Evaluating Dominance Styles in Assamese and Rhesus Macaques

Researchers have suggested that several types of agonistic and affiliative behavior covary as a set of species-specific traits, and have used the term dominance style to describe the covariation. We compared measures of dominance style between a group of Assamese macaques (Macaca assamensis) and a group of rhesus macaques (M. mulatta), though kinship information was unknown. Assamese and rhesus female-female dyads each showed a low proportion of counter aggression and a low conciliatory tendency, suggesting that they have despotic social relationships. They also showed a despotic pattern on several other types of agonistic and affiliative behavior, such as approach outcomes and grooming distributions, which is consistent with the covariation of dominance style traits. Assamese male-male dyads showed relatively high levels of reconciliation and counter aggression versus other macaque males portrayed in the literature, suggesting that Assamese males have a tolerant dominance style. Insofar as macaque dominance style depends on the behavior of females, we suggest that Assamese macaques, like rhesus macaques, have despotic social relationships, which contrasts with evidence of a strong correlation between phylogeny and dominance style in macaques. Further, our results indicate that strong male bonding and tolerant dominance relationships among males are independent of female dominance style. Lastly, some measures of agonistic behavior, such as rate of aggression or proportion of bites, are likely altered in competitive environments and thus are not useful indicators of dominance style.