Abstract # 962 Event # 108:

Scheduled for Friday, August 19, 2005 09:45 AM-10:00 AM: Session 8 (Mayfair Room) Oral Presentation

Feeding competition in long-tailed macaques (Macaca fascicularis): Can females by-pass the dominance order?

C. Dubuc and B. Chapais
Département d'anthropologie, Université de Montréal, C.P. 6128 , Succursale Centre-ville, Montréal, Québec H3C 3J7, Canada
     In primate species with clear dominance relationships the rank order markedly restricts the access of lower-ranking females to clumped resources. However, they may attempt to by-pass dominance order whenever benefits exceed costs. To investigate this issue, we studied a tactic that consisted of reaching the feeding site before the highest-ranking individuals, in a captive group of long-tailed macaques (27 individuals). To evaluate various levels of aggression risks, we submitted the group to two experimental contexts (N = 12 tests/context) differing in spatial distribution of a fixed amount of food (large versus small patches). Our results confirmed that contest competition was induced by the two contexts but was stronger in the small-patch context (i.e., higher risks). We tested our results by comparing females against themselves (Wilcoxon test). All intermediate- and low-ranking adult females (n = 9) did use the tactic at some point during the experiments and thus obtained significantly more food than when they did not in both contexts (P < 0.02; P < 0.05), without experiencing significantly more aggression. However, they used the tactic significantly less frequently when resources were more clumped (P = 0.05) and descriptive results suggest that having a preferential relationship with a high-ranking individual may have promoted the subjects‚ use of the tactic. These results indicated that females of the studied group could reach the feeding site before the highest-ranking individuals, but did so especially when risks were sufficiently low.