Male Affiliation as an Alternative Mating Strategy in Japanese Macaques

Session: (In-Person) Poster Presentation

In non-human primates, dominance is often considered the primary strategy for securing mating opportunities. However, while dominance is certainly an influential factor in an individual’s reproductive success, the ability to form and maintain strong social relationships serves a similar purpose, especially for those individuals who are unable to hold a high dominance rank. Social bonding is predictive of cooperation, higher rates of tolerance, lower rates of aggression, and reproductive success. Japanese macaques (Macaca fuscata) form complex inter-male social networks, with an individual’s position in the network potentially impacting their reproductive success. In this study, we aimed to examine the inter-relatedness of dominance, positive male-male relationships, and reproductive success. Using behavioral data collected at the Oregon National Primate Research Center, we calculated simulated rank orders and constructed social networks based on grooming interactions between adult males. We then investigated correlations between the number of infants a male sired and the male’s age, dominance rank, and social network positionality. Although the most dominant male was more reproductively successful than many lower-ranking individuals, the male with the most offspring was one who had a more central position within the social network. These findings offer a preliminary model for better understanding male social bonding as an alternative mating strategy.