Male and female human social bonding strategies are both culturally and genetically shaped. Chimpanzees, our phylogenetically joint closest living relatives, exhibit complex social structures and show impressive cultural diversity. Whether chimpanzee male and female bonding patterns are culturally shaped remains unclear. Studies of wild chimpanzees bonding across sex show that in some communities males show strong bonds with other males, whereas in others females form particularly strong intra-sex bonds. This suggests that there may be cultural variation in chimpanzee social bonding patterns, but excluding genetic or ecological explanations when comparing different wild populations is difficult. Here, we applied social network analysis to examine male and female social bonds in two neighbouring semi-wild chimpanzee groups of comparable ecological conditions and subspecies compositions, but that differ in demographic makeup. Results showed differences in bonding strategies across the two groups. While female-female proximity associations were significantly stronger in Group 1 (which had an even distribution of males and females) than Group 2 (which had a higher proportion of females than males), there were no such differences for male-male or male-female associations. Conversely, female-female grooming bonds were stronger in Group 2 than Group 1. We also found that, in line with captive studies but contrasting research with wild chimpanzees, maternal kinship strongly predicted proximity and grooming patterns across the groups. Our findings suggest that, as with humans, male and female chimpanzee social bonds are influenced by the specific social group they live in, rather than predisposed sex-based bonding strategies.
|Date made available||2022|