The Bonobo (Pan paniscus), sometimes called the "pygmy chimpanzee", is one of the two species comprising the genusPan; both members of that genus are technically "chimpanzees", though the term is frequently used to refer only to the other member of the genus, Pan troglodytes, the Common Chimpanzee. To avoid confusion, this article will use "chimpanzee" only to refer to both members of the genus.
Bonobos diverged from common chimpanzees after the last common chimpanzee ancestor diverged from its last common ancestor with humans; as no other species from the human line of the branching have survived, bonobos and common chimpanzees are our closest living relatives, sharing approximately 98.4% of their DNA with us. Bonobos passed the mirror-recognition test for self-awareness in 1994. They communicate through primarily vocal means, in a language that has not yet been deciphered; however, we do understand some of their natural hand gestures, such as their invitation to play. Three bonobos, Kanzi, Panbanisha and Nyota, have been taught a vocabulary of about 400 words which they can type using a special keyboard of lexigrams (geometric symbols), and can respond to spoken sentences. Some, such as philosopherPeter Singer, argue that these results qualify them for the same rights as humans.
Bonobos live in a fusion-fission pattern: a tribe of about a hundred will split into small groups during the day while looking for food, and then come back together to sleep. Unlike common chimpanzees, who have been known to hunt monkeys, bonobos are primarily vegetarian, although they do eat insects and have been observed occasionally catching small mammals such as squirrels. Their primary food source is fruit.
Sue Savage-Rumbaugh and Roger Lewin, Kanzi: The Ape at the Brink of the Human Mind, John Wiley, September, 1994, hardcover, 299 pages, ISBN 0471585912; trade paperback, reissue, September, 1998, ISBN 047115959X