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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. 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. Examples of applied research include testing disease treatments, breeding, defense research, and
toxicology Toxicology is a scientific discipline, overlapping with biology, chemistry, pharmacology, and medicine, that involves the study of the adverse effects of chemical substances on living organisms and the practice of diagnosing and treating expo ...
, including cosmetics testing. In education, animal testing is sometimes a component of biology or psychology courses. The practice is regulated to varying degrees in different countries. It was estimated in 2010 that the annual use of
vertebrate Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, ...
animals—from
zebrafish The zebrafish (''Danio rerio'') is a freshwater fish belonging to the minnow family ( Cyprinidae) of the order Cypriniformes. Native to South Asia, it is a popular aquarium fish, frequently sold under the trade name zebra danio (and thus often ...
to non-human
primates Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians (monkeys and apes, the latter including huma ...
—ranges from tens to over 100 million.Meredith Cohn (26 August 2010).
Alternatives to Animal Testing Gaining Ground
" ''The Baltimore Sun''.
In the
European Union The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been des ...
, vertebrate species represent 93% of animals used in research, and 11.5 million animals were used there in 2011. By one estimate, the number of mice and rats used in the United States alone in 2001 was 80 million.Carbone, Larry. (2004). What Animals Want: Expertise and Advocacy in Laboratory Animal Welfare Policy. In 2013 it was reported that mammals (mice and rats), fish, amphibians, and reptiles together accounted for over 85% of research animals.


Definitions

The terms ''animal testing, animal experimentation, animal research'', ''
in vivo Studies that are ''in vivo'' (Latin for "within the living"; often not italicized in English) are those in which the effects of various biological entities are tested on whole, living organisms or cells, usually animals, including humans, and ...
'' testing, and
vivisection Vivisection () is surgery conducted for experimental purposes on a living organism, typically animals with a central nervous system, to view living internal structure. The word is, more broadly, used as a pejorative catch-all term for experiment ...
have similar
denotation In linguistics and philosophy, the denotation of an expression is its literal meaning. For instance, the English word "warm" denotes the property of being warm. Denotation is contrasted with other aspects of meaning including connotation. For inst ...
s but different
connotation A connotation is a commonly understood cultural or emotional association that any given word or phrase carries, in addition to its explicit or literal meaning, which is its denotation. A connotation is frequently described as either positive o ...
s. Literally, "vivisection" means "live sectioning" of an animal, and historically referred only to experiments that involved the
dissection Dissection (from Latin ' "to cut to pieces"; also called anatomization) is the dismembering of the body of a deceased animal or plant to study its anatomical structure. Autopsy is used in pathology and forensic medicine to determine the cause o ...
of live animals. The term is occasionally used to refer pejoratively to any experiment using living animals; for example, the ''Encyclopædia Britannica'' defines "vivisection" as: "Operation on a living animal for experimental rather than healing purposes; more broadly, all experimentation on live animals",Croce, Pietro (1999). ''Vivisection or Science? An Investigation into Testing Drugs and Safeguarding Health''. Zed Books, . although dictionaries point out that the broader definition is "used only by people who are opposed to such work". The word has a negative connotation, implying torture, suffering, and death. The word "vivisection" is preferred by those opposed to this research, whereas scientists typically use the term "animal experimentation". The following text excludes as much as possible practices related to ''in vivo''
veterinary surgery Veterinary surgery is surgery performed on animals by veterinarians, whereby the procedures fall into three broad categories: orthopaedics (bones, joints, muscles), soft tissue surgery (skin, body cavities, cardiovascular system, GI/urogenital/ ...
, which is left to the discussion of
vivisection Vivisection () is surgery conducted for experimental purposes on a living organism, typically animals with a central nervous system, to view living internal structure. The word is, more broadly, used as a pejorative catch-all term for experiment ...
.


History

The earliest references to animal testing are found in the writings of the
Greeks The Greeks or Hellenes (; el, Έλληνες, ''Éllines'' ) are an ethnic group and nation indigenous to the Eastern Mediterranean and the Black Sea regions, namely Greece, Cyprus, Albania, Italy, Turkey, Egypt, and, to a lesser extent, oth ...
in the 2nd and 4th centuries BCE.
Aristotle Aristotle (; grc-gre, Ἀριστοτέλης ''Aristotélēs'', ; 384–322 BC) was a Greek philosopher and polymath during the Classical period in Ancient Greece. Taught by Plato, he was the founder of the Peripatetic school of phil ...
and
Erasistratus Erasistratus (; grc-gre, Ἐρασίστρατος; c. 304 – c. 250 BC) was a Greek anatomist and royal physician under Seleucus I Nicator of Syria. Along with fellow physician Herophilus, he founded a school of anatomy in Alexandria, where the ...
were among the first to perform experiments on living animals.
Galen Aelius Galenus or Claudius Galenus ( el, Κλαύδιος Γαληνός; September 129 – c. AD 216), often Anglicized as Galen () or Galen of Pergamon, was a Greek physician, surgeon and philosopher in the Roman Empire. Considered to be one of ...
, a 2nd-century Roman physician, performed ''
post-mortem An autopsy (post-mortem examination, obduction, necropsy, or autopsia cadaverum) is a surgical procedure that consists of a thorough examination of a corpse by dissection to determine the cause, mode, and manner of death or to evaluate any dis ...
'' dissections of pigs and goats.
Avenzoar Abū Marwān ‘Abd al-Malik ibn Zuhr ( ar, أبو مروان عبد الملك بن زهر), traditionally known by his Latinized name Avenzoar (; 1094–1162), was an Arab physician, surgeon, and poet. He was born at Seville in medieval An ...
, a 12th-century Arabic physician in
Moorish Spain Al-Andalus translit. ; an, al-Andalus; ast, al-Ándalus; eu, al-Andalus; ber, ⴰⵏⴷⴰⵍⵓⵙ, label= Berber, translit=Andalus; ca, al-Àndalus; gl, al-Andalus; oc, Al Andalús; pt, al-Ândalus; es, al-Ándalus () was the Mu ...
introduced an experimental method of testing surgical procedures before applying them to human patients. Animals have repeatedly been used throughout the history of biomedical research. In 1831, the founders of the
Dublin Zoo Dublin Zoo ( ga, Zú Bhaile Átha Cliath), in Phoenix Park, Dublin, is a zoo in Ireland, and one of Dublin's most popular attractions. Established and designed in 1830 by Decimus Burton, it opened the following year. Today it focuses on conserv ...
were members of the medical profession who were interested in studying animals while they were alive and when they were dead. In the 1880s,
Louis Pasteur Louis Pasteur (, ; 27 December 1822 – 28 September 1895) was a French chemist and microbiologist renowned for his discoveries of the principles of vaccination, microbial fermentation and pasteurization, the latter of which was named afte ...
convincingly showed the
germ theory The germ theory of disease is the currently accepted scientific theory for many diseases. It states that microorganisms known as pathogens or "germs" can lead to disease. These small organisms, too small to be seen without magnification, invade ...
of medicine by inducing
anthrax Anthrax is an infection caused by the bacterium ''Bacillus anthracis''. It can occur in four forms: skin, lungs, intestinal, and injection. Symptom onset occurs between one day and more than two months after the infection is contracted. The sk ...
in sheep. In the 1880s,
Robert Koch Heinrich Hermann Robert Koch ( , ; 11 December 1843 – 27 May 1910) was a German physician and microbiologist. As the discoverer of the specific causative agents of deadly infectious diseases including tuberculosis, cholera (though the Vibrio ...
infected mice and guinea pigs with anthrax and
tuberculosis Tuberculosis (TB) is an infectious disease usually caused by '' Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, in ...
. In the 1890s,
Ivan Pavlov Ivan Petrovich Pavlov ( rus, Ива́н Петро́вич Па́влов, , p=ɪˈvan pʲɪˈtrovʲɪtɕ ˈpavləf, a=Ru-Ivan_Petrovich_Pavlov.ogg; 27 February 1936), was a Russian and Soviet experimental neurologist, psychologist and physiol ...
famously used dogs to describe
classical conditioning Classical conditioning (also known as Pavlovian or respondent conditioning) is a behavioral procedure in which a biologically potent stimulus (e.g. food) is paired with a previously neutral stimulus (e.g. a triangle). It also refers to the learni ...
. In World War I, German agents infected sheep bound for Russia with
anthrax Anthrax is an infection caused by the bacterium ''Bacillus anthracis''. It can occur in four forms: skin, lungs, intestinal, and injection. Symptom onset occurs between one day and more than two months after the infection is contracted. The sk ...
, and inoculated mules and horses of the French cavalry with the equine
glanders Glanders is a contagious zoonotic infectious disease that occurs primarily in horses, mules, and donkeys. It can be contracted by other animals, such as dogs, cats, pigs, goats, and humans. It is caused by infection with the bacterium ''Burkhol ...
disease. Between 1917 and 1918, the Germans infected mules in Argentina bound for American forces, resulting in the death of 200 mules.
Insulin Insulin (, from Latin ''insula'', 'island') is a peptide hormone produced by beta cells of the pancreatic islets encoded in humans by the ''INS'' gene. It is considered to be the main anabolic hormone of the body. It regulates the metabolism o ...
was first isolated from dogs in 1922, and later revolutionized the treatment of
diabetes Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ap ...
. On 3 November 1957, a Soviet dog,
Laika Laika (russian: link=no, Лайка; – 3 November 1957) was a Soviet space dog who was one of the first animals in space and the first to orbit the Earth. A stray mongrel from the streets of Moscow, she flew aboard the Sputnik 2 spacecra ...
, became the first of many animals to orbit the earth. In the 1970s, antibiotic treatments and vaccines for
leprosy Leprosy, also known as Hansen's disease (HD), is a long-term infection by the bacteria ''Mycobacterium leprae'' or ''Mycobacterium lepromatosis''. Infection can lead to damage of the nerves, respiratory tract, skin, and eyes. This nerve damag ...
were developed using armadillos, then given to humans. The ability of humans to change the
genetics Genetics is the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinian friar wor ...
of animals took an enormous step forward in 1974 when
Rudolf Jaenisch Rudolf Jaenisch (born April 22, 1942) is a Professor of Biology at MIT and a founding member of the Whitehead Institute for Biomedical Research. He is a pioneer of transgenic science, in which an animal’s genetic makeup is altered. Jaenisch h ...
could produce the first transgenic mammal, by integrating DNA from
simians The simians, anthropoids, or higher primates are an infraorder (Simiiformes ) of primates containing all animals traditionally called monkeys and apes. More precisely, they consist of the parvorders New World monkeys (Platyrrhini) and Catarrhi ...
into the
genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding ge ...
of mice. This genetic research progressed rapidly and, in 1996,
Dolly the sheep Dolly (5 July 1996 – 14 February 2003) was a female Finnish Dorset sheep and the first mammal cloned from an adult somatic cell. She was cloned by associates of the Roslin Institute in Scotland, using the process of nuclear transfer from a ...
was born, the first mammal to be
cloned Cloning is the process of producing individual organisms with identical or virtually identical DNA, either by natural or artificial means. In nature, some organisms produce clones through asexual reproduction. In the field of biotechnology, c ...
from an adult cell.
Toxicology Toxicology is a scientific discipline, overlapping with biology, chemistry, pharmacology, and medicine, that involves the study of the adverse effects of chemical substances on living organisms and the practice of diagnosing and treating expo ...
testing became important in the 20th century. In the 19th century, laws regulating drugs were more relaxed. For example, in the US, the government could only ban a drug after they had prosecuted a company for selling products that harmed customers. However, in response to the
Elixir Sulfanilamide disaster Elixir sulfanilamide was an improperly prepared sulfonamide (medicine), sulfonamide antibiotic that caused mass poisoning in the United States in 1937. It is believed to have killed more than 100 people. The public outcry caused by this incident a ...
of 1937 in which the eponymous drug killed over 100 users, the US Congress passed laws that required safety testing of drugs on animals before they could be marketed. Other countries enacted similar legislation. In the 1960s, in reaction to the
Thalidomide Thalidomide, sold under the brand names Contergan and Thalomid among others, is a medication used to treat a number of cancers (including multiple myeloma), graft-versus-host disease, and a number of skin conditions including complications of ...
tragedy, further laws were passed requiring safety testing on pregnant animals before a drug can be sold.


Historical debate

As the experimentation on animals increased, especially the practice of vivisection, so did criticism and controversy. In 1655, the advocate of
Galen Aelius Galenus or Claudius Galenus ( el, Κλαύδιος Γαληνός; September 129 – c. AD 216), often Anglicized as Galen () or Galen of Pergamon, was a Greek physician, surgeon and philosopher in the Roman Empire. Considered to be one of ...
ic physiology
Edmund O'Meara Edmund O'Meara ( ga, Éamonn Ó Meadhra, also known as Edmund Meara; 1614–1681) was an Irish physiologist and one of the last prominent champions of the medical ideas of Galen. Son of Dermod O'Meara who was a physician, poet and author. O'Meara i ...
said that "the miserable torture of vivisection places the body in an unnatural state". Ryder, Richard D. (2000). ''Animal Revolution: Changing Attitudes Towards Speciesism''. Berg Publishers, p. 54 ."Animal Experimentation: A Student Guide to Balancing the Issues"
Australian and New Zealand Council for the Care of Animals in Research and Teaching (ANZCCART), accessed 12 December 2007, cites original reference in Maehle, A-H. and Tr6hler, U. ''Animal experimentation from antiquity to the end of the eighteenth century: attitudes and arguments''. In N. A. Rupke (ed.) Vivisection in Historical Perspective. Croom Helm, London, 1987, p. 22.
O'Meara and others argued pain could affect animal physiology during vivisection, rendering results unreliable. There were also objections ethically, contending that the benefit to humans did not justify the harm to animals. Early objections to animal testing also came from another angle—many people believed animals were inferior to humans and so different that results from animals could not be applied to humans. On the other side of the debate, those in favor of animal testing held that experiments on animals were necessary to advance medical and biological knowledge.
Claude Bernard Claude Bernard (; 12 July 1813 – 10 February 1878) was a French physiologist. Historian I. Bernard Cohen of Harvard University called Bernard "one of the greatest of all men of science". He originated the term ''milieu intérieur'', and the a ...
—who is sometimes known as the "prince of vivisectors"Croce, Pietro. ''Vivisection or Science? An Investigation into Testing Drugs and Safeguarding Health''. Zed Books, 1999, p. 11. and the father of physiology, and whose wife, Marie Françoise Martin, founded the first anti-vivisection society in France in 1883—famously wrote in 1865 that "the science of life is a superb and dazzlingly lighted hall which may be reached only by passing through a long and ghastly kitchen"."In sickness and in health: vivisection's undoing"
''The Daily Telegraph'', November 2003
Arguing that "experiments on animals are entirely conclusive for the
toxicology Toxicology is a scientific discipline, overlapping with biology, chemistry, pharmacology, and medicine, that involves the study of the adverse effects of chemical substances on living organisms and the practice of diagnosing and treating expo ...
and hygiene of man effects of these substances are the same on man as on animals, save for differences in degree", Bernard established animal experimentation as part of the standard
scientific method The scientific method is an empirical method for acquiring knowledge that has characterized the development of science since at least the 17th century (with notable practitioners in previous centuries; see the article history of scientific m ...
.LaFollette, H., Shanks, N.
Animal Experimentation: the Legacy of Claude Bernard
, ''International Studies in the Philosophy of Science'' (1994) pp. 195–210.
In 1896, the physiologist and physician Dr. Walter B. Cannon said "The antivivisectionists are the second of the two types Theodore Roosevelt described when he said, 'Common sense without conscience may lead to crime, but conscience without common sense may lead to folly, which is the handmaiden of crime. These divisions between pro- and anti-animal testing groups first came to public attention during the
Brown Dog affair The Brown Dog affair was a political controversy about vivisection that raged in Britain from 1903 until 1910. It involved the infiltration of University of London medical lectures by Swedish feminists, battles between medical students and the ...
in the early 1900s, when hundreds of medical students clashed with anti-vivisectionists and police over a memorial to a vivisected dog.Mason, Peter
''The Brown Dog Affair''
. Two Sevens Publishing, 1997.
In 1822, the first animal protection law was enacted in the British parliament, followed by the Cruelty to Animals Act (1876), the first law specifically aimed at regulating animal testing. The legislation was promoted by
Charles Darwin Charles Robert Darwin ( ; 12 February 1809 – 19 April 1882) was an English naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended fr ...
, who wrote to
Ray Lankester Sir Edwin Ray Lankester (15 May 1847 – 13 August 1929) was a British zoologist.New International Encyclopaedia. An invertebrate zoologist and evolutionary biologist, he held chairs at University College London and Oxford University. He was th ...
in March 1871: "You ask about my opinion on vivisection. I quite agree that it is justifiable for proper investigations on physiology; but not for mere damnable and detestable curiosity. It is a subject which makes me sick with horror, so I will not say another word about it, else I shall not sleep to-night." In response to the lobbying by anti-vivisectionists, several organizations were set up in Britain to defend animal research:
The Physiological Society The Physiological Society, founded in 1876, is a learned society for physiologists Physiology (; ) is the scientific study of functions and mechanisms in a living system. As a sub-discipline of biology, physiology focuses on how organism ...
was formed in 1876 to give physiologists "mutual benefit and protection", the Association for the Advancement of Medicine by Research was formed in 1882 and focused on policy-making, and the
Research Defence Society The Research Defence Society was a British scientific society and lobby group, founded by Stephen Paget, in 1908, to fight against the anti-vivisectionist "enemies of reason" at the beginning of the 20th century. At the end of 2008, after being a ...
(now
Understanding Animal Research Understanding Animal Research (UAR) is a British membership organisation formed in late 2008 through the merger of the Research Defence Society and the Coalition for Medical Progress. Its main aims are to "explain why animals are used in medical ...
) was formed in 1908 "to make known the facts as to experiments on animals in this country; the immense importance to the welfare of mankind of such experiments and the great saving of human life and health directly attributable to them". Opposition to the use of animals in medical research first arose in the United States during the 1860s, when
Henry Bergh Henry Bergh (August 29, 1813 – March 12, 1888) founded the American Society for the Prevention of Cruelty to Animals (ASPCA) in April, 1866, three days after the first effective legislation against animal cruelty in the United States was passed ...
founded the
American Society for the Prevention of Cruelty to Animals The American Society for the Prevention of Cruelty to Animals (ASPCA) is a non-profit organization dedicated to preventing animal cruelty. Based in New York City since its inception in 1866, the organization's mission is "to provide effective mea ...
(ASPCA), with America's first specifically anti-vivisection organization being the American AntiVivisection Society (AAVS), founded in 1883. Antivivisectionists of the era generally believed the spread of mercy was the great cause of civilization, and vivisection was cruel. However, in the USA the antivivisectionists' efforts were defeated in every legislature, overwhelmed by the superior organization and influence of the medical community. Overall, this movement had little legislative success until the passing of the
Laboratory Animal Welfare Act The Animal Welfare Act (Laboratory Animal Welfare Act of 1966, ) was signed into law by President Lyndon B. Johnson on August 24, 1966. It is the main federal law in the United States that regulates the treatment of animals in research and exhibi ...
, in 1966.


Care and use of animals


Regulations and laws

The regulations that apply to animals in laboratories vary across species. In the U.S., under the Animal Welfare Act and the ''Guide for the Care and Use of Laboratory Animals'' (the ''Guide''), published by the National Academy of Sciences, any procedure can be performed on an animal if it can be successfully argued that it is scientifically justified. Researchers are required to consult with the institution's veterinarian and its
Institutional Animal Care and Use Committee Institutional Animal Care and Use Committees (IACUCs) are centrally important in applying laws about animal research in the United States. Similar systems operate in other countries, but generally under different titles; for example, in Canada a t ...
(IACUC), which every research facility is obliged to maintain.Carbone, pp. 68–69. The IACUC must ensure that alternatives, including non-animal alternatives, have been considered, that the experiments are not unnecessarily duplicative, and that pain relief is given unless it would interfere with the study. The IACUCs regulate all vertebrates in testing at institutions receiving federal funds in the USA. Although the Animal Welfare Act does not include purpose-bred rodents and birds, these species are equally regulated under Public Health Service policies that govern the IACUCs. The Public Health Service policy oversees the Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC). The CDC conducts infectious disease research on nonhuman primates, rabbits, mice, and other animals, while FDA requirements cover use of animals in pharmaceutical research. Animal Welfare Act (AWA) regulations are enforced by the USDA, whereas Public Health Service regulations are enforced by OLAW and in many cases by AAALAC. According to the 2014 U.S. Department of Agriculture Office of the Inspector General (OIG) report—which looked at the oversight of animal use during a three-year period—"some Institutional Animal Care and Use Committees ...did not adequately approve, monitor, or report on experimental procedures on animals". The OIG found that "as a result, animals are not always receiving basic humane care and treatment and, in some cases, pain and distress are not minimized during and after experimental procedures". According to the report, within a three-year period, nearly half of all American laboratories with regulated species were cited for AWA violations relating to improper IACUC oversight. The USDA OIG made similar findings in a 2005 report. With only a broad number of 120 inspectors, the United States Department of Agriculture (USDA) oversees more than 12,000 facilities involved in research, exhibition, breeding, or dealing of animals. Others have criticized the composition of IACUCs, asserting that the committees are predominantly made up of animal researchers and university representatives who may be biased against animal welfare concerns. Larry Carbone, a laboratory animal veterinarian, writes that, in his experience, IACUCs take their work very seriously regardless of the species involved, though the use of
non-human primates Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians (monkeys and apes, the latter including huma ...
always raises what he calls a "red flag of special concern". A study published in ''Science'' magazine in July 2001 confirmed the low reliability of IACUC reviews of animal experiments. Funded by the National Science Foundation, the three-year study found that animal-use committees that do not know the specifics of the university and personnel do not make the same approval decisions as those made by animal-use committees that do know the university and personnel. Specifically, blinded committees more often ask for more information rather than approving studies. Scientists in India are protesting a recent guideline issued by the University Grants Commission to ban the use of live animals in universities and laboratories.


Numbers

Accurate global figures for animal testing are difficult to obtain; it has been estimated that 100 million vertebrates are experimented on around the world every year, 10–11 million of them in the EU. The
Nuffield Council on Bioethics The Nuffield Council on Bioethics is a UK-based independent charitable body, which examines and reports on bioethical issues raised by new advances in biological and medical research. Established in 1991, the Council is funded by the Nuffield F ...
reports that global annual estimates range from 50 to 100 million animals. None of the figures include invertebrates such as shrimp and fruit flies. The USDA/APHIS has published the 2016 animal research statistics. Overall, the number of animals (covered by the Animal Welfare Act) used in research in the US rose 6.9% from 767,622 (2015) to 820,812 (2016). This includes both public and private institutions. By comparing with EU data, where all
vertebrate Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, ...
species are counted,
Speaking of Research Speaking of Research (SR) is an international group which "aims to provide accurate information about the importance of animal research in medical and veterinary science". It was founded in March 2008 by Tom Holder, an "energetic young British ac ...
estimated that around 12 million vertebrates were used in research in the US in 2016. A 2015 article published in the ''
Journal of Medical Ethics The ''Journal of Medical Ethics'' is a monthly peer-reviewed academic journal covering the field of bioethics that was established in 1975. According to the ''Journal Citation Reports'', the journal has a 2019 impact factor of 2.021, ranking it fou ...
'', argued that the use of animals in the US has dramatically increased in recent years. Researchers found this increase is largely the result of an increased reliance on genetically modified mice in animal studies. In 1995, researchers at Tufts University Center for Animals and Public Policy estimated that 14–21 million animals were used in American laboratories in 1992, a reduction from a high of 50 million used in 1970. In 1986, the U.S. Congress Office of Technology Assessment reported that estimates of the animals used in the U.S. range from 10 million to upwards of 100 million each year, and that their own best estimate was at least 17 million to 22 million. In 2016, the Department of Agriculture listed 60,979 dogs, 18,898 cats, 71,188 non-human primates, 183,237 guinea pigs, 102,633 hamsters, 139,391 rabbits, 83,059 farm animals, and 161,467 other mammals, a total of 820,812, a figure that includes all mammals except purpose-bred mice and rats. The use of dogs and cats in research in the U.S. decreased from 1973 to 2016 from 195,157 to 60,979, and from 66,165 to 18,898, respectively. In the UK, Home Office figures show that 3.79 million procedures were carried out in 2017. 2,960 procedures used non-human primates, down over 50% since 1988. A "procedure" refers here to an experiment that might last minutes, several months, or years. Most animals are used in only one procedure: animals are frequently euthanized after the experiment; however death is the endpoint of some procedures. The procedures conducted on animals in the UK in 2017 were categorised as – *43% (1.61 million) were assessed as sub-threshold *4% (0.14 million) were assessed as non-recovery *36% (1.35 million) were assessed as mild *15% (0.55 million) were assessed as moderate *4% (0.14 million) were assessed as severe A 'severe' procedure would be, for instance, any test where death is the end-point or fatalities are expected, whereas a 'mild' procedure would be something like a blood test or an MRI scan.


The Three Rs

The Three Rs (3Rs) are guiding principles for more ethical use of animals in testing. These were first described by W.M.S. Russell and R.L. Burch in 1959. The 3Rs state: #Replacement which refers to the preferred use of non-animal methods over animal methods whenever it is possible to achieve the same scientific aims. These methods include computer modeling. #Reduction which refers to methods that enable researchers to obtain comparable levels of information from fewer animals, or to obtain more information from the same number of animals. #Refinement which refers to methods that alleviate or minimize potential pain, suffering or distress, and enhance animal welfare for the animals used. These methods include non-invasive techniques. The 3Rs have a broader scope than simply encouraging alternatives to animal testing, but aim to improve animal welfare and scientific quality where the use of animals can not be avoided. These 3Rs are now implemented in many testing establishments worldwide and have been adopted by various pieces of legislation and regulations. Despite the widespread acceptance of the 3Rs, many countries—including Canada, Australia, Israel, South Korea, and Germany—have reported rising experimental use of animals in recent years with increased use of mice and, in some cases, fish while reporting declines in the use of cats, dogs, primates, rabbits, guinea pigs, and hamsters. Along with other countries, China has also escalated its use of GM animals, resulting in an increase in overall animal use.


Invertebrates

Although many more invertebrates than vertebrates are used in animal testing, these studies are largely unregulated by law. The most frequently used invertebrate species are ''
Drosophila melanogaster ''Drosophila melanogaster'' is a species of fly (the taxonomic order Diptera) in the family Drosophilidae. The species is often referred to as the fruit fly or lesser fruit fly, or less commonly the "vinegar fly" or "pomace fly". Starting with Ch ...
'', a fruit fly, and ''
Caenorhabditis elegans ''Caenorhabditis elegans'' () is a free-living transparent nematode about 1 mm in length that lives in temperate soil environments. It is the type species of its genus. The name is a blend of the Greek ''caeno-'' (recent), ''rhabditis'' (ro ...
'', a
nematode The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-Parasitism, parasitic nematodes also known as eelworms. They are a diverse animal phylum inhab ...
worm. In the case of ''C. elegans'', the worm's body is completely transparent and the precise lineage of all the organism's cells is known, while studies in the fly ''D. melanogaster'' can use an amazing array of genetic tools. These invertebrates offer some advantages over vertebrates in animal testing, including their short life cycle and the ease with which large numbers may be housed and studied. However, the lack of an adaptive
immune system The immune system is a network of biological processes that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as cancer cells and objects such as wood splinte ...
and their simple organs prevent worms from being used in several aspects of medical research such as vaccine development. Similarly, the fruit fly
immune system The immune system is a network of biological processes that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as cancer cells and objects such as wood splinte ...
differs greatly from that of humans, and diseases in insects can be different from diseases in vertebrates; however, fruit flies and
waxworms Waxworms are the caterpillar larvae of wax moths, which belong to the family Pyralidae (snout moths). Two closely related species are commercially bred – the lesser wax moth (''Achroia grisella'') and the greater wax moth (''Galleria m ...
can be useful in studies to identify novel virulence factors or pharmacologically active compounds. Several invertebrate systems are considered acceptable alternatives to vertebrates in early-stage discovery screens. Because of similarities between the innate immune system of insects and mammals, insects can replace mammals in some types of studies. ''Drosophila melanogaster'' and the ''
Galleria mellonella ''Galleria mellonella'', the greater wax moth or honeycomb moth, is a moth of the family Pyralidae. ''G. mellonella'' is found throughout the world. It is one of two species of wax moths, with the other being the lesser wax moth. ''G. mellonella' ...
'' waxworm have been particularly important for analysis of virulence traits of mammalian pathogens. Waxworms and other insects have also proven valuable for the identification of pharmaceutical compounds with favorable bioavailability. The decision to adopt such models generally involves accepting a lower degree of biological similarity with mammals for significant gains in experimental throughput.


Vertebrates

In the U.S., the numbers of rats and mice used is estimated to be from 11 million to between 20 and 100 million a year. Other rodents commonly used are guinea pigs, hamsters, and gerbils. Mice are the most commonly used vertebrate species because of their size, low cost, ease of handling, and fast reproduction rate. Mice are widely considered to be the best model of inherited human disease and share 95% of their
gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...
s with humans. With the advent of
genetic engineering Genetic engineering, also called genetic modification or genetic manipulation, is the modification and manipulation of an organism's genes using technology. It is a set of technologies used to change the genetic makeup of cells, including t ...
technology, genetically modified mice can be generated to order and can provide models for a range of human diseases. Rats are also widely used for physiology, toxicology and cancer research, but genetic manipulation is much harder in rats than in mice, which limits the use of these rodents in basic science. Over 500,000 fish and 9,000 amphibians were used in the UK in 2016. The main species used is the zebrafish, ''
Danio rerio The zebrafish (''Danio rerio'') is a freshwater fish belonging to the minnow family (Cyprinidae) of the order Cypriniformes. Native to South Asia, it is a popular aquarium fish, frequently sold under the trade name zebra danio (and thus often ...
'', which are translucent during their embryonic stage, and the African clawed frog, ''
Xenopus laevis The African clawed frog (''Xenopus laevis'', also known as the xenopus, African clawed toad, African claw-toed frog or the ''platanna'') is a species of African aquatic frog of the family Pipidae. Its name is derived from the three short claws ...
''. Over 20,000 rabbits were used for animal testing in the UK in 2004.
Albino Albinism is the congenital absence of melanin in an animal or plant resulting in white hair, feathers, scales and skin and pink or blue eyes. Individuals with the condition are referred to as albino. Varied use and interpretation of the term ...
rabbits are used in eye irritancy tests (
Draize test The Draize test is an acute toxicity test devised in 1944 by Food and Drug Administration (FDA) toxicologists John H. Draize and Jacob M. Spines. Initially used for testing cosmetics, the procedure involves applying 0.5 mL or 0.5 g of ...
) because rabbits have less tear flow than other animals, and the lack of eye pigment in albinos make the effects easier to visualize. The numbers of rabbits used for this purpose has fallen substantially over the past two decades. In 1996, there were 3,693 procedures on rabbits for eye irritation in the UK, and in 2017 this number was just 63. Rabbits are also frequently used for the production of polyclonal antibodies.


Cats

Cats are most commonly used in neurological research. In 2016, 18,898 cats were used in the United States alone, around a third of which were used in experiments which have the potential to cause "pain and/or distress" though only 0.1% of cat experiments involved potential pain which was not relieved by anesthetics/analgesics. In the UK, just 198 procedures were carried out on cats in 2017. The number has been around 200 for most of the last decade.


Dogs

Dogs are widely used in biomedical research, testing, and education—particularly
beagle The beagle is a breed of small scent hound, similar in appearance to the much larger foxhound. The beagle was developed primarily for hunting hare, known as beagling. Possessing a great sense of smell and superior tracking instincts, the ...
s, because they are gentle and easy to handle, and to allow for comparisons with historical data from beagles (a Reduction technique). They are used as models for human and veterinary diseases in cardiology,
endocrinology Endocrinology (from '' endocrine'' + '' -ology'') is a branch of biology and medicine dealing with the endocrine system, its diseases, and its specific secretions known as hormones. It is also concerned with the integration of developmental event ...
, and bone and joint studies, research that tends to be highly invasive, according to the
Humane Society of the United States The Humane Society of the United States (HSUS) is an American nonprofit organization that focuses on animal welfare and opposes animal-related cruelties of national scope. It uses strategies that are beyond the abilities of local organizations. ...
.Dog profile
The Humane Society of the United States
The most common use of dogs is in the safety assessment of new medicines for human or veterinary use as a second species following testing in rodents, in accordance with the regulations set out in the
International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use The International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) is an initiative that brings together regulatory authorities and pharmaceutical industry to discuss scientific and technical aspects of pha ...
. One of the most significant advancements in medical science involves the use of dogs in developing the answers to insulin production in the body for diabetics and the role of the pancreas in this process. They found that the pancreas was responsible for producing insulin in the body and that removal of the pancreas, resulted in the development of diabetes in the dog. After re-injecting the pancreatic extract, (insulin), the blood glucose levels were significantly lowered. The advancements made in this research involving the use of dogs has resulted in a definite improvement in the quality of life for both humans and animals. The U.S. Department of Agriculture's Animal Welfare Report shows that 60,979 dogs were used in USDA-registered facilities in 2016. In the UK, according to the UK Home Office, there were 3,847 procedures on dogs in 2017. Of the other large EU users of dogs, Germany conducted 3,976 procedures on dogs in 2016 and France conducted 4,204 procedures in 2016. In both cases this represents under 0.2% of the total number of procedures conducted on animals in the respective countries.


Zebrafish

Zebrafish The zebrafish (''Danio rerio'') is a freshwater fish belonging to the minnow family ( Cyprinidae) of the order Cypriniformes. Native to South Asia, it is a popular aquarium fish, frequently sold under the trade name zebra danio (and thus often ...
are commonly used for the basic study and development of various
cancer Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...
s. Used to explore the immune system and genetic strains. They are low in cost, small size, fast reproduction rate, and able to observe cancer cells in real time. Humans and Zebrafish share
neoplasm A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...
similarities which is why they are used for research. The National Library of Medicine shows many examples of the types of cancer Zebrafish are used in. The use of Zebrafish have allowed them to find differences between MYC-driven pre-B vs T-ALL and be exploited to discover novel pre-B ALL therapies on Acute lymphocytic
leukemia Leukemia ( also spelled leukaemia and pronounced ) is a group of blood cancers that usually begin in the bone marrow and result in high numbers of abnormal blood cells. These blood cells are not fully developed and are called ''blasts'' or ' ...
. The National Library of Medicine also explains how a neoplasm is difficult to diagnose at an early stage. Understanding the molecular mechanism of digestive tract tumorigenesis and searching for new treatments is the current research. Zebrafish and humans share similar gastric cancer cells in the gastric cancer xenotransplantation model. This allowed researchers to find that Triphala could inhibit the growth and metastasis of gastric cancer cells. Since zebrafish liver cancer genes are related with humans they have become widely used in liver cancer search, as will as many other cancers.


Non-human primates

Non-human primates (NHPs) are used in toxicology tests, studies of AIDS and hepatitis, studies of
neurology Neurology (from el, wikt:νεῦρον, νεῦρον (neûron), "string, nerve" and the suffix wikt:-logia, -logia, "study of") is the branch of specialty (medicine), medicine dealing with the diagnosis and treatment of all categories of co ...
, behavior and cognition, reproduction,
genetics Genetics is the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinian friar wor ...
, and
xenotransplantation Xenotransplantation (''xenos-'' from the Greek meaning "foreign" or strange), or heterologous transplant, is the transplantation of living cells, tissues or organs from one species to another. Such cells, tissues or organs are called xenograft ...
. They are caught in the wild or purpose-bred. In the United States and China, most primates are domestically purpose-bred, whereas in Europe the majority are imported purpose-bred. The
European Commission The European Commission (EC) is the executive of the European Union (EU). It operates as a cabinet government, with 27 members of the Commission (informally known as "Commissioners") headed by a President. It includes an administrative body o ...
reported that in 2011, 6,012 monkeys were experimented on in European laboratories. According to the
U.S. Department of Agriculture The United States Department of Agriculture (USDA) is the federal executive department responsible for developing and executing federal laws related to farming, forestry, rural economic development, and food. It aims to meet the needs of com ...
, there were 71,188 monkeys in U.S. laboratories in 2016. 23,465 monkeys were imported into the U.S. in 2014 including 929 who were caught in the wild. Most of the NHPs used in experiments are
macaque The macaques () constitute a genus (''Macaca'') of gregarious Old World monkeys of the subfamily Cercopithecinae. The 23 species of macaques inhabit ranges throughout Asia, North Africa, and (in one instance) Gibraltar. Macaques are principally ...
s; but
marmoset The marmosets (), also known as zaris or sagoin, are 22 New World monkey species of the genera ''Callithrix'', ''Cebuella'', ''Callibella'', and ''Mico''. All four genera are part of the biological family Callitrichidae. The term "marmoset" is ...
s,
spider monkey Spider monkeys are New World monkeys belonging to the genus ''Ateles'', part of the subfamily Atelinae, family Atelidae. Like other atelines, they are found in tropical forests of Central and South America, from southern Mexico to Brazil. The g ...
s, and
squirrel monkey Squirrel monkeys are New World monkeys of the genus ''Saimiri''. ''Saimiri'' is the only genus in the subfamily Saimirinae. The name of the genus is of Tupi origin (''sai-mirím'' or ''çai-mbirín'', with ''sai'' meaning 'monkey' and ''mirím'' ...
s are also used, and
baboon Baboons are primates comprising the genus ''Papio'', one of the 23 genera of Old World monkeys. There are six species of baboon: the hamadryas baboon, the Guinea baboon, the olive baboon, the yellow baboon, the Kinda baboon and the chacma ba ...
s and
chimpanzee The chimpanzee (''Pan troglodytes''), also known as simply the chimp, is a species of great ape native to the forest and savannah of tropical Africa. It has four confirmed subspecies and a fifth proposed subspecies. When its close relative th ...
s are used in the US. , there are approximately 730 chimpanzees in U.S. laboratories. In a survey in 2003, it was found that 89% of singly-housed primates exhibited self-injurious or abnormal
stereotypy A stereotypy (, or ) is a repetitive or ritualistic movement, posture, or utterance. Stereotypies may be simple movements such as body rocking, or complex, such as self-caressing, crossing and uncrossing of legs, and marching in place. They are ...
ical behaviors including pacing, rocking, hair pulling, and biting among others. The first transgenic primate was produced in 2001, with the development of a method that could introduce new genes into a
rhesus macaque The rhesus macaque (''Macaca mulatta''), colloquially rhesus monkey, is a species of Old World monkey. There are between six and nine recognised subspecies that are split between two groups, the Chinese-derived and the Indian-derived. Generally b ...
. This transgenic technology is now being applied in the search for a treatment for the
genetic disorder A genetic disorder is a health problem caused by one or more abnormalities in the genome. It can be caused by a mutation in a single gene (monogenic) or multiple genes (polygenic) or by a chromosomal abnormality. Although polygenic disorders ...
Huntington's disease Huntington's disease (HD), also known as Huntington's chorea, is a neurodegenerative disease that is mostly inherited. The earliest symptoms are often subtle problems with mood or mental abilities. A general lack of coordination and an unst ...
. Notable studies on non-human primates have been part of the polio vaccine development, and development of
Deep Brain Stimulation Deep brain stimulation (DBS) is a neurosurgical procedure involving the placement of a medical device called a neurostimulator, which sends electrical impulses, through implanted electrodes, to specific targets in the brain (the brain nucleu ...
, and their current heaviest non-toxicological use occurs in the monkey AIDS model, SIV.Kathleen M. Conlee, Erika H. Hoffeld and Martin L. Stephens (2004
Demographic Analysis of Primate Research in the United States
''ATLA'' 32, Supplement 1, 315–22
In 2008 a proposal to ban all primates experiments in the EU has sparked a vigorous debate.


Sources

Animals used by laboratories are largely supplied by specialist dealers. Sources differ for vertebrate and invertebrate animals. Most laboratories breed and raise flies and worms themselves, using strains and mutants supplied from a few main stock centers. For vertebrates, sources include breeders and dealers like
Covance Labcorp Drug Development is a contract research organization (CRO) headquartered in Burlington, North Carolina, providing nonclinical, preclinical, clinical and commercialization services to pharmaceutical and biotechnology industries. Formerly ...
and
Charles River Laboratories Charles River Laboratories International, Inc., is an American pharmaceutical company specializing in a variety of preclinical and clinical laboratory, gene therapy and cell therapy services for the Pharmaceutical, Medical device and Biotechnolo ...
who supply purpose-bred and wild-caught animals; businesses that trade in wild animals such as
Nafovanny Nafovanny in Vietnam is the largest captive-breeding primate facility in the world, supplying long-tailed macaques (''Macaca fascicularis'') to animal testing laboratories, including Huntingdon Life Sciences in the UK and Covance in Germany. Ba ...
; and dealers who supply animals sourced from pounds, auctions, and newspaper ads.
Animal shelter An animal shelter or pound is a place where stray, lost, abandoned or surrendered animals – mostly dogs and cats – are housed. The word "pound" has its origins in the animal pounds of agricultural communities, where stray livestock would ...
s also supply the laboratories directly. Large centers also exist to distribute strains of
genetically modified animal Genetically modified animals are animals that have been genetically modified for a variety of purposes including producing drugs, enhancing yields, increasing resistance to disease, etc. The vast majority of genetically modified animals are at the ...
s; the
International Knockout Mouse Consortium The International Knockout Mouse Consortium (IKMC) is a scientific endeavour to produce a collection of mouse embryonic stem cell lines that together lack every gene in the genome, and then to distribute the cells to scientific researchers to crea ...
, for example, aims to provide
knockout mice A knockout mouse, or knock-out mouse, is a genetically modified mouse (''Mus musculus'') in which researchers have inactivated, or "knocked out", an existing gene by replacing it or disrupting it with an artificial piece of DNA. They are importan ...
for every gene in the mouse genome. In the U.S., Class A breeders are licensed by the U.S. Department of Agriculture (USDA) to sell animals for research purposes, while Class B dealers are licensed to buy animals from "random sources" such as auctions, pound seizure, and newspaper ads. Some Class B dealers have been accused of kidnapping pets and illegally trapping strays, a practice known as ''bunching''.Class B dealers
, Humane Society of the United States.
It was in part out of public concern over the sale of pets to research facilities that the 1966 Laboratory Animal Welfare Act was ushered in—the Senate Committee on Commerce reported in 1966 that stolen pets had been retrieved from Veterans Administration facilities, the Mayo Institute, the University of Pennsylvania, Stanford University, and Harvard and Yale Medical Schools. The USDA recovered at least a dozen stolen pets during a raid on a Class B dealer in Arkansas in 2003.
The Humane Society of the United States
Four states in the U.S.—
Minnesota Minnesota () is a state in the upper midwestern region of the United States. It is the 12th largest U.S. state in area and the 22nd most populous, with over 5.75 million residents. Minnesota is home to western prairies, now given over to ...
,
Utah Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to it ...
,
Oklahoma Oklahoma (; Choctaw language, Choctaw: ; chr, ᎣᎧᎳᎰᎹ, ''Okalahoma'' ) is a U.S. state, state in the South Central United States, South Central region of the United States, bordered by Texas on the south and west, Kansas on the nor ...
, and
Iowa Iowa () is a state in the Midwestern region of the United States, bordered by the Mississippi River to the east and the Missouri River and Big Sioux River to the west. It is bordered by six states: Wisconsin to the northeast, Illinois to the ...
—require their shelters to provide animals to research facilities. Fourteen states explicitly prohibit the practice, while the remainder either allow it or have no relevant legislation.Animal Testing: Where Do the Animals Come From?
American Society for the Prevention of Cruelty to Animals. According to the ASPCA, the following states prohibit shelters from providing animals for research: Connecticut, Delaware, Hawaii, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, South Carolina, Vermont, and West Virginia.
In the European Union, animal sources are governed by ''Council Directive 86/609/EEC'', which requires lab animals to be specially bred, unless the animal has been lawfully imported and is not a wild animal or a stray. The latter requirement may also be exempted by special arrangement. In 2010 the Directive was revised with
EU Directive 2010/63/EU Directive 2010/63/EU is the European Union (EU) legislation "on the protection of animals used for scientific purposes" and is one of the most stringent ethical and welfare standards worldwide. The Directive repealed Directive 86/609/EEC. It b ...
. In the UK, most animals used in experiments are bred for the purpose under the 1988 Animal Protection Act, but wild-caught primates may be used if exceptional and specific justification can be established. The United States also allows the use of wild-caught primates; between 1995 and 1999, 1,580 wild baboons were imported into the U.S. Over half the primates imported between 1995 and 2000 were handled by
Charles River Laboratories Charles River Laboratories International, Inc., is an American pharmaceutical company specializing in a variety of preclinical and clinical laboratory, gene therapy and cell therapy services for the Pharmaceutical, Medical device and Biotechnolo ...
, or by
Covance Labcorp Drug Development is a contract research organization (CRO) headquartered in Burlington, North Carolina, providing nonclinical, preclinical, clinical and commercialization services to pharmaceutical and biotechnology industries. Formerly ...
, which is the single largest importer of primates into the U.S.


Pain and suffering

The extent to which animal testing causes
pain Pain is a distressing feeling often caused by intense or damaging stimuli. The International Association for the Study of Pain defines pain as "an unpleasant sensory and emotional experience associated with, or resembling that associated with, ...
and
suffering Suffering, or pain in a broad sense, may be an experience of unpleasantness or aversion, possibly associated with the perception of harm or threat of harm in an individual. Suffering is the basic element that makes up the negative valence of a ...
, and the capacity of animals to experience and comprehend them, is the subject of much debate. According to the USDA, in 2016 501,560 animals (61%) (not including rats, mice, birds, or invertebrates) were used in procedures that did not include more than momentary pain or distress. 247,882 (31%) animals were used in procedures in which pain or distress was relieved by anesthesia, while 71,370 (9%) were used in studies that would cause pain or distress that would not be relieved. Since 2014, in the UK, every research procedure was retrospectively assessed for severity. The five categories are "sub-threshold", "mild", "moderate", "severe" and "non-recovery", the latter being procedures in which an animal is
anesthetized Anesthesia is a state of controlled, temporary loss of sensation or awareness that is induced for medical or veterinary purposes. It may include some or all of analgesia (relief from or prevention of pain), paralysis (muscle relaxation), am ...
and subsequently killed without recovering
consciousness Consciousness, at its simplest, is sentience and awareness of internal and external existence. However, the lack of definitions has led to millennia of analyses, explanations and debates by philosophers, theologians, linguisticians, and scien ...
. In 2017, 43% (1.61 million) were assessed as sub-threshold, 4% (0.14 million) were assessed as non-recovery, 36% (1.35 million) were assessed as mild, 15% (0.55 million) were assessed as moderate and 4% (0.14 million) were assessed as severe. The idea that animals might not feel pain as human beings feel it traces back to the 17th-century French philosopher,
René Descartes René Descartes ( or ; ; Latinized: Renatus Cartesius; 31 March 1596 – 11 February 1650) was a French philosopher, scientist, and mathematician, widely considered a seminal figure in the emergence of modern philosophy and science. Mathem ...
, who argued that animals do not experience pain and suffering because they lack
consciousness Consciousness, at its simplest, is sentience and awareness of internal and external existence. However, the lack of definitions has led to millennia of analyses, explanations and debates by philosophers, theologians, linguisticians, and scien ...
.Carbone, p. 149. Bernard Rollin of
Colorado State University Colorado State University (Colorado State or CSU) is a public land-grant research university in Fort Collins, Colorado. It is the flagship university of the Colorado State University System. Colorado State University is classified among "R1: ...
, the principal author of two U.S. federal laws regulating pain relief for animals, writes that researchers remained unsure into the 1980s as to whether animals experience pain, and that veterinarians trained in the U.S. before 1989 were simply taught to ignore animal pain.Rollin, Bernard. ''The Unheeded Cry: Animal Consciousness, Animal Pain, and Science''. New York: Oxford University Press, 1989, pp. xii, 117–18, cited in Carbone 2004, p. 150. In his interactions with scientists and other veterinarians, he was regularly asked to "prove" that animals are conscious, and to provide "scientifically acceptable" grounds for claiming that they feel pain. Carbone writes that the view that animals feel pain differently is now a minority view. Academic reviews of the topic are more equivocal, noting that although the argument that animals have at least simple conscious thoughts and feelings has strong support, some critics continue to question how reliably animal mental states can be determined. However, some canine experts are stating that, while intelligence does differ animal to animal, dogs have the intelligence of a two to two-and-a-half-year old. This does support the idea that dogs, at the very least, have some form of consciousness. The ability of invertebrates to experience pain and suffering is less clear, however, legislation in several countries (e.g. U.K.,
New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...
, Norway) protects some invertebrate species if they are being used in animal testing. In the U.S., the defining text on animal welfare regulation in animal testing is the ''Guide for the Care and Use of Laboratory Animals''. This defines the parameters that govern animal testing in the U.S. It states "The ability to experience and respond to pain is widespread in the animal kingdom...Pain is a stressor and, if not relieved, can lead to unacceptable levels of stress and distress in animals." The Guide states that the ability to recognize the symptoms of pain in different species is vital in efficiently applying pain relief and that it is essential for the people caring for and using animals to be entirely familiar with these symptoms. On the subject of analgesics used to relieve pain, the Guide states "The selection of the most appropriate analgesic or anesthetic should reflect professional judgment as to which best meets clinical and humane requirements without compromising the scientific aspects of the research protocol". Accordingly, all issues of animal pain and distress, and their potential treatment with analgesia and anesthesia, are required regulatory issues in receiving animal protocol approval. In 2019, Katrien Devolder and Matthias Eggel proposed gene editing research animals to remove the ability to feel pain. This would be an intermediate step towards eventually stopping all experimentation on animals and adopting
alternatives Founded in 1994, Alternatives, Action and Communication Network for International Development, is a non-governmental, international solidarity organization based in Montreal, Quebec, Canada. Alternatives works to promote justice and equality a ...
. Additionally, this would not stop research animals from experiencing psychological harm.


Euthanasia

Regulations require that scientists use as few animals as possible, especially for terminal experiments. However, while policy makers consider suffering to be the central issue and see animal euthanasia as a way to reduce suffering, others, such as the
RSPCA The Royal Society for the Prevention of Cruelty to Animals (RSPCA) is a charity operating in England and Wales that promotes animal welfare. The RSPCA is funded primarily by voluntary donations. Founded in 1824, it is the oldest and largest an ...
, argue that the lives of laboratory animals have intrinsic value. Regulations focus on whether particular methods cause
pain Pain is a distressing feeling often caused by intense or damaging stimuli. The International Association for the Study of Pain defines pain as "an unpleasant sensory and emotional experience associated with, or resembling that associated with, ...
and
suffering Suffering, or pain in a broad sense, may be an experience of unpleasantness or aversion, possibly associated with the perception of harm or threat of harm in an individual. Suffering is the basic element that makes up the negative valence of a ...
, not whether their death is undesirable in itself.Carbone, Larry. "Euthanasia," in Bekoff, M. and Meaney, C. ''Encyclopedia of Animal Rights and Welfare''. Greenwood Publishing Group, pp. 164–66, cited in Carbone 2004, pp. 189–90. The animals are euthanized at the end of studies for sample collection or
post-mortem examination An autopsy (post-mortem examination, obduction, necropsy, or autopsia cadaverum) is a surgical procedure that consists of a thorough examination of a corpse by dissection to determine the cause, mode, and manner of death or to evaluate any dis ...
; during studies if their pain or suffering falls into certain categories regarded as unacceptable, such as depression, infection that is unresponsive to treatment, or the failure of large animals to eat for five days; or when they are unsuitable for breeding or unwanted for some other reason. Methods of euthanizing laboratory animals are chosen to induce rapid unconsciousness and death without pain or distress. The methods that are preferred are those published by councils of veterinarians. The animal can be made to inhale a gas, such as
carbon monoxide Carbon monoxide (chemical formula CO) is a colorless, poisonous, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the simple ...
and
carbon dioxide Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transpar ...
, by being placed in a chamber, or by use of a face mask, with or without prior sedation or anesthesia.
Sedative A sedative or tranquilliser is a substance that induces sedation by reducing irritability or excitement. They are CNS depressants and interact with brain activity causing its deceleration. Various kinds of sedatives can be distinguished, but t ...
s or
anesthetic An anesthetic (American English) or anaesthetic (British English; see spelling differences) is a drug used to induce anesthesia ⁠— ⁠in other words, to result in a temporary loss of sensation or awareness. They may be divided into two ...
s such as
barbiturate Barbiturates are a class of depressant drugs that are chemically derived from barbituric acid. They are effective when used medically as anxiolytics, hypnotics, and anticonvulsants, but have physical and psychological addiction potential as we ...
s can be given
intravenously Intravenous therapy (abbreviated as IV therapy) is a medical technique that administers fluids, medications and nutrients directly into a person's vein. The intravenous route of administration is commonly used for rehydration or to provide nutrie ...
, or inhalant anesthetics may be used. Amphibians and fish may be immersed in water containing an anesthetic such as
tricaine Tricaine mesylate (Tricaine methanesulfonate, TMS, MS-222, Syncaine, Tricaine-S,), is white powder used for anesthesia, sedation, or euthanasia of fish. TMS is the only anesthetic licensed in the United States for fin fish that are intended for ...
. Physical methods are also used, with or without sedation or anesthesia depending on the method. Recommended methods include
decapitation Decapitation or beheading is the total separation of the head from the body. Such an injury is invariably fatal to humans and most other animals, since it deprives the brain of oxygenated blood, while all other organs are deprived of the i ...
(beheading) for small rodents or rabbits.
Cervical dislocation Cervical dislocation is a common method of animal euthanasia. It refers to a technique used in physical euthanasia of small animals by applying pressure to the neck and dislocating the spinal column from the skull or brain.
(breaking the neck or spine) may be used for birds, mice, rats and rabbits. High-intensity microwave
irradiation Irradiation is the process by which an object is exposed to radiation. The exposure can originate from various sources, including natural sources. Most frequently the term refers to ionizing radiation, and to a level of radiation that will serve ...
of the brain can preserve brain tissue and induce death in less than 1 second, but this is currently only used on rodents. Captive bolts may be used, typically on dogs, ruminants, horses, pigs and rabbits. It causes death by a concussion to the brain. Gunshot may be used, but only in cases where a penetrating captive bolt may not be used. Some physical methods are only acceptable after the animal is unconscious.
Electrocution Electrocution is death or severe injury caused by electric shock from electric current passing through the body. The word is derived from "electro" and "execution", but it is also used for accidental death. The term "electrocution" was coined ...
may be used for cattle, sheep, swine, foxes, and mink after the animals are unconscious, often by a prior electrical stun.
Pithing Pithing is a technique used to immobilize or kill an animal by inserting a needle or metal rod into its brain. It is regarded as a humane means of immobilizing small animals being observed in experiments, and while once common in commercial slau ...
(inserting a tool into the base of the brain) is usable on animals already unconscious. Slow or rapid freezing, or inducing
air embolism An air embolism, also known as a gas embolism, is a blood vessel blockage caused by one or more bubbles of air or other gas in the circulatory system. Air can be introduced into the circulation during surgical procedures, lung over-expansion i ...
are acceptable only with prior anesthesia to induce unconsciousness.


Research classification


Pure research

Basic or pure research investigates how organisms behave, develop, and function. Those opposed to animal testing object that pure research may have little or no practical purpose, but researchers argue that it forms the necessary basis for the development of applied research, rendering the distinction between pure and applied research—research that has a specific practical aim—unclear."Select Committee on Animals in Scientific Procedures Report"
House of Lords, 16 July 2002. See chapter 3: "The purpose and nature of animal experiments." Retrieved 6 July 2010.
Pure research uses larger numbers and a greater variety of animals than applied research. Fruit flies, nematode worms, mice and rats together account for the vast majority, though small numbers of other species are used, ranging from
sea slugs Sea slug is a common name for some marine invertebrates with varying levels of resemblance to terrestrial slugs. Most creatures known as sea slugs are gastropods, i.e. they are sea snails (marine gastropod mollusks) that over evolutionary tim ...
through to
armadillo Armadillos (meaning "little armored ones" in Spanish) are New World placental mammals in the order Cingulata. The Chlamyphoridae and Dasypodidae are the only surviving families in the order, which is part of the superorder Xenarthra, along wi ...
s. Examples of the types of animals and experiments used in basic research include: *Studies on ''
embryogenesis An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm ...
'' and ''
developmental biology Developmental biology is the study of the process by which animals and plants grow and develop. Developmental biology also encompasses the biology of Regeneration (biology), regeneration, asexual reproduction, metamorphosis, and the growth and di ...
''. Mutants are created by adding
transposon A transposable element (TE, transposon, or jumping gene) is a nucleic acid sequence in DNA that can change its position within a genome, sometimes creating or reversing mutations and altering the cell's genetic identity and genome size. Transpo ...
s into their
genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding ge ...
s, or specific genes are deleted by
gene targeting Gene targeting (also, replacement strategy based on homologous recombination) is a genetic technique that uses homologous recombination to modify an endogenous gene. The method can be used to delete a gene, remove exons, add a gene and modify ind ...
. By studying the changes in development these changes produce, scientists aim to understand both how organisms normally develop, and what can go wrong in this process. These studies are particularly powerful since the basic controls of development, such as the
homeobox A homeobox is a DNA sequence, around 180 base pairs long, that regulates large-scale anatomical features in the early stages of embryonic development. For instance, mutations in a homeobox may change large-scale anatomical features of the full- ...
genes, have similar functions in organisms as diverse as fruit flies and man. * Experiments into ''behavior'', to understand how organisms detect and interact with each other and their environment, in which fruit flies, worms, mice, and rats are all widely used. Studies of brain function, such as memory and social behavior, often use rats and birds. For some species, behavioral research is combined with enrichment strategies for animals in captivity because it allows them to engage in a wider range of activities. * Breeding experiments to study ''
evolution Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...
'' and ''
genetics Genetics is the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinian friar wor ...
''. Laboratory mice, flies, fish, and worms are
inbred Inbreeding is the production of offspring from the mating or breeding of individuals or organisms that are closely related genetically. By analogy, the term is used in human reproduction, but more commonly refers to the genetic disorders and o ...
through many generations to create strains with defined characteristics. These provide animals of a known genetic background, an important tool for genetic analyses. Larger mammals are rarely bred specifically for such studies due to their slow rate of reproduction, though some scientists take advantage of inbred domesticated animals, such as dog or cattle breeds, for
comparative In general linguistics, the comparative is a syntactic construction that serves to express a comparison between two (or more) entities or groups of entities in quality or degree - see also comparison (grammar) for an overview of comparison, as wel ...
purposes. Scientists studying how animals evolve use many animal species to see how variations in where and how an organism lives (their
niche Niche may refer to: Science *Developmental niche, a concept for understanding the cultural context of child development *Ecological niche, a term describing the relational position of an organism's species *Niche differentiation, in ecology, the ...
) produce
adaptation In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the po ...
s in their physiology and
morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines * Morphology (archaeology), study of the shapes or forms of artifacts * Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies ...
. As an example,
stickleback The sticklebacks are a family of ray-finned fishes, the Gasterosteidae which have a Holarctic distribution in fresh, brackish and marine waters. They were thought to be related to the pipefish and seahorses but are now thought to be more closel ...
s are now being used to study how many and which types of mutations are selected to produce adaptations in animals' morphology during the evolution of new species.


Applied research

Applied research aims to solve specific and practical problems. These may involve the use of
animal model An animal model (short for animal disease model) is a living, non-human, often genetic-engineered animal used during the research and investigation of human disease, for the purpose of better understanding the disease process without the risk of ha ...
s of diseases or conditions, which are often discovered or generated by pure research programmes. In turn, such applied studies may be an early stage in the
drug discovery In the fields of medicine, biotechnology and pharmacology, drug discovery is the process by which new candidate medications are discovered. Historically, drugs were discovered by identifying the active ingredient from traditional remedies or by ...
process. Examples include: *
Genetic modification Genetic engineering, also called genetic modification or genetic manipulation, is the modification and manipulation of an organism's genes using technology. It is a set of technologies used to change the genetic makeup of cells, including t ...
of animals to study disease. Transgenic animals have specific genes inserted, modified or removed, to mimic specific conditions such as
single gene disorders A genetic disorder is a health problem caused by one or more abnormalities in the genome. It can be caused by a mutation in a single gene (monogenic) or multiple genes (polygenic) or by a chromosomal abnormality. Although polygenic disorders ...
, such as
Huntington's disease Huntington's disease (HD), also known as Huntington's chorea, is a neurodegenerative disease that is mostly inherited. The earliest symptoms are often subtle problems with mood or mental abilities. A general lack of coordination and an unst ...
. Other models mimic complex, multifactorial diseases with genetic components, such as
diabetes Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ap ...
, or even transgenic mice that carry the same mutations that occur during the development of
cancer Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...
. These models allow investigations on how and why the disease develops, as well as providing ways to develop and test new treatments. The vast majority of these transgenic models of human disease are lines of mice, the mammalian species in which genetic modification is most efficient. Smaller numbers of other animals are also used, including rats, pigs, sheep, fish, birds, and amphibians. *Studies on models of naturally occurring disease and condition. Certain domestic and wild animals have a natural propensity or predisposition for certain conditions that are also found in humans. Cats are used as a model to develop immunodeficiency virus vaccines and to study
leukemia Leukemia ( also spelled leukaemia and pronounced ) is a group of blood cancers that usually begin in the bone marrow and result in high numbers of abnormal blood cells. These blood cells are not fully developed and are called ''blasts'' or ' ...
because their natural predisposition to
FIV Feline immunodeficiency virus (FIV) is a ''Lentivirus'' that affects cats worldwide, with 2.5% to 4.4% of felines being infected. FIV was first isolated in 1986, by Niels C Pedersen and Janet K. Yamamoto at the UC Davis School of Veterinary ...
and
Feline leukemia virus Feline leukemia virus (FeLV) is a retrovirus that infects cats. FeLV can be transmitted from infected cats when the transfer of saliva or nasal secretions is involved. If not defeated by the animal's immune system, the virus weakens the cat's i ...
. Certain breeds of dog experience
narcolepsy Narcolepsy is a long-term neurological disorder that involves a decreased ability to regulate sleep–wake cycles. Symptoms often include periods of excessive daytime sleepiness and brief involuntary sleep episodes. About 70% of those affec ...
making them the major model used to study the human condition.
Armadillo Armadillos (meaning "little armored ones" in Spanish) are New World placental mammals in the order Cingulata. The Chlamyphoridae and Dasypodidae are the only surviving families in the order, which is part of the superorder Xenarthra, along wi ...
s and humans are among only a few animal species that naturally have
leprosy Leprosy, also known as Hansen's disease (HD), is a long-term infection by the bacteria ''Mycobacterium leprae'' or ''Mycobacterium lepromatosis''. Infection can lead to damage of the nerves, respiratory tract, skin, and eyes. This nerve damag ...
; as the bacteria responsible for this disease cannot yet be grown in culture, armadillos are the primary source of
bacilli Bacilli is a taxonomic class of bacteria that includes two orders, Bacillales and Lactobacillales, which contain several well-known pathogens such as ''Bacillus anthracis'' (the cause of anthrax). ''Bacilli'' are almost exclusively gram-positive ...
used in leprosy vaccines. *Studies on induced animal models of human diseases. Here, an animal is treated so that it develops
pathology Pathology is the study of the causes and effects of disease or injury. The word ''pathology'' also refers to the study of disease in general, incorporating a wide range of biology research fields and medical practices. However, when used in ...
and symptoms that resemble a human disease. Examples include restricting blood flow to the brain to induce
stroke A stroke is a medical condition in which poor blood flow to the brain causes cell death. There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. Both cause parts of the brain to stop functionin ...
, or giving
neurotoxin Neurotoxins are toxins that are destructive to nerve tissue (causing neurotoxicity). Neurotoxins are an extensive class of exogenous chemical neurological insultsSpencer 2000 that can adversely affect function in both developing and mature ner ...
s that cause damage similar to that seen in
Parkinson's disease Parkinson's disease (PD), or simply Parkinson's, is a long-term degenerative disorder of the central nervous system that mainly affects the motor system. The symptoms usually emerge slowly, and as the disease worsens, non-motor symptoms becom ...
. Much animal research into potential treatments for humans is wasted because it is poorly conducted and not evaluated through systematic reviews. For example, although such models are now widely used to study Parkinson's disease, the British anti-vivisection interest group
BUAV Cruelty Free International is an animal protection and advocacy group that campaigns for the abolition of all animal experiments. They organise certification of cruelty-free products which are marked with the symbol of a leaping bunny. It was ...
argues that these models only superficially resemble the disease symptoms, without the same time course or cellular pathology. In contrast, scientists assessing the usefulness of
animal models of Parkinson's disease Animal models of Parkinson's disease are essential in the research field and widely used to study Parkinson's disease. Parkinson's disease is a neurodegenerative disorder, characterized by the loss of dopaminergic neurons in the substantia nigra ...
, as well as the medical research charity ''The Parkinson's Appeal'', state that these models were invaluable and that they led to improved surgical treatments such as
pallidotomy Pallidotomy is a neurosurgical procedure. It is used to treat Parkinson's disease and some other conditions, often as an alternative to deep brain stimulation. It involves placing a tiny electrical probe in the globus pallidus, one of the basal g ...
, new drug treatments such as
levodopa -DOPA, also known as levodopa and -3,4-dihydroxyphenylalanine, is an amino acid that is made and used as part of the normal biology of some plants and animals, including humans. Humans, as well as a portion of the other animals that utilize -DOPA ...
, and later
deep brain stimulation Deep brain stimulation (DBS) is a neurosurgical procedure involving the placement of a medical device called a neurostimulator, which sends electrical impulses, through implanted electrodes, to specific targets in the brain (the brain nucleu ...
. *Animal testing has also included the use of
placebo A placebo ( ) is a substance or treatment which is designed to have no therapeutic value. Common placebos include inert tablets (like sugar pills), inert injections (like Saline (medicine), saline), sham surgery, and other procedures. In general ...
testing. In these cases animals are treated with a substance that produces no pharmacological effect, but is administered in order to determine any biological alterations due to the experience of a substance being administered, and the results are compared with those obtained with an active compound.


Xenotransplantation

Xenotransplantation Xenotransplantation (''xenos-'' from the Greek meaning "foreign" or strange), or heterologous transplant, is the transplantation of living cells, tissues or organs from one species to another. Such cells, tissues or organs are called xenograft ...
research involves transplanting tissues or organs from one species to another, as a way to overcome the shortage of human organs for use in
organ transplant Organ transplantation is a medical procedure in which an organ is removed from one body and placed in the body of a recipient, to replace a damaged or missing organ. The donor and recipient may be at the same location, or organs may be transpo ...
s. Current research involves using primates as the recipients of organs from pigs that have been genetically modified to reduce the primates'
immune response An immune response is a reaction which occurs within an organism for the purpose of defending against foreign invaders. These invaders include a wide variety of different microorganisms including viruses, bacteria, parasites, and fungi which could ...
against the pig tissue. Although
transplant rejection Transplant rejection occurs when Organ transplant, transplanted tissue is rejected by the recipient's immune system, which destroys the transplanted tissue. Transplant rejection can be lessened by determining the molecular similitude between don ...
remains a problem, recent clinical trials that involved implanting pig insulin-secreting cells into diabetics did reduce these people's need for insulin. Documents released to the news media by the animal rights organization
Uncaged Campaigns Uncaged Campaigns is a Sheffield, UK, based anti-vivisection, not-for-profit organisation and a registered company limited by guarantee. History Uncaged Campaigns was established in 1993 by Angela Roberts and Lynn Williamson. They are a peaceful i ...
showed that, between 1994 and 2000, wild baboons imported to the UK from Africa by Imutran Ltd, a subsidiary of
Novartis Novartis AG is a Swiss-American multinational pharmaceutical corporation based in Basel, Switzerland and Cambridge, Massachusetts, United States (global research).name="novartis.com">https://www.novartis.com/research-development/research-loc ...
Pharma AG, in conjunction with Cambridge University and
Huntingdon Life Sciences Huntingdon Life Sciences (HLS) was a contract research organisation (CRO) founded in 1951 in Cambridgeshire, England. It had two laboratories in the United Kingdom and one in the United States. With over 1,600 staff, it was until 2015 the larges ...
, to be used in experiments that involved grafting pig tissues, had serious and sometimes fatal injuries. A scandal occurred when it was revealed that the company had communicated with the British government in an attempt to avoid regulation.Townsend, Mark (20 April 2003)
"Exposed: secrets of the animal organ lab"
, ''The Guardian''.


Toxicology testing

Toxicology testing, also known as safety testing, is conducted by pharmaceutical companies testing drugs, or by contract animal testing facilities, such as
Huntingdon Life Sciences Huntingdon Life Sciences (HLS) was a contract research organisation (CRO) founded in 1951 in Cambridgeshire, England. It had two laboratories in the United Kingdom and one in the United States. With over 1,600 staff, it was until 2015 the larges ...
, on behalf of a wide variety of customers.Household Product Tests
BUAV Cruelty Free International is an animal protection and advocacy group that campaigns for the abolition of all animal experiments. They organise certification of cruelty-free products which are marked with the symbol of a leaping bunny. It was ...
According to 2005 EU figures, around one million animals are used every year in Europe in toxicology tests; which are about 10% of all procedures.Fifth Report on the Statistics on the Number of Animals used for Experimental and other Scientific Purposes in the Member States of the European Union
''Commission of the European Communities'', published November 2007
According to ''Nature'', 5,000 animals are used for each chemical being tested, with 12,000 needed to test pesticides. The tests are conducted without
anesthesia Anesthesia is a state of controlled, temporary loss of sensation or awareness that is induced for medical or veterinary purposes. It may include some or all of analgesia (relief from or prevention of pain), paralysis (muscle relaxation), ...
, because interactions between drugs can affect how animals detoxify chemicals, and may interfere with the results. Toxicology tests are used to examine finished products such as
pesticide Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and lampri ...
s,
medication A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy (pharmacotherapy) is an important part of the medical field and re ...
s,
food additives Food additives are substances added to food to preserve flavor or enhance taste, appearance, or other sensory qualities. Some additives have been used for centuries as part of an effort to preserve food, for example vinegar (pickling), salt (salt ...
, packing materials, and
air freshener Air fresheners are consumer products that typically emit fragrance and are used in homes or commercial interiors such as restrooms, foyers, hallways, vestibules and other smaller indoor areas, as well as larger areas such as hotel lobbies, auto d ...
, or their chemical ingredients. Most tests involve testing ingredients rather than finished products, but according to
BUAV Cruelty Free International is an animal protection and advocacy group that campaigns for the abolition of all animal experiments. They organise certification of cruelty-free products which are marked with the symbol of a leaping bunny. It was ...
, manufacturers believe these tests overestimate the toxic effects of substances; they therefore repeat the tests using their finished products to obtain a less toxic label. The substances are applied to the skin or dripped into the eyes; injected
intravenous Intravenous therapy (abbreviated as IV therapy) is a medical technique that administers fluids, medications and nutrients directly into a person's vein. The intravenous route of administration is commonly used for rehydration or to provide nutrie ...
ly,
intramuscular Intramuscular injection, often abbreviated IM, is the injection of a substance into a muscle. In medicine, it is one of several methods for parenteral administration of medications. Intramuscular injection may be preferred because muscles have l ...
ly, or subcutaneously; inhaled either by placing a mask over the animals and restraining them, or by placing them in an inhalation chamber; or administered orally, through a tube into the stomach, or simply in the animal's food. Doses may be given once, repeated regularly for many months, or for the lifespan of the animal. There are several different types of
acute toxicity Acute toxicity describes the adverse effects of a substance that result either from a single exposure or from multiple exposures in a short period of time (usually less than 24 hours). To be described as ''acute'' toxicity, the adverse effect ...
tests. The ("Lethal Dose 50%") test is used to evaluate the toxicity of a substance by determining the dose required to kill 50% of the test animal
population Population typically refers to the number of people in a single area, whether it be a city or town, region, country, continent, or the world. Governments typically quantify the size of the resident population within their jurisdiction using a ...
. This test was removed from
OECD The Organisation for Economic Co-operation and Development (OECD; french: Organisation de coopération et de développement économiques, ''OCDE'') is an intergovernmental organisation with 38 member countries, founded in 1961 to stimulate e ...
international guidelines in 2002, replaced by methods such as the
fixed dose procedure The fixed-dose procedure (FDP), proposed in 1992 by the British Toxicology Society, is a method to assess a substance's acute oral toxicity Toxicity is the degree to which a chemical substance or a particular mixture of substances can dama ...
, which use fewer animals and cause less suffering. Abbott writes that, as of 2005, "the LD50 acute toxicity test ... still accounts for one-third of all animal oxicitytests worldwide". Irritancy can be measured using the
Draize test The Draize test is an acute toxicity test devised in 1944 by Food and Drug Administration (FDA) toxicologists John H. Draize and Jacob M. Spines. Initially used for testing cosmetics, the procedure involves applying 0.5 mL or 0.5 g of ...
, where a test substance is applied to an animal's eyes or skin, usually an albino rabbit. For Draize eye testing, the test involves observing the effects of the substance at intervals and grading any damage or irritation, but the test should be halted and the animal killed if it shows "continuing signs of severe pain or distress". The
Humane Society of the United States The Humane Society of the United States (HSUS) is an American nonprofit organization that focuses on animal welfare and opposes animal-related cruelties of national scope. It uses strategies that are beyond the abilities of local organizations. ...
writes that the procedure can cause redness, ulceration, hemorrhaging, cloudiness, or even blindness. This test has also been criticized by scientists for being cruel and inaccurate, subjective, over-sensitive, and failing to reflect human exposures in the real world. Although no accepted ''in vitro'' alternatives exist, a modified form of the Draize test called the ''low volume eye test'' may reduce suffering and provide more realistic results and this was adopted as the new standard in September 2009.Draize rabbit eye test replacement milestone welcomed
''Dr Hadwen Trust'' (2009-09-21)
However, the Draize test will still be used for substances that are not severe irritants. The most stringent tests are reserved for drugs and foodstuffs. For these, a number of tests are performed, lasting less than a month (acute), one to three months (subchronic), and more than three months (chronic) to test general toxicity (damage to organs), eye and skin irritancy,
mutagen In genetics, a mutagen is a physical or chemical agent that permanently changes nucleic acid, genetic material, usually DNA, in an organism and thus increases the frequency of mutations above the natural background level. As many mutations can ca ...
icity,
carcinogen A carcinogen is any substance, radionuclide, or radiation that promotes carcinogenesis (the formation of cancer). This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes. Several radioactive substan ...
icity, teratogenicity, and reproductive problems. The cost of the full complement of tests is several million dollars per substance and it may take three or four years to complete. These toxicity tests provide, in the words of a 2006
United States National Academy of Sciences The National Academy of Sciences (NAS) is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the Nati ...
report, "critical information for assessing hazard and risk potential". Animal tests may overestimate risk, with
false positive A false positive is an error in binary classification in which a test result incorrectly indicates the presence of a condition (such as a disease when the disease is not present), while a false negative is the opposite error, where the test result ...
results being a particular problem, but false positives appear not to be prohibitively common. Variability in results arises from using the effects of high doses of chemicals in small numbers of laboratory animals to try to predict the effects of low doses in large numbers of humans. Although relationships do exist, opinion is divided on how to use data on one species to predict the exact level of risk in another. Scientists face growing pressure to move away from using traditional animal toxicity tests to determine whether manufactured chemicals are safe. Among variety of approaches to toxicity evaluation the ones which have attracted increasing interests are in vitro cell-based sensing methods applying fluorescence.


Cosmetics testing

Cosmetics testing on animals is particularly controversial. Such tests, which are still conducted in the U.S., involve general toxicity, eye and skin irritancy,
phototoxic Phototoxicity, also called photoirritation, is a chemically induced skin irritation, requiring light, that does not involve the immune system. It is a type of photosensitivity. The skin response resembles an exaggerated sunburn. The involved chemi ...
ity (toxicity triggered by
ultraviolet Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nanometer, nm (with a corresponding frequency around 30 Hertz, PHz) to 400 nm (750 Hertz, THz), shorter than that of visible light, but longer than ...
light) and mutagenicity. Cosmetics testing on animals is banned in India, the United Kingdom, the European Union, Israel and Norway while legislation in the U.S. and Brazil is currently considering similar bans. In 2002, after 13 years of discussion, the European Union agreed to phase in a near-total ban on the sale of animal-tested cosmetics by 2009, and to ban all cosmetics-related animal testing. France, which is home to the world's largest cosmetics company, L'Oreal, has protested the proposed ban by lodging a case at the
European Court of Justice The European Court of Justice (ECJ, french: Cour de Justice européenne), formally just the Court of Justice, is the supreme court of the European Union in matters of European Union law. As a part of the Court of Justice of the European Un ...
in
Luxembourg Luxembourg ( ; lb, Lëtzebuerg ; french: link=no, Luxembourg; german: link=no, Luxemburg), officially the Grand Duchy of Luxembourg, ; french: link=no, Grand-Duché de Luxembourg ; german: link=no, Großherzogtum Luxemburg is a small lan ...
, asking that the ban be quashed. The ban is also opposed by the European Federation for Cosmetics Ingredients, which represents 70 companies in Switzerland, Belgium, France, Germany, and Italy.Osborn, Andrew & Gentleman, Ameli
"Secret French move to block animal-testing ban"
''The Guardian'' (19 August 2003). Retrieved 27 February 2008.
In October 2014, India passed stricter laws that also ban the importation of any cosmetic products that are tested on animals.


Drug testing

Before the early 20th century, laws regulating drugs were lax. Currently, all new pharmaceuticals undergo rigorous animal testing before being licensed for human use. Tests on pharmaceutical products involve: * ''metabolic tests'', investigating
pharmacokinetics Pharmacokinetics (from Ancient Greek ''pharmakon'' "drug" and ''kinetikos'' "moving, putting in motion"; see chemical kinetics), sometimes abbreviated as PK, is a branch of pharmacology dedicated to determining the fate of substances administered ...
—how drugs are absorbed,
metabolized Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...
and
excreted Excretion is a process in which metabolic waste is eliminated from an organism. In vertebrates this is primarily carried out by the lungs, kidneys, and skin. This is in contrast with secretion, where the substance may have specific tasks after lea ...
by the body when introduced orally,
intravenous Intravenous therapy (abbreviated as IV therapy) is a medical technique that administers fluids, medications and nutrients directly into a person's vein. The intravenous route of administration is commonly used for rehydration or to provide nutrie ...
ly, intraperitoneally,
intramuscular Intramuscular injection, often abbreviated IM, is the injection of a substance into a muscle. In medicine, it is one of several methods for parenteral administration of medications. Intramuscular injection may be preferred because muscles have l ...
ly, or transdermally. * ''toxicology tests'', which gauge
acute Acute may refer to: Science and technology * Acute angle ** Acute triangle ** Acute, a leaf shape in the glossary of leaf morphology * Acute (medicine), a disease that it is of short duration and of recent onset. ** Acute toxicity, the adverse eff ...
, sub-acute, and
chronic toxicity Chronic toxicity, the development of adverse effects as a result of long term exposure to a contaminant or other stressor, is an important aspect of aquatic toxicology. Adverse effects associated with chronic toxicity can be directly lethal but are ...
. Acute toxicity is studied by using a rising dose until signs of toxicity become apparent. Current European legislation demands that "acute toxicity tests must be carried out in two or more mammalian species" covering "at least two different routes of administration". Sub-acute toxicity is where the drug is given to the animals for four to six weeks in doses below the level at which it causes rapid poisoning, in order to discover if any toxic drug metabolites build up over time. Testing for chronic toxicity can last up to two years and, in the European Union, is required to involve two species of mammals, one of which must be non-rodent. * ''efficacy studies'', which test whether experimental drugs work by inducing the appropriate illness in animals. The drug is then administered in a double-blind controlled trial, which allows researchers to determine the effect of the drug and the dose-response curve. * Specific tests on ''reproductive function'', ''embryonic toxicity'', or ''carcinogenic potential'' can all be required by law, depending on the result of other studies and the type of drug being tested.


Education

It is estimated that 20 million animals are used annually for educational purposes in the United States including, classroom observational exercises, dissections and live-animal surgeries. Frogs,
fetal pigs Fetal pigs are unborn pigs used in elementary as well as advanced biology classes as objects for dissection. Pigs, as a mammalian species, provide a good specimen for the study of physiological systems and processes due to the similarities between ...
, perch, cats, earthworms, grasshoppers, crayfish and starfish are commonly used in classroom dissections. Alternatives to the use of animals in classroom dissections are widely used, with many U.S. States and school districts mandating students be offered the choice to not dissect. Citing the wide availability of alternatives and the decimation of local frog species, India banned dissections in 2014. The Sonoran Arthropod Institute hosts an annual Invertebrates in Education and Conservation Conference to discuss the use of invertebrates in education. There also are efforts in many countries to find alternatives to using animals in education. The NORINA database, maintained by Norecopa, lists products that may be used as alternatives or supplements to animal use in education, and in the training of personnel who work with animals. These include alternatives to dissection in schools.
InterNICHE InterNICHE (International Network for Humane Education; ), is a Nonprofit organization, non-profit organization and an international network based in the United Kingdom that promotes the use of humane alternatives within Biology, biological sc ...
has a similar database and a loans system. In November 2013, the U.S.-based company Backyard Brains released for sale to the public what they call the "Roboroach", an "electronic backpack" that can be attached to
cockroach Cockroaches (or roaches) are a paraphyletic group of insects belonging to Blattodea, containing all members of the group except termites. About 30 cockroach species out of 4,600 are associated with human habitats. Some species are well-known as ...
es. The operator is required to amputate a cockroach's antennae, use sandpaper to wear down the shell, insert a wire into the
thorax The thorax or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the cre ...
, and then glue the
electrode An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit (e.g. a semiconductor, an electrolyte, a vacuum or air). Electrodes are essential parts of batteries that can consist of a variety of materials de ...
s and
circuit board A printed circuit board (PCB; also printed wiring board or PWB) is a medium used in Electrical engineering, electrical and electronic engineering to connect electronic components to one another in a controlled manner. It takes the form of a L ...
onto the insect's back. A
mobile phone app A mobile application or app is a computer program or software application designed to run on a mobile device such as a phone, tablet, or watch. Mobile applications often stand in contrast to desktop applications which are designed to run on d ...
can then be used to control it via
Bluetooth Bluetooth is a short-range wireless technology standard that is used for exchanging data between fixed and mobile devices over short distances and building personal area networks (PANs). In the most widely used mode, transmission power is limi ...
. It has been suggested that the use of such a device may be a teaching aid that can promote interest in science. The makers of the "Roboroach" have been funded by the
National Institute of Mental Health The National Institute of Mental Health (NIMH) is one of 27 institutes and centers that make up the National Institutes of Health (NIH). The NIH, in turn, is an agency of the United States Department of Health and Human Services and is the prima ...
and state that the device is intended to encourage children to become interested in
neuroscience Neuroscience is the scientific study of the nervous system (the brain, spinal cord, and peripheral nervous system), its functions and disorders. It is a multidisciplinary science that combines physiology, anatomy, molecular biology, development ...
.


Defense

Animals are used by the military to develop weapons, vaccines, battlefield surgical techniques, and defensive clothing. For example, in 2008 the United States
Defense Advanced Research Projects Agency The Defense Advanced Research Projects Agency (DARPA) is a research and development agency of the United States Department of Defense responsible for the development of emerging technologies for use by the military. Originally known as the Adv ...
used live pigs to study the effects of
improvised explosive device An improvised explosive device (IED) is a bomb constructed and deployed in ways other than in conventional military action. It may be constructed of conventional military explosives, such as an artillery shell, attached to a detonating mechan ...
explosions on internal organs, especially the brain. In the US military,
goat The goat or domestic goat (''Capra hircus'') is a domesticated species of goat-antelope typically kept as livestock. It was domesticated from the wild goat (''C. aegagrus'') of Southwest Asia and Eastern Europe. The goat is a member of the a ...
s are commonly used to train
combat medic A combat medic, or healthcare specialist, is responsible for providing emergency medical treatment at a point of wounding in a combat or training environment, as well as primary care and health protection and evacuation from a point of injury ...
s. (Goats have become the main animal species used for this purpose after the Pentagon phased out using dogs for medical training in the 1980s.) While modern
mannequins A mannequin (also called a dummy, lay figure, or dress form) is a doll, often articulated, used by artists, tailors, dressmakers, window dressers and others, especially to display or fit clothing and show off different fabrics and textiles. Pr ...
used in medical training are quite efficient in simulating the behavior of a human body, some trainees feel that "the goat exercise provide a sense of urgency that only real life trauma can provide". Nevertheless, in 2014, the
U.S. Coast Guard The United States Coast Guard (USCG) is the maritime security, search and rescue, and law enforcement service branch of the United States Armed Forces and one of the country's eight uniformed services. The service is a maritime, military, mul ...
announced that it would reduce the number of animals it uses in its training exercises by half after
PETA Peta or PETA may refer to: Acronym * Pembela Tanah Air, a militia established by the occupying Japanese in Indonesia in 1943 * People for the Ethical Treatment of Animals, an American animal rights organization * People Eating Tasty Animals, an ...
released video showing Guard members cutting off the limbs of unconscious goats with tree trimmers and inflicting other injuries with a shotgun, pistol, ax and a scalpel. That same year, citing the availability of human simulators and other alternatives, the Department of Defense announced it would begin reducing the number of animals it uses in various training programs. In 2013, several
Navy A navy, naval force, or maritime force is the branch of a nation's armed forces principally designated for naval warfare, naval and amphibious warfare; namely, lake-borne, riverine, littoral zone, littoral, or ocean-borne combat operations and ...
medical centers stopped using ferrets in intubation exercises after complaints from
PETA Peta or PETA may refer to: Acronym * Pembela Tanah Air, a militia established by the occupying Japanese in Indonesia in 1943 * People for the Ethical Treatment of Animals, an American animal rights organization * People Eating Tasty Animals, an ...
. Besides the United States, six out of 28 NATO countries, including Poland and Denmark, use live animals for combat medic training.


Ethics

Most animals are
euthanized Animal euthanasia ( euthanasia from el, εὐθανασία; "good death") is the act of killing an animal or allowing it to die by withholding extreme medical measures. Reasons for euthanasia include incurable (and especially painful) conditi ...
after being used in an experiment.Carbone, p. 22. Sources of laboratory animals vary between countries and species; most animals are purpose-bred, while a minority are caught in the wild or supplied by dealers who obtain them from auctions and pounds."Use of Laboratory Animals in Biomedical and Behavioral Research", Institute for Laboratory Animal Research, The National Academies Press, 1988 .Gillham, Christina (17 February 2006)
"Bought to be sold"
''Newsweek''.
Supporters of the use of animals in experiments, such as the British
Royal Society The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, re ...
, argue that virtually every medical achievement in the 20th century relied on the use of animals in some way.The use of non-human animals in research: a guide for scientists
The Royal Society The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, re ...
, 2004, p. 1
The Institute for Laboratory Animal Research of the United States
National Academy of Sciences The National Academy of Sciences (NAS) is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the Nati ...
has argued that animal research cannot be replaced by even sophisticated computer models, which are unable to deal with the extremely complex interactions between molecules, cells, tissues, organs, organisms and the environment.
Animal rights Animal rights is the philosophy according to which many or all sentient animals have moral worth that is independent of their utility for humans, and that their most basic interests—such as avoiding suffering—should be afforded the sa ...
organizations—such as
PETA Peta or PETA may refer to: Acronym * Pembela Tanah Air, a militia established by the occupying Japanese in Indonesia in 1943 * People for the Ethical Treatment of Animals, an American animal rights organization * People Eating Tasty Animals, an ...
and
BUAV Cruelty Free International is an animal protection and advocacy group that campaigns for the abolition of all animal experiments. They organise certification of cruelty-free products which are marked with the symbol of a leaping bunny. It was ...
—question the need for and legitimacy of animal testing, arguing that it is
cruel Cruelty is the pleasure in inflicting suffering or inaction towards another's suffering when a clear remedy is readily available. Sadism can also be related to this form of action or concept. Cruel ways of inflicting suffering may involve vi ...
and poorly regulated, that medical progress is actually held back by misleading animal models that cannot reliably predict effects in humans, that some of the tests are outdated, that the costs outweigh the benefits, or that animals have the intrinsic right not to be used or harmed in experimentation.


Viewpoints

The moral and ethical questions raised by performing experiments on animals are subject to debate, and viewpoints have shifted significantly over the 20th century. There remain disagreements about which procedures are useful for which purposes, as well as disagreements over which ethical principles apply to which species. A 2015 Gallup poll found that 67% of Americans were "very concerned" or "somewhat concerned" about animals used in research. A Pew poll taken the same year found 50% of American adults opposed the use of animals in research. Still, a wide range of viewpoints exist. The view that animals have moral rights (
animal rights Animal rights is the philosophy according to which many or all sentient animals have moral worth that is independent of their utility for humans, and that their most basic interests—such as avoiding suffering—should be afforded the sa ...
) is a philosophical position proposed by
Tom Regan Tom Regan (; November 28, 1938 – February 17, 2017) was an American philosopher who specialized in animal rights theory. He was professor emeritus of philosophy at North Carolina State University, where he had taught from 1967 until his reti ...
, among others, who argues that animals are beings with beliefs and desires, and as such are the "subjects of a life" with moral value and therefore moral rights. Regan still sees ethical differences between killing human and non-human animals, and argues that to save the former it is permissible to kill the latter. Likewise, a "moral dilemma" view suggests that avoiding potential benefit to humans is unacceptable on similar grounds, and holds the issue to be a dilemma in balancing such harm to humans to the harm done to animals in research.Chapter 14, Discussion of ethical issues, p . 244
in
The ethics of research involving animals
at the Nuffield Council on Bioethics. Published 25 May 2005
In contrast, an abolitionist view in animal rights holds that there is no moral justification for any harmful research on animals that is not to the benefit of the individual animal. Bernard Rollin argues that benefits to human beings cannot outweigh animal suffering, and that human beings have no moral right to use an animal in ways that do not benefit that individual.
Donald Watson Donald Watson (2 September 1910 – 16 November 2005) was an English animal rights advocate who co-founded The Vegan Society. Early life Watson was born in Mexborough, Yorkshire, the son of a headmaster in a mining community. As a child, Watson ...
has stated that
vivisection Vivisection () is surgery conducted for experimental purposes on a living organism, typically animals with a central nervous system, to view living internal structure. The word is, more broadly, used as a pejorative catch-all term for experiment ...
and animal experimentation "is probably the cruelest of all Man's attack on the rest of Creation." Another prominent position is that of philosopher
Peter Singer Peter Albert David Singer (born 6 July 1946) is an Australian moral philosopher, currently the Ira W. DeCamp Professor of Bioethics at Princeton University. He specialises in applied ethics and approaches ethical issues from a secular, ...
, who argues that there are no grounds to include a being's species in considerations of whether their suffering is important in
utilitarian In ethical philosophy, utilitarianism is a family of normative ethical theories that prescribe actions that maximize happiness and well-being for all affected individuals. Although different varieties of utilitarianism admit different charac ...
moral considerations.Rollin, Bernard E. (1998) "The moral status of animals and their use as experimental subjects," in Kuhse, Helga and Singer, Peter (eds.). "A Companion to Bioethics". Blackwell Publishing, .
Malcolm Macleod Malcolm Macleod (born in Edinburgh in 1965) is a Scottish neurologist and translational neuroscientist. Biography Macleod spent his early years in Achiltibuie and Inverness. He attended the Leachkin Primary School, Jedburgh Grammar School and ...
and collaborators argue that most controlled animal studies do not employ
randomization Randomization is the process of making something random. Randomization is not haphazard; instead, a random process is a sequence of random variables describing a process whose outcomes do not follow a deterministic pattern, but follow an evolution d ...
,
allocation concealment In a randomized experiment, allocation concealment hides the sorting of trial participants into treatment groups so that this knowledge cannot be exploited. Adequate allocation concealment serves to prevent study participants from influencing treatm ...
, and blinding outcome assessment, and that failure to employ these features exaggerates the apparent benefit of drugs tested in animals, leading to a failure to translate much animal research for human benefit. Governments such as the Netherlands and New Zealand have responded to the public's concerns by outlawing invasive experiments on certain classes of non-human primates, particularly the
great apes The Hominidae (), whose members are known as the great apes or hominids (), are a taxonomic family of primates that includes eight extant species in four genera: '' Pongo'' (the Bornean, Sumatran and Tapanuli orangutan); ''Gorilla'' (the east ...
. In 2015, captive chimpanzees in the U.S. were added to the
Endangered Species Act The Endangered Species Act of 1973 (ESA or "The Act"; 16 U.S.C. § 1531 et seq.) is the primary law in the United States for protecting imperiled species. Designed to protect critically imperiled species from extinction as a "consequence of ec ...
adding new road blocks to those wishing to experiment on them. Similarly, citing ethical considerations and the availability of alternative research methods, the U.S.
NIH The National Institutes of Health, commonly referred to as NIH (with each letter pronounced individually), is the primary agency of the United States government responsible for biomedical and public health research. It was founded in the late ...
announced in 2013 that it would dramatically reduce and eventually phase out experiments on chimpanzees. The British government has required that the cost to animals in an experiment be weighed against the gain in knowledge. Some medical schools and agencies in China, Japan, and South Korea have built
cenotaph A cenotaph is an empty tomb or a monument erected in honour of a person or group of people whose remains are elsewhere. It can also be the initial tomb for a person who has since been reinterred elsewhere. Although the vast majority of cenot ...
s for killed animals. In Japan there are also annual memorial services (''Ireisai'' 慰霊祭) for animals sacrificed at medical school. Various specific cases of animal testing have drawn attention, including both instances of beneficial scientific research, and instances of alleged ethical violations by those performing the tests. The fundamental properties of muscle physiology were determined with work done using frog muscles (including the force generating mechanism of all muscle, the length-tension relationship, and the force-velocity curve), and frogs are still the preferred model organism due to the long survival of muscles ''in vitro'' and the possibility of isolating intact single-fiber preparations (not possible in other organisms). Modern
physical therapy Physical therapy (PT), also known as physiotherapy, is one of the allied health professions. It is provided by physical therapists who promote, maintain, or restore health through physical examination, diagnosis, management, prognosis, patient ...
and the understanding and treatment of muscular disorders is based on this work and subsequent work in mice (often engineered to express disease states such as
muscular dystrophy Muscular dystrophies (MD) are a genetically and clinically heterogeneous group of rare neuromuscular diseases that cause progressive weakness and breakdown of skeletal muscles over time. The disorders differ as to which muscles are primarily affe ...
). In February 1997 a team at the
Roslin Institute The Roslin Institute is an animal sciences research institute at Easter Bush, Midlothian, Scotland, part of the University of Edinburgh, and is funded by the Biotechnology and Biological Sciences Research Council. It is best known for creati ...
in Scotland announced the birth of Dolly the sheep, the first mammal to be
cloned Cloning is the process of producing individual organisms with identical or virtually identical DNA, either by natural or artificial means. In nature, some organisms produce clones through asexual reproduction. In the field of biotechnology, c ...
from an adult
somatic cell A somatic cell (from Ancient Greek σῶμα ''sôma'', meaning "body"), or vegetal cell, is any biological cell forming the body of a multicellular organism other than a gamete, germ cell, gametocyte or undifferentiated stem cell. Such cells compo ...
. Concerns have been raised over the mistreatment of primates undergoing testing. In 1985 the case of Britches, a macaque monkey at the
University of California, Riverside The University of California, Riverside (UCR or UC Riverside) is a public land-grant research university in Riverside, California. It is one of the ten campuses of the University of California system. The main campus sits on in a suburban distr ...
, gained public attention. He had his eyelids sewn shut and a sonar sensor on his head as part of an experiment to test
sensory substitution Sensory substitution is a change of the characteristics of one sensory modality into stimuli of another sensory modality. A sensory substitution system consists of three parts: a sensor, a coupling system, and a stimulator. The sensor records stimu ...
devices for blind people. The laboratory was raided by
Animal Liberation Front The Animal Liberation Front (ALF) is an international, Leaderless resistance, leaderless, decentralized political and social resistance movement that engages in and promotes non-violent direct action in protest against incidents of animal cruelt ...
in 1985, removing Britches and 466 other animals. The National Institutes of Health conducted an eight-month investigation and concluded, however, that no corrective action was necessary. During the 2000s other cases have made headlines, including experiments at the
University of Cambridge , mottoeng = Literal: From here, light and sacred draughts. Non literal: From this place, we gain enlightenment and precious knowledge. , established = , other_name = The Chancellor, Masters and Schola ...
and
Columbia University Columbia University (also known as Columbia, and officially as Columbia University in the City of New York) is a private research university in New York City. Established in 1754 as King's College on the grounds of Trinity Church in Manhatt ...
in 2002. In 2004 and 2005, undercover footage of staff of
Covance Labcorp Drug Development is a contract research organization (CRO) headquartered in Burlington, North Carolina, providing nonclinical, preclinical, clinical and commercialization services to pharmaceutical and biotechnology industries. Formerly ...
's, a
contract research organization In the life sciences, a contract research organization (CRO) is a company that provides support to the pharmaceutical, biotechnology, and medical device industries in the form of research services outsourced on a contract basis. A CRO may provid ...
that provides animal testing services,
Virginia Virginia, officially the Commonwealth of Virginia, is a state in the Mid-Atlantic and Southeastern regions of the United States, between the Atlantic Coast and the Appalachian Mountains. The geography and climate of the Commonwealth ar ...
lab was shot by
People for the Ethical Treatment of Animals People for the Ethical Treatment of Animals (PETA; , stylized as PeTA) is an American animal rights nonprofit organization based in Norfolk, Virginia, and led by Ingrid Newkirk, its international president. PETA reports that PETA entities have ...
(PETA). Following release of the footage, the U.S. Department of Agriculture fined Covance $8,720 for 16 citations, three of which involved lab monkeys; the other citations involved administrative issues and equipment.


Threats to researchers

Threats of violence to animal researchers are not uncommon. In 2006, a primate researcher at the
University of California, Los Angeles The University of California, Los Angeles (UCLA) is a public land-grant research university in Los Angeles, California. UCLA's academic roots were established in 1881 as a teachers college then known as the southern branch of the California St ...
(UCLA) shut down the experiments in his lab after threats from animal rights activists. The researcher had received a grant to use 30
macaque The macaques () constitute a genus (''Macaca'') of gregarious Old World monkeys of the subfamily Cercopithecinae. The 23 species of macaques inhabit ranges throughout Asia, North Africa, and (in one instance) Gibraltar. Macaques are principally ...
monkeys for vision experiments; each monkey was anesthetized for a single physiological experiment lasting up to 120 hours, and then euthanized. The researcher's name, phone number, and address were posted on the website of the
Primate Freedom Project ] The Primate Freedom Project is a 501(c)(3) not-for-profit grassroots animal rights organization based in Atlanta, Georgia. It is dedicated to ending the use of nonhuman primates in biomedical and harmful behavioral experimentation. The project i ...
. Demonstrations were held in front of his home. A
Molotov cocktail A Molotov cocktail (among several other names – ''see other names'') is a hand thrown incendiary weapon constructed from a frangible container filled with flammable substances equipped with a fuse (typically a glass bottle filled with flamma ...
was placed on the porch of what was believed to be the home of another UCLA primate researcher; instead, it was accidentally left on the porch of an elderly woman unrelated to the university. The
Animal Liberation Front The Animal Liberation Front (ALF) is an international, Leaderless resistance, leaderless, decentralized political and social resistance movement that engages in and promotes non-violent direct action in protest against incidents of animal cruelt ...
claimed responsibility for the attack. As a result of the campaign, the researcher sent an email to the Primate Freedom Project stating "you win", and "please don't bother my family anymore". In another incident at UCLA in June 2007, the Animal Liberation Brigade placed a bomb under the car of a UCLA children's
ophthalmologist Ophthalmology ( ) is a surgery, surgical subspecialty within medicine that deals with the diagnosis and treatment of eye disorders. An ophthalmologist is a physician who undergoes subspecialty training in medical and surgical eye care. Followin ...
who experiments on cats and rhesus monkeys; the bomb had a faulty fuse and did not detonate. In 1997, PETA filmed staff from
Huntingdon Life Sciences Huntingdon Life Sciences (HLS) was a contract research organisation (CRO) founded in 1951 in Cambridgeshire, England. It had two laboratories in the United Kingdom and one in the United States. With over 1,600 staff, it was until 2015 the larges ...
, showing dogs being mistreated. The employees responsible were dismissed, with two given community service orders and ordered to pay £250 costs, the first lab technicians to have been prosecuted for animal cruelty in the UK. The
Stop Huntingdon Animal Cruelty Stop Huntingdon Animal Cruelty (SHAC) was an international animal rights campaign to close down Huntingdon Life Sciences (HLS), Europe's largest contract Animal testing, animal-testing laboratory. HLS tests medical and non-medical substances on ...
campaign used tactics ranging from non-violent protest to the alleged firebombing of houses owned by executives associated with HLS's clients and investors. The
Southern Poverty Law Center The Southern Poverty Law Center (SPLC) is an American 501(c)(3) nonprofit legal advocacy organization specializing in civil rights and public interest litigation. Based in Montgomery, Alabama, it is known for its legal cases against white su ...
, which monitors US domestic extremism, has described SHAC's ''modus operandi'' as "frankly terroristic tactics similar to those of anti-abortion extremists," and in 2005 an official with the FBI's counter-terrorism division referred to SHAC's activities in the United States as domestic terrorist threats. 13 members of SHAC were jailed for between 15 months and eleven years on charges of conspiracy to blackmail or harm HLS and its suppliers.Evers, Marco
"Resisting the Animal Avengers", Part 1
''Der Spiegel'', 19 November 2007.
Weaver, Matthew
"Animal rights activists jailed for terrorising suppliers to Huntingdon Life Sciences"
''The Guardian'', 25 October 2010.
These attacks—as well as similar incidents that caused the
Southern Poverty Law Center The Southern Poverty Law Center (SPLC) is an American 501(c)(3) nonprofit legal advocacy organization specializing in civil rights and public interest litigation. Based in Montgomery, Alabama, it is known for its legal cases against white su ...
to declare in 2002 that the animal rights movement had "clearly taken a turn toward the more extreme"—prompted the US government to pass the
Animal Enterprise Terrorism Act The Animal Enterprise Terrorism Act (AETA) of 2006 is a United States federal law (; ) that prohibits any person from engaging in certain conduct "for the purpose of damaging or interfering with the operations of an animal enterprise." The statut ...
and the UK government to add the offense of "Intimidation of persons connected with animal research organisation" to the
Serious Organised Crime and Police Act 2005 The Serious Organized Crime and Police Act 2005 (c.15) (often abbreviated to SOCPA or SOCAP) is an Act of the Parliament of the United Kingdom aimed primarily at creating the Serious Organised Crime Agency. It also significantly extended and si ...
. Such legislation and the arrest and imprisonment of activists may have decreased the incidence of attacks.


Scientific criticism

Systematic review A systematic review is a Literature review, scholarly synthesis of the evidence on a clearly presented topic using critical methods to identify, define and assess research on the topic. A systematic review extracts and interprets data from publ ...
s have pointed out that animal testing often fails to accurately mirror outcomes in humans. For instance, a 2013 review noted that some 100 vaccines have been shown to prevent HIV in animals, yet none of them have worked on humans. Effects seen in animals may not be replicated in humans, and vice versa. Many
corticosteroid Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex of vertebrates, as well as the synthetic analogues of these hormones. Two main classes of corticosteroids, glucocorticoids and mineralocorticoids, are involv ...
s cause birth defects in animals, but not in humans. Conversely,
thalidomide Thalidomide, sold under the brand names Contergan and Thalomid among others, is a medication used to treat a number of cancers (including multiple myeloma), graft-versus-host disease, and a number of skin conditions including complications of ...
causes serious birth defects in humans, but not in some animals such as mice (however, it does cause birth defects in rabbits). A 2004 paper concluded that much animal research is wasted because systemic reviews are not used, and due to poor methodology. A 2006 review found multiple studies where there were promising results for new drugs in animals, but human clinical studies did not show the same results. The researchers suggested that this might be due to researcher bias, or simply because animal models do not accurately reflect human biology. Lack of meta-reviews may be partially to blame. Poor methodology is an issue in many studies. A 2009 review noted that many animal experiments did not use
blinded experiment In a blind or blinded experiment, information which may influence the participants of the experiment is withheld until after the experiment is complete. Good blinding can reduce or eliminate experimental biases that arise from a participants' expec ...
s, a key element of many scientific studies in which researchers are not told about the part of the study they are working on to reduce bias. A 2021 paper found, in a sample of Open Access Alzheimer Disease studies, that if the authors omit from the title that the experiment was performed in mice, the News Headline follow suit, and that also the Twitter repercussion is higher.


Activism

There are various examples of activists utilizing Freedom of Information Act (FOIA) requests to obtain information about taxpayer funding of animal testing. For example, the White Coat Waste Project, a group of activists that hold that taxpayers should not have to pay $20 billion every year for experiments on animals, highlighted that the
National Institute of Allergy and Infectious Diseases The National Institute of Allergy and Infectious Diseases (NIAID, ) is one of the 27 institutes and centers that make up the National Institutes of Health (NIH), an agency of the United States Department of Health and Human Services (HHS). NIAID's ...
provided $400,000 in taxpayer money to fund experiments in which 28 beagles were infected by disease-causing parasites. The White Coat Project found reports that said dogs taking part in the experiments were "vocalizing in pain" after being injected with foreign substances. Following public outcry, People for the Ethical Treatment of Animals (PETA) made a call to action that all members of the
National Institute of Health The National Institutes of Health, commonly referred to as NIH (with each letter pronounced individually), is the primary agency of the United States government responsible for biomedical and public health research. It was founded in the late 1 ...
resign effective immediately and that there is a "need to find a new NIH director to replace the outgoing
Francis Collins Francis Sellers Collins (born April 14, 1950) is an American physician-geneticist who discovered the genes associated with a number of diseases and led the Human Genome Project. He is the former director of the National Institutes of Health ( ...
who will shut down research that violates the dignity of nonhuman animals."


Alternatives to animal testing

Most scientists and governments state that animal testing should cause as little suffering to animals as possible, and that animal tests should only be performed where necessary. The "Three Rs" are guiding
principles A principle is a proposition or value that is a guide for behavior or evaluation. In law, it is a rule that has to be or usually is to be followed. It can be desirably followed, or it can be an inevitable consequence of something, such as the la ...
for the use of animals in research in most countries. Whilst replacement of animals, i.e. alternatives to animal testing, is one of the principles, their scope is much broader. Although such principles have been welcomed as a step forwards by some animal welfare groups, they have also been criticized as both outdated by current research, and of little practical effect in improving animal welfare. The scientists and engineers at Harvard's Wyss Institute have created "organs-on-a-chip", including the "lung-on-a-chip" and "gut-on-a-chip". Researchers at cellasys in Germany developed a "skin-on-a-chip". These tiny devices contain human cells in a 3-dimensional system that mimics human organs. The chips can be used instead of animals in ''
in vitro ''In vitro'' (meaning in glass, or ''in the glass'') studies are performed with microorganisms, cells, or biological molecules outside their normal biological context. Colloquially called "test-tube experiments", these studies in biology an ...
'' disease research, drug testing, and toxicity testing. Researchers have also begun using 3-D bioprinters to create human tissues for ''in vitro'' testing. Another non-animal research method is ''
in silico In biology and other experimental sciences, an ''in silico'' experiment is one performed on computer or via computer simulation. The phrase is pseudo-Latin for 'in silicon' (correct la, in silicio), referring to silicon in computer chips. It ...
'' or computer simulation and mathematical modeling which seeks to investigate and ultimately predict toxicity and drug effects on humans without using animals. This is done by investigating test compounds on a molecular level using recent advances in technological capabilities with the ultimate goal of creating treatments unique to each patient.
Microdosing Microdosing, or micro-dosing, is a technique for studying the behaviour of drugs in humans through the administration of doses so low ("sub-therapeutic") they are unlikely to produce whole-body effects, but high enough to allow the cellular resp ...
is another alternative to the use of animals in experimentation. Microdosing is a process whereby volunteers are administered a small dose of a test compound allowing researchers to investigate its pharmacological affects without harming the volunteers. Microdosing can replace the use of animals in pre-clinical drug screening and can reduce the number of animals used in safety and toxicity testing. Additional alternative methods include
positron emission tomography Positron emission tomography (PET) is a functional imaging technique that uses radioactive substances known as radiotracers to visualize and measure changes in Metabolism, metabolic processes, and in other physiological activities including bl ...
(PET), which allows scanning of the
human brain The human brain is the central organ of the human nervous system, and with the spinal cord makes up the central nervous system. The brain consists of the cerebrum, the brainstem and the cerebellum. It controls most of the activities of the ...
''in vivo'', and
comparative In general linguistics, the comparative is a syntactic construction that serves to express a comparison between two (or more) entities or groups of entities in quality or degree - see also comparison (grammar) for an overview of comparison, as wel ...
epidemiological Epidemiology is the study and analysis of the distribution (who, when, and where), patterns and determinants of health and disease conditions in a defined population. It is a cornerstone of public health, and shapes policy decisions and evidenc ...
studies of disease
risk factor In epidemiology, a risk factor or determinant is a variable associated with an increased risk of disease or infection. Due to a lack of harmonization across disciplines, determinant, in its more widely accepted scientific meaning, is often use ...
s among human populations. Simulators and computer programs have also replaced the use of animals in
dissection Dissection (from Latin ' "to cut to pieces"; also called anatomization) is the dismembering of the body of a deceased animal or plant to study its anatomical structure. Autopsy is used in pathology and forensic medicine to determine the cause o ...
, teaching and training exercises. Official bodies such as the European Centre for the Validation of Alternative Test Methods of the
European Commission The European Commission (EC) is the executive of the European Union (EU). It operates as a cabinet government, with 27 members of the Commission (informally known as "Commissioners") headed by a President. It includes an administrative body o ...
, the Interagency Coordinating Committee for the Validation of Alternative Methods in the US, ZEBET in Germany, and the Japanese Center for the Validation of Alternative Methods (among others) also promote and disseminate the 3Rs. These bodies are mainly driven by responding to regulatory requirements, such as supporting the cosmetics testing ban in the EU by validating alternative methods. The European Partnership for Alternative Approaches to Animal Testing serves as a liaison between the European Commission and industries. The European Consensus Platform for Alternatives coordinates efforts amongst EU member states. Academic centers also investigate alternatives, including the Center for Alternatives to Animal Testing at the
Johns Hopkins University Johns Hopkins University (Johns Hopkins, Hopkins, or JHU) is a private university, private research university in Baltimore, Maryland. Founded in 1876, Johns Hopkins is the oldest research university in the United States and in the western hem ...
and the NC3Rs in the UK.


See also

*
Bateson's cube Bateson's cube is a model of the cost–benefit analysis for animal research developed by Professor Patrick Bateson, president of the Zoological Society of London. Bateson's cube evaluates proposed research through three criteria: * the degree of ...
*
Effect of psychoactive drugs on animals Psychoactive drugs, such as caffeine, amphetamine, mescaline, lysergic acid diethylamide (LSD), marijuana, chloral hydrate, theophylline, IBMX and others, can have strong effects on certain animals. It is believed that plants developed caffe ...
* Human subject research *
Krogh's principle Krogh's principle states that "for such a large number of problems there will be some animal of choice, or a few such animals, on which it can be most conveniently studied." This concept is central to those disciplines of biology that rely on the c ...
*
Microphysiometry Microphysiometry is the ''in vitro'' measurement of the functions and activities of life or of living matter (as organs, tissues, or cells) and of the physical and chemical phenomena involved on a very small (micrometer) scale. The term microphysiom ...
*
The People's Petition The People's Petition was an online campaign to express support for medical experimentation using animals in the United Kingdom. Within a year of launch the number of signatures exceeded 21,850 and included Tony Blair, the then-serving Prime Min ...
*
Preclinical imaging Preclinical imaging is the visualization of living animals for research purposes, such as drug development. Imaging modalities have long been crucial to the researcher in observing changes, either at the organ, tissue, cell, or molecular level, i ...
*
Remote control animal Remote control animals are animals that are controlled remotely by humans. Some applications require electrodes to be implanted in the animal's nervous system connected to a receiver which is usually carried on the animal's back. The animals are ...
*
Sentinel species Sentinel species are organisms, often animals, used to detect risks to humans by providing advance warning of a danger. The terms primarily apply in the context of environmental hazards rather than those from other sources. Some animals can act ...
*
Sham feeding Sham feeding is any procedure that mimics normal food consumption but where food and drink are not actually digested or absorbed. It is generally used in experiments studying hunger, eating or digestion, and is a predominant method used in studying ...
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U.S. Meat Animal Research Center The Roman L. Hruska U.S. Meat Animal Research Center (USMARC) is a livestock research facility in Clay Center, Nebraska. The center researches methods for increasing the efficiency of livestock production. The center maintains around 30,000 animal ...
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Women and animal advocacy Women have played a central role in animal advocacy since the 19th century. The animal advocacy movement – embracing animal rights, animal welfare, and anti-vivisectionism – has been disproportionately initiated and led by women, p ...


References


Citations


Works cited

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Further reading

* Conn, P. Michael and Parker, James V (2008). The Animal Research War, Palgrave Macmillan, *


External links

* * {{Authority control Animal test conditions Bioethics Biology experiments Ethically disputed research practices towards animals Ethics and statistics Laboratory techniques Research methods