International Journal of Primatology

, Volume 28, Issue 2, pp 369–387

Social Relationships among Males in Multimale Siamang Groups


DOI: 10.1007/s10764-007-9122-z

Cite this article as:
Lappan, S. Int J Primatol (2007) 28: 369. doi:10.1007/s10764-007-9122-z


I quantified social and spatial interactions among adults in 4 multimale siamang (Symphalangus syndactylus) groups to evaluate the importance of aggression and avoidance in mediating male-male relationships. Actual genetic relationships among adults are unknown, but available mitochondrial data suggest that in 3 of 4 groups, neither male was the offspring or maternal sibling of the female, whereas in the fourth group, a matrilineal relationship between the female and 1 adult male was not excluded. Rates of aggression involving male-male dyads were very low. One male-female dyad maintained closer spatial cohesion than those of other adult dyads in 3 of 4 groups. Nonetheless, all adult males spent substantial percentages of their time ≤20 m from other adults in their groups. The percentages of time that male-male dyads spent in social grooming interactions did not differ from those of male-female dyads. In 3 groups, both males copulated with the group female. While previous studies have reported high rates of aggression between adult males and subadult male group members in siamangs, my results suggest that male-male relationships in multimale groups at Way Canguk were relatively harmonious. Acceptance of multimale grouping (and in some cases sexual polyandry) suggests that the benefits outweigh the costs under some circumstances. If there was a genetic relationship between males, then tolerance of delayed dispersal and copulation with the adult female may function as a form of parental investment. Males may also benefit from multimale grouping via enhanced territorial defense or reduced costs of mate defense.


aggression flexible grouping and mating gibbon polyandry 

Copyright information

© Springer Science+Business Media, LLC 2007

Authors and Affiliations

  1. 1.Department of AnthropologySan Diego State UniversitySan DiegoUSA

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