Data from: Chimpanzee communities differ in their inter- and intrasexual social relationships

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.