BONOBO

(Pan paniscus), also called pygmy chimpanzee tailless, manlike primate belonging to the family Pongidae (great apes). The bonobo was regarded as a subspecies of the chimpanzee (P. troglodytes) until 1933, when it was first classified as a separate species. The bonobo closely resembles the chimpanzee in both physical appearance and mode of life, though with a few differences. It has a more restricted range than the chimpanzee, being found only in the lowland rainforests of central Congo (Kinshasa). The bonobo is about the same size as the chimpanzee; adult males weigh 4050 kg (90110 pounds) and females weigh about 3035 kg (6575 pounds), while members of both sexes stand about 115 cm (3.8 feet) when erect. The bonobo has longer and more slender arms, a slender body, and a less protruding face than does the chimpanzee, however. Bonobos feed mostly in trees and descend to the ground to move to other food trees. They eat mostly fruits, supplemented by leaves, seeds, grass, and such animals as caterpillars, rodents, and even young duiker antelopes. They are active during the day and build sleeping nests at night. They form communities of 50120 individuals occupying a home range area of 2060 square km (722 square miles); the community is in turn composed of groups of 215 individuals who forage together but whose membership is continually changing. Bonobo females with their young form the core of most groups, with males tending to follow the lead of mature females. Female bonobos are sexually active for more of the time than their chimpanzee counterparts; they bear offspring at roughly five-year intervals and resume copulating with males within a year of giving birth. Bonobos sometimes mate using a face-to-face position, which is rarely seen among chimpanzees. The number of bonobos in the wild is shrinking, largely because of human destruction of their forest homelands and illegal hunting. The species is listed as endangered in the Red Data Book and had an estimated population of fewer than 15,000 in the late 20th century. Bonobos are not often kept in captivity.