Chimpanzee

Chimpanzees are highly intelligent and emotional animals. They demonstrate many humanlike traits, such as a rudimentary culture, in their adaptive responses to environmental challenges.

Physical Characteristics of Chimpanzees
Woodland chimpanzees weigh between 73 and 132 pounds. The bonobo weighs from seventythree to ninety-nine pounds. Females are about 10 percent smaller than males. Chimpanzees have powerful arms and shoulders and locomote through knuckle-walking, a form of quadrupedalism, although they are occasionally bipedal, and can also brachiate (swing through trees and branches). Chimpanzee forelimbs (arms) are longer than their hindlimbs. Vision is in color and highly acute. Chimpanzees have short thumbs, and their grasping ability is somewhat impaired relative to humans. Both Pan troglodytes and Pan piniscus are promiscuous. Females of each species exhibit sexual swelling when they are receptive to mating; however, there is no consistent breeding season.

Ecology and Diet
Chimpanzees at one time inhabited a three-thousand mile belt across equatorial Africa. Today their distribution is limited, and in some regions they are extinct or disappearing. Chimpanzee home ranges vary in size depending upon food resources and other ecological dynamics. The home range of the woodland chimpanzee can be from 2 to 215 square miles, whereas the bonobo's home range is from 7 to 19 square miles. Water availability, nesting trees, and seasonal food resources define ranges, and chimpanzees can cover several miles in a day. Adult male chimpanzees patrol their ranges to ensure the exclusiveness of a community's domain. Aggression as a result of invasion and intercommunity destruction has been documented by Jane Goodall. Chimpanzees are omnivorous: Their diet consists of a great variety of vegetal foods, as well as insects, grubs, bird eggs, and small mammals. While leaves and fruit define much of the chimpanzee's diet, colobus monkeys, young bush bucks, and young baboons obtain supplemental protein through cooperative hunts.

Group Life and Learning
Chimpanzees of both species reside in fissionfusion communities. Membership within community subgroups can change throughout the day. Males and females strive to attain dominance, or elevated status, which provides access to preferred food resources and desirable mates. Physical size, strength, and age influence the attainment of position within a dominance hierarchy. Hierarchies function to minimize chaos within the community.Woodland chimpanzee communities range from 20 to over 100; bonobo groups range from 50 to 120 individuals. Social interaction is enhanced on the individual level through social grooming. Mutual grooming, or cleaning the hair carefully, is an act denoting friendship and intimacy. Learning accounts for much of chimpanzee behavior, acquired through play and observation. Tool use, a learned behavior, has been observed frequently among woodland chimpanzees, much less so among the bonobo. Tools (sticks, rocks, branches, leaves) have been used, and in some instances modified, in order to access and extract underground termites from their nests for consumption; to intimidate other animals; to facilitate drinking; to clean the body; and to crack open nuts. Chimpanzee behaviors associated with meat eating include begging and the subsequent sharing of the kill by the hunters. Cannibalism and infanticideamongchimpanzees have also been observed. Chimpanzees are emotional animals that require reassurance that they are part of the community. Touching and embracing among individuals are common behaviors.