Social organization of the pygmy chimpanzee (Pan paniscus): Multivariate analysis of intracommunity associations

Abstract

AbstractWe examined association patterns of wild, nonprovisioned pygmy chimpanzees in the central rain forest of Zaire. Associations among individuals within two communities (Hedons and Rangers) and one splinter group (Blobs) were described using two measures: the proportion of time spent together in parties, and the proportion of time spent in close proximity while feeding. Patterns were exposed using multivariate analysis and tested using nonparametric (Mantel) tests. Associations among females characterized the social interactions of both Hedons and Blobs. Associations among males, and between males and females, were common only for the Rangers. Parties of Blobs tended to be small (average size: 4), whereas parties of Hedons were of variable size (average: 7), and those of Rangers were predominantly large (average: 10). Thus, variation in association patterns corresponded loosely to differences in party size. Associations among females were most prevalent in small parties. By contrast, associations among males and between males and females were more apparent in large parties. This intracommunity correlation of social organization and party size parallels differences between the Lomako and Wamba study sites. This relationship may reflect the importance of female alliances when food is limited and the ability of single males to monopolize small, but not large, parties of associated females.