smaller of two species of chimpanzee, genus Pan. Whereas the common chimpanzee, P. troglodytes, lives in forests across most of equatorial Africa, the bonobo, P. paniscus (sometimes called the pygmy chimpanzee), is found only in the Congo (Kinshasa) S of the Congo River. The bonobo has a more slender body build than the common chimpanzee, but there is considerable overlap in overall size (head-and-body length and weight) among individuals of the two species.
Bonobos share many behavioral traits with common chimpanzees; e.g., they tend to associate in groups, are day-active, build sleeping nests in trees, and eat mostly fruit and other vegetable matter. Their groups are usually larger than those of common chimpanzees, however, and often the females are closely bonded and tend to dominate males. Moreover, both males and females appear to use sexual contact as a means of communication and a way to ease tensions that might otherwise erupt into conflict, though there is evidence to suggest this is much more common in captive, rather than wild, bonobos. Bonobos are generally less violent than common chimpanzees, and there are fewer conflicts between neighboring bonobo communities. Both bonobos and common chimpanzees have been able to learn the meanings of many human words (although they cannot vocalize them), and they can be trained to communicate with humans by using sign language or symbol boards.
The bonobo is listed as an endangered species. The few thousand that remain in the wild are hunted by humans, and their habitat is being fragmented by encroaching human settlement, agriculture, and logging operations. Bonobos are classified in the phylum Chordata, subphylum Vertebrata, class Mammalia, order Primates, family Hominidae.