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Description

FACT FILE:
Swahili Name:Sokwe Mtu
Scientific Name:Pan troglodytes
Size:3 to 41/2 feet tall standing bipedal
Weight:55 to 110 pounds
Lifespan:50 years
Habitat:Forest
Diet:Omnivorous forager/hunter
Gestation:8 months
Predators:Humans, leopards

Noisy and curious, intelligent and social, the chimpanzee is the mammal most like a human. Chimpanzees fascinate humans and are favorites both in zoos and the wild.

Three subspecies of common chimpanzees are distributed across the forest zone of Africa from Guinea to western Tanzania and Uganda. Another species of chimpanzees, the bonobo (Pan paniscus), is found exclusively in central Democratic Republic of Congo. In East Africa the chimpanzee is found in the wild in Tanzania and Uganda, but only in captivity in Kenya. Gombe National Park in Tanzania is the first park in Africa specifically created for chimpanzees.

Physical Characteristics
The chimpanzee has a thickset body with long arms, short legs and no tail. Much of the body is covered with long black hair, but the face, ears, fingers and toes are bare. They have hands that can grip firmly, allowing them to pick up objects. The discovery that they used "tools" for certain purposes surprised the world.

Habitat
Chimps are mainly found in rain forests and wet savannas. While they spend equal time on land and in trees, they do most of their feeding and sleeping in trees.

Behavior
Chimps live in groups called troops, of some 30 to 80 individuals. These large groups are made up of smaller, very flexible groups of just a few animals, perhaps all females, all males or a mixed group.

Chimps sometimes chew leaves to make them absorbent and then use them as a sponge, dipping them in water and sucking out the moisture. They also use grass stems or twigs as tools, poking them into termite or ant nests and eating the insects that cling to them. They are able to wedge nuts between the roots of a tree and break the shells open with a stone.

Chimps are both arboreal and terrestrial, spending much of their daytime hours on the ground. They are quadrupedal, walking quickly on all fours with the fingers half-flexed to support the weight of the forequarters on the knuckles. They occasionally walk erect for short distances.

Chimps are agile climbers, building nests high up in trees to rest in during midday and sleep in at night. They construct new nests in minutes by bending branches, intertwining them to form a platform and lining the edges with twigs. In some areas chimps make nests on the ground.

Diet
Chimps are diurnal (but often active on moonlit nights) and begin their activities at dawn. After descending from their night nests they hungrily feed on fruits, their principal diet, and on leaves, buds and blossoms. After a while their feeding becomes more selective, and they will choose only the ripest fruit. They usually pick fruit with their hands, but they eat berries and seeds directly off the stem with their lips. Their diet consists of up to 80 different plant foods.

Caring for the Young
The female chimp has an estrus cycle of about 34 to 35 days. While in heat, the bare skin on her bottom becomes pink and swollen, and she may mate with several males. She normally gives birth to just one baby, which clings tightly to her breast and, like a human baby, develops rather slowly. An infant can sit up at 5 months and stand with support at 6 months. It is still suckled and sleeps with its mother until about 3 years of age, finally becoming independent and separating from her at about 4 years. Sexual maturity is reached between 8 and 10 years.

Chimps are among the noisiest of all wild animals and use a complicated system of sounds to communicate with each other. A loud "wraaa" call, which can be heard more than a mile away, warns of something unusual or disturbing. They hoot "hoo-hoo-hoo," scream, grunt and drum on hollow trees with the flat of their hands, sometimes for hours.

Chimps touch each other a great deal and may kiss when they meet. They also hold hands and groom each other. An adult chimp often has a special "friend" or companion with which it spends a lot of time. Female chimps give their young a great deal of attention and help each other with babysitting chores. Older chimps in the group are usually quite patient with energetic youngsters.

Predators
The number of chimps in the wild is steadily decreasing. The wilderness areas necessary to their survival are disappearing at an alarming rate as more forests are cut down for farming and other activities. As the human's closest relative the chimp is vulnerable to many of the same diseases, and their capture for medical research contributes to their decline, especially in West Africa. as more forests are cut down for farm activities. In addition, recent outbreaks of the incurable disease Ebola hemorrhagic fever, threaten to decimate important chimpanzee populations in the Republic of Congo and Gabon.

Did you know?
Chimpanzees use large sticks and branches as clubs or throw them at enemies like leopards and humans.
Chimps supplement their diets with meat, such as young antelopes or goats. Their most frequent victims, however, are other primates such as young baboons, colobus monkeys and blue monkeys.
BehaviourChimpanzee vs. bonobo
Anatomical differences between the common chimpanzee and the bonobo are slight, but sexual and social behaviours are markedly different. The common chimpanzee has anomnivorous diet , a troop hunting culture based on beta males led by an alpha male , and highly complex social relationships. The bonobo, on the other hand, has a mostly frugivorous diet and an egalitarian , nonviolent ,matriarchal , sexually receptive behaviour .[29] Bonobos frequently have sex, sometimes to help prevent and resolve conflicts. Different groups of chimpanzees also have different cultural behaviour with preferences for types of tools.[30] The common chimpanzee tends to display greater aggression than does the bonobo.[31] The average captive chimpanzee sleeps 9.7 hours per day.[32]
Contrary to what the scientific name (Pan troglodytes ) may suggest, chimpanzees do not typically spend their time in caves, but there have been reports of some of them seeking refugee in caves because of the heat during daytime.[33]
ChimpanzeesSocial structureChimpanzees live in large multi-male and multi-female social groups , which are called communities. Within a community, the position of an individual and the influence the individual has on others dictates a definite social hierarchy . Chimpanzees live in a leaner hierarchy wherein more than one individual may be dominant enough to dominate other members of lower rank. Typically, a dominant male is referred to as the alpha male . The alpha male is the highest-ranking male that controls the group and maintains order during disputes. In chimpanzee society, the 'dominant male' sometimes is not the largest or strongest male but rather the most manipulative and political male that can influence the goings on within a group. Male chimpanzees typically attain dominance by cultivating allies who will support that individual during future ambitions for power. The alpha male regularly displays by puffing his normally slim coat up to increase view size and charge to seem as threatening and as powerful as possible; this behaviour serves to intimidate other members and thereby maintain power and authority, and it may be fundamental to the alpha male's holding on to his status. Lower-ranking chimpanzees will show respect by submissively gesturing in body language or reaching out their hands while grunting. Female chimpanzees will show deference to the alpha male by presenting their hindquarters.
Female chimpanzees also have a hierarchy, which is influenced by the position of a female individual within a group. In some chimpanzee communities, the young females may inherit high status from a high-ranking mother. Dominant females will also ally to dominate lower-ranking females: whereas males mainly seek dominant status for its associated mating privileges and sometimes violent domination of subordinates, females seek dominant status to acquire resources such as food, as high-ranking females often have first access to them. Both genders acquire dominant status to improve social standing within a group.
Community female acceptance is necessary for alpha male status; females must ensure that their group visits places that supply them with enough food. A group of dominant females will sometimes oust an alpha male which is not to their preference and back another male, in whom they see potential for leading the group as a successful alpha male.
Intelligence
Further information: Primate cognition
Chimpanzees make tools and use them to acquire foods and for social displays; they have sophisticated hunting strategies requiring cooperation, influence and rank; they are status conscious, manipulative and capable of deception; they can learn to use symbols and understand aspects of human language including some relationalsyntax , concepts of number and numerical sequence;[34] and they are capable of spontaneous planning for a future state or event.[35]
Tool use
In October 1960, Jane Goodall observed the use of tools among chimpanzees[ dubious – discuss ]. Recent research indicates that chimpanzees' use of stone tools dates back at least 4,300 years (about 2,300 BC).[36] One example of chimpanzee tool usage behavior includes the use of a large stick as a tool to dig into termite mounds, and the subsequent use of a small stick altered into a tool that is used to "fish" the termites out of the mound.[37] Chimpanzees are also known to use smaller stones as hammers and a large one as an anvil in order to break open nuts.[38]
In the 1970s, reports of chimpanzees using rocks or sticks as weapons were anecdotal and controversial.[39] However, a 2007 study claimed to reveal the use of spears, which common chimpanzees in Senegal sharpen with their teeth and use to stab and pry Senegal bushbabies out of small holes in trees.[40] [41]
Prior to the discovery of tool use in chimps, humans were believed to be the only species to make and use tools; however, now several othertool-using species are now known.[42] [43]
Nest-building
Nest-building, sometimes considered to be a form of tool use, is seen when chimpanzees construct arboreal night nests by lacing together branches from one or more trees to build a safe, comfortable place to sleep; infants learn this process by watching their mothers. The nest provides a sort of mattress, which is supported by strong branches for a foundation, and then lined with softer leaves and twigs; the minimum diameter is 5 metres (16 ft) and may be located at a height of 3 to 45 metres (10 to 150 ft). Both day and night nests are built, and may be located in groups.[44] A study in 2014 found that the Muhimbi tree is favoured for nest building by chimpanzees in Uganda due to its physical properties, such as bending strength, inter-node distance, and leaf surface area.[45]
Altruism and emotivity
Studies have shown chimpanzees engage in apparently altruistic behaviour within groups.[46] [47] Some researchers have suggested that chimpanzees are indifferent to the welfare of unrelated group members,[48] but a more recent study of wild chimpanzees found that both male and female adults would adopt orphaned young of their group. Also, different groups sometimes share food, form coalitions, and cooperate in hunting and border patrolling.[49] Sometimes, chimpanzees have adopted young that come from unrelated groups. And in some rare cases, even male chimps have been shown to take care of abandoned infant chimps of an unrelated group, though in most cases they would kill the infant.[ citation needed]
According to a literature summary by James W. Harrod, evidence forchimpanzee emotivity includes display of mourning ; "incipient romantic love "; rain dances ; appreciation of natural beauty (such as a sunset over a lake); curiosity and respect towards other wildlife (such as thepython , which is neither a threat nor a food source to chimpanzees); altruism toward other species (such as feeding turtles); and animism , or "pretend play", when chimps cradle and groom rocks or sticks.[50]
Communication between chimpanzees
Chimps communicate in a manner that is similar to that of human nonverbal communication, using vocalizations, hand gestures, and facial expressions. There is even some evidence that they can recreate human speech.[51] Research into the chimpanzee brain has revealed that when chimpanzees communicate, an area in the brain is activated which is in the same position as the language center called Broca's area in human brains.[52]
There is some debate as to whether chimpanzees have the ability to express hierarchical ideas in language. Studies have found that chimps are capable of learning a limited set of sign language symbols, which they can use to communicate with human trainers. However, it is clear that there are distinct limits to the complexity of knowledge structures with which chimps are capable of dealing[ citation needed]. The sentences that they can express are limited to specific simple noun-verb sequences, and are they do not seem capable of the extent of thought complexity characteristic of humans.
Aggression
Adult common chimpanzees, particularly males, can be very aggressive. They are highly territorial and are known to kill other chimps.[53]
Hunting
Chimpanzees also engage in targeted hunting of lower-order primates, such as the red colobus [54] and bush babies ,[55] [56] and use the meat from these kills as a "social tool" within their community.[57] [ how?]
Puzzle solving
In February 2013, a study found that chimpanzees solve puzzles for entertainment.[58]
Chimpanzees in human history
Chimps, as well as other apes, had also been purported to have been known to ancient writers, but mainly as myths and legends on the edge of European and Near Eastern societal consciousness. Apes are mentioned variously by Aristotle . The English word ape translates Hebrew qőf in English translations of the Bible (1 Kings 10:22), but the word may refer to a monkey rather than an ape proper.
The diary of Portuguese explorer Duarte Pacheco Pereira (1506), preserved in the Portuguese National Archive (Torre do Tombo), is probably the first written document to acknowledge that chimpanzees built their own rudimentary tools. The first of these early transcontinental chimpanzees came from Angola and were presented as a gift to Frederick Henry, Prince of Orange in 1640, and were followed by a few of its brethren over the next several years. Scientists described these first chimpanzees as "pygmies ", and noted the animals' distinct similarities to humans. The next two decades, a number of the creatures were imported into Europe, mainly acquired by various zoological gardens as entertainment for visitors.
Darwin's theory of natural selection (published in 1859) spurred scientific interest in chimpanzees, as in much of life science , leading eventually to numerous studies of the animals in the wild and captivity. The observers of chimpanzees at the time were mainly interested in behaviour as it related to that of humans. This was less strictly and disinterestedly scientific than it might sound, with much attention being focused on whether or not the animals had traits that could be considered 'good'; the intelligence of chimpanzees was often significantly exaggerated, as immortalized in Hugo Rheinhold 's Affe mit Schädel (see image, left). By the end of the 19th century, chimpanzees remained very much a mystery to humans, with very little factual scientific information available.
In the 20th century, a new age of scientific research into chimpanzee behaviour began. Before 1960, almost nothing was known about chimpanzee behaviour in their natural habitats. In July of that year, Jane Goodall set out to Tanzania 's Gombe forest to live among the chimpanzees, where she primarily studied the members of the Kasakela chimpanzee community . Her discovery that chimpanzees made and used tools was groundbreaking, as humans were previously believed to be the only species to do so. The most progressive early studies on chimpanzees were spearheaded primarily by Wolfgang Köhler and Robert Yerkes , both of whom were renowned psychologists. Both men and their colleagues established laboratory studies of chimpanzees focused specifically on learning about the intellectual abilities of chimpanzees, particularly problem-solving . This typically involved basic, practical tests on laboratory chimpanzees, which required a fairly high intellectual capacity (such as how to solve the problem of acquiring an out-of-reach banana ). Notably, Yerkes also made extensive observations of chimpanzees in the wild which added tremendously to the scientific understanding of chimpanzees and their behaviour. Yerkes studied chimpanzees until World War II , while Köhler concluded five years of study and published his famous Mentality of Apes in 1925 (which is coincidentally when Yerkes began his analyses), eventually concluding, "chimpanzees manifest intelligent behaviour of the general kind familiar in human beings ... a type of behaviour which counts as specifically human" (1925).[59]
The August 2008 issue of the American Journal of Primatology reported results of a year-long study of chimpanzees in Tanzania’s Mahale Mountains National Park , which produced evidence of chimpanzees becoming sick from viral infectious diseases they had likely contracted from humans. Molecular, microscopic and epidemiological investigations demonstrated the chimpanzees living at Mahale Mountains National Park have been suffering from a respiratory disease that is likely caused by a variant of a human paramyxovirus .[60]
Research and study of chimpanzees
See also: Animal testing on non-human primates § Chimpanzees in the U.S.

As of November 2007, about 1,300 chimpanzees were housed in 10 U.S. laboratories (out of 3,000 great apes living in captivity there), either wild-caught, or acquired from circuses, animal trainers, or zoos.[61] Most of the labs either conduct or make the chimps available for invasive research,[62] 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".[63] Two federally funded laboratories use chimps: the Yerkes National Primate Research Center at Emory University in Atlanta, Georgia, and the Southwest National Primate Center in San Antonio, Texas.[64] Five hundred chimps have been retired from laboratory use in the U.S. and live in animal sanctuaries in the U.S. or Canada.[62]
himpanzees used in biomedical research tend to be used repeatedly over decades, rather than used and killed as with most laboratory animals. Some individual chimps currently in U.S. laboratories have been used in experiments for over 40 years.[65] According to Project R&R , a campaign to release chimps held in U.S. labs—run by the New England Anti-Vivisection Society in conjunction with Jane Goodall and other primate researchers—the oldest known chimp in a U.S. lab is Wenka, which was born in a laboratory in Florida on May 21, 1954.[66] 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 the subject of research into alcohol use, oral contraceptives, aging, and cognitive studies.[67]
With the publication of the chimpanzee genome , plans to increase the use of chimps in labs are reportedly increasing, with some scientists arguing that the federal moratorium on breeding chimps for research should be lifted.[64] [68] A five-year moratorium was imposed by the U.S. National Institutes of Health in 1996, because too many chimps had been bred for HIV research, and it has been extended annually since 2001.[64]
Other researchers argue that chimps are unique animals and either should 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, given chimpanzees' sense of self, tool use, and genetic similarity to human beings, studies using chimps should follow the ethical guidelines used for human subjects unable to give consent.[64] Also, a recent study suggests chimpanzees which are retired from labs exhibit a form ofposttraumatic stress disorder .[69] 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."[64]
An increasing number of governments are enacting a great ape research ban forbidding the use of chimpanzees and other great apes in research or toxicology testing.[70] As of 2006, Austria , New Zealand , the Netherlands , Sweden , and the UK had introduced such bans.[71]
Studies of language
Main article: Great ape language
Scientists have long been fascinated with the studies of language, believing it to be a unique human cognitive ability. To test this hypothesis, scientists have attempted to teach human language to several species of great apes. One early attempt by Allen and Beatrix Gardner in the 1960s involved spending 51 months teaching American Sign Language (ASL) to a chimpanzee named Washoe . The Gardners reported Washoe learned 151 signs, and she had spontaneously taught them to other chimpanzees.[72] Over a longer period of time, Washoe learned over 800 signs.[73]
Debate is ongoing among some scientists (such as David Premack ), about non-human great apes' ability to learn language. Since the early reports on Washoe, numerous other studies have been conducted, with varying levels of success,[74] including one involving a chimpanzee named jokingly Nim Chimpsky , 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 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 simply 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.[75]
Memory
A 30-year study at Kyoto University 's Primate Research Institute has shown that chimps are able to learn to recognise the numbers 1 through 9 and their values. The chimps further show an aptitude for photographic memory , demonstrated in experiments in which the jumbled digits are flashed onto a computer screen for less than a quarter of a second, after which the chimp, Ayumu , is able to correctly and quickly point to the positions where they appeared in ascending order. The same experiment was failed by human world memory champion Ben Pridmore on most attempts.[76]
Laughter in apes
Laughter might not be confined or unique to humans. The differences between chimpanzee and human laughter may be the result of adaptations that have evolved to enable human speech. Self-awareness of one's situation as seen in the mirror test , or the ability to identify with another's predicament (see mirror neurons ), are prerequisites for laughter,[ citation needed] so animals may be laughing for the same reasons that humans do.
Chimpanzees, gorillas , and orangutans show laughter-like vocalizations in response to physical contact, such as wrestling, play-chasing, or tickling . This is documented in wild and captive chimpanzees. Common 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. One study analyzed and recorded sounds made by human babies andbonobos when tickled. Although the bonobo's laugh was a higher frequency, the laugh followed a pattern similar to that of human babies and included similar facial expressions. 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.[77]
See also: Laughter in animals
Chimps listed as endangered in the US
The US Fish and Wildlife Service finalized a rule on June 12, 2015, creating very strict regulations, practically barring any activity with chimpanzees other than for scientific, preservation-oriented purposes.[78]
Chimpanzees as pets
See also: Exotic pet

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 confiscate chimpanzees from people keeping them as pets.[79]
Chimpanzees are popular as wild pets in many areas despite their strength, aggression, and wild nature. Even in areas where keeping non-human primates as pets is illegal, the exotic pet trade continues to prosper and some people keep chimpanzees as pets mistakenly believing that they will bond with them for life. As they grow, so do their strength and aggression; some owners and others interacting with the animals have lost fingers and suffered severe facial damage among other injuries sustained in attacks. In addition to the animals' hostile potential and strength well beyond any human being, chimpanzees physically mature a lot more proportionally than do human beings, and even among the most cleanly and well-organized of housekeepers, maintaining cleanliness and control of chimpanzees is physically demanding to the point that it is impossible for humans to control, especially due to the animals' strength and aggression.[80] [ dead link]
Chimpanzees in popular culture
See also: List of fictional primates

Chimpanzees have been commonly stereotyped in popular culture , where they are most often cast in standardized roles as childlike companions, sidekicks or clowns .[81] 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. Accordingly, entertainment acts featuring chimpanzees dressed up as humans have been traditional staples of circuses and stage shows .[81]
In the age of television, a new genre of chimp act emerged in the United States : series whose cast consisted entirely of chimpanzees dressed as humans and "speaking" lines dubbed by human actors.[81] These shows, examples of which include Lancelot Link, Secret Chimp in the 1970s or The Chimp Channel in the 1990s, relied on the novelty of their ape cast to make their timeworn, low comedy gags funny.[81] Their chimpanzee "actors" were as interchangeable as the apes in a circus act, being amusing as chimpanzees and not as individuals.[81] Animal rights groups have urged a stop to this practice, considering it animal abuse.[82]
When chimpanzees appear in other TV shows, they generally do so as comic relief sidekicks to humans. In that role, for instance, J. Fred Muggs appeared with Today Show hostDave Garroway in the 1950s, Judy on Daktari in the 1960s and Darwin on The Wild Thornberrys in the 1990s.[81] In contrast to the fictional depictions of other animals, such as dogs (as in Lassie ), dolphins (Flipper ), horses (The Black Stallion ) or even other great apes (King Kong ), chimpanzee characters and actions are rarely relevant to the plot.[81]
Chimpanzees in science fiction
The rare depictions of chimpanzees as individuals rather than stock characters, and as central rather than incidental to the plot[81] are generally found in works of science fiction .Robert A. Heinlein 's short story "Jerry Was a Man " (1947) centers on a genetically enhanced chimpanzee suing for better treatment. The 1972 film Conquest of the Planet of the Apes , the third sequel of Planet of the Apes , portrays a futuristic revolt of enslaved apes led by the only talking chimpanzee, Caesar , against their human masters.[81] This concept was revisited in the 2011 film Rise of the Planet of the Apes , again with a chimpanzee protagonist named Caesar. Another short story, "The Pope of the Chimps" byRobert Silverberg , set in the present day, shows the development of the first signs of religiosity in a group of chimpanzees, much to the surprise of the humans observing them.David Brin 's Uplift novels present a future in which humans have "uplifted " chimpanzees (and certain other species) with human-level sapience .

Description

FACT FILE:
Swahili Name:Sokwe Mtu
Scientific Name:Pan troglodytes
Size:3 to 41/2 feet tall standing bipedal
Weight:55 to 110 pounds
Lifespan:50 years
Habitat:Forest
Diet:Omnivorous forager/hunter
Gestation:8 months
Predators:Humans, leopards

Noisy and curious, intelligent and social, the chimpanzee is the mammal most like a human. Chimpanzees fascinate humans and are favorites both in zoos and the wild.

Three subspecies of common chimpanzees are distributed across the forest zone of Africa from Guinea to western Tanzania and Uganda. Another species of chimpanzees, the bonobo (Pan paniscus), is found exclusively in central Democratic Republic of Congo. In East Africa the chimpanzee is found in the wild in Tanzania and Uganda, but only in captivity in Kenya. Gombe National Park in Tanzania is the first park in Africa specifically created for chimpanzees.

Physical Characteristics
The chimpanzee has a thickset body with long arms, short legs and no tail. Much of the body is covered with long black hair, but the face, ears, fingers and toes are bare. They have hands that can grip firmly, allowing them to pick up objects. The discovery that they used "tools" for certain purposes surprised the world.

Habitat
Chimps are mainly found in rain forests and wet savannas. While they spend equal time on land and in trees, they do most of their feeding and sleeping in trees.

Behavior
Chimps live in groups called troops, of some 30 to 80 individuals. These large groups are made up of smaller, very flexible groups of just a few animals, perhaps all females, all males or a mixed group.

Chimps sometimes chew leaves to make them absorbent and then use them as a sponge, dipping them in water and sucking out the moisture. They also use grass stems or twigs as tools, poking them into termite or ant nests and eating the insects that cling to them. They are able to wedge nuts between the roots of a tree and break the shells open with a stone.

Chimps are both arboreal and terrestrial, spending much of their daytime hours on the ground. They are quadrupedal, walking quickly on all fours with the fingers half-flexed to support the weight of the forequarters on the knuckles. They occasionally walk erect for short distances.

Chimps are agile climbers, building nests high up in trees to rest in during midday and sleep in at night. They construct new nests in minutes by bending branches, intertwining them to form a platform and lining the edges with twigs. In some areas chimps make nests on the ground.

Diet
Chimps are diurnal (but often active on moonlit nights) and begin their activities at dawn. After descending from their night nests they hungrily feed on fruits, their principal diet, and on leaves, buds and blossoms. After a while their feeding becomes more selective, and they will choose only the ripest fruit. They usually pick fruit with their hands, but they eat berries and seeds directly off the stem with their lips. Their diet consists of up to 80 different plant foods.

Caring for the Young
The female chimp has an estrus cycle of about 34 to 35 days. While in heat, the bare skin on her bottom becomes pink and swollen, and she may mate with several males. She normally gives birth to just one baby, which clings tightly to her breast and, like a human baby, develops rather slowly. An infant can sit up at 5 months and stand with support at 6 months. It is still suckled and sleeps with its mother until about 3 years of age, finally becoming independent and separating from her at about 4 years. Sexual maturity is reached between 8 and 10 years.

Chimps are among the noisiest of all wild animals and use a complicated system of sounds to communicate with each other. A loud "wraaa" call, which can be heard more than a mile away, warns of something unusual or disturbing. They hoot "hoo-hoo-hoo," scream, grunt and drum on hollow trees with the flat of their hands, sometimes for hours.

Chimps touch each other a great deal and may kiss when they meet. They also hold hands and groom each other. An adult chimp often has a special "friend" or companion with which it spends a lot of time. Female chimps give their young a great deal of attention and help each other with babysitting chores. Older chimps in the group are usually quite patient with energetic youngsters.

Predators
The number of chimps in the wild is steadily decreasing. The wilderness areas necessary to their survival are disappearing at an alarming rate as more forests are cut down for farming and other activities. As the human's closest relative the chimp is vulnerable to many of the same diseases, and their capture for medical research contributes to their decline, especially in West Africa. as more forests are cut down for farm activities. In addition, recent outbreaks of the incurable disease Ebola hemorrhagic fever, threaten to decimate important chimpanzee populations in the Republic of Congo and Gabon.

Did you know?
Chimpanzees use large sticks and branches as clubs or throw them at enemies like leopards and humans.
Chimps supplement their diets with meat, such as young antelopes or goats. Their most frequent victims, however, are other primates such as young baboons, colobus monkeys and blue monkeys.
BehaviourChimpanzee vs. bonobo
Anatomical differences between the common chimpanzee and the bonobo are slight, but sexual and social behaviours are markedly different. The common chimpanzee has anomnivorous diet , a troop hunting culture based on beta males led by an alpha male , and highly complex social relationships. The bonobo, on the other hand, has a mostly frugivorous diet and an egalitarian , nonviolent ,matriarchal , sexually receptive behaviour .[29] Bonobos frequently have sex, sometimes to help prevent and resolve conflicts. Different groups of chimpanzees also have different cultural behaviour with preferences for types of tools.[30] The common chimpanzee tends to display greater aggression than does the bonobo.[31] The average captive chimpanzee sleeps 9.7 hours per day.[32]
Contrary to what the scientific name (Pan troglodytes ) may suggest, chimpanzees do not typically spend their time in caves, but there have been reports of some of them seeking refugee in caves because of the heat during daytime.[33]
ChimpanzeesSocial structureChimpanzees live in large multi-male and multi-female social groups , which are called communities. Within a community, the position of an individual and the influence the individual has on others dictates a definite social hierarchy . Chimpanzees live in a leaner hierarchy wherein more than one individual may be dominant enough to dominate other members of lower rank. Typically, a dominant male is referred to as the alpha male . The alpha male is the highest-ranking male that controls the group and maintains order during disputes. In chimpanzee society, the 'dominant male' sometimes is not the largest or strongest male but rather the most manipulative and political male that can influence the goings on within a group. Male chimpanzees typically attain dominance by cultivating allies who will support that individual during future ambitions for power. The alpha male regularly displays by puffing his normally slim coat up to increase view size and charge to seem as threatening and as powerful as possible; this behaviour serves to intimidate other members and thereby maintain power and authority, and it may be fundamental to the alpha male's holding on to his status. Lower-ranking chimpanzees will show respect by submissively gesturing in body language or reaching out their hands while grunting. Female chimpanzees will show deference to the alpha male by presenting their hindquarters.
Female chimpanzees also have a hierarchy, which is influenced by the position of a female individual within a group. In some chimpanzee communities, the young females may inherit high status from a high-ranking mother. Dominant females will also ally to dominate lower-ranking females: whereas males mainly seek dominant status for its associated mating privileges and sometimes violent domination of subordinates, females seek dominant status to acquire resources such as food, as high-ranking females often have first access to them. Both genders acquire dominant status to improve social standing within a group.
Community female acceptance is necessary for alpha male status; females must ensure that their group visits places that supply them with enough food. A group of dominant females will sometimes oust an alpha male which is not to their preference and back another male, in whom they see potential for leading the group as a successful alpha male.
Intelligence
Further information: Primate cognition
Chimpanzees make tools and use them to acquire foods and for social displays; they have sophisticated hunting strategies requiring cooperation, influence and rank; they are status conscious, manipulative and capable of deception; they can learn to use symbols and understand aspects of human language including some relationalsyntax , concepts of number and numerical sequence;[34] and they are capable of spontaneous planning for a future state or event.[35]
Tool use
In October 1960, Jane Goodall observed the use of tools among chimpanzees[ dubious – discuss ]. Recent research indicates that chimpanzees' use of stone tools dates back at least 4,300 years (about 2,300 BC).[36] One example of chimpanzee tool usage behavior includes the use of a large stick as a tool to dig into termite mounds, and the subsequent use of a small stick altered into a tool that is used to "fish" the termites out of the mound.[37] Chimpanzees are also known to use smaller stones as hammers and a large one as an anvil in order to break open nuts.[38]
In the 1970s, reports of chimpanzees using rocks or sticks as weapons were anecdotal and controversial.[39] However, a 2007 study claimed to reveal the use of spears, which common chimpanzees in Senegal sharpen with their teeth and use to stab and pry Senegal bushbabies out of small holes in trees.[40] [41]
Prior to the discovery of tool use in chimps, humans were believed to be the only species to make and use tools; however, now several othertool-using species are now known.[42] [43]
Nest-building
Nest-building, sometimes considered to be a form of tool use, is seen when chimpanzees construct arboreal night nests by lacing together branches from one or more trees to build a safe, comfortable place to sleep; infants learn this process by watching their mothers. The nest provides a sort of mattress, which is supported by strong branches for a foundation, and then lined with softer leaves and twigs; the minimum diameter is 5 metres (16 ft) and may be located at a height of 3 to 45 metres (10 to 150 ft). Both day and night nests are built, and may be located in groups.[44] A study in 2014 found that the Muhimbi tree is favoured for nest building by chimpanzees in Uganda due to its physical properties, such as bending strength, inter-node distance, and leaf surface area.[45]
Altruism and emotivity
Studies have shown chimpanzees engage in apparently altruistic behaviour within groups.[46] [47] Some researchers have suggested that chimpanzees are indifferent to the welfare of unrelated group members,[48] but a more recent study of wild chimpanzees found that both male and female adults would adopt orphaned young of their group. Also, different groups sometimes share food, form coalitions, and cooperate in hunting and border patrolling.[49] Sometimes, chimpanzees have adopted young that come from unrelated groups. And in some rare cases, even male chimps have been shown to take care of abandoned infant chimps of an unrelated group, though in most cases they would kill the infant.[ citation needed]
According to a literature summary by James W. Harrod, evidence forchimpanzee emotivity includes display of mourning ; "incipient romantic love "; rain dances ; appreciation of natural beauty (such as a sunset over a lake); curiosity and respect towards other wildlife (such as thepython , which is neither a threat nor a food source to chimpanzees); altruism toward other species (such as feeding turtles); and animism , or "pretend play", when chimps cradle and groom rocks or sticks.[50]
Communication between chimpanzees
Chimps communicate in a manner that is similar to that of human nonverbal communication, using vocalizations, hand gestures, and facial expressions. There is even some evidence that they can recreate human speech.[51] Research into the chimpanzee brain has revealed that when chimpanzees communicate, an area in the brain is activated which is in the same position as the language center called Broca's area in human brains.[52]
There is some debate as to whether chimpanzees have the ability to express hierarchical ideas in language. Studies have found that chimps are capable of learning a limited set of sign language symbols, which they can use to communicate with human trainers. However, it is clear that there are distinct limits to the complexity of knowledge structures with which chimps are capable of dealing[ citation needed]. The sentences that they can express are limited to specific simple noun-verb sequences, and are they do not seem capable of the extent of thought complexity characteristic of humans.
Aggression
Adult common chimpanzees, particularly males, can be very aggressive. They are highly territorial and are known to kill other chimps.[53]
Hunting
Chimpanzees also engage in targeted hunting of lower-order primates, such as the red colobus [54] and bush babies ,[55] [56] and use the meat from these kills as a "social tool" within their community.[57] [ how?]
Puzzle solving
In February 2013, a study found that chimpanzees solve puzzles for entertainment.[58]
Chimpanzees in human history
Chimps, as well as other apes, had also been purported to have been known to ancient writers, but mainly as myths and legends on the edge of European and Near Eastern societal consciousness. Apes are mentioned variously by Aristotle . The English word ape translates Hebrew qőf in English translations of the Bible (1 Kings 10:22), but the word may refer to a monkey rather than an ape proper.
The diary of Portuguese explorer Duarte Pacheco Pereira (1506), preserved in the Portuguese National Archive (Torre do Tombo), is probably the first written document to acknowledge that chimpanzees built their own rudimentary tools. The first of these early transcontinental chimpanzees came from Angola and were presented as a gift to Frederick Henry, Prince of Orange in 1640, and were followed by a few of its brethren over the next several years. Scientists described these first chimpanzees as "pygmies ", and noted the animals' distinct similarities to humans. The next two decades, a number of the creatures were imported into Europe, mainly acquired by various zoological gardens as entertainment for visitors.
Darwin's theory of natural selection (published in 1859) spurred scientific interest in chimpanzees, as in much of life science , leading eventually to numerous studies of the animals in the wild and captivity. The observers of chimpanzees at the time were mainly interested in behaviour as it related to that of humans. This was less strictly and disinterestedly scientific than it might sound, with much attention being focused on whether or not the animals had traits that could be considered 'good'; the intelligence of chimpanzees was often significantly exaggerated, as immortalized in Hugo Rheinhold 's Affe mit Schädel (see image, left). By the end of the 19th century, chimpanzees remained very much a mystery to humans, with very little factual scientific information available.
In the 20th century, a new age of scientific research into chimpanzee behaviour began. Before 1960, almost nothing was known about chimpanzee behaviour in their natural habitats. In July of that year, Jane Goodall set out to Tanzania 's Gombe forest to live among the chimpanzees, where she primarily studied the members of the Kasakela chimpanzee community . Her discovery that chimpanzees made and used tools was groundbreaking, as humans were previously believed to be the only species to do so. The most progressive early studies on chimpanzees were spearheaded primarily by Wolfgang Köhler and Robert Yerkes , both of whom were renowned psychologists. Both men and their colleagues established laboratory studies of chimpanzees focused specifically on learning about the intellectual abilities of chimpanzees, particularly problem-solving . This typically involved basic, practical tests on laboratory chimpanzees, which required a fairly high intellectual capacity (such as how to solve the problem of acquiring an out-of-reach banana ). Notably, Yerkes also made extensive observations of chimpanzees in the wild which added tremendously to the scientific understanding of chimpanzees and their behaviour. Yerkes studied chimpanzees until World War II , while Köhler concluded five years of study and published his famous Mentality of Apes in 1925 (which is coincidentally when Yerkes began his analyses), eventually concluding, "chimpanzees manifest intelligent behaviour of the general kind familiar in human beings ... a type of behaviour which counts as specifically human" (1925).[59]
The August 2008 issue of the American Journal of Primatology reported results of a year-long study of chimpanzees in Tanzania’s Mahale Mountains National Park , which produced evidence of chimpanzees becoming sick from viral infectious diseases they had likely contracted from humans. Molecular, microscopic and epidemiological investigations demonstrated the chimpanzees living at Mahale Mountains National Park have been suffering from a respiratory disease that is likely caused by a variant of a human paramyxovirus .[60]
Research and study of chimpanzees
See also: Animal testing on non-human primates § Chimpanzees in the U.S.

As of November 2007, about 1,300 chimpanzees were housed in 10 U.S. laboratories (out of 3,000 great apes living in captivity there), either wild-caught, or acquired from circuses, animal trainers, or zoos.[61] Most of the labs either conduct or make the chimps available for invasive research,[62] 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".[63] Two federally funded laboratories use chimps: the Yerkes National Primate Research Center at Emory University in Atlanta, Georgia, and the Southwest National Primate Center in San Antonio, Texas.[64] Five hundred chimps have been retired from laboratory use in the U.S. and live in animal sanctuaries in the U.S. or Canada.[62]
himpanzees used in biomedical research tend to be used repeatedly over decades, rather than used and killed as with most laboratory animals. Some individual chimps currently in U.S. laboratories have been used in experiments for over 40 years.[65] According to Project R&R , a campaign to release chimps held in U.S. labs—run by the New England Anti-Vivisection Society in conjunction with Jane Goodall and other primate researchers—the oldest known chimp in a U.S. lab is Wenka, which was born in a laboratory in Florida on May 21, 1954.[66] 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 the subject of research into alcohol use, oral contraceptives, aging, and cognitive studies.[67]
With the publication of the chimpanzee genome , plans to increase the use of chimps in labs are reportedly increasing, with some scientists arguing that the federal moratorium on breeding chimps for research should be lifted.[64] [68] A five-year moratorium was imposed by the U.S. National Institutes of Health in 1996, because too many chimps had been bred for HIV research, and it has been extended annually since 2001.[64]
Other researchers argue that chimps are unique animals and either should 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, given chimpanzees' sense of self, tool use, and genetic similarity to human beings, studies using chimps should follow the ethical guidelines used for human subjects unable to give consent.[64] Also, a recent study suggests chimpanzees which are retired from labs exhibit a form ofposttraumatic stress disorder .[69] 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."[64]
An increasing number of governments are enacting a great ape research ban forbidding the use of chimpanzees and other great apes in research or toxicology testing.[70] As of 2006, Austria , New Zealand , the Netherlands , Sweden , and the UK had introduced such bans.[71]
Studies of language
Main article: Great ape language
Scientists have long been fascinated with the studies of language, believing it to be a unique human cognitive ability. To test this hypothesis, scientists have attempted to teach human language to several species of great apes. One early attempt by Allen and Beatrix Gardner in the 1960s involved spending 51 months teaching American Sign Language (ASL) to a chimpanzee named Washoe . The Gardners reported Washoe learned 151 signs, and she had spontaneously taught them to other chimpanzees.[72] Over a longer period of time, Washoe learned over 800 signs.[73]
Debate is ongoing among some scientists (such as David Premack ), about non-human great apes' ability to learn language. Since the early reports on Washoe, numerous other studies have been conducted, with varying levels of success,[74] including one involving a chimpanzee named jokingly Nim Chimpsky , 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 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 simply 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.[75]
Memory
A 30-year study at Kyoto University 's Primate Research Institute has shown that chimps are able to learn to recognise the numbers 1 through 9 and their values. The chimps further show an aptitude for photographic memory , demonstrated in experiments in which the jumbled digits are flashed onto a computer screen for less than a quarter of a second, after which the chimp, Ayumu , is able to correctly and quickly point to the positions where they appeared in ascending order. The same experiment was failed by human world memory champion Ben Pridmore on most attempts.[76]
Laughter in apes
Laughter might not be confined or unique to humans. The differences between chimpanzee and human laughter may be the result of adaptations that have evolved to enable human speech. Self-awareness of one's situation as seen in the mirror test , or the ability to identify with another's predicament (see mirror neurons ), are prerequisites for laughter,[ citation needed] so animals may be laughing for the same reasons that humans do.
Chimpanzees, gorillas , and orangutans show laughter-like vocalizations in response to physical contact, such as wrestling, play-chasing, or tickling . This is documented in wild and captive chimpanzees. Common 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. One study analyzed and recorded sounds made by human babies andbonobos when tickled. Although the bonobo's laugh was a higher frequency, the laugh followed a pattern similar to that of human babies and included similar facial expressions. 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.[77]
See also: Laughter in animals
Chimps listed as endangered in the US
The US Fish and Wildlife Service finalized a rule on June 12, 2015, creating very strict regulations, practically barring any activity with chimpanzees other than for scientific, preservation-oriented purposes.[78]
Chimpanzees as pets
See also: Exotic pet

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 confiscate chimpanzees from people keeping them as pets.[79]
Chimpanzees are popular as wild pets in many areas despite their strength, aggression, and wild nature. Even in areas where keeping non-human primates as pets is illegal, the exotic pet trade continues to prosper and some people keep chimpanzees as pets mistakenly believing that they will bond with them for life. As they grow, so do their strength and aggression; some owners and others interacting with the animals have lost fingers and suffered severe facial damage among other injuries sustained in attacks. In addition to the animals' hostile potential and strength well beyond any human being, chimpanzees physically mature a lot more proportionally than do human beings, and even among the most cleanly and well-organized of housekeepers, maintaining cleanliness and control of chimpanzees is physically demanding to the point that it is impossible for humans to control, especially due to the animals' strength and aggression.[80] [ dead link]
Chimpanzees in popular culture
See also: List of fictional primates

Chimpanzees have been commonly stereotyped in popular culture , where they are most often cast in standardized roles as childlike companions, sidekicks or clowns .[81] 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. Accordingly, entertainment acts featuring chimpanzees dressed up as humans have been traditional staples of circuses and stage shows .[81]
In the age of television, a new genre of chimp act emerged in the United States : series whose cast consisted entirely of chimpanzees dressed as humans and "speaking" lines dubbed by human actors.[81] These shows, examples of which include Lancelot Link, Secret Chimp in the 1970s or The Chimp Channel in the 1990s, relied on the novelty of their ape cast to make their timeworn, low comedy gags funny.[81] Their chimpanzee "actors" were as interchangeable as the apes in a circus act, being amusing as chimpanzees and not as individuals.[81] Animal rights groups have urged a stop to this practice, considering it animal abuse.[82]
When chimpanzees appear in other TV shows, they generally do so as comic relief sidekicks to humans. In that role, for instance, J. Fred Muggs appeared with Today Show hostDave Garroway in the 1950s, Judy on Daktari in the 1960s and Darwin on The Wild Thornberrys in the 1990s.[81] In contrast to the fictional depictions of other animals, such as dogs (as in Lassie ), dolphins (Flipper ), horses (The Black Stallion ) or even other great apes (King Kong ), chimpanzee characters and actions are rarely relevant to the plot.[81]
Chimpanzees in science fiction
The rare depictions of chimpanzees as individuals rather than stock characters, and as central rather than incidental to the plot[81] are generally found in works of science fiction .Robert A. Heinlein 's short story "Jerry Was a Man " (1947) centers on a genetically enhanced chimpanzee suing for better treatment. The 1972 film Conquest of the Planet of the Apes , the third sequel of Planet of the Apes , portrays a futuristic revolt of enslaved apes led by the only talking chimpanzee, Caesar , against their human masters.[81] This concept was revisited in the 2011 film Rise of the Planet of the Apes , again with a chimpanzee protagonist named Caesar. Another short story, "The Pope of the Chimps" byRobert Silverberg , set in the present day, shows the development of the first signs of religiosity in a group of chimpanzees, much to the surprise of the humans observing them.David Brin 's Uplift novels present a future in which humans have "uplifted " chimpanzees (and certain other species) with human-level sapience .