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The Common Chimpanzee (Pan troglodytes) is one of the great apes. Most often it is called the Chimpanzee (or more colloquially
Chimp), even tough the term often is used in the broader sense to include the Common Chimpanzee and its cousin
the Bonobo or Pygmy Chimpanzee which was not recognized as an independent species until
quite recently.
Anatomical differences between the two species are slight, but in sexual and social behaviour there are some marked
distinctions. For example, the Chimpanzee has a troop hunting culture based on beta males led by a relatively weak alpha, an
omnivorous diet, and a complex culture with long bonds. The Bonobo, on the other hand, is sexually promiscuous.
Biologists believe that the Chimpanzee and the Bonobo are our closest evolutionary relatives; they branched off from our
latest common ancestor as recently as 4 to 7 million years ago, and we share 98-99.4% of our DNA with them, which prompted Jared Diamond to use the term
"the third chimpanzee" for our own species. Some believe that assigning the Chimpanzee and Bonobo to a different genus or even family than
humans, a taxonomic division that goes back to Linnaeus and that he
later regretted, is not justified on biological grounds, and in fact amounts to an instance of anthropocentrism. Many modern primatologists
now place all the great apes, including humans, into one family, with all but the Orangutan in the same subfamily.
Several subspecies of chimpanzee have been recognized:
- Pan troglodytes troglodytes, Central Common or Black-faced Chimpanzee
- Pan troglodytes verus, Western Common or Pale-faced Chimpanzee
- Pan troglodytes vellerosus, West Nigerian/East Cameroon Chimpanzee
- Pan troglodytes schweinfurthii, Eastern Common or Long-haired Chimpanzee
Basic facts
The Chimpanzees is found in the tropical forests and wet savannahs of Western and Central Africa. It used to inhabit most of
this region, but its habitat has been dramatically reduced in recent years.
Adults in the wild can measure up to 130 cm (females) or 160 cm (males), and weigh between 40 and 70 kg, but are much stronger
than humans. Their body is covered by a coarse dark brown hair, except for the face, fingers, toes, palms of the hands and soles
of the feet. Both their thumbs and their big toes are opposable, allowing a precision grip. The gestation period is 8 months.
Infants are weaned when they are about 3 years old, but usually maintain a close relationship with their mother for several years
more. Puberty is reached at the age of 8-10, and their lifespan in captivity is about 50 years.
The Chimpanzee lives in groups called communities that range from about 20 to more than 150 members, consisting of several
males, females and juveniles. However, most of the time they travel around in small parties of just a few individuals. It is both
arboreal and terrestrial, spending equal time in the trees and on the ground. Its habitual gait is quadrupedal, using the soles
of its feet and resting on its knuckles, but it can walk upright for a short distance.
Diet is mainly vegetarian (fruit, leaves, nuts, seeds, tubers...), supplemented by insects and small prey; there are instances
of hunting. In some cases—such as killing leopard cubs—this hunting seems
to be primarily a protective effort by the Chimpanzee, rather than being motivated by hunger. However, the Chimpanzee sometimes
bands together and hunts Red Colobus Monkeys for meat; this shows that they are capable of group hunting like humans, and have a
taste for flesh. Isolated cases of cannibalism have been documented.
Chimp genome project
Human and Chimpanzee chromosomes are very similar. The major difference is
that humans have two less chromosomes than do other great apes. In the human evolutionary lineage, two ancestral ape chromosomes
fused at their telomeres producing human chromosome 2. There are only 9 other major
chromosomal differences between chimps and humans, chromosome segment inversions on human chromosomes 1, 4, 5, 9, 12, 15, 16, 17,
18. After the completion of the Human genome project, a
chimp genome project was initiated. In December of 2003 a preliminary analysis of 7600 genes shared between the chimp and human
genomes confirmed that certain genes such as the forkhead-box P2 transcription factor have undergone rapid evolution in the human lineage. This gene is involved in
human speech development. Several genes involved in hearing were also found to have changed rapidly during human evolution,
suggesting selection involving human language-related behavior. Human-chimp DNA differences are about 10 times the typical
difference between pairs of humans.
See Also
External Links
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