Abstract # 215:

Scheduled for Friday, June 19, 2015 06:00 PM-08:00 PM: (Cascade AJBCD) Poster Presentation


INFLUENCES OF INTRAGROUP SCRAMBLE COMPETITION AND INTERGROUP CONTEST COMPETITION WITHIN THE MODULAR SOCIETY OF RED-SHANKED DOUCS (PYGATHRIX NEMAEUS) IN SON TRA NATURE RESERVE, VIETNAM

L. R. Ulibarri1, B. Hoang3, C. Nguyen2 and U. Streicher1
1Department of Anthropology, University of Oregon, Eugene, Oregon 97405, USA, 2Frankfurt Zoological Society, Cuc Phuong National Park, Vietnam, 3Environmental Monitoring Center, Department of Environment, Quang Nhai, Vietnam
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     From 2010 through mid 2011, 259 hours of behavioral data were gathered on the red-shanked doucs (Pygathrix nemaeus) in Son Tra Nature Reserve, Da Nang, Vietnam. The red-shanked doucs are an endangered primate, and Son Tra contains the second largest remaining population of doucs in Vietnam. Data was gathered on social structures and organization, group and unit cohesion, activity patterns, ranging behaviors, and feeding ecology. The social organization of the doucs consisted of groups (average of 18 individuals) composed of an average of 3 units or subgroups (average of 7 individuals). Unit and group member was stable and did not change. Daily, the doucs followed an activity budget pattern typical for the genus Pygathrix, and exhibited a daily fission-fusion pattern between units which was significantly correlated to their daily activity budgets. When units were fused they rested significantly more and when units were fissioned they moved, fed, and vocalized significantly more, and were significantly more vigilant. We argue that this is an adaptation to avoiding intragroup scramble competition, and the effects of both intragroup scramble and intergroup contest competition in maintaining contact and coordination between dispersed foraging units within a modular society.