Socially tolerant relationships among wild male moor macaques (Macaca maura)

Abstract

Researchers are increasingly documenting the existence of social tolerance and affiliative behavior among primate males, including in male-dispersing species. We investigated the nature of male social relationships in a relatively understudied macaque species, the moor macaque (Macaca maura), in order to expand our knowledge of male social relationships in male dispersing primates. The classification of social styles for primates rests largely on data about female social relationships. Therefore, by providing data on male–male relationships, we also contribute to our understanding of social style variation within the genus Macaca. Observations were conducted on a wild yet well-habituated group in Bantimurung-Bulusaraung National Park in South Sulawesi, Indonesia. We collected focal animal and ad libitum data on four adult males, recording social behavior during 209 contact hours over two field seasons in 2010 and 2011. The adult male moor macaques in this study did not interact frequently. Interactions that did occur more frequently involved affiliation rather than aggression, with greetings being the most common form of interaction. Greetings occurred in a predominately neutral context and were more common between specific males with uncertain or ambiguous dominance relationships and low-quality relationships, but the initiation of greetings was not linked to dominance rank. These results suggest that greetings enable males to communicate information about their willingness to invest in the relationship, representing one way for adult males to ease social tension and build social bonds. To expand our understanding of social style variation in Macaca, we compared our data to those published for other macaque taxa. In the present study, the observed pattern of aggression (i.e., low rate, low to moderate intensity and high symmetry) was consistent with the species’ social style classification as highly tolerant. The relatively low grooming rate and low percentage of counteraggression, however, were more consistent with the social style of less tolerant taxa. Further research is needed to determine what factors explain this pattern of social tolerance among male moor macaques.