Chimpanzee

The first use of the name chimpanze is recorded in The London Magazine in 1738, glossed as meaning "mockman" in a language of "the Angolans" (reportedly modern Vili (Civili), a Kongo language of the coast, has the comparable ci-mpenzi). The spelling chimpanzee is found in a 1758 supplement to ''Chamber's Cyclopædia''. The colloquialism "chimp" was most likely coined some time in the late 1870s. The genus name Pan derives from the Greek god, while the specific name troglodytes was taken from the Troglodytae, a mythical race of cave-dwellers; it had first been proposed for the genus but a genus of wren took priority. ==Taxonomy==

The first great ape known to Western science in the 17th century was the "orang-outang" (genus Pongo), the local Malay name being recorded in Java by the Dutch physician Jacobus Bontius. In 1641, the Dutch anatomist Nicolaes Tulp applied the name to a chimpanzee or bonobo brought to the Netherlands from Angola. Another Dutch anatomist, Peter Camper, dissected specimens from Central Africa and Southeast Asia in the 1770s, noting the differences between the African and Asian apes. The German naturalist Johann Friedrich Blumenbach classified the chimpanzee as Simia troglodytes by 1775. Another German naturalist, Lorenz Oken, coined the genus Pan in 1816. The bonobo was recognised as distinct from the chimpanzee by 1933. Both chimpanzees and humans are part of the Hominidae, or, hominids, whose members are known as the great apes, are a taxonomic family of primates that includes eight extant species in four genera: Pongo (the Bornean, Sumatran and Tapanuli orangutan); Gorilla (the eastern and western gorilla); Pan (the chimpanzee and the bonobo); and Homo, of which only modern humans (Homo sapiens) remain. The academic Jared Diamond has offered the opinion that humans might be looked at as the "third chimpanzee" after referencing the bonobos as the second one. Evolution Despite a large number of Homo fossil finds, Pan fossils were not described until 2005. Existing chimpanzee populations in West and Central Africa do not overlap with the major human fossil sites in East Africa, but chimpanzee fossils have now been reported from Kenya. This indicates that both humans and members of the Pan clade were present in the East African Rift Valley during the Middle Pleistocene. Evolutionary biologists and paleontologists have attempted to reconstruct the last common ancestor of Homo and Pan. By the end of the 20th century, it was assumed that humans evolved from a chimpanzee-like ancestor. A 2015 study of Ardipithecus, an early human relative dated 4.4 mya, disputed this interpretation. The study concluded that humans, chimpanzees and bonobos evolved from a generalised species that lacked the derived traits of both genera. Subsequent studies disputed this, finding that the hand of Ardipithecus was adapted for suspension climbing and the heel for vertical climbing, much like modern African apes. Anthropologist Alice Roberts indicates that at least 24 species of hominin have appeared after the divergence of humans from chimpanzees estimated at 10 to 7 million years ago. According to studies published in 2017 by researchers at George Washington University, bonobos, along with chimpanzees, split from the human line about 8 million years ago; then bonobos split from the common chimpanzee line about 2 million years ago. Another 2017 genetic study suggests ancient gene flow (introgression) between 200,000 and 550,000 years ago from the bonobo into the ancestors of central and eastern chimpanzees. Roberts states that the examination of DNA in close relatives of chimpanzees, humans and gorillas makes note that they have a common ancestor in the orangutan with each differing in their own genetic composition by 3.1% from the orangutan. The comparable difference in DNA between the chimpanzee and the gorilla is 1.6% difference, and between chimpanzees and humans is 1.2% difference. Subspecies and population status Four subspecies of the chimpanzee have been recognised, with the possibility of a fifth: • Central chimpanzee or the tschego (Pan troglodytes troglodytes), found in Cameroon, the Central African Republic, Equatorial Guinea, Gabon, the Republic of the Congo, and the Democratic Republic of the Congo, with about 140,000 individuals existing in the wild. • Western chimpanzee (P. troglodytes verus), found in Ivory Coast, Guinea, Liberia, Mali, Sierra Leone, Guinea-Bissau, Senegal, and Ghana with about 52,800 individuals still in existence. • Nigeria-Cameroon chimpanzee (P. troglodytes ellioti (also known as P. t. vellerosus)), • Eastern chimpanzee (P. troglodytes schweinfurthii), found in the Central African Republic, South Sudan, the Democratic Republic of the Congo, Uganda, Rwanda, Burundi, Tanzania, and Zambia, with approximately 180,000–256,000 individuals still existing in the wild. • Southeastern chimpanzee, P. troglodytes marungensis, in Burundi, Rwanda, Tanzania, and Uganda. Colin Groves argues that this is a subspecies, created by enough variation between the northern and southern populations of P. t. schweinfurthii, (compared to 20,383 in the human proteome). The DNA sequences of humans and chimpanzees are very similar and the difference in protein number mostly arises from incomplete sequences in the chimpanzee genome. Both species differ by about 35 million single-nucleotide changes, five million insertion/deletion events and various chromosomal rearrangements. Typical human and chimpanzee protein homologs differ in an average of only two amino acids. About 30% of all human proteins are identical in sequence to the corresponding chimpanzee protein. Humans have 23 pairs of chromosomes and other great apes, such as chimpanzees, have 24 pairs of chromosomes. In the human evolutionary lineage, two ancestral ape chromosomes fused at their telomeres, producing human chromosome 2. Another study showed that patterns of DNA methylation, which are a known regulation mechanism for gene expression, differ in the prefrontal cortex of humans versus chimpanzees, and implicated this difference in the evolutionary divergence of the two species. The published chimpanzee genome differs from that of the human genome by 1.23% in direct sequence comparisons. Around 20% of this figure is accounted for by variation within each species, leaving only ~1.06% consistent sequence divergence between humans and chimps at shared genes. This nucleotide by nucleotide difference is dwarfed, however, by the portion of each genome that is not shared, including around 6% of functional genes that are unique to either humans or chimps. In other words, the considerable observable differences between humans and chimps may be due as much or more to genome level variation in the number, function and expression of genes rather than DNA sequence changes in shared genes. On average, a typical human protein-coding gene differs from its chimpanzee ortholog by only two amino acid substitutions; nearly one third of human genes have exactly the same protein translation as their chimpanzee orthologs. A major difference between the two genomes is human chromosome 2, which is equivalent to a fusion product of chimpanzee chromosomes 12 and 13 (later renamed to chromosomes 2A and 2B, respectively). In comparing the human genome to that of both chimpanzees and bonobos, a 2021 study by Yafei Mao found that the human genome was closer to the chimpanzee in same segments (2.55%), and the bonobo in others (2.52%). ==Characteristics==

Adult chimpanzees have an average standing height of . Wild adult males weigh between , and females weigh between . In exceptional cases, certain individuals may considerably exceed these measurements, standing over on two legs and weighing up to in captivity. The chimpanzee is more robustly built than the bonobo but less than the gorilla. The arms of a chimpanzee are longer than its legs and can reach below the knees. The hands have long fingers with short thumbs and flat fingernails. The feet are adapted for grasping, and the big toe is opposable. The pelvis is long with an extended ilium. A chimpanzee's head is rounded with a prominent and prognathous face and a pronounced brow ridge. It has forward-facing eyes, a small nose, rounded non-lobed ears and a long mobile upper lip. Additionally, adult males have sharp canine teeth. Like all great apes, it has a dental formula of , that is, two incisors, one canine, two premolars, and three molars on both halves of each jaw. Chimpanzees lack the prominent sagittal crest and associated head and neck musculature of gorillas. Chimpanzee bodies are covered by coarse hair, except for the face, fingers, toes, palms of the hands, and soles of the feet. Chimpanzees lose more hair as they age and develop bald spots. The hair of a chimpanzee is typically black but can be brown or ginger. As they get older, white or grey patches may appear, particularly on the chin and lower region. Facial pigmentation increases with age and exposure to ultraviolet light. Females develop swelling pink skin when in oestrus. Chimpanzees are adapted for both arboreal and terrestrial locomotion. Arboreal locomotion consists of vertical climbing and brachiation. On the ground, chimpanzees move both quadrupedally and bipedally. These movements appear to have similar energy costs. As with bonobos and gorillas, chimpanzees move quadrupedally by knuckle-walking, which probably evolved independently in Pan and Gorilla. Their muscles are 50% stronger per weight than those of humans due to higher content of fast twitch muscle fibres, one of the chimpanzee's adaptations for climbing and swinging. According to Japan's Asahiyama Zoo, the grip strength of an adult chimpanzee is estimated to be , while other sources claim figures of up to . The chimpanzee brain is around 66% smaller than that of a human's while the skull has an average endocranial volume of 400 cm3 compared to 1,201 cm3 for humans. The brains also show differences in neuron connectivity that are independent of size. While chimpanzees and humans have the same basic wiring, those of the former are more attuned for quick and direct action, while the latter are more adapted for higher cognition. ==Ecology==

The chimpanzee is a highly adaptable species. It lives in a variety of habitats, including dry savanna, evergreen rainforest, montane forest, swamp forest, and dry woodland-savanna mosaic. In Gombe, the chimpanzee mostly uses semideciduous and evergreen forest as well as open woodland. At Bossou, the chimpanzee inhabits multistage secondary deciduous forest, which has grown after shifting cultivation, as well as primary forest and grassland. At Taï, it is found in the last remaining tropical rain forest in Ivory Coast. The chimpanzee has an advanced cognitive map of its home range and can repeatedly find food. The chimpanzee builds a sleeping nest in a tree in a different location each night, never using the same nest more than once. Chimpanzees sleep alone in separate nests except for infants or juvenile chimpanzees, which sleep with their mothers. A study in Budongo Forest, Uganda found that 64.5% of their feeding time concentrated on fruits (84.6% of which being ripe), particularly those from two species of Ficus, Maesopsis eminii, and Celtis gomphophylla. In addition, 19% of feeding time was spent on arboreal leaves, mostly Broussonetia papyrifera and Celtis mildbraedii. While the chimpanzee is mostly herbivorous, it does eat honey, soil, insects, birds and their eggs, and small to medium-sized mammals, including other primates. Insect species consumed include the weaver ant Oecophylla longinoda, Macrotermes termites, and honey bees. Despite the fact that chimpanzees are known to hunt and to collect both insects and other invertebrates, such food actually makes up a very small portion of their diet, from as little as 2% yearly to as much as 65 grams of animal flesh per day for each adult chimpanzee in peak hunting seasons. This also varies from troop to troop and year to year. However, in all cases, the majority of their diet consists of fruits, leaves, roots, and other plant matter. Female chimpanzees appear to consume much less animal flesh than males, according to several studies. Jane Goodall documented many occasions within Gombe Stream National Park of chimpanzees and western red colobus monkeys ignoring each other despite close proximity. Chimpanzees do not appear to directly compete with gorillas in areas where they overlap. When fruit is abundant, gorilla and chimpanzee diets converge, but when fruit is scarce gorillas resort to vegetation. The two apes may also feed on different species, whether fruit or insects. Interactions between them can range from friendly and even stable social bonding, to avoidance, to aggression and even predation of infants on the part of chimpanzees. Mortality and health ) The average lifespan of a wild chimpanzee is relatively short. They usually live less than 15 years, although individuals that reach 12 years may live an additional 15 years. On rare occasions, wild chimpanzees may live nearly 60 years. Captive chimpanzees tend to live longer than most wild ones, with median lifespans of 31.7 years for males and 38.7 years for females. The oldest-known male captive chimpanzee to have been documented lived to 66 years, and the oldest female, Little Mama, was nearly 80 years old. Leopards prey on chimpanzees in some areas. It is possible that much of the mortality caused by leopards can be attributed to individuals that have specialised in killing chimpanzees. There is at least one record of chimpanzees killing a leopard cub after mobbing it and its mother in their den. Four chimpanzees could have fallen prey to lions at Mahale Mountains National Park. Although no other instances of lion predation on chimpanzees have been recorded, lions likely do kill chimpanzees occasionally, and the larger group sizes of savanna chimpanzees may have developed as a response to threats from these big cats. Chimpanzees may react to lions by fleeing up trees, vocalising, or hiding in silence. ''. Chimpanzees and humans share only 50% of their parasite and microbe species. This is due to the differences in environmental and dietary adaptations; human internal parasite species overlap more with omnivorous, savanna-dwelling baboons. The chimpanzee is host to the louse species Pediculus schaeffi, a close relative of P. humanus, which infests human head and body hair. By contrast, the human pubic louse Pthirus pubis is closely related to Pthirus gorillae, which infests gorillas. A 2017 study of gastrointestinal parasites of wild chimpanzees in degraded forest in Uganda found nine species of protozoa, five nematodes, one cestode, and one trematode. The most prevalent species was the protozoan Troglodytella abrassarti. ==Behaviour==

Behaviour of chimpanzees has been studied from multiple perspectives including their group structure, their mating preferences, their parenting capacities, the limits of their communication abilities, their hunting abilities and their ritual behaviour. Group structure Chimpanzees live in communities that typically range from around 15 to more than 150 members but spend most of their time traveling in small, temporary groups consisting of a few individuals. These groups may consist of any combination of age and sexes. Both males and females sometimes travel alone. This fission–fusion society may include groups of four types: all-male, adult females and offspring, adults of both sexes, or one female and her offspring. These smaller groups emerge in a variety of types, for a variety of purposes. For example, an all-male troop may be organised to hunt for meat, while a group consisting of lactating females serves to act as a "nursery group" for the young. However, this unusual fission-fusion social structure, "in which portions of the parent group may on a regular basis separate from and then rejoin the rest", is highly variable in terms of which particular individual chimpanzees congregate at a given time. This is caused mainly by the large measure of individual autonomy that individuals have within their fission-fusion social groups. , Uganda. Male chimpanzees exist in a linear dominance hierarchy. Top-ranking males tend to be aggressive even during dominance stability. This is probably due to the chimpanzee's fission-fusion society, with male chimpanzees leaving groups and returning after extended periods of time. With this, a dominant male is unsure if any "political maneuvering" has occurred in his absence and must re-establish his dominance. Thus, a large amount of aggression occurs within five to fifteen minutes after a reunion. During these encounters, displays of aggression are generally preferred over physical attacks. Males maintain and improve their social ranks by forming coalitions, which have been characterised as "exploitative" and based on an individual's influence in agonistic interactions. Being in a coalition allows males to dominate a third individual when they could not by themselves, as politically apt chimpanzees can exert power over aggressive interactions regardless of their rank. Coalitions can also give an individual male the confidence to challenge a dominant or larger male. The more allies a male has, the better his chance of becoming dominant. However, most changes in hierarchical rank are caused by dyadic interactions. Low-ranking males frequently switch sides in disputes between more dominant individuals. Low-ranking males benefit from an unstable hierarchy and often find increased sexual opportunities if a dispute or conflict occurs. While chimpanzee social structure is often referred to as patriarchal, it is not entirely unheard of for females to forge coalitions against males. There is also at least one recorded case of females securing a dominant position over males in their respective troop, albeit in a captive environment. Social grooming appears to be important in the formation and maintenance of coalitions. It is more common among adult males than either between adult females or between males and females. Chimpanzees have been described as highly territorial and will frequently kill other chimpanzees, although Margaret Power wrote in her 1991 book The Egalitarians that the field studies from which the aggressive data came, Gombe and Mahale, used artificial feeding systems that increased aggression in the chimpanzee populations studied. Thus, the behaviour may not reflect innate characteristics of the species as a whole. Patrols from smaller groups are more likely to avoid contact with their neighbours. Patrols from large groups even take over a smaller group's territory, gaining access to more resources, food, and females. West African chimpanzee males are also less aggressive with female chimpanzees in general. While chimpanzees are popularly thought of as more war-like than bonobos, primatologist Christine Webb concludes that "Through an analysis of various chimpanzee and bonobo sanctuary communities, we've found that variation within the two species is greater than differences between them". Mating and parenting Chimpanzees mate throughout the year, although the number of females in oestrus varies seasonally in a group. Female chimpanzees are more likely to come into oestrus when food is readily available. Oestrous females exhibit sexual swellings. Chimpanzees are promiscuous; during oestrus, females mate with several males in their community, while males have large testicles for sperm competition. Other forms of mating also exist. A community's dominant males sometimes restrict reproductive access to females. A male and female can form a consortship and mate outside their community. In addition, females sometimes leave their community and mate with males from neighboring communities. These alternative mating strategies give females more mating opportunities without losing the support of the males in their community. Females sometimes practice infanticide. This may be related to the dominance hierarchy in females or may simply be pathological. Inbreeding was studied in a relatively undisturbed eastern chimpanzee community that displayed substantial bisexual philopatry. Despite an increased inbreeding risk incurred by females who do not disperse before reaching reproductive age, these females were still able to avoid producing inbred offspring. The gestation period is eight months. Male chimpanzees continue to associate with the females they impregnated and interact with and support their offspring. Orphaned chimpanzees are occasionally adopted by adult males who will be "as protective as any mother" and tend to their needs. Newborn chimpanzees are helpless. For example, their grasping reflex is not strong enough to support them for more than a few seconds. For their first 30 days, infants cling to their mother's bellies. Infants are unable to support their own weight for their first two months and need their mothers' support. Wild chimps are seen to exhibit both "secure" and "insecure" attachment styles, with the offspring looking to the mother for comfort in the former and more independent offspring in the latter. However, wild chimps rarely demonstrate "disorganised" attachment styles (maladaptive parent-offspring bonds caused by abuse or neglect); researchers note such attachment styles are mostly observed in captive chimps raised around humans. When they reach five to six months, infants ride on their mothers' backs. They remain in continual contact for the rest of their first year. When they reach two years of age, they are able to move and sit independently and start moving beyond the arms' reach of their mothers. By four to six years, chimpanzees are weaned and infancy ends. The juvenile period for chimpanzees lasts from their sixth to ninth years. Juveniles remain close to their mothers but increasingly begin to interact with other members of their community. Adolescent females move between groups and are supported by their mothers in agonistic encounters. Adolescent males spend time with adult males in social activities like hunting and patrolling the boundaries of their territory. Communication Chimpanzees use facial expressions, postures, and sounds to communicate with each other. Chimpanzees have expressive faces that are important in close-up communications. When frightened, a "full closed grin" causes nearby individuals to be fearful, as well. Playful chimpanzees display an open-mouthed grin. Chimpanzees may also express themselves with the "pout", which is made in distress, the "sneer", which is made when threatening or fearful, and "compressed-lips face", which is a type of display. When submitting to a dominant individual, a chimpanzee crunches, bobs, and extends a hand. When in an aggressive mode, a chimpanzee swaggers bipedally, hunched over and arms waving, in an attempt to exaggerate its size. While travelling, chimpanzees keep in contact by beating their hands and feet against the trunks of large trees, an act that is known as "drumming". They also do this when encountering individuals from other communities. Vocalisations are also important in chimpanzee communication. The most common call in adults is the "pant-hoot", which may signal social rank and bond along with keeping groups together. Pant-hoots are made of four parts, starting with soft "hoos", the introduction; that gets louder and louder, the build-up; and climax into screams and sometimes barks; these die down back to soft "hoos" during the letdown phase as the call ends. While both adults and infants are taken, adult male colobus monkeys will attack the hunting chimps. When caught and killed, the meal is distributed to all hunting party members and even bystanders. ==Intelligence==

from Histoire naturelle des mammifères (1854). Chimpanzees display numerous signs of intelligence, from the ability to remember symbols In one study, two young chimpanzees showed retention of mirror self-recognition after one year without access to mirrors. Chimpanzees have been observed to use insects to treat their own wounds and those of others. They catch them and apply them directly to the injury. Chimpanzees also display signs of culture among groups, with the learning and transmission of variations in grooming, tool use and foraging techniques leading to local traditions. A 30-year study at Kyoto University's Primate Research Institute has shown that chimpanzees are able to learn to recognise the numbers 1 to 9 and their values. The chimpanzees further show an aptitude for eidetic memory, demonstrated in experiments in which the jumbled digits are flashed onto a computer screen for less than a quarter of a second. One chimpanzee, Ayumu, was able to correctly and quickly point to the positions where they appeared in ascending order. Ayumu performed better than human adults who were given the same test. (1911). In controlled experiments on cooperation, chimpanzees show a basic understanding of cooperation, and recruit the best collaborators. In a group setting with a device that delivered food rewards only to cooperating chimpanzees, cooperation first increased, then, due to competitive behaviour, decreased, before finally increasing to the highest level through punishment and other arbitrage behaviour. Great apes show laughter-like vocalisations in response to physical contact, such as wrestling, play chasing, or tickling. This is documented in wild and captive chimpanzees. Chimpanzee laughter is not readily recognisable to humans as such, because it is generated by alternating inhalations and exhalations that sound more like breathing and panting. Instances in which nonhuman primates have expressed joy have been reported. Humans and chimpanzees share similar ticklish areas of the body, such as the armpits and belly. The enjoyment of tickling in chimpanzees does not diminish with age. A 2022 study reported that chimpanzees crushed and applied insects to their own wounds and the wounds of other chimpanzees. Chimpanzees display different behaviour in response to a dying or dead group member. When witnessing a sudden death, the other group members act in frenzy, with vocalisations, aggressive displays, and touching of the corpse. In one case chimpanzees cared for a dying elder, and then attended and cleaned the corpse. Afterward, they avoided the spot where the elder had died, and behaved in a more subdued manner. Mothers have been reported to carry around and groom their dead infants for several days. Experimenters now and then witness behaviour that cannot be readily reconciled with chimpanzee intelligence or theory of mind. Wolfgang Köhler, for instance, reported insightful behaviour in chimpanzees, but he likewise often observed that they experienced "special difficulty" in solving simple problems. Researchers also reported that, when faced with a choice between two persons, chimpanzees were just as likely to beg food from a person who could see the begging gesture as from a person who could not, thereby raising the possibility that chimpanzees lack theory of mind. By contrast, Hare, Call, and Tomasello found that subordinate chimpanzees were able to use the knowledge state of dominant rival chimpanzees to determine which container of hidden food they approached. Tool use Nearly all chimpanzee populations have been recorded using tools. They modify sticks, rocks, grass, and leaves and use them when foraging for termites and ants, nuts, honey, algae or water. Despite the lack of complexity, forethought and skill are apparent in making these tools. Chimpanzees have used stone tools since at least 4,300 years ago. A chimpanzee from the Kasakela chimpanzee community was the first nonhuman animal reported making a tool, by modifying a twig to use as an instrument for extracting termites from their mound. At Taï, chimpanzees simply use their hands to extract termites. Chimpanzees also fish for ants using the same tactic. Some forethought in this activity is apparent, as these tools are not found together or where the nuts are collected. Nut cracking is also difficult and must be learned. West African chimpanzees in Senegal were found to sharpen sticks with their teeth, which were then used to spear Senegal bushbabies out of small holes in trees. An eastern chimpanzee has been observed using a modified branch as a tool to capture a squirrel. Chimpanzees living in Tanzania were found to deliberately choose plants that provide materials that produce more flexible tools for termite fishing. Whilst experimental studies on captive chimpanzees have found that many of their species-typical tool-use behaviour can be individually learnt by each chimpanzees, a 2021 study on their abilities to make and use stone flakes, in a similar way as hypothesised for early hominins, did not find this behaviour across two populations of chimpanzees—suggesting that this behaviour is outside the chimpanzee species-typical range. Speech and language 's ('Ape with skull'), Scientists have attempted to teach human language to several species of great ape. One early attempt by Allen and Beatrix Gardner in the 1960s involved spending 51 months teaching American Sign Language to a chimpanzee named Washoe. The Gardners reported that Washoe learned 151 signs, and had spontaneously taught them to other chimpanzees, including her adopted son, Loulis. Over a longer period of time, Washoe was reported to have learned over 350 signs. Debate is ongoing among scientists such as David Premack about chimpanzees' ability to learn language. Since the early reports on Washoe, numerous other studies have been conducted, with varying levels of success. One involved a chimpanzee jokingly named Nim Chimpsky (in allusion to the theorist of language Noam Chomsky), trained by Herbert Terrace of Columbia University. Although his initial reports were quite positive, in November 1979, Terrace and his team, including psycholinguist Thomas Bever, re-evaluated the videotapes of Nim with his trainers, analyzing them frame by frame for signs, as well as for exact context (what was happening both before and after Nim's signs). In the reanalysis, Terrace and Bever concluded that Nim's utterances could be explained merely as prompting on the part of the experimenters, as well as mistakes in reporting the data. "Much of the apes' behaviour is pure drill", he said. "Language still stands as an important definition of the human species". In this reversal, Terrace now argued Nim's use of ASL was not like human language acquisition. Nim never initiated conversations himself, rarely introduced new words, and mostly imitated what the humans did. More importantly, Nim's word strings varied in their ordering, suggesting that he was incapable of syntax. Nim's sentences also did not grow in length, unlike human children whose vocabulary and sentence length show a strong positive correlation. Chomsky has voiced opposition to the viewpoint of Terrace and Bever based upon his theory of the inheritance of language capacity as being limited to human inheritance alone among all animals. ==Human relations==

In culture and entertainment , Liberia The Gio people of Liberia and the Hemba people of the Congo make chimpanzee masks. Gio masks are crude and blocky, and worn when teaching young people how not to behave. The Hemba masks have a smile that suggests drunken anger, insanity or horror and are worn during rituals at funerals, representing the "awful reality of death". The masks may also serve to guard households and protect both human and plant fertility. Stories have been told of chimpanzees kidnapping and raping women. In Western popular culture, chimpanzees have occasionally been stereotyped as childlike companions, sidekicks or clowns. They are especially suited for the latter role on account of their prominent facial features, long limbs and fast movements, which humans often find amusing. Chimpanzees in media include Judy on the television series Daktari in the 1960s and Darwin on The Wild Thornberrys in the 1990s. In contrast to the fictional depictions of other animals, such as dogs (as in Lassie), dolphins (Flipper), horses (Black Beauty) or even other great apes (King Kong), chimpanzee characters and actions are rarely relevant to the plot. Depictions of chimpanzees as individuals rather than stock characters, and as central rather than incidental to the plot can be found in science fiction. Robert A. Heinlein's 1947 short story "Jerry Was a Man" concerns a genetically enhanced chimpanzee suing for better treatment. The 1972 film Conquest of the Planet of the Apes, the third sequel of the 1968 film Planet of the Apes, portrays a futuristic revolt of enslaved apes led by the only talking chimpanzee, Caesar, against their human masters. From 1926 until 1972, London Zoo, followed by several other zoos around the world, held a chimpanzees' tea party daily. Animal rights groups have urged a stop to such acts, considering them abusive. As pets Chimpanzees have traditionally been kept as pets in a few African villages, especially in the Democratic Republic of Congo. In Virunga National Park in the east of the country, the park authorities regularly seize chimpanzees from people keeping them as pets. Outside their range, chimpanzees are popular as exotic pets despite their strength and aggression. Even in places where keeping non-human primates as pets is illegal, the exotic pet trade continues to prosper, leading to injuries from attacks. Use in research Hundreds of chimpanzees have been kept in laboratories for research. Most such laboratories either conduct or make the animals 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". Research chimpanzees tend to be used repeatedly over decades for up to 40 years, unlike the pattern of use of most laboratory animals. Two federally funded American laboratories use chimpanzees: the Yerkes National Primate Research Center at Emory University in Atlanta, Georgia, and the Southwest National Primate Center in San Antonio, Texas. Five hundred chimpanzees have been retired from laboratory use in the US and live in animal sanctuaries in the US or Canada. However, in 2007, the NIH made the moratorium permanent. , the first great ape in space, before being inserted into his Mercury-Redstone 2 capsule on 31 January 1961 Other researchers argue that chimpanzees either should not be used in research, or should be treated differently, for instance with legal status as persons. Pascal Gagneux, an evolutionary biologist and primate expert at the University of California, San Diego, argues, given chimpanzees' sense of self, tool use, and genetic similarity to human beings, studies using chimpanzees should follow the ethical guidelines used for human subjects unable to give consent. Stuart Zola, director of the Yerkes 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." Trials already under way were however allowed to run their course. Chimpanzees including the female Ai have been studied at the Primate Research Institute of Kyoto University, Japan, formerly directed by Tetsuro Matsuzawa, since 1978. As of 2021, 12 chimpanzees were held at the facility. Two chimpanzees have been sent into outer space as NASA research subjects. Ham, the first great ape in space, was launched in the Mercury-Redstone 2 capsule on 31 January 1961, and survived the suborbital flight. Enos, the third primate to orbit Earth after Soviet cosmonauts Yuri Gagarin and Gherman Titov, flew on Mercury-Atlas 5 on 29 November of the same year. Field study used to feed and observe the chimpanzees Jane Goodall undertook the first long-term field study of the chimpanzee, begun in Tanzania at Gombe Stream National Park in 1960. Other long-term studies begun in the 1960s include Adriaan Kortlandt's in the eastern Democratic Republic of the Congo and Toshisada Nishida's in Mahale Mountains National Park in Tanzania. Current understanding of the species' typical behaviour and social organisation has been formed largely from Goodall's ongoing 60-year Gombe research study. Goodall research common chimpanzee social and family life beginning with the Kasakela chimpanzee community in Gombe Stream National Park, Tanzania, in 1960, contained much original commentary about their experienced emotional life. She also observed behaviour often considered human, such as hugs, kisses, pats on the back, and even tickling. In Uganda, several attacks on children have happened, some of them fatal. Some of these attacks may have been due to the chimpanzees being intoxicated (from alcohol obtained from rural brewing operations) and becoming aggressive towards humans. Human interactions with chimpanzees may be especially dangerous if the chimpanzees perceive humans as potential rivals. At least six cases of chimpanzees snatching and eating human babies are documented. A chimpanzee's strength and sharp teeth mean that attacks, even on adult humans, can cause severe injuries. This was evident after the attack and near death of former NASCAR driver St. James Davis, who was mauled by two escaped chimpanzees while he and his wife were celebrating the birthday of their former pet chimpanzee. Another example of chimpanzees being aggressive toward humans occurred in 2009 in Stamford, Connecticut, when a , 13-year-old pet chimpanzee named Travis attacked his owner's friend, who lost her hands, eyes, nose, and part of her maxilla from the attack. Human immunodeficiency virus Two primary classes of human immunodeficiency virus (HIV) infect humans: HIV-1 and HIV-2. HIV-1 is the more virulent and easily transmitted, and is the source of the majority of HIV infections throughout the world; HIV-2 occurs mostly in west Africa. Both types originated in west and central Africa, jumping from other primates to humans. HIV-1 has evolved from a simian immunodeficiency virus (SIVcpz) found in the subspecies P. t. troglodytes of southern Cameroon. Kinshasa, in the Democratic Republic of Congo, has the greatest genetic diversity of HIV-1 so far discovered, suggesting the virus has been there longer than anywhere else. HIV-2 crossed species from a different strain of HIV, found in the sooty mangabey monkeys in Guinea-Bissau. ==Conservation==

The chimpanzee is on the IUCN Red List as an endangered species. Chimpanzees are legally protected in most of their range and are found both in and outside national parks. Between 172,700 and 299,700 individuals are thought to be living in the wild, Chimpanzees are listed in Appendix I of the Convention on International Trade in Endangered Species (CITES), meaning that commercial international trade in wild-sourced specimens is prohibited and all other international trade (including in parts and derivatives) is regulated by the CITES permitting system. The biggest threats to the chimpanzee are habitat destruction, poaching, and disease. Chimpanzee habitats have been limited by deforestation in both West and Central Africa. Road building has caused habitat degradation and fragmentation of chimpanzee populations and may allow poachers more access to areas that had not been seriously affected by humans. Although deforestation rates are low in western Central Africa, selective logging may take place outside national parks. Chimpanzees are a common target for poachers. In Ivory Coast, chimpanzees make up 1–3% of bushmeat sold in urban markets. They are also taken, often illegally, for the pet trade and are hunted for medicinal purposes in some areas. Farmers sometimes kill chimpanzees that threaten their crops; others are unintentionally maimed or killed by snares meant for other animals. Infectious diseases are a main cause of death for chimpanzees. They succumb to many diseases that afflict humans because the two species are so similar. As the human population grows, so does the risk of disease transmission between humans and chimpanzees. ==See also==