Abstract # 27:

Scheduled for Thursday, June 21, 2007 02:15 PM-02:30 PM: Session 5 (North Main Hall E) Oral Presentation

Post-conflict Interactions with Bystanders in Tibetan Macaques (Macaca thibetana huangshanensis)

C. S. Ionica1,2, C. Berman2,3 and J. Li4
1Laboratory Comparative Ethology, NICHD, NIH, Dickerson, MD 20842, USA, 2Department of Anthropology, SUNY Buffalo, 14261 USA, 3Program in Evolution, Ecology and Behavior, SUNY Buffalo, 14261 USA, 4School of Life Sciences, Anhui University, Hefei, Anhui Province, China 230039
     Post-conflict (PC) interactions with bystanders have been hypothesized to reduce anxiety and/or stop aggression in former combatants (uncertainty reduction hypothesis - URH). We analyzed the patterns of such interactions (redirected aggression, affiliation with, and non-aggressive interventions by bystanders) in a wild but provisioned group of Tibetan macaques at Huangshan, China. We contrasted 5-minute PC samples with matched control samples (MC) on the same focal individuals (PC-MC method; 572 PC-MC pairs). Analyses [Wilcoxon Signed Rank Tests, N=25, a=0.05] showed that at an individual level, redirection by losers, bystander interventions, and affiliation with bystanders occurred consistently and significantly earlier or only during PCs than MCs. Former combatants initiated affiliation with bystanders significantly more often than they received it, but only after losing rather than after winning [N=20 for winning]. Initial redirection against identified monkeys occurred down the hierarchy [Binomial Sign Test, p(86:89, 0.50)=0.001]. Among anxiety indicators, only the rate of body shaking was elevated during PCs [above 95% CI for MCs]. Chi-squared analyses [a=0.05] showed frequencies of body shaking and being aggressively targeted during PCs decreased significantly below MC levels after affiliation with former opponents, but not after interactions with bystanders. These results are not entirely supportive for URH predictions, and suggest that an enforced dominance hierarchy characterizes this subspecies.