Chimpanzee Collaborartoy (2001). The Face of Change.  Retrieved May 3, 2006 from <https://www.glaserfoundation.org/program_areas/pdf/faceofchange1.pdf>
  • Threatened Chimps May Hold Key to AIDS. China Daily, June 2005.  Retrieved May 3, 2006 from <https://www.chinadaily.com.cn/english/doc/2005-06/10/content_450297.htm>.

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