title: Non-monogamous copulations and potential within-group mating competition in white-faced saki monkeys (Pithecia pithecia).
abstract: Many primates display within-species variation in social organization and mating system. Individuals of these species may be confronted with both the challenges of between-group competition to exclude same-sex competitors as well as within-group competition for mating opportunities. Free-ranging white-faced saki monkeys (Pithecia pithecia) live in both male-female pairs and small multi-male, multi-female groups. Despite commonly held views that this species is monogamous, there are currently no published accounts of mating patterns in the genus Pithecia. I recorded copulations and sexual behavior from three free-ranging groups of white-faced sakis at Brownsberg Naturepark, Suriname over a period of 17 months. Groups displayed both monogamous and polygynandrous mating. Individuals in polygynandrous groups were not observed to mate more frequently with certain partners. Copulation harassment occurred in 8.6% of copulations (total N = 81) and was performed by both sexes. This harassment successfully prevented ejaculation in six out of seven instances and harassment by males resulted in male-male aggression on four occasions. Two cases of female-directed sexual aggression by males were also observed, which may indicate that males use sexual coercion to influence female mating behavior. Although based on a small number of groups, these data show that white-faced sakis display variability in mating system and that this variability is not directly dictated by social organization. Furthermore, groups with promiscuous copulations exhibit behaviors indicative of within-group mating competition.
authors: Department of Anthropology, Kent State University, Kent, OH, USA. cthompson@neomed.edu
authors: Cynthia L
authors: CL
authors: Thompson
mesh_terms: D000818:Animals; D005260:Female; D008297:Male; D053820:Pitheciidae / Q000502:physiology*; D012726:Sexual Behavior, Animal / Q000502:physiology*