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Friday, June 16, 2023

Animal testing on non-human primates

Two primates in a laboratory cage
 

Experiments involving non-human primates (NHPs) include toxicity testing for medical and non-medical substances; studies of infectious disease, such as HIV and hepatitis; neurological studies; behavior and cognition; reproduction; genetics; and xenotransplantation. Around 65,000 NHPs are used every year in the United States, and around 7,000 across the European Union. Most are purpose-bred, while some are caught in the wild.

Their use is controversial. According to the Nuffield Council on Bioethics, NHPs are used because their brains share structural and functional features with human brains, but "while this similarity has scientific advantages, it poses some difficult ethical problems, because of an increased likelihood that primates experience pain and suffering in ways that are similar to humans." Some of the most publicized attacks on animal research facilities by animal rights groups have occurred because of primate research. Some primate researchers have abandoned their studies because of threats or attacks.

In December 2006, an inquiry chaired by Sir David Weatherall, emeritus professor of medicine at Oxford University, concluded that there is a "strong scientific and moral case" for using primates in some research. The British Union for the Abolition of Vivisection argues that the Weatherall report failed to address "the welfare needs and moral case for subjecting these sensitive, intelligent creatures to a lifetime of suffering in UK labs".

Legal status

Human beings are recognized as persons and protected in law by the United Nations Universal Declaration of Human Rights and by all governments to varying degrees. Non-human primates are not classified as persons in most jurisdictions, which largely means their individual interests have no formal recognition or protection. The status of non-human primates has generated much debate, particularly through the Great Ape Project (GAP), which argues that great apes (gorillas, orangutans, chimpanzees, bonobos) should be given limited legal status and the protection of three basic interests: the right to live, the protection of individual liberty, and the prohibition of torture.

In 1997, the United Kingdom announced a policy of no longer granting licenses for research involving great apes, the first ever measure to ban primate use in research. Announcing the UK’s ban, the British Home Secretary said: "[T]his is a matter of morality. The cognitive and behavioural characteristics and qualities of these animals mean it is unethical to treat them as expendable for research." Britain continues to use other primates in laboratories, such as macaques and marmosets. In 2006 the permanency of the UK ban was questioned by Colin Blakemore, head of the Medical Research Council. Blakemore, while stressing he saw no "immediate need" to lift the ban, argued "that under certain circumstances, such as the emergence of a lethal pandemic virus that only affected the great apes, including man, then experiments on chimps, orang-utans and even gorillas may become necessary." The British Union for the Abolition of Vivisection described Blakemore's stance as "backward-looking." In 1999, New Zealand was the first country to ban experimentation on great apes by law.

On June 25, 2008, Spain became the first country to announce that it will extend rights to the great apes in accordance with GAP's proposals. An all-party parliamentary group advised the government to write legislation giving chimpanzees, gorillas and orangutans the right to life, to liberty, and the right not to be used in experiments. The New York Times reported that the legislation will make it illegal to kill apes, except in self-defense. Torture, which will include medical experiments, will be not allowed, as will arbitrary imprisonment, such as for circuses or films.

An increasing number of other governments are enacting bans. As of 2006, Austria, New Zealand (restrictions on great apes only and not a complete ban), the Netherlands, Sweden, and the United Kingdom had introduced either de jure or de facto bans. The ban in Sweden does not extend to non-invasive behavioral studies, and graduate work on great ape cognition in Sweden continues to be carried out on zoo gorillas, and supplemented by studies of chimpanzees held in the U.S. Sweden's legislation also bans invasive experiments on gibbons.

In December 2005, Austria outlawed experiments on any apes, unless it is conducted in the interests of the individual animal. In 2002, Belgium announced that it was working toward a ban on all primate use, and in the UK, 103 MPs signed an Early Day Motion calling for an end to primate experiments, arguing that they cause suffering and are unreliable. No licenses for research on great apes have been issued in the UK since 1998. The Boyd Group, a British group comprising animal researchers, philosophers, primatologists, and animal advocates, has recommended a global prohibition on the use of great apes.

The use of non-human primates in the EU is regulated under the Directive 2010/63/EU. The directive took effect on January 1, 2013. The directive permits the use of non-human primates if no other alternative methods are available. Testing on non-human primates is permitted for basic and applied research, quality and safety testing of drugs, food and other products and research aimed on the preservation of the species. The use of great apes is generally not permitted, unless it is believed that the actions are essential to preserve the species or in relation to an unexpected outbreak of a life-threatening or debilitating clinical condition in human beings. The directive stresses the use of the 3R principle (replacement, refinement, reduction) and animal welfare when conducting animal testing on non-human primates.

A 2013 amendment to the German Animal Welfare Act, with special regulations for monkeys, resulted in a near total ban on the use of great apes as laboratory animals. The last time great apes were used in laboratory experiments in Germany was 1991.

Species and numbers used

Covance primate-testing lab, Vienna, Virginia, 2004–05

Most of the NHPs used are one of three species of macaques, accounting for 79% of all primates used in research in the UK, and 63% of all federally funded research grants for projects using primates in the U.S. Lesser numbers of marmosets, tamarins, spider monkeys, owl monkeys, vervet monkeys, squirrel monkeys, and baboons are used in the UK and the U.S. Great apes have not been used in the UK since a government policy ban in 1998. In the U.S., research laboratories employ the use of 1,133 chimpanzees as of October 2006.

Data reported by region
Country Total Reporting Year Procedures/Animals
Austria 0 2017 Procedures
Belgium 40 2016 Procedures
Bulgaria 0 2017 Procedures
Canada 7556 2016 Animals
Croatia 0 2016 Procedures
Cyprus 0 2016 Procedures
Czech Republic 36 2017 Animals
Denmark 0 2016 Procedures
Estonia 0 2016 Procedures
Finland 0 2016 Procedures
France 3508 2016 Procedures
Germany 2418 2016 Procedures
Greece 3 2016 Procedures
Hungary 0 2016 Procedures
Ireland 0 2016 Procedures
Israel 35 2017 Animals
Italy 511 2016 Procedures
Latvia 0 2016 Procedures
Lithuania 0 2015 Procedures
Luxembourg 0 2017 Animals
Malta 0 2016 Procedures
Netherlands 120 2016 Procedures
New Zealand 0 2015 Animals
Poland 0 2016 Procedures
Portugal 0 2014 Procedures
Romania 0 2015 Procedures
Slovakia 0 2017 Procedures
Slovenia 0 2016 Procedures
Spain 228 2016 Procedures
South Korea 2403 2017 Animals
Sweden 38 2016 Procedures
Switzerland 181 2017 Animals
United Kingdom 2960 2017 Procedures
United States 71188 2016 Animals

Most primates are purpose-bred, while some are caught in the wild. In 2011 in the EU, 0.05% of animals used in animal testing procedures were non-human primates.

In 1996, the British Animal Procedures Committee recommended new measures for dealing with NHPs. The use of wild-caught primates was banned, except where "exceptional and specific justification can be established"; specific justification must be made for the use of Old World primates (but not for the use of New World primates); approval for the acquisition of primates from overseas is conditional upon their breeding or supply center being acceptable to the Home Office; and each batch of primates acquired from overseas must be separately authorized.

Prevalence

There are indications that NHP use is on the rise in some countries, in part because biomedical research funds in the U.S. have more than doubled since the 1990s. In 2000, the NIH published a report recommending that the Regional Primate Research Center System be renamed the National Primate Research Center System and calling for an increase in the number of NHPs available to researchers, and stated that "nonhuman primates are crucial for certain types of biomedical and behavioral research." This assertion has been challenged. In the U.S., the Oregon and California National Primate Research Centers and New Iberia Research Center have expanded their facilities.

In 2000 the National Institutes of Health (NIH) invited applications for the establishment of new breeding specific pathogen free colonies; and a new breeding colony projected to house 3,000 NHPs has been set up in Florida. The NIH's National Center for Research Resources claimed a need to increase the number of breeding colonies in its 2004–2008 strategic plan, as well as to set up a database, using information provided through a network of National Primate Research Centers, to allow researchers to locate NHPs with particular characteristics. China is also increasing its NHP use, and is regarded as attractive to Western companies because of the low cost of research, the relatively lax regulations and the increase in animal-rights activism in the West.

In 2013, British Home Office figures show that the number of primates used in the UK was at 2,440, down 32% from 3,604 NHPs in 1993. Over the same time period, the number of procedures involving NHPs fell 29% from 4,994 from to 3,569 procedures.

Sources

The American Society of Primatologists writes that most NHPs in laboratories in the United States are bred domestically. Between 12,000–15,000 are imported each year, specifically rhesus macaque monkeys, cynomolgus (crab-eating) macaque monkeys, squirrel monkeys, owl monkeys, and baboons. Monkeys are imported from China, Mauritius, the Philippines, and Peru.

China exported over 12,000 macaques for research in 2001 (4,500 to the U.S.), all from self-sustaining purpose-bred colonies. The second largest source is Mauritius, from which 3,440 purpose-bred cynomolgus macaques were exported to the U.S. in 2001.

In Europe, an estimated 70% of research primates are imported, and the rest are purpose-bred in Europe. Around 74% of these imports come from China, with most of the rest coming from Mauritius.

Use

General

NHPs are used in research into HIV, neurology, behavior, cognition, reproduction, Parkinson's disease, stroke, malaria, respiratory viruses, infectious disease, genetics, xenotransplantation, drug abuse, and also in vaccine and drug testing. According to The Humane Society of the United States, chimpanzees are most often used in hepatitis research, and monkeys in SIV research. Animals used in hepatitis and SIV studies are often caged alone.

Eighty-two percent of primate procedures in the UK in 2006 were in applied studies, which the Home Office defines as research conducted for the purpose of developing or testing commercial products. Toxicology testing is the largest use, which includes legislatively required testing of drugs. The second largest category of research using primates is "protection of man, animals, or environment", accounting for 8.9% of all procedures in 2006. The third largest category is "fundamental biological research", accounting for 4.9% of all UK primate procedures in 2006. This includes neuroscientific study of the visual system, cognition, and diseases such as Parkinson's, involving techniques such as inserting electrodes to record from or stimulate the brain, and temporary or permanent inactivation of areas of tissue.

Primates are the species most likely to be re-used in experiments. The Research Defence Society writes that re-use is allowed if the animals have been used in mild procedures with no lasting side-effects. This is contradicted by Dr. Gill Langley of the British Union for the Abolition of Vivisection, who gives as an example of re-use the licence granted to Cambridge University to conduct brain experiments on marmosets. The protocol sheet stated that the animals would receive "multiple interventions as part of the whole lesion/graft repair procedure." Under the protocol, a marmoset could be given acute brain lesions under general anaesthetic, followed by tissue implantation under a second general anaesthetic, followed again central cannula implantation under a third. The re-use is allowable when required to meet scientific goals, such as this case in which some procedures are required as preparatory for others.

Methods of restraint

A primate trained to place his head and hands in holes in the front of his cage. The holes are placed in such a way as to allow the primate to reach for food while presenting his head for the experiment.

One of the disadvantages of using NHPs is that they can be difficult to handle, and various methods of physical restraint have to be used. Viktor Reinhardt of the Wisconsin Regional Primate Research Center writes that scientists may be unaware of the way in which their research animals are handled, and therefore fail to take into account the effect the handling may have had on the animals' health, and thereby on any data collected. Reinhardt writes that primatologists have long recognized that restraint methods may introduce an "uncontrolled methodological variable", by producing resistance and fear in the animal. "Numerous reports have been published demonstrating that non-human primates can readily be trained to cooperate rather than resist during common handling procedures such as capture, venipuncture, injection and veterinary examination. Cooperative animals fail to show behavioural and physiological signs of distress."

Reinhardt lists common restraint methods as: squeeze-back cages, manual restraint, restraint boards, restraint chairs, restraint chutes, tethering, and nets. Alternatives include:

  • chemical restraint; for example, ketamine, a sedative, may be given to the animal before a restraint procedure, reducing stress-hormone production;
  • psychological support, in which an animal under restraint has visual and auditory contact with the animal's cage-mate. Blood pressure and heart rate responses to restraint have been measurably reduced using psychological support.
  • training animals to cooperate with restraint. Such methods have been used and resulted in unmeasurable stress hormone responses to venipuncture, and no notable distress to being captured in a transport box.

Chimpanzees in the United States

Chimpanzee Enos, the third primate to orbit Earth, before the 1961 flight of Mercury-Atlas 5

As of 2013, the U.S. and Gabon were the only countries that still allowed chimpanzees to be used for medical experiments. The U.S. is the world's largest user of chimpanzees for biomedical research, with approximately 1,200 individual subjects in U.S. labs as of middle 2011, dropping to less than 700 as of 2016. Japan also still keeps a dozen chimpanzees in a research project for chimpanzee cognition (see Ai (chimpanzee)).

Chimpanzees routinely live 30 years in captivity, and can reach 60 years of age.

Most of the labs either conduct or make the chimpanzees available for invasive research, defined as "inoculation with an infectious agent, surgery or biopsy conducted for the sake of research and not for the sake of the chimpanzee, and/or drug testing." Two federally funded laboratories have used chimps: Yerkes National Primate Research Center at Emory University in Atlanta, Georgia, and the Southwest National Primate Research Center in San Antonio, Texas. By 2008, five hundred chimps had been retired from laboratory use in the U.S. and live in sanctuaries in the U.S. or Canada.

Their importation from the wild was banned in 1973. From then until 1996, chimpanzees in U.S. facilities were bred domestically. Some others were transferred from the entertainment industry to animal testing facilities as recently as 1983, although it is not known if any animals that were transferred from the entertainment industry are still in testing centers. Animal sanctuaries were not an option until the first North American sanctuary that would accept chimpanzees opened in 1976.

In 1986, to prepare for research on AIDS, the U.S. bred them aggressively, with 315 breeding chimpanzees used to produce 400 offspring. By 1996, it was clear that SIV/HIV-2/SHIV in macaque monkeys was a preferred scientific AIDS model to the chimpanzees, which meant there was a surplus. A five-year moratorium on breeding was therefore imposed by the U.S. National Institutes of Health (NIH) that year, and it has been extended annually since 2001. As of October 2006, the chimpanzee population in US laboratories had declined to 1133 from a peak of 1500 in 1996.

Chimpanzees tend to be used repeatedly over decades, rather than used and killed as with most laboratory animals. Some individual chimpanzees currently in U.S. laboratories have been used in experiments for over 40 years. The oldest known chimpanzee in a U.S. lab is Wenka, who was born in a laboratory in Florida on May 21, 1954. She was removed from her mother on the day of birth to be used in a vision experiment that lasted 17 months, then sold as a pet to a family in North Carolina. She was returned to the Yerkes National Primate Research Center in 1957 when she became too big to handle. Since then, she has given birth six times, and has been used in research into alcohol use, oral contraceptives, aging, and cognitive studies.

With the publication of the chimpanzee genome, there are reportedly plans to increase the use of chimpanzees in labs, with scientists arguing that the federal moratorium on breeding chimpanzees for research should be lifted. Other researchers argue that chimpanzees are unique animals and should either not be used in research, or should be treated differently. Pascal Gagneux, an evolutionary biologist and primate expert at the University of California, San Diego, argues that, given chimpanzees' sense of self, tool use, and genetic similarity to human beings, studies using chimpanzees should follow the ethical guidelines that are used for human subjects unable to give consent. Stuart Zola, director of the Yerkes National Primate Research Laboratory, disagrees. He told National Geographic: "I don't think we should make a distinction between our obligation to treat humanely any species, whether it's a rat or a monkey or a chimpanzee. No matter how much we may wish it, chimps are not human."

In January 2011 the Institute of Medicine was asked by the NIH to examine whether the government should keep supporting biomedical research on chimpanzees. The NIH called for the study after protests by the Humane Society of the United States, primatologist Jane Goodall and others, when it announced plans to move 186 semi-retired chimpanzees back into active research. On December 15, 2011, the Institute of Medicine committee concluded in their "Chimpanzees in Biomedical and Behavioral Research: Assessing the Necessity" report that, "while the chimpanzee has been a valuable animal model in past research, most current use of chimpanzees for biomedical research is unnecessary," as scientific research indicated a decreasing need for the use of chimpanzees due to the emergence of non-chimpanzee models. Later that day Francis Collins, a head of the NIH, said the agency would stop issuing new awards for research involving chimpanzees until the recommendations developed by the IOM are implemented.

On 21 September 2012, the NIH announced that 110 chimpanzees owned by the government were to be retired. The NIH owned about 500 chimpanzees for research, and this move signified the first step to wind down its investment in chimpanzee research, according to Collins. Housed at the New Iberia Research Center in Louisiana, 10 of the retired chimpanzees were to go to the chimpanzee sanctuary Chimp Haven while the rest were to go to Texas Biomedical Research Institute in San Antonio. However, concerns over the chimpanzees' status in the Texas Biomedical Research Institute as ‘research ineligible’ rather than ‘retired’ prompted the NIH to reconsider the plan. On 17 October 2012, it was announced that as many chimpanzees as possible will be relocated to Chimp Haven by August 2013, and that eventually all 110 will move there.

In 2013 the NIH agreed with the IOM's recommendations that experimentation on chimpanzees was unnecessary and rarely helped in advancing human health for infectious diseases and that the NIH would phase out most of its government-funded experiments on chimpanzees. On 22 January 2013, an NIH task force released a report calling for the government to retire most of the chimpanzees under U.S. government support. The panel concluded that the animals provide little benefit in biomedical discoveries except in a few disease cases which can be supported by a small population of 50 primates for future research. It suggested that other approaches, such as genetically altered mice, should be developed and refined instead. On 13 November 2013, Congress and the Senate passed ‘The Chimpanzee Health Improvement, Maintenance and Protection Act’, which approved funding to expand the capacity of Chimp Haven and other chimpanzee sanctuaries, allowing for the transfer of almost all of the apes owned by the federal government to live in a more natural and group environment. The transfer was expected to take up to five years, at which point all but 50 chimpanzees were to have been successfully ‘retired’.

On 11 June 2013, the US Fish and Wildlife Service (USFWS) proposed to list captive chimpanzees as endangered, matching its existing classification for wild chimpanzees. Until the USFWS proposal, chimpanzees were the only species with a split listing that did not also classify captive members of the species as endangered. Before the proposal gained final approval, it was unclear what effect it would have on laboratory research.

Two years later, on June 16, 2015, the USFWS announced that it has designated both captive and wild chimpanzees as endangered. In November 2015 the NIH announced it would no longer support biomedical research on chimpanzees and release its remaining 50 chimpanzees to sanctuaries. The agency would also develop a plan for phasing out NIH support for the remaining chimps that are supported by, but not owned by, the NIH.

In January 2014, Merck & Co. announced that the company will not use chimpanzees for research, joining over 20 pharmaceutical companies and contract laboratories that have made the commitment. As the trend continues, it is estimated the remaining non-government owned 1,000 chimpanzees will be retired to sanctuaries around 2020.

Notable studies

Polio

In the 1940s, Jonas Salk used rhesus monkey cross-contamination studies to isolate the three forms of the polio virus that crippled hundreds of thousands of people yearly across the world at the time. Salk's team created a vaccine against the strains of polio in cell cultures of green monkey kidney cells. The vaccine was made publicly available in 1955, and reduced the incidence of polio 15-fold in the USA over the following five years.

Albert Sabin made a superior "live" vaccine by passing the polio virus through animal hosts, including monkeys. The vaccine was produced for mass consumption in 1963 and is still in use today. It had virtually eradicated polio in the United States by 1965.

Split-brain experiments

In the 1950s, Roger Sperry developed split-brain preparations in non-human primates that emphasized the importance of information transfer that occurred in these neocortical connections. For example, learning on simple tasks, if restricted in sensory input and motor output to one hemisphere of a split-brain animal, would not transfer to the other hemisphere. The right brain has no idea what the left brain is up to, if these specific connections are cut. Those experiments were followed by tests on human beings with epilepsy who had undergone split-brain surgery, which established that the neocortical connections between hemispheres are the principal route for cognition to transfer from one side of the brain to another. These experiments also formed the modern basis for lateralization of function in the human brain.

Vision experiments

In the 1960s, David Hubel and Torsten Wiesel demonstrated the macrocolumnar organization of visual areas in cats and monkeys, and provided physiological evidence for the critical period for the development of disparity sensitivity in vision (i.e., the main cue for depth perception). They were awarded a Nobel Prize for their work.

Deep-brain stimulation

In 1983, designer drug users took MPTP, which created a Parkinsonian syndrome. Later that same year, researchers reproduced the effect in non-human primates. Over the next seven years, the brain areas that were over- and under-active in Parkinson's were mapped out in normal and MPTP-treated macaque monkeys using metabolic labelling and microelectrode studies. In 1990, deep brain lesions were shown to treat Parkinsonian symptoms in macaque monkeys treated with MPTP, and these were followed by pallidotomy operations in humans with similar efficacy. By 1993, it was shown that deep brain stimulation could effect the same treatment without causing a permanent lesion of the same magnitude. Deep brain stimulation has largely replaced pallidotomy for treatment of Parkinson's patients that require neurosurgical intervention. Current estimates are that 20,000 Parkinson's patients have received this treatment.

AIDS

The non-human primate models of AIDS, using HIV-2, SHIV, and SIV in macaques, have been used as a complement to ongoing research efforts against the virus. The drug tenofovir has had its efficacy and toxicology evaluated in macaques, and found longterm-highdose treatments had adverse effects not found using short term-high dose treatment followed by long term-low dose treatment. This finding in macaques was translated into human dosing regimens. Prophylactic treatment with anti-virals has been evaluated in macaques, because introduction of the virus can only be controlled in an animal model. The finding that prophylaxis can be effective at blocking infection has altered the treatment for occupational exposures, such as needle exposures. Such exposures are now followed rapidly with anti-HIV drugs, and this practice has resulted in measurable transient virus infection similar to the NHP model. Similarly, the mother-to-fetus transmission, and its fetal prophylaxis with antivirals such as tenofovir and AZT, has been evaluated in controlled testing in macaques not possible in humans, and this knowledge has guided antiviral treatment in pregnant mothers with HIV. "The comparison and correlation of results obtained in monkey and human studies is leading to a growing validation and recognition of the relevance of the animal model. Although each animal model has its limitations, carefully designed drug studies in nonhuman primates can continue to advance our scientific knowledge and guide future clinical trials."

Treatment of anxiety and depression

The reason for studying primates is due to the similar complexity of the cerebral processes in the human brain which controls emotional responses and can be beneficial for testing new pharmacological treatments. An experiment published in the Neuroscience & Biobehavioral Reviews describes habituation of the black-tufted marmoset in a figure eight maze model. They were presented with a taxidermized wild-cat, rattlesnake, a hawk as well as a stuffed toy bear on one side of the maze. Two cameras and a two way mirror was used to observe the difference between the monkeys natural behaviors versus the behaviors expressed by the diazepam induced monkeys in thirteen different locations inside the maze. Scientist Barros and his colleagues created this model to allow the monkeys to roam a less confined environment and slightly eliminate outside factors that may induce stress.

Allegations

Many of the best-known allegations of abuse made by animal protection or animal rights groups against animal-testing facilities involve non-human primates.

University of Wisconsin–Madison

The so-called "pit of despair" was used in experiments conducted on rhesus macaque monkeys during the 1970s by American comparative psychologist Harry Harlow at the University of Wisconsin–Madison. The aim of the research was to produce clinical depression. The vertical chamber was a stainless-steel bin with slippery sides that sloped to a rounded bottom. A 3/8 in. wire mesh floor 1 in. above the bottom of the chamber allowed waste material to drop out of holes. The chamber had a food box and a water-bottle holder, and was covered with a pyramid top so that the monkeys were unable to escape. Harlow placed baby monkeys in the chamber alone for up to six weeks. Within a few days, they stopped moving about and remained huddled in a corner. The monkeys generally exhibited marked social impairment and peer hostility when removed from the chamber; most did not recover.

University of California, Riverside

On April 21, 1985, activists of the Animal Liberation Front (ALF) broke into the UC Riverside laboratories and removed hundreds of animals. According to Vicky Miller of PETA, who reported the raid to newswire services, UC-Riverside "has been using animals in experiments on sight deprivation and isolation for the last two years and has recently received a grant, paid for with our tax dollars, to continue torturing and killing animals." According to UCR officials, the ALF claims of animal mistreatment were "absolutely false," and the raid would result in long-term damage to some of the research projects, including those aimed at developing devices and treatment for blindness. UCR officials also reported the raid also included smashing equipment and resulted in several hundred thousand dollars of damage.

Covance

In Germany in 2004, journalist Friedrich Mülln took undercover footage of staff in Covance in Münster, Europe's largest primate-testing center. Staff were filmed handling monkeys roughly, screaming at them, and making them dance to blaring music. The monkeys were shown isolated in small wire cages with little or no natural light, no environmental enrichment, and subjected to high noise levels from staff shouting and playing the radio. Primatologist Jane Goodall described their living conditions as "horrendous."

A veterinary toxicologist employed as a study director at Covance in Vienna, Virginia, from 2002 to 2004, told city officials in Chandler, Arizona, that Covance was dissecting monkeys while the animals were still alive and able to feel pain. The employee approached the city with her concerns when she learned that Covance planned to build a new laboratory in Chandler.

She alleged that three monkeys in the Vienna laboratory had pushed themselves up on their elbows and had gasped for breath after their eyes had been removed, and while their intestines were being removed during necropsies (autopsy). When she expressed concern at the next study directors' meeting, she says she was told that it was just a reflex. She told city officials that she believed such movements were not reflexes but suggested "botched euthanasia performed by inadequately trained personnel." She alleged that she was ridiculed and subjected to thinly veiled threats when she contacted her supervisors about the issue.

University of Cambridge

BUAV alleges that monkeys were left unattended for up to 15 hours after having parts of their brains removed to induce strokes.
 

In the UK, after an undercover investigation in 1998, the British Union for the Abolition of Vivisection (BUAV), a lobby group, reported that researchers in Cambridge University's primate-testing labs were sawing the tops off marmosets' heads, inducing strokes, then leaving them overnight without veterinarian care, because staff worked only nine to five. The experiments used marmosets that were first trained to perform certain behavioral and cognitive tasks, then re-tested after brain damage to determine how the damage had affected their skills. The monkeys were deprived of food and water to encourage them to perform the tasks, with water being withheld for 22 out of every 24 hours.

The Research Defence Society defended Cambridge's research. The RDS wrote that the monkeys were fully anaesthetised, and appropriate pain killers were given after the surgery. "On recovery from the anaesthesia, the monkeys were kept in an incubator, offered food and water and monitored at regular intervals until the early evening. They were then allowed to sleep in the incubators until the next morning. No monkeys died unattended during the night after stroke surgery." A court rejected BUAV's application for a judicial review. BUAV appealed.

Columbia University

In 2003, CNN reported that a post-doctoral veterinarian at Columbia University complained to the university's Institutional Animal Care and Use Committee about experiments being conducted on baboons by E. Sander Connolly, an assistant professor of neurosurgery. The experiment involved a left transorbital craniectomy to expose the left internal carotid artery to occlude the blood supply to the brain. A clamp was placed on this blood vessel until the stroke was induced, after which Connolly would test a potential neuroprotective drug which if effective, would be used to treat humans suffering from stroke.

Connolly developed this methodology to make more consistent stroke infarcts in primates, which would improve the detection of differences in stroke treatment groups, and "provide important information not obtainable in rodent models." The baboons were kept alive after the surgery for observation for three to ten days in a state of "profound disability" which would have been "terrifying," according to neurologist Robert Hoffman. Connolly's published animal model states that animals were kept alive for three days, and that animals that were successfully self-caring were kept alive for 10 days. People for the Ethical Treatment of Animals has expressed strong opposition to this experiment and has written multiple letters to the NIH and other federal agencies to halt further mistreatment of baboons and other animals at Columbia.

An investigation by the U.S. Department of Agriculture found "no indication that the experiments...violated federal guidelines." The Dean of Research at Columbia's School of Medicine said that Connolly had stopped the experiments because of threats from animal rights activists, but still believed his work was humane and potentially valuable.

Attacks on researchers

In 2006, activists forced a primate researcher at UCLA to shut down the experiments in his lab. His name, phone number, and address were posted on the website of the UCLA Primate Freedom Project, along with a description of his research, which stated that he had "received a grant to kill 30 macaque monkeys for vision experiments. Each monkey is first paralyzed, then used for a single session that lasts up to 120 hours, and finally killed." Demonstrations were held outside his home. A Molotov cocktail 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 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, who performs experiments on cats and rhesus monkeys; the bomb had a faulty fuse and did not detonate. UCLA is now refusing Freedom of Information Act requests for animal medical records.

The house of UCLA researcher Edythe London was intentionally flooded on October 20, 2007, in an attack claimed by the Animal Liberation Front. London conducts research on addiction using non-human primates, and no claims were made by the ALF of any violation of any rules or regulations regarding the use of animals in research. London responded by writing an op-ed column in the LA Times titled "Why I use laboratory animals."

In 2009, a UCLA neurobiologist known for using animals to research drug addiction and other psychiatric disorders had his car burned for the second time.

China

In infectious disease research, China invests more than the U.S. does in conducting research on non-human primates. "Select agents and toxins" refers to a list of over 60 substances that pose the greatest risk to public health, and China uses non-human primates to test treatment of these select agents and toxins more than the U.S. does.

Great Ape Project

From Wikipedia, the free encyclopedia
 
Great Ape Project
Founded1993
FounderPeter Singer and Paola Cavalieri
FocusAnimal rights
Websitewww.projetogap.org.br/en/

The Great Ape Project (GAP), founded in 1993, is an international organization of primatologists, anthropologists, ethicists, and others who advocate a United Nations Declaration of the Rights of Great Apes that would confer basic legal rights on non-human great apes: bonobos, chimpanzees, gorillas and orangutans.

The rights suggested are the right to life, the protection of individual liberty, and the prohibition of torture. The organization also monitors individual great ape activity in the United States through a census program. Once rights are established, GAP would demand the release of great apes from captivity; currently 3,100 are held in the U.S., including 1,280 in biomedical research facilities.

The Great Ape Project (book)

The 1994 book The Great Ape Project: Equality Beyond Humanity, edited by philosophers Paola Cavalieri and Peter Singer, features contributions from thirty-four authors, including Jane Goodall and Richard Dawkins, who have submitted articles voicing their support for the project. The authors write that human beings are intelligent animals with a varied social, emotional, and cognitive life. If great apes also display such attributes, the authors argue, they deserve the same consideration humans extend to members of their own species.

The book highlights findings that support the capacity of great apes to possess rationality and self-consciousness, and the ability to be aware of themselves as distinct entities with a past and future. Documented conversations (in sign languages) with individual great apes are the basis for these findings. Other subjects addressed within the book include the division placed between humans and great apes, great apes as persons, progress in gaining rights for the severely intellectually disabled (once an overlooked minority), and the situation of great apes in the world today.

World Declaration on Great Apes

The Great Ape Project is campaigning to have the United Nations endorse a World Declaration on Great Apes. This would extend what the project calls the "community of equals" to include chimpanzees, gorillas and orangutans. The declaration seeks to extend to non-human great apes the protection of three basic interests: the right to life, the protection of individual liberty, and the prohibition of torture.

Right to life

The declaration states that members of the community of equals, which includes humans, have an essential right to life and may not be killed except in certain strictly defined circumstances such as self-defense.

Protection of individual liberty

The declaration states that members of the community of equals are not to be deprived of their liberty, and are entitled to immediate release where there has been no form of due process. Under the proposed declaration, the detention of great apes who have not been convicted of any crime or who are not criminally liable should be permitted only where it can be shown that the detention is in their own interests or is necessary to protect the public. The declaration says there must be a right of appeal, either directly or through an advocate, to a judicial tribunal.

Prohibition of torture

The declaration prohibits the torture, defined as the deliberate infliction of severe pain, on any great ape, whether wantonly or because of a perceived benefit to others. Under International Human Rights Law this is a jus cogens principle and under all major human rights documents it cannot at any time be derogated by any State.

Opposition

Professor Colin Blakemore, head of the Medical Research Council in the United Kingdom from 2003–2007, is opposed to granting rights to non-human apes, stating "I can see no current necessity for the use of great apes, and I'm pleased that they're not being used and that every effort is being made to reduce the use of other primates. But I worry about the principle of where the moral boundaries lie. There is only one very secure definition that can be made, and that is between our species and others." Blakemore suggests that it would be necessary to perform research on great apes if humans were threatened by a pandemic virus that afflicted only humans and other great apes. The British Union for the Abolition of Vivisection described Blakemore's stance as "backward-looking".

Recent developments

United States

A study commissioned by the National Institute of Health (NIH) and conducted by the Institute of Medicine (IOM) concluded in a report (see report brief) released on 15 December 2011 that "while the chimpanzee has been a valuable animal model in past research, most current use of chimpanzees for biomedical research is unnecessary". The primary recommendation is that the use of chimpanzees in research be guided by a set of principles and criteria, in effect to greatly limit government-funded research using chimpanzees. Falling short of calling for the out-right ban of using chimpanzees for research, the report acknowledged that new emerging, or re-emerging diseases may require the use of chimpanzees, echoing Professor Colin Blakemore's concern.

Francis Collins, Director of NIH announced on the same day the report was released that he accepted the recommendations and will develop the implementation plan which includes the forming of an expert committee to review all submitted grant applications and projects already underway involving the use of chimpanzees. Furthermore, no new grant applications using chimpanzees will be reviewed until further notice.

On 21 September 2012, NIH announced that 110 chimpanzees owned by the government will be retired. NIH owns about 500 chimpanzees for research, this move signifies the first step to wind down NIH's investment in chimpanzee research, according to Francis Collins. Currently housed at the New Iberia Research Center in Louisiana, 10 of the retired chimpanzees will go to the chimpanzee sanctuary Chimp Haven while the rest will go to Texas Biomedical Research Institute in San Antonio. However concerns over the chimpanzee's status in the Texas Biomedical Research Institute as "research ineligible" rather than "retired" prompted NIH to reconsider the plan and it announced on 17 October 2012 that as many chimpanzees as possible will be relocated to Chimp Haven by August 2013 and eventually all 110 will move there.

On 22 January 2013, a NIH task force released a report calling for the government to retire most of the chimpanzees the U.S. government support. The panel concluded that the animals provide little benefit in biomedical discoveries except in a few disease cases which can be supported by a small population of 50 primates for future research. Other approaches such as genetically altered mice should be developed and refined.

On 13 November 2013, the U.S. House of Representatives and the U.S. Senate passed The Chimpanzee Health Improvement, Maintenance and Protection Act, approving the funding to expand the capacity of Chimp Haven and other chimpanzee sanctuaries, thus allowing the transfer of almost all of the apes owned by the federal government to live in a more natural and group environment than in the laboratory. The transfer is expected to take five years when all but 50 chimpanzees, which will remain with the NIH, will be "retired".

Germany

The Great Ape Project achieved many of its goals in its early years: New Zealand completely banned invasive experiments on great apes in 1999, as did the Balearic Islands (an autonomous region of the monarchy of Spain) in 2007, deciding to implement certain fundamental rights for great apes in their code of law. However, the project entered a long period of political stagnation in Europe. All hopes that the achievements on the Balearic Islands would spark off further steps on the mainland of Spain and from there to other European countries proved to be futile. Efforts in Spain were largely curtailed due to the influence of the Catholic Church, obstructing the project's goals. In 2011, however, the project was given an official relaunch in Germany, supported by the Germany-based Giordano-Bruno-Stiftung.

Great Ape Project Germany filed an official law initiative in spring of 2014, to have the aforesaid fundamental rights for great apes implemented into the constitutional law of the Federal Republic of Germany. The goal was (and still is) to have the animal welfare law extended to specifically grant the great apes the rights needed, to give them the chance, to have legal guardians representing their interests. In analogy to infants or of people suffering from dementia or Alzheimer disease, who cannot speak for themselves, legal guardians could file lawsuits against anyone violating the fundamental rights of the apes. Right now there are only animal protection laws, giving the animals no active legitimization.

Ape

From Wikipedia, the free encyclopedia
Hominoids or apes
Temporal range: Miocene-Holocene
Man of the woods.JPG
Sumatran orangutan (Pongo abelli)
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Suborder: Haplorhini
Infraorder: Simiiformes
Parvorder: Catarrhini
Superfamily: Hominoidea
Gray, 1825
Type species
Homo sapiens
Families

sister: Cercopithecoidea

Apes (collectively Hominoidea /hɒmɪˈnɔɪdi.ə/) are a clade of Old World simians native to sub-Saharan Africa and Southeast Asia (though they were more widespread in Africa, most of Asia, and as well as Europe in prehistory), which together with its sister group Cercopithecidae form the catarrhine clade, cladistically making them monkeys. Apes do not have tails due to a mutation of the TBXT gene. In traditional and non-scientific use, the term "ape" can include tailless primates taxonomically considered Cercopithecidae (such as the Barbary ape and black ape), and is thus not equivalent to the scientific taxon Hominoidea. There are two extant branches of the superfamily Hominoidea: the gibbons, or lesser apes; and the hominids, or great apes.

  • The family Hylobatidae, the lesser apes, include four genera and a total of 20 species of gibbon, including the lar gibbon and the siamang, all native to Asia. They are highly arboreal and bipedal on the ground. They have lighter bodies and smaller social groups than great apes.
  • The family Hominidae (hominids), the great apes, include four genera comprising three extant species of orangutans and their subspecies, two extant species of gorillas and their subspecies, two extant species of panins (bonobos and chimpanzees) and their subspecies, and humans in a single extant subspecies.

Except for gorillas and humans, hominoids are agile climbers of trees. Apes eat a variety of plant and animal foods, with the majority of food being plant foods, which can include fruits, leaves, stalks, roots and seeds, including nuts and grass seeds. Human diets are sometimes substantially different from that of other hominoids due in part to the development of technology and a wide range of habitation. Humans are by far the most numerous of the hominoid species, in fact outnumbering all other primates by a factor of several thousand to one.

All non-human hominoids are rare and threatened with extinction. The eastern hoolock gibbon is the least threatened, only being vulnerable to extinction. Five gibbon species are critically endangered, as are all species of orangutan and gorilla. The remaining species of gibbon, the bonobo, and all four species of chimpanzees are endangered. The chief threat to most of the endangered species is loss of tropical rainforest habitat, though some populations are further imperiled by hunting for bushmeat. The great apes of Africa are also facing threat from the Ebola virus. Currently considered to be the greatest threat to survival of African apes, Ebola infection is responsible for the death of at least one third of all gorillas and chimpanzees since 1990.

Name and terminology

"Ape", from Old English apa, is a word of uncertain origin. The term has a history of rather imprecise usage—and of comedic or punning usage in the vernacular. Its earliest meaning was generally of any non-human anthropoid primate, as is still the case for its cognates in other Germanic languages. Later, after the term "monkey" had been introduced into English, "ape" was specialized to refer to a tailless (therefore exceptionally human-like) primate. Thus, the term "ape" obtained two different meanings, as shown in the 1911 Encyclopædia Britannica entry: it could be used as a synonym for "monkey" and it could denote the tailless human-like primate in particular.

Some, or recently all, hominoids are also called "apes", but the term is used broadly and has several different senses within both popular and scientific settings. "Ape" has been used as a synonym for "monkey" or for naming any primate with a human-like appearance, particularly those without a tail. Biologists have traditionally used the term "ape" to mean a member of the superfamily Hominoidea other than humans, but more recently to mean all members of Hominoidea. So "ape"—not to be confused with "great ape"—now becomes another word for hominoid including humans.

The taxonomic term hominoid is derived from, and intended as encompassing, the hominids, the family of great apes. Both terms were introduced by Gray (1825). The term hominins is also due to Gray (1824), intended as including the human lineage (see also Hominidae#Terminology, Human taxonomy).

The distinction between apes and monkeys is complicated by the traditional paraphyly of monkeys: Apes emerged as a sister group of Old World Monkeys in the catarrhines, which are a sister group of New World Monkeys. Therefore, cladistically, apes, catarrhines and related contemporary extinct groups such as Parapithecidaea are monkeys as well, for any consistent definition of "monkey". "Old World Monkey" may also legitimately be taken to be meant to include all the catarrhines, including apes and extinct species such as Aegyptopithecus, in which case the apes, Cercopithecoidea and Aegyptopithecus emerged within the Old World Monkeys.

The primates called "apes" today became known to Europeans after the 18th century. As zoological knowledge developed, it became clear that taillessness occurred in a number of different and otherwise distantly related species. Sir Wilfrid Le Gros Clark was one of those primatologists who developed the idea that there were trends in primate evolution and that the extant members of the order could be arranged in an ".. ascending series", leading from "monkeys" to "apes" to humans. Within this tradition "ape" came to refer to all members of the superfamily Hominoidea except humans. As such, this use of "apes" represented a paraphyletic grouping, meaning that, even though all species of apes were descended from a common ancestor, this grouping did not include all the descendant species, because humans were excluded from being among the apes.

Traditionally, the English-language vernacular name "apes" does not include humans, but phylogenetically, humans (Homo) form part of the family Hominidae within Hominoidea. Thus, there are at least three common, or traditional, uses of the term "ape": non-specialists may not distinguish between "monkeys" and "apes", that is, they may use the two terms interchangeably; or they may use "ape" for any tailless monkey or non-human hominoid; or they may use the term "ape" to just mean the non-human hominoids.

Modern taxonomy aims for the use of monophyletic groups for taxonomic classification; Some literature may now use the common name "ape" to mean all members of the superfamily Hominoidea, including humans. For example, in his 2005 book, Benton wrote "The apes, Hominoidea, today include the gibbons and orang-utan ... the gorilla and chimpanzee ... and humans". Modern biologists and primatologists refer to apes that are not human as "non-human" apes. Scientists broadly, other than paleoanthropologists, may use the term "hominin" to identify the human clade, replacing the term "hominid". See terminology of primate names.

See below, History of hominoid taxonomy, for a discussion of changes in scientific classification and terminology regarding hominoids.

Evolution

Although the hominoid fossil record is still incomplete and fragmentary, there is now enough evidence to provide an outline of the evolutionary history of humans. Previously, the divergence between humans and other extant hominoids was thought to have occurred 15 to 20 million years ago, and several species of that time period, such as Ramapithecus, were once thought to be hominins and possible ancestors of humans. But, later fossil finds indicated that Ramapithecus was more closely related to the orangutan; and new biochemical evidence indicates that the last common ancestor of humans and non-hominins (that is, the chimpanzees) occurred between 5 and 10 million years ago, and probably nearer the lower end of that range (more recent); see Chimpanzee–human last common ancestor (CHLCA).

Taxonomic classification and phylogeny

Genetic analysis combined with fossil evidence indicates that hominoids diverged from the Old World monkeys about 25 million years ago (mya), near the Oligocene–Miocene boundary. The gibbons split from the rest about 18 mya, and the hominid splits happened 14 mya (Pongo), 7 mya (Gorilla), and 3–5 mya (Homo & Pan). In 2015, a new genus and species were described, Pliobates cataloniae, which lived 11.6 mya, and appears to predate the split between Hominidae and Hylobatidae.

Skeletons of members of the ape superfamily, Hominoidea. There are two extant families: Hominidae, the "great apes"; and Hylobatidae, the gibbons, or "lesser apes".
From left: Comparison of size of gibbon, human, chimpanzee, gorilla and orangutan. Non-human hominoids do not stand upright as their normal posture.

The families, and extant genera and species of hominoids are:

History of hominoid taxonomy

The history of hominoid taxonomy is complex and somewhat confusing. Recent evidence has changed our understanding of the relationships between the hominoids, especially regarding the human lineage; and the traditionally used terms have become somewhat confused. Competing approaches to methodology and terminology are found among current scientific sources. Over time, authorities have changed the names and the meanings of names of groups and subgroups as new evidence — that is, new discoveries of fossils and tools and of observations in the field, plus continual comparisons of anatomy and DNA sequences — has changed the understanding of relationships between hominoids. There has been a gradual demotion of humans from being 'special' in the taxonomy to being one branch among many. This recent turmoil (of history) illustrates the growing influence on all taxonomy of cladistics, the science of classifying living things strictly according to their lines of descent.

Today, there are eight extant genera of hominoids. They are the four genera in the family Hominidae, namely Homo, Pan, Gorilla, and Pongo; plus four genera in the family Hylobatidae (gibbons): Hylobates, Hoolock, Nomascus and Symphalangus. (The two subspecies of hoolock gibbons were recently moved from the genus Bunopithecus to the new genus Hoolock and re-ranked as species; a third species was described in January 2017).

In 1758, Carl Linnaeus, relying on second- or third-hand accounts, placed a second species in Homo along with H. sapiens: Homo troglodytes ("cave-dwelling man"). Although the term "Orang Outang" is listed as a variety – Homo sylvestris – under this species, it is nevertheless not clear to which animal this name refers, as Linnaeus had no specimen to refer to, hence no precise description. Linnaeus may have based Homo troglodytes on reports of mythical creatures, then-unidentified simians, or Asian natives dressed in animal skins. Linnaeus named the orangutan Simia satyrus ("satyr monkey"). He placed the three genera Homo, Simia and Lemur in the order of Primates.

The troglodytes name was used for the chimpanzee by Blumenbach in 1775, but moved to the genus Simia. The orangutan was moved to the genus Pongo in 1799 by Lacépède.

Linnaeus's inclusion of humans in the primates with monkeys and apes was troubling for people who denied a close relationship between humans and the rest of the animal kingdom. Linnaeus's Lutheran archbishop had accused him of "impiety". In a letter to Johann Georg Gmelin dated 25 February 1747, Linnaeus wrote:

It is not pleasing to me that I must place humans among the primates, but man is intimately familiar with himself. Let's not quibble over words. It will be the same to me whatever name is applied. But I desperately seek from you and from the whole world a general difference between men and simians from the principles of Natural History. I certainly know of none. If only someone might tell me one! If I called man a simian or vice versa I would bring together all the theologians against me. Perhaps I ought to, in accordance with the law of Natural History.

Accordingly, Johann Friedrich Blumenbach in the first edition of his Manual of Natural History (1779), proposed that the primates be divided into the Quadrumana (four-handed, i.e. apes and monkeys) and Bimana (two-handed, i.e. humans). This distinction was taken up by other naturalists, most notably Georges Cuvier. Some elevated the distinction to the level of order.

However, the many affinities between humans and other primates – and especially the "great apes" – made it clear that the distinction made no scientific sense. In his 1871 book The Descent of Man, and Selection in Relation to Sex, Charles Darwin wrote:

The greater number of naturalists who have taken into consideration the whole structure of man, including his mental faculties, have followed Blumenbach and Cuvier, and have placed man in a separate Order, under the title of the Bimana, and therefore on an equality with the orders of the Quadrumana, Carnivora, etc. Recently many of our best naturalists have recurred to the view first propounded by Linnaeus, so remarkable for his sagacity, and have placed man in the same Order with the Quadrumana, under the title of the Primates. The justice of this conclusion will be admitted: for in the first place, we must bear in mind the comparative insignificance for classification of the great development of the brain in man, and that the strongly marked differences between the skulls of man and the Quadrumana (lately insisted upon by Bischoff, Aeby, and others) apparently follow from their differently developed brains. In the second place, we must remember that nearly all the other and more important differences between man and the Quadrumana are manifestly adaptive in their nature, and relate chiefly to the erect position of man; such as the structure of his hand, foot, and pelvis, the curvature of his spine, and the position of his head.

Changes in taxonomy and terminology

Humans the non-apes: Until about 1960, taxonomists typically divided the superfamily Hominoidea into two families. The science community treated humans and their extinct relatives as the outgroup within the superfamily; that is, humans were considered as quite distant from kinship with the "apes". Humans were classified as the family Hominidae and were known as the "hominids". All other hominoids were known as "apes" and were referred to the family Pongidae.
Hominoid taxonomy 1.svg
The "great apes" in Pongidae: The 1960s saw the methodologies of molecular biology applied to primate taxonomy. Goodman's 1964 immunological study of serum proteins led to re-classifying the hominoids into three families: the humans in Hominidae; the great apes in Pongidae; and the "lesser apes" (gibbons) in Hylobatidae. However, this arrangement had two trichotomies: Pan, Gorilla, and Pongo of the "great apes" in Pongidae, and Hominidae, Pongidae, and Hylobatidae in Hominoidea. These presented a puzzle; scientists wanted to know which genus speciated first from the common hominoid ancestor.
Hominoid taxonomy 2.svg
Gibbons the outgroup: New studies indicated that gibbons, not humans, are the outgroup within the superfamily Hominoidea, meaning: the rest of the hominoids are more closely related to each other than (any of them) are to the gibbons. With this splitting, the gibbons (Hylobates, et al.) were isolated after moving the great apes into the same family as humans. Now the term "hominid" encompassed a larger collective taxa within the family Hominidae. With the family trichotomy settled, scientists could now work to learn which genus is 'least' related to the others in the subfamily Ponginae.
Hominoid taxonomy 3.svg
Orangutans the outgroup: Investigations comparing humans and the three other hominid genera disclosed that the African apes (chimpanzees and gorillas) and humans are more closely related to each other than any of them are to the Asian orangutans (Pongo); that is, the orangutans, not humans, are the outgroup within the family Hominidae. This led to reassigning the African apes to the subfamily Homininae with humans—which presented a new three-way split: Homo, Pan, and Gorilla.
Hominoid taxonomy 4.svg
Hominins: In an effort to resolve the trichotomy, while preserving the nostalgic "outgroup" status of humans, the subfamily Homininae was divided into two tribes: Gorillini, comprising genus Pan and genus Gorilla; and Hominini, comprising genus Homo (the humans). Humans and close relatives now began to be known as "hominins", that is, of the tribe Hominini. Thus, the term "hominin" succeeded to the previous use of "hominid", which meaning had changed with changes in Hominidae (see above: 3rd graphic, "Gibbons the outgroup").
Hominoid taxonomy 5.svg
Gorillas the outgroup: New DNA comparisons now provided evidence that gorillas, not humans, are the outgroup in the subfamily Homininae; this suggested that chimpanzees should be grouped with humans in the tribe Hominini, but in separate subtribes. Now the name "hominin" delineated Homo plus those earliest Homo relatives and ancestors that arose after the divergence from the chimpanzees. (Humans are no longer classified as an outgroup, but are a branch, deep in the tree of the pre-1960s ape group).
Hominoid taxonomy 6.svg
Speciation of gibbons: Later DNA comparisons disclosed previously unknown speciation of genus Hylobates (gibbons) into four genera: Hylobates, Hoolock, Nomascus, and Symphalangus. The ordering of speciation of these four genera are being investigated as of 2022.
Hominoid taxonomy 7.svg

Characteristics

Like those of the orangutan, the shoulder joints of hominoids are adapted to brachiation, or movement by swinging in tree branches.

The lesser apes are the gibbon family, Hylobatidae, of sixteen species; all are native to Asia. Their major differentiating characteristic is their long arms, which they use to brachiate through trees. Their wrists are ball and socket joints as an evolutionary adaptation to their arboreal lifestyle. Generally smaller than the African apes, the largest gibbon, the siamang, weighs up to 14 kg (31 lb); in comparison, the smallest "great ape", the bonobo, is 34 to 60 kg (75 to 132 lb).

The superfamily Hominoidea falls within the parvorder Catarrhini, which also includes the Old World monkeys of Africa and Eurasia. Within this grouping, the two families Hylobatidae and Hominidae can be distinguished from Old World monkeys by the number of cusps on their molars; hominoids have five in the "Y-5" molar pattern, whereas Old World monkeys have only four in a bilophodont pattern.

Further, in comparison with Old World monkeys, hominoids are noted for: more mobile shoulder joints and arms due to the dorsal position of the scapula; broader ribcages that are flatter front-to-back; and a shorter, less mobile spine, with greatly reduced caudal (tail) vertebrae—resulting in complete loss of the tail in extant hominoid species. These are anatomical adaptations, first, to vertical hanging and swinging locomotion (brachiation) and, later, to developing balance in a bipedal pose. Note there are primates in other families that also lack tails, and at least one, the pig-tailed langur, is known to walk significant distances bipedally. The front of the ape skull is characterised by its sinuses, fusion of the frontal bone, and by post-orbital constriction.

Distinction from monkeys

Cladistically, apes, catarrhines, and extinct species such as Aegyptopithecus and Parapithecidaea, are monkeys, so one can only specify ape features not present in other monkeys.

Unlike most monkeys, apes do not possess a tail. Monkeys are more likely to be in trees and use their tails for balance. While the great apes are considerably larger than monkeys, gibbons (lesser apes) are smaller than some monkeys. Apes are considered to be more intelligent than monkeys, which are considered to have more primitive brains.

The enzyme urate oxidase has become inactive in all apes, its function having been lost in two primate lineages during the middle Miocene; first in the common ancestors of Hominidae, and later in the common ancestor of Hylobatidae. It has been hypothesized that in both incidents it was a mutation that occurred in apes living in Europe when the climate was getting colder, leading to starvation during winter. The mutation changed the biochemistry of the apes and made it easier to accumulate fat, which allowed the animals to survive longer periods of starvation. When they migrated to Asia and Africa, this genetic trait remained.

Behaviour

Major studies of behaviour in the field were completed on the three better-known "great apes", for example by Jane Goodall, Dian Fossey and Birute Galdikas. These studies have shown that in their natural environments, the non-human hominoids show sharply varying social structure: gibbons are monogamous, territorial pair-bonders, orangutans are solitary, gorillas live in small troops with a single adult male leader, while chimpanzees live in larger troops with bonobos exhibiting promiscuous sexual behaviour. Their diets also vary; gorillas are foliovores, while the others are all primarily frugivores, although the common chimpanzee hunts for meat. Foraging behaviour is correspondingly variable.

Diet

Apart from humans and gorillas, apes eat a predominantly frugivorous diet, mostly fruit, but supplemented with a variety of other foods. Gorillas are predominately folivorous, eating mostly stalks, shoots, roots and leaves with some fruit and other foods. Non-human apes usually eat a small amount of raw animal foods such as insects or eggs. In the case of humans, migration and the invention of hunting tools and cooking has led to an even wider variety of foods and diets, with many human diets including large amounts of cooked tubers (roots) or legumes. Other food production and processing methods including animal husbandry and industrial refining and processing have further changed human diets. Humans and other apes occasionally eat other primates. Some of these primates are now close to extinction with habitat loss being the underlying cause.

Cognition

A series of images showing a gorilla utilizing a small tree trunk as a tool to maintain balance as she fished for aquatic herbs

All the non-human hominoids are generally thought of as highly intelligent, and scientific study has broadly confirmed that they perform very well on a wide range of cognitive tests—though there is relatively little data on gibbon cognition. The early studies by Wolfgang Köhler demonstrated exceptional problem-solving abilities in chimpanzees, which Köhler attributed to insight. The use of tools has been repeatedly demonstrated; more recently, the manufacture of tools has been documented, both in the wild and in laboratory tests. Imitation is much more easily demonstrated in "great apes" than in other primate species. Almost all the studies in animal language acquisition have been done with "great apes", and though there is continuing dispute as to whether they demonstrate real language abilities, there is no doubt that they involve significant feats of learning. Chimpanzees in different parts of Africa have developed tools that are used in food acquisition, demonstrating a form of animal culture.

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