Taxonomic lineage

Genus Pan (chimpanzee) belongs family Hominidae (great apes) together with Gorilla, Homo (human), and Pongo (orangutan). The orangutan is the most primitive of great apes and is separated in the subfamily Ponginae. Thus, great hominoid trio consists of Homo, Pan and Gorilla. Chimpanzee is considered to be the closest human relative.

The vernacular name chimpanzee is a Bantu word used originally in northern Angola and Congo to refer to these animals.

cellular organisms - Eukaryota - Fungi/Metazoa group - Metazoa - Eumetazoa - Bilateria - Coelomata - Deuterostomia - Chordata - Craniata - Vertebrata - Gnathostomata - Teleostomi - Euteleostomi - Sarcopterygii - Tetrapoda - Amniota - Mammalia - Theria - Eutheria - Euarchontoglires - Primates - Haplorrhini - Simiiformes - Catarrhini - Hominoidea - Hominidae - Homininae - Pan - Pan troglodytes

Subspecies

Pan troglodytes schweinfurthii
Pan troglodytes troglodytes
Pan troglodytes vellerosus
Pan troglodytes verus

Brief facts

• Distribution

  The geographic range of the species is included within an area between about 10°N to 8°S and 15°W to 32°E. Isolated populations of chimpanzees are known from Sudan and Tanzania, as well as in the West Africa forest. Elevation range is from sea level in West Africa to about 2,750 m in the Ruwenzoni Mountains on the Congo-Uganda border. Pan t. verus occurs in the western portions of the range; P. t. vellerosus and P. t. troglodytes inhabit forested regions from the Niger river to Sanaga and from Sanaga to Congo, respectively, and in the far east, from the northwestern corner of Zaire into western Uganda and Tanzania, P. troglodytes schweinfurthi is found. It is estimated that only about 35,000 animals still may survive in all known potential habitats. Pan troglodytes troglodytes co-exist with Gorilla gorilla (western lowland gorillas). Both species were observed to forage on the same fruit trees. The geographic range of P. troglodytes has little or no overlap with that of the congeneric form, P. panicus, which is found the region bordered by the Congo and Lualaba rivers in central Congo. However, if the two species occur in sympatry, behavioral differences may prevent intermingling between the species.

  

• Ecology

  Throughout most of the geographic range, chimpanzees inhabit either tropical rain forest or tropical closed forest. In West Africa, this ape occurs in savanna, scrub and gallery forests. In East Africa, chimpanzees occupy deciduous woodlands, savannas, and dense rain forests at all elevations.

• Nesting

  All great apes build nests that serve as resting or sleeping platforms. Nests are constructed from herbs, twigs and branches and provide comfort and protection from elements. Chimpanzee build their nests on the trees at average height of 17-25 meters - significantly higher than sympatric gorillas who also make nests on the ground. Unlike gorillas, chimpanzees prefer nesting in open understorey habitats in Gilbertiodendron forests and rarely visit swamped forests frequented by gorillas. Usually new nests are built every night.

• Appearance

  The common chimpanzee is a large and stocky ape. The face is prominent and prognathous. The narial region is catarrhine (nostrils are close together and directed frontward or downward). When standing erect, chimpanzees are 1 to 1.7 m tall. The arms are long (the spread of the arms is 1.5 times the height of an individual) and legs are short. Unlike other anthropoids chimpanzees do not have glans penis. The penis is thin, and tapered to a point. Ears are small, rounded and without lobes. The facial pigmentation ranges from pale to mottled to darkly pigmented. The pelage is coarse and generally black but white hairs grow on chins of adults of both sexes.

• Feeding activities

  In the wild, chimpanzees spend much of their time either feeding or traveling from one food source to another. In this way animals may move from 1 to 16 km per day within the home range of a group. Chimpanzees usually feed intensively for at least 2 hours in the morning, feed, rest, and wander during the middle part of the day, and feed intensively again in late afternoon before making nests for the night.
  In general, chimpanzees are omnivorous and frugivorous diet probably is most common throughout the geographic range of the species. Chimpanzees also eat insects and, sometimes, capture and kill prey for meat. Cannibalism among chimpanzees has been reported; infanticide is committed by both males and females.

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Life history

Average ovarian period length is 37.3 +/- 3.6 days (Young and Yerkes, 1943).

Interbirth interval is about 68 months (wild chimpanzees require a mean of 42 months to regain fertility after previous birth). Potential fertility is about 5. Number raised to sexual maturity is about 2-3 individuals. Thus, fertility data suggest that speed of chimpanzees' reproduction is barely sufficient to maintain their population level.

• Prenatal
  • Embryo MeSH Average gestation period is about 232 days (Dahl, 1999).
• Post natal
  • Neonate Typically, a single young is born, weighing about 2 kg. Twinning is rare, but may be more common than in humans. Neonate is held close to mother's chest.
  • Infant Young chimpanzee until weaning. From age of 3-6 months, infant is usually transported on mother's back. Weaning typically occurs around 3.5-4.5 years of age. By this time, the infant must learn feeding techniques and reach sufficient physical dexterity and strength to find and take solid food in amounts necessary for nutritional independence. Although mother may share or allow infant to take some scraps from her, their quality and quantity are usually not enough for the infant's further growth and development. Males start practicing in mating around this age.
  • Juvenile From weaning 7 years of age until puberty (about 7 years old for males as well as females). Immature young chimp stays close to its mother and depend on her for protection, education and psychological support. Immediately after weaning, juvenile chimpanzee can hardly survive without mother. However, orphans are often adopted by an older relatives.
  • Adolescent From 7 to 10 years of age for females and from 7 to 12 years for males. In the wild, males are first seen to ejaculate around the age of 9 years. Wild female chimpanzees begin to show sexual swellings at about 8-9 years of age with menarche occurring 1-3 years later. A period of adolescent fertility follows during which young females mate but do not conceive. At this time, females may become the focus of sexual parties and may transfer into a neighboring chimpanzee community.
  • Subadult From 10 to 13 years of age for females and from 12 to 15 years for males. At this age, males start establishing themselves in the dominance hierarchy. Their social activities around the age of 10 years lead to the parting of ways between a mother and her son.
  • Adult Females are considered fully adult around the age of 13 years, whereas males reach maturity later, around 15 years when they reach adult weight and social maturity. In the wild, males weigh between 34 and 70 kg. Females are smaller, weighing between 26 and 50 kg. Adult sizes: P. t. schweinfurthii < P. t. verus < P. t. troglodytes. Age of first birth ranges from 10.5 years in well-fed captive chimpanzees to 15 and older in wild chimpanzee. Attainment of minimal weight (around 33-38 kg) is important factor affecting fertility. Wild chimpanzees live between 38 and 40 years with some captive chimpanzees living 50-60 years. Oldest chimpanzee ever to give birth was a 56-year-old female Suzie. at a zoo in northeast Kansas.

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References

• Disotell TR. 'Chumanzee' evolution: the urge to diverge and merge. Genome Biol. 2006;7(11):240.

  

  The scenario proposed by Patterson et al. (Patterson N, Richter DJ, Gnerre S, Lander ES, Reich D. Genetic evidence for complex speciation of humans and chimpanzees. Nature. 2006;441:1103–1108) for the human-chimpanzee split. An initial divergence between the human and chimpanzee lineages was followed by a period of hybridization and, eventually, by full speciation. Mya, million years ago.

• Yamamoto S, Humle T, Tanaka M. Chimpanzees help each other upon request. PLoS One. 2009 Oct 14;4(10):e7416.

  

  Tool transfer upon recipient's request. A chimpanzee (Mari) in the near-side booth picks up a stick and hands it over to her partner (Pendesa) in the far-side booth who requested the tool by poking her arm through the hole between the booths.

• Hockings KJ, Humle T, Anderson JR, Biro D, Sousa C, Ohashi G, Matsuzawa T. Chimpanzees share forbidden fruit. PLoS One. 2007 Sep 12;2(9):e886.

  

  An adult male chimpanzee obtains cultivated papaya fruit.

• de Waal FB. With a little help from a friend. PLoS Biol. 2007 Jul;5(7):e190.

  

  Apes Often Show So-Called "Targeted Helping", which is aid tailored to the other's specific needs. In this case, a mother chimpanzee reaches out to help her juvenile son out of a tree after he screamed and begged (see hand gesture). (Photograph by F.B.M. de Waal)

• Boesch C, Bolé C, Eckhardt N, Boesch H. Altruism in forest chimpanzees: the case of adoption. PLoS One. 2010 Jan 27;5(1):e8901.

  

  The adult male Porthos with his adopted female infant Gia.

• Ghobrial L, Lankester F, Kiyang JA, Akih AE, de Vries S, Fotso R, Gadsby EL, Jenkins PD Jr, Gonder MK. Tracing the origins of rescued chimpanzees reveals widespread chimpanzee hunting in Cameroon. BMC Ecol. 2010 Jan 22;10:2.

  

  Chimpanzee subspecies and georeferenced DNA sampling distributions.
  A) Distribution of chimpanzee subspecies. Chimpanzees belong to a single species (Pan troglodytes) that is divided into four subspecies. Phylogenetic analyses of mtDNA suggest that these subspecies are divided into two geographically and genetically defined groups that split about 0.5 mya: a western African group (P. t. verus and P. t. ellioti [known until recently as P. t. vellerosus) and a central/eastern African group (P. t. troglodytes and P. t. schweinfurthii). A phylogeographic break between these two groups occurs at the Sanaga River in central Cameroon, separating populations of P. t. ellioti north of the river from P. t. troglodytes south of the river. However, the Sanaga does not stop dispersal between subspecies completely because some gene flow between them occurs near the confluence of the Sanaga and its main tributary, the Mbam River.
  B) Map of Cameroon and Nigeria showing collection sites of georeferenced chimpanzee DNA samples. Sampling sites shown on the map are: Ise Forest Reserve (ISFR), Cross River National Park (CRNP), Akoh Zanto (AKZN), Gashaka Gumti National Park (GGNP), Mount Cameroon (MTCM), Mosse (MSSE), Manb'ra (MANB), Douala-Edea Forest Reserve (DEFR), Campo-Ma'an National Park (CMNP) and Dja Biosphere Reserve (DJBR).

• Knight A. The beginning of the end for chimpanzee experiments? Philos Ethics Humanit Med. 2008; 3: 16.

  

  Chimpanzee experiments 1995–2004 (total 749).

• Jones C et al. Pan troglodytes. Mammalian Species, No. 529, Pan troglodytes (May 17, 1996), PP. 1-9.
• Manson JH, Wrangham RW. Intergroup aggression in chimpanzees and humans. Current Anthropology, Vol. 32, No. 4 (Aug. - Oct., 1991), pp. 369-390.
• de Waal FBM. The integration of dominance and social bonding in primates. Quarterly Review of Biology, Vol. 61, No. 4 (Dec., 1986), pp. 459-479.
• Tutin CEG. Mating patterns and reproductive strategies in a community of wild chimpanzees (Pan troglodytes schweinfurthii) Behavioral Ecology and Sociobiology, Volume 6, Number 1, 29-38.
• Tutin CEG. Mating patterns and reproductive strategies in a community of wild chimpanzees (Pan troglodytes schweinfurthii) Behavioral Ecology and Sociobiology, Volume 6, Number 1, 29-38.
• Sanz C et al. Distinguishing between the nests of sympatric chimpanzees and gorillas Am Nat. 2007 May;169(5):684-9.
• Ellegren H. Evolution: natural selection in the evolution of humans and chimps. Curr Biol. 2005 Nov 22;15(22):R919-22.
• Matsuzawa T. The chimpanzee mind: in search of the evolutionary roots of the human mind. Anim Cogn. 2009 Oct;12 Suppl 1:S1-9.
• Warneken F, Tomasello M. Varieties of altruism in children and chimpanzees. Trends Cogn Sci. 2009 Sep;13(9):397-402.
• Kehrer-Sawatzki H, Cooper DN. Structural divergence between the human and chimpanzee genomes. Hum Genet. 2007 Feb;120(6):759-78. Epub 2006 Oct 26.
• Hirata S. Chimpanzee social intelligence: selfishness, altruism, and the mother-infant bond. Primates. 2009 Jan;50(1):3-11.
• Shefferly, N. 2005. "Pan troglodytes" (On-line), Animal Diversity Web. Accessed September 08, 2010. Animal Diversity Web
• Gomes CM, Boesch C. Wild Chimpanzees Exchange Meat for Sex on a Long-Term Basis. PLoS ONE. 2009; 4(4): e5116.

Cover image (left) credit: http://kotomatrix.ru/