Abstract # 129:

Scheduled for Sunday, September 18, 2011 11:15 AM-11:30 AM: Session 17 (Meeting Room 408) Oral Presentation


NONLINEAR DOMINANCE HIERARCHIES IN CAPTIVE RHESUS MACAQUE (MACACA MULATTA) SOCIETIES

B. A. Beisner1,2, M. McAssey3, F. Hsieh3 and B. McCowan2,4
1The Pennsylvania State University, Anthropology Department, University Park, PA 16802, USA, 2California National Primate Research Center, University of California Davis, Davis CA 95616, 3Statistics Department, University of California Davis, Davis CA 95616, 4Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, CA 95616
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Dominance hierarchies are a common feature of animal societies in which group members are usually arranged into a linear hierarchy. However, the dominance hierarchy may not always follow a linear pattern, particularly in larger groups and those with complex social relationships. Rather the social hierarchy may exist along a continuum between a sequential dominance hierarchy and an egalitarian society where some group members have clear dominance relationships while others do not. We used a network approach (dominance transitivity) to assess the dominance structure of seven captive groups of rhesus macaques (120-200 animals/group) at the California National Primate Research Center by combining inferences of dyadic dominance relationships from their interactions with common third parties via multiple network pathways. All seven groups showed evidence of a corporative network structure in which the hierarchy consists of multiple tiers: one “governing" group (alpha-matriline) at the top tier, and multiple lower tiers, each of which may contain several parallel subgroups (e.g., parallel matrilines). Linear ranks are found only among individuals in the same matriline or among tiers, whereas ranks among matrilines of the same tier are unclear. Corporative network structure is common in human societies, but to our knowledge has not been previously demonstrated in primate societies. We suggest that the assumption of linearity in primate dominance hierarchies be reevaluated, particularly for large social groups or those with matrilineal structure.