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Chimpanzee, Chimpanzee

Chimpanzee are thought to have split from human evolution about 6 million years ago and thus the two chimpanzee species are the closest living relatives to humans; all being members of the Hominini tribe (along with extinct species of Hominina subtribe). Chimpanzees are the only known members of the Panina subtribe. The two Pan species split only about one million years ago.

Existing chimpanzee populations in West and Central Africa do not overlap with the major human fossil sites in East Africa. However, chimpanzee fossils have now been reported from Kenya. This would indicate that both humans and members of the Pan clade were present in the East African Rift Valley during the Middle Pleistocene.

The common chimps long arms, when extended, have a span half again as long as the bodys height and are longer than its legs. The bonobo is a little shorter and thinner than the common chimpanzee but has longer limbs. Both species use their long, powerful arms for climbing in trees. On the ground, chimpanzees usually walk on all fours using their knuckles for support with their hands clenched, a form of locomotion called knuckle-walking. Chimpanzee feet are better suited for walking than are those of the orangutan because the chimps soles are broader and the toes shorter. Both the common chimpanzee and bonobo can walk upright on two legs when carrying objects with their hands and arms. The coat is dark; the face, fingers, palms of the hands, and soles of the feet are hairless; and the chimp has no tail. A bony shelf over the eyes gives the forehead a receding appearance, and the nose is flat. Although the jaws protrude, the lips are thrust out only when a chimp pouts. The brain of a chimpanzee is about half the size of the human brain. "Chimpanzee," Microsoft Encarta Online Encyclopedia 2008http://encarta.msn.com 1997-2008 Microsoft Corporation. All Rights Reserved.

The Common Chimpanzee has an omnivorous diet, a troop hunting culture based on beta males led by an alpha male, and highly complex social relationships.

The Bonobo has proportionately longer upper limbs and tends to walk upright more often than the Common Chimpanzee. A University of Chicago Medical Centre study has found significant genetic differences between chimpanzee populations.

Recent research indicates that chimpanzee stone tool use dates to at least 4300 years ago.

Since the early reports on Washoe, numerous other studies have been conducted with varying levels of success http://www.greatapetrust.org/bonobo/language/ , including one involving a chimpanzee named Nim Chimpsky trained by Herbert Terrace of Columbia University. Although his initial reports were quite positive, in November of 1979, Terrace and his team 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 Nims signs). In the re-analysis, Terrace concluded that Nims 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 behavior is pure drill, he said. Language still stands as an important definition of the human species. In this reversal, Terrace now argued that Nims 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. Nims sentences also did not grow in length, unlike human children whose vocabulary and sentence length show a strong positive correlation.

Common Chimpanzee laughter is not readily recognizable to humans as such, because it is generated by alternating inhalations and exhalations that sound more like breathing and panting. There are instances in which non-human primates have been reported to have expressed joy. One study analysed and recorded sounds made by human babies and Bonobos when tickled. It found, that 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.

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 who examined these rare specimens were baffled, and described these first chimpanzees as "pygmies", and noted the animals' distinct similarities to humans. The next two decades would see a number of the creatures imported into Europe, mainly acquired by various zoological gardens as entertainment for visitors.

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 Schdel (see image, left), where an apparently learned chimpanzee contemplates a human skull. At one point there was even a scheme drawn up to domesticate chimpanzees in order to have them perform various menial tasks. (i.e. factory work) By the end of the 1800s chimpanzees remained very much a mystery to humans, with very little factual scientific information available.

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 Khler 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 Khler concluded five years of study and published his famous Mentality of Apes in 1925 (which is coincidentally when Yerkes began his analyses), eventually concluding that "chimpanzees manifest intelligent behaviour of the general kind familiar in human beings ... a type of behaviour which counts as specifically human" (1925).

Molecular, microscopic and epidemiological investigations demonstrated that 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.

Pascal Gagneux, an evolutionary biologist and primate expert at the University of California, San Diego, argues that, given chimpanzees' sense of self, tool use, and genetic similarity to human beings, studies using chimps should follow the ethical guidelines that are used for human subjects unable to give consent.

Some of these attacks are presumed to be due to chimpanzees being intoxicated (from alcohol obtained from rural brewing operations) and mistaking human children for the Western Red Colobus, one of their favourite meals.

Robert A. Heinlein's short story Jerry Was a Man of 1947 centers on a genetically enhanced chimpanzee suing for better treatment, a theme also echoed in David Brin's 1990s Uplift series. In film, the 1972 movie Conquest of the Planet of the Apes centers around a fierce revolt of enslaved apes, led by the chimpanzee Caesar, against their human masters.

Source: Wikipedia > Chimpanzee