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Researchers find social cultures among chimpanzees

20. November 2018



Current research results from Leipzig University show that groups of chimpanzees living separately show differences in social behaviour that are stable over time. These differences could be the result of cultural learning.

An international research group, together with members of the Leipzig Research Center for Early Childhood Development (LFE) of Leipzig University, has researched four groups of chimpanzees in the Chimfunshi Wildlife Orphanage in Zambia over three years. During this time, they have studied different aspects of their social behaviour – for example, how many individuals live together in small temporary groups, how spatially close individuals are to each other on average, and how often they groom each other. The groups showed the greatest differences in the number of individuals they spend time with, also known as subgroup size. Two of the groups formed significantly larger subgroups than the other two groups. “The most social group was also shown in the other aspects of social. The chimpanzees in these groups were on average spatially closer to each other and did much more grooming than the other groups,” explains the senior author of the study, LFE Director Prof. Dr. Daniel Haun. He and his colleagues recently published their findings in the renowned journal “Proceedings of the National Academy of Sciences of the United States of America” (PNAS).

“The conditions in this chimpanzee sanctuary provide us with a unique opportunity to study cultural differences among chimpanzees,” says Sarah DeTroy, a Chimfunshi researcher and LFE member. In most cases, researchers compare groups of wild chimpanzees that live in different environments and have large genetic differences. In these cases, they cannot exclude the influence of these factors on the observed behavioural differences between groups. Since the chimpanzees in Chimfunshi all live in the same environment and there are no systematic genetic differences between them, researchers are able to investigate how other processes, such as social learning, can explain differences between chimpanzee groups.

“Although we have not directly investigated the origins of these differences in this study, we know that chimpanzees can learn socially from each other and that primates can adapt their social behavior to their context. The individuals in the respective groups may have observed interaction patterns of other chimpanzees, such as general proximity and frequency of fur care, and learned them socially,” explains Prof. Haun.

Over one hundred rescued chimpanzees and their offspring live in the Chimfunshi Chimpanzee Sanctuary. The research team has been working with the chimpanzees for over ten years, investigating various aspects of their behavior and cognition, such as their tendency to conform, the emergence and transmission of cultural “trends”, and their grieving behavior. “Over the years, we have observed great variability in the behavior of chimpanzees in Chimfunshi. This recent study shows part of the extent and stability of the differences in general sociability and provides us with a basis to understand how these differences might affect other behaviors such as cooperation and prosociality,” says Haun.

Original title of the publication in PNAS:

“Population-specific social dynamics in chimpanzees”, https://doi.org/10.1073/pnas.1722614115

Madlen Bartholmeß
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