Bonobos are the enigmatic fifth member of the great ape family which also consists of orang-utans, gorillas, common chimpanzees and humans. In the same way as we relate to common chimpanzees, the DNA recipe which makes up humans differs by around 1% to that which makes up bonobos, making them both equally our closest living genetic relatives. Their scientific name (Pan paniscus), means ‘diminutive Pan’: a minute version of the goat-horned and legged Greek forest god, who enjoyed some nymph debauchery while playing the pan flute in mythological times. This term has only been used to designate the bonobo since 1933 as prior to that date, bonobos were largely unknown or misunderstood to be dwarf chimpanzees.
Although the common chimpanzee and the bonobo are both members of the chimpanzee family, they are indeed distinct species which are thought to have diverged due to environmental change. Between 1.5 and 2 million years ago, the Congo river formed and started its course, which separates the North-western area of the land of Congo into two pieces. It is understood that the appearance of the Congo river led to a speciation event, where the ancestors of bonobos and common chimpanzees became isolated from each other both physically and socially on either side of the river. This theory is supported by the estimation that the genetic material of both species differs by a number of mutations which needed between 1 and 2 million years to arise.
It is thought that there was a stark difference in the availability of food resources on one side of the Congo river compared to the other, and that this factor is crucially important in understanding the physical and behavioural contrast between the common chimpanzee and the bonobo. The southern area home to bonobos is characterized by lush jungle rich in foodstuffs, where every individual could afford to share what they had, while common chimpanzees probably had to compete and find innovative and sometimes devious methods to forage enough food to survive on the northern divide. These differential ecological conditions are thought to explain why bonobos have adopted some rather more peaceful social dynamics than common chimpanzees.
Indeed, the bonobo is an ape of a gentle nature. While the common chimpanzee society is one based on male dominance where individuals are seen to habitually raid steal and murder; bonobo societies are female-led but relatively egalitarian, and they have never been witnessed to kill another of their own kind. The key to the peaceful group cohesion of bonobos seems to be the way in which they deal with social tension, having replaced aggression with sex. For bonobos, sexuality and sociality are one and the same, leading to all group members interacting together sexually, regardless of age or gender. Female-female sex is particularly important among bonobos, as females leave their natal group at adolescence to avoid inbreeding, and use sex with the females in their new group to form and maintain bonds. The strong social bonding between females and the fact that sex is more powerful than aggression among bonobos, means that females are able to dominate males even though they are smaller in size.
Bonobos also use sexual contact to make sure that situations of potential conflict remain peaceful, such as at times of feeding. If a group of bonobos encounters a source of food, they will react by engaging in rapid successions of plentiful sexual encounters for everyone, before proceeding to the harmonious sharing of the food source.
These behavioural features of bonobo life have earned them the nickname in the popular press of ‘hippie apes’ or ‘make-love-not-war apes’, while common chimpanzees are increasingly demonized in contrast. Although there is debate regarding the true significance of bonobo behaviour and its evolution, there is no doubt that our two closest relatives are divergent in their natures. This idea is highlighted by primatologist Frans de Waal who has spent many years arguing that human nature may not be inherently selfish and violent, as there is such variation in the natural behaviour of our two closest relatives. De Waal illustrates this point with the story of the bombing of Hellabrun in Germany during the second World War, where explosions caused all the bonobos in a nearby zoo to die out of fright while the common chimpanzees were apparently not affected.
Bonobos only live in the Democratic Republic of Congo, which has been a war torn region for many years. Civil hostilities and monetary struggles in the country have led to the rapidly increasing destruction of the habitat of bonobos, as well as to their mass murder for the black market bushmeat trade. Furthermore, the political and social instability of the country makes it very challenging to establish successful conservation projects to help bonobos. These factors, coupled with the fact that bonobo population growth is slow, have led to a dramatic loss of wild bonobos over recent times and they are now gravely endangered.
If you want to help stop the decline of bonobo population numbers, there are many ways to get involved in conservation work, good information sources are the Great Ape Trust and Bonobo Conservation Initiative websites:
To find out more about bonobos, watch this amazing TED talk by Susan Savage Rumbaugh on her work with bonobos, showing some of their abilities such as writing, the playing of musical instruments and Pacman: