If you scratch me, I will scratch you
Not only are bonobos genetically close to humans, but in some respects they also behave quite humanely. This is what makes dwarf chimpanzees interesting to evolutionary biologists: apes cultivate their neighborly relationships in a particular way.
WWhy help strangers, even share food with them, if you’re not sure it’s worth it for yourself? Such behavior is considered prosocial, almost primordial, but can also be observed in other primates. At least among bonobos who, together with chimpanzees, are among man’s closest relatives.
Therefore, observations of how these apes 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 with gifts of food.
With their study published in the specialized journal “Science”, the zoologist Liran Samuni and the biologist Martin Surbeck of Harvard University in Boston integrate previous reports on the social behavior of bonobos. Both study 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 now evaluating observations of two bonobo groups documented over a two-year period in the “Kokolopori Bonobo Reserve” in the Democratic Republic of Congo. They also took into consideration whether blood relatives were preferable. Or if strangers also benefit from the charity.
And sure enough: the monkeys were feeding some neighbors. Contacts where groups met could last 14 days, but some lasted less than an hour, and individual interactions were not casual but selective.
In their study, Samuni and Surbeck focus on three forms of interaction: grooming or grooming, forming alliances, and sharing food. They examined 31 adult animals divided into two social groups; Approximately 7,900 interactions were evaluated. This time aggressive or sexual behavior was ignored: “Here cooperation refers to behaviors whose evolution is fundamentally difficult to explain,” explains Surbeck. In these cases, the beneficiaries would benefit more, to the detriment of the actor in question.
In the case of grooming, a bonobo’s “loss” is small because this favor is often immediately reciprocated; When it comes to food, the give-and-take ratio is significantly worse in a direct comparison, yet it is often shared. Especially with those who, on the whole, proved to be equally generous.
“We’ve shown that a facility that brings animals together that are willing to cooperate can mean we can observe these behaviors on a regular basis,” Surbeck says. And looking at 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 today depend more than ever on business relationships. According to Surbeck, research is still ongoing to determine what influence sexual activities have on bonobo cooperation.