A study conducted by international primatologists has discovered that chimpanzees and bonobos form friendship circles that closely resemble those of humans. This research challenges the previous notion that the interactions of these primates were merely utilitarian or hierarchical.
The research team, led by Catherine Hobaiter from the University of St Andrews, conducted a detailed analysis of grooming and mutual support practices in various ape communities over a long period to understand their social bonds.
Friendship circles in chimpanzees and bonobos
The collected data shows that these primates maintain close and lasting bonds with a small group of deep friendships, similar to best friends in humans.
In addition to these intimate relationships, the apes also maintain more superficial social ties, replicating the human social structure documented by psychologists and anthropologists.
This social pattern suggests a common root in the evolution of socialization, tracing back to a common ancestor we share with these primates.
In the observations, chimpanzees and bonobos divide their interactions into concentric levels, where physical contact decreases as they move away from the most intimate core.
For example, a chimpanzee typically has two or three close allies for tasks such as territorial defense and grooming, while the second circle encompasses about ten associates with whom they collaborate in food searching.
Finally, there is a periphery of occasional interactions that help avoid open conflicts within their community.
Grooming, or mutual grooming, is key in these relationships, functioning as a social currency that reduces stress by lowering cortisol levels.
This behavior is not random, as the apes consistently choose the same companions over time.
Even after confrontations, intimate friendships usually endure, demonstrating their resilience despite tensions.
These findings suggest that primates, like humans, need emotional support networks to thrive in competitive environments.
The similarity in social structures reinforces the hypothesis that shared cognitive limitations restrict the ability to manage relationships in both species.
