Animal testing

A Wistar laboratory rat
Description	Around 50–100 million vertebrate animals are used in experiments annually.
Subjects	Animal testing, science, medicine, animal welfare, animal rights, ethics

Animal testing, also known as animal experimentation, animal research, and in vivo testing, is the use of non-human animals in experiments that seek to control the variables that affect the behavior or biological system under study. This approach can be contrasted with field studies in which animals are observed in their natural environments or habitats. Experimental research with animals is usually conducted in universities, medical schools, pharmaceutical companies, defense establishments, and commercial facilities that provide animal-testing services to the industry.^[1] The focus of animal testing varies on a continuum from pure research, focusing on developing fundamental knowledge of an organism, to applied research, which may focus on answering some questions of great practical importance, such as finding a cure for a disease.^[2] Examples of applied research include testing disease treatments, breeding, defense research, and toxicology, including cosmetics testing. In education, animal testing is sometimes a component of biology or psychology courses.^[3] The practice is regulated to varying degrees in different countries.^[4]

It was estimated in 2010 that the annual use of vertebrate animals—from zebrafish to non-human primates—ranges from tens to over 100 million.^[5] In the European Union, vertebrate species represent 93% of animals used in research,^[6] and 11.5 million animals were used there in 2011.^[7] By one estimate, the number of mice and rats used in the United States alone in 2001 was 80 million.^[8] In 2013, it was reported that mammals (mice and rats), fish, amphibians, and reptiles together accounted for over 85% of research animals.^[9] In 2022, a law was passed in the United States that eliminated the FDA requirement that all drugs be tested on animals.^[10]

Animal testing is regulated differently in different countries: in some cases it is strictly controlled while others have more relaxed regulations. There are ongoing debates about the ethics and necessity of animal testing. Proponents argue that it has led to significant advancements in medicine and other fields while opponents raise concerns about cruelty towards animals and question its effectiveness.^[11][12]

There are efforts underway to find alternatives to animal testing such as computer simulation models, organs-on-chips technology that mimics human organs for lab tests,^[13] microdosing techniques which involve administering small doses of test compounds to volunteers instead of animals for safety tests or drug screenings; positron emission tomography (PET) scans which allow scanning of the human brain without harming humans; comparative epidemiological studies among human populations; simulators and computer programs for teaching purposes; among others.^[14][15][16]

Animal testing can be inaccurate because experiments on animals do not always correctly mimic human body responses. ^[17]