RANGEĬhimpanzees are found across a west-east belt in equatorial Africa. The average lifespan of chimpanzees is 40 to 45 years, though it is considerably longer for captive chimpanzees (Macdonald 2001). All chimpanzees build sleeping nests in trees at night (Rowe 1996). Chimpanzees are both terrestrial and arboreal, with the amount of time spent on the ground varying between study sites and between sexes (Doran 1996). Locomotion patterns include quadrupedal knuckle walking and occasional bipedalism. They have prominent ears and both males and females have white beards. Pan troglodytesĬhimpanzees are all black but are born with pale faces and a white tail tuft, both of which darken with age. Males and females have an average height of 816 mm (2.68 ft) (Rowe 1996). They have a more robust build than bonobos ( Pan paniscus) and are slightly sexually dimorphic with males, on average, weighing 40 to 60 kg (88.2 to 132 lb) and females, on average, weighing 32 to 47 kg (70.5 to 104 lb) (Rowe 1996). MORPHOLOGYĬhimpanzees exhibit very little morphological differences between subspecies. For example, by categorizing chimpanzees as Homo, it might be considered unethical to keep them in zoos or use them in research. The implications of changing the taxonomical categorization could have enormous impacts on how chimpanzees are perceived and the rights extended to them. The Hominoidea.Some argue that chimpanzees should be categorized in the same genus as humans, Homo, based on the fact that chimpanzees and humans diverged only 4 to 6 million years ago (Groves 2001). Tuttle RH (1969) Quantitative and functional studies on the hands of the Anthropoidea I. Tuttle RH (1967) Knuckle-walking and the evolution of hominoid hands. Thorpe SKS, Crompton RH, Gunther MM, Ker RF, Alexander RM (1999) Dimensions and moment arms of the hind- and forelimb muscles of common chimpanzees ( Pan troglodytes). Smith SL (1995) Pattern profile analysis of hominid and chimpanzee hand bones. Milner TE, Dhaliwal SS (2002) Activation of intrinsic and extrinsic finger muscles in relation to the fingertip force vector. Marzke MW, Marzke RF, Linscheid RL, Smutz P, Steinberg B, Reece S, An KN (1999) Chimpanzee thumb muscle cross sections, moment arms and potential torques, and comparisons with humans. World Scientific, SingaporeĬlarys JP, Marfell-Jones MJ (1986) Anthropometric prediction of component tissue masses in the minor limb segments of the human body. J Hand Surg Am 6:209–219Ĭhao EYS, An KN, Cooney WP, Linscheid RL (1989) Biomechanics of the hand, a basic research study. Shortening of the metacarpals and the intervening interosseous muscles might accordingly be a prerequisite for the evolution of human precision-grip capabilities.īrand PW, Beach RB, Thompson DE (1981) Relative tension and potential excursion of muscles in the forearm and hand. This suggests that the human intrinsic muscle architecture is relatively more adapted to dexterous manipulative functions. However, a new finding was that relative PCSA, which reflects a muscle’s capacity to generate force, might have increased slightly in humans as a result of relatively shorter muscle fiber length. The interosseous muscles were also confirmed to be relatively larger in the chimpanzee. Comparisons of the hand musculature of the measured chimpanzee with corresponding published human data indicated that the chimpanzee has relatively larger forearm flexors but smaller thenar eminence muscles, as observed in previous studies. The consistency of our measurements was confirmed by comparison with the published data on chimpanzees. We dissected the forearms and hands of a female chimpanzee and systematically recorded mass, fiber length, and physiological cross-sectional area (PCSA) of all muscles including those of intrinsic muscles that have not been reported previously.
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