Patterns of coalition formation in long-tailed Macaques (Macaca fascicularis) in Indonesia, Kalimantan.

Abstract

In this study, kin selection, reciprocal altruism and mutualism were proposed to influence the patterns of coalition formation in a group of free-ranging long-tailed macaques (Macaca fascicularis). Coalitionary support has shown significant relationship with kinship and reciprocation of the supportive act itself. There was no evidence grooming-support interchange. Examination of sex differences had suggested that females are nepotistic towards their maternal kin and for males; mutualism was identified as the main influence to providing agonistic support. In addition, due to high despotism in long-tailed macaques, individuals engaged in low cost conservative and bridging coalitions, which can serve as a way to maintain one’s rank. This showed that most coalitions formed in the group reinforced the existing hierarchy.