Chimpanzees and Bonobos Form Human-Like Social Networks

Chimpanzees and bonobos organize their social relationships in ways similar to humans, according to a new study. Researchers found that these great apes form close inner circles and wider networks of weaker social connections. The study, conducted by scientists from Utrecht University and Universidad Carlos III de Madrid, analyzed grooming behavior in 24 groups of chimpanzees and bonobos.

Grooming is a key social activity for apes, strengthening bonds and maintaining relationships. The research team used a mathematical model to examine how individual apes distributed their social effort. They observed that most apes dedicated significant grooming time to a small number of preferred partners. They also maintained less intensive relationships with many other individuals.

This layered social structure mirrors how human friendship circles are organized. Apes in larger groups were more selective about their social attention, a pattern also seen in human social networks. However, chimpanzees and bonobos showed differences in their social strategies.

Bonobos distributed their grooming time more evenly among group members, creating a more egalitarian network. Chimpanzees focused more effort on a smaller number of favored companions. As chimpanzees aged, they became more selective, investing in fewer social partners. Bonobos did not exhibit this narrowing of social circles over time.

Lead author Edwin van Leeuwen suggested that bonobos' more egalitarian social systems might contribute to their fluid relationships. These bonds can even transcend group boundaries, which is rare in chimpanzees. The findings indicate that similar principles govern social relationship formation across species.

This research provides insight into the evolution of complex social structures. Understanding these patterns could improve knowledge of cooperation, social learning, and emotional well-being in both humans and other animals.