Chimpanzee Physical Characteristics
All primates have some standard features, such as opposable thumbs and the capacity to rotate the radio and ulna bones of the arms against each other. However, chimpanzees have a unique appearance and anatomy that allows them to move quickly on the trees as well as to manipulate objects skillfully.
Chimpanzees can walk on two legs for a brief period, being more common in bonobos.
It is easy to note the similarities between the anatomy of a human being and that of a chimpanzee. But the latter have unique characteristics like its robust and sturdy body, several times more than that of a person. They are quadruped animals, so they move with their four limbs, but can walk on two legs for a short time; this ability is even more frequent in bonobos (Pan paniscus).
Their head is rounded and rests on a short neck. The two eyes are located on the front, facing forward, while the nose is small and the ears are large. Soft lips protrude from the face, which can be skin-toned or completely dark.
The torso is barrel-shaped. From the trunk, two arms and two flexible legs emerge that are the limbs; the former are longer than the latter. They walk on the soles of the feet and the knuckles of the hands. All their fingers are thick, and their thumbs can touch the tips of all other fingers.
A rough and dark hair covers their body, except on the face, ears, and palms of hands and feet. Young chimpanzees have a white hair tuft on their back that disappears when they grow.
Both species, Bonobos (Pan paniscus) and common chimpanzees (Pan troglodytes) are similar, but differ by the following:
The bonobos are more graceful, thinner and slightly smaller than the chimpanzees.
The hair in bonobos’ head has a backward direction, instead of sideward like the chimpanzees.
The face of the common chimpanzees has a light pinkish tone, which contrasts with the black face of the bonobos.
Common chimpanzees have slightly shorter limbs.
The breasts of the bonobo females may be larger than those of the common chimpanzee females.
The length of adults varies. Common chimpanzees measure from 63 to 94 centimeters from the nose to the rump while in four legs and weigh from 32 to 60 kilograms. Bonobos measure from 70 to 83 cm, and they weigh from 34 to 60 kilos. The males are larger than the females, and some reach up to 1.2 meters height while standing on their two legs.
The largest bone in their body is the humerus.
The skeleton of chimpanzees is hard and very resistant. It has a relatively large skull and a protuberance in it, called the sagittal crest, slightly pronounced. The vertebral column has 32 vertebrae, which has great flexibility in the neck area where they have seven vertebrae; besides they have four lumbar, 13 thoracics, five sacrals and three vestigial that make the coccyx. The largest bone in their body is the humerus.
The jaws have an evident prognathism, this is, they protrude forward. On the eyes, they have raised bones, which make up the supraorbital torus. The bone of the nose is flat. Inside the mouth, they have large molar teeth and canines, and the two front teeth are slightly apart.
The cranial capacity of the common chimpanzees is around 320-480 cubic centimeters, while in bonobos it is around 350 cubic centimeters (cc). In general, the volume ranges from 282 to 500 cc. The volume within the skull of chimpanzees is smaller than humans but large enough to solve the problems that occur in their natural habitat.
Friderun Ankel-Simons. Primate Anatomy: An Introduction. Academic Press, 2010.
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