Sexual competition is highly prevalent within groups of macaques. Therefore, the animals are tended to avoid potentially interfering group members when having sex.
Until now, it was unclear how this avoidance behavior exactly occurs. In a new study, a team of Dutch biologists monitored the sexual behavior of a group macaques to investigate which group members are avoided as bystanders, how the macaques react to the presence of bystanders and whether mating partners separate themselves from the group in a tactical way.
The researchers observed that both male and female bystanders tried to interrupt the sexual behavior of their group members, and that bystanders of both sexes were avoided by mating macaques. The strength of this effect increased when male bystanders were of higher rank.
Furthermore they found that both males and females barely initiated sex when surrounded by group members. During mating, both sexes paid close attention to the presence of bystanders.
The researchers argue that the monkeys’ “sneaky sex” is not the result of tactical deception. However, the monkeys do make sure they mate on places out of sight of the alpha male. In the periphery of the group, among males of lower rank, the animals grab every opportunity to have secret sex.
Overduin-de Vries, A., Olesen, C., Vries, H., Spruijt, B., & Sterck, E. (2012). Sneak copulations in long-tailed macaques (Macaca fascicularis): no evidence for tactical deception Behavioral Ecology and Sociobiology DOI: 10.1007/s00265-012-1430-4