If you scratch me, I’ll scratch you
Bonobos are not only genetically close to humans, but they also behave quite humanly in some ways. This is what makes dwarf chimpanzees interesting to evolutionary biologists: monkeys cultivate their neighborly relationships in a special way.
W.Why help strangers, and even share food with them, if you’re not sure if it’s worth it for you? This behavior is considered prosocial, almost primary, but can also be observed in other primates. At least among bonobos, which, along with chimpanzees, are among the closest relatives of humans.
Therefore, observations of how these monkeys interact with each other can provide evolutionary biologists with important clues about how cooperative behavior evolved in humans. And a recent study shows that bonobos also maintain neighborly relationships. They strengthen them strategically, peacefully. For example, through personal care, grooming or gifts of food.
With their study published in the specialized journal Science, zoologist Liran Samuni and biologist Martin Surbeck from Harvard University in Boston complement previous reports on the social behavior of bonobos. Both investigate how different species of great apes come into contact within their own group and with members of other communities.
For the current analysis, Samuni and Surbeck are evaluating observations of two groups of bonobos that were documented over a two-year period in the “Kokolopori Bonobo Reserve” in the Democratic Republic of the Congo. They also took into account whether blood relatives were preferred. Or if strangers also benefit from charity.
And indeed: the monkeys did feed certain neighbors. Contacts when groups met could last 14 days, but some lasted less than an hour, and individual interactions were not random but selective.
In their study, Samuni and Surbeck focus on three forms of interaction: grooming or preening, forming alliances, and sharing food. They observed 31 adult animals that were divided into two social groups; Around 7,900 interactions were evaluated. This time aggressive or sexual behaviors were ignored: “Here, cooperation refers to behaviors whose evolution is fundamentally difficult to explain,” explains Surbeck. In these cases, the recipients would benefit more, at the expense of the actor in question.
In the case of grooming, a bonobo’s “loss” is small because this favor is usually immediately reciprocated; When it comes to food, the balance of give and take is significantly worse in direct comparison, and yet it is often shared. Especially with those who, on the whole, proved to be just as generous.
“We showed that a structure that brings together animals willing to cooperate can mean that we can observe these behaviors on a regular basis,” says Surbeck. And with a view to emerging social networks, he and his colleague deduce from their observations that peaceful exchange and sharing, especially of food, play a key role in cooperation.
This probably also applies to people, who now depend more than ever on business relationships. According to Surbeck, research is still being done to determine what influence sexual activities have on the cooperation of bonobos.