Bonobos are highly intelligent, social animals. They live in stable communities that may have up to 150 members, although these will usually split into smaller groups in order to forage or travel (2). Swellings on the rump advertise a female's receptivity to mating; there is no specific breeding season (5). A single offspring is born after around eight months of gestation and will be cared for by its mother for almost five years (6). Bonobo society has some very marked differences to those of chimpanzees and this has fascinated researchers since their discovery. In both, males remain in their natal group whilst females disperse, but in contrast to the male-dominated chimpanzee society, females in bonobo groups develop strong relationships and males will often defer to them during feeding (2). The cooperative hunting and aggressive raids on neighbouring groups that male chimpanzees partake in have not been seen amongst bonobos and it may be that these differences are related to a more reliable and widely available food source (2). One of the other striking features of bonobo society is sex, which is commonly used for social communication in order to diffuse situations and create bonds (2). Males and females engage in these encounters with their own sex as well as the opposite sex (2).
Bonobos spend virtually all of their time in the trees, foraging for fruit and sleeping in nests constructed in the branches; on the ground they travel by 'knuckle walking' (2). Fruit makes up a large part of the bonobo diet but they will also consume other plant materials and small vertebrates should the opportunity arise. This species appears to depend more on plant stems in its diet than chimpanzees do, perhaps again explaining the lack of aggression in bonobo groups (2).