Within-group spatial position and activity budget of wild sooty mangabeys (Cercocebus atys) in Taï National Park, Côte d’Ivoire

Abstract

Within social groups, feeding competition and predation pressure affect individual spatial position. The costs and benefits associated to each position are likely to influence the time that individuals allocate to different activities. Whether the effect of spatial positioning on activity budget differs between individuals of different sex or dominance rank remains unclear. This study aimed at investigating the effect of within-group spatial position on the activity budget of male and female sooty mangabeys. Focal behavioral observations was used to collect the individual location and behavior every 15 minutes (N=5115 locations) on 29 individuals from a wild group of sooty mangabeys (Cercocebus atys) in the Taï National Park. The joint effect of rank, sex and spatial position on individual‟s activity budget was investigated. Females were more central in the group and both fed and rested more than males, independently of their rank. High-ranking  individuals from both sexes were more likely to be central and both fed and rested longer than low-ranking ones. Females and high-ranking individuals from both sexes benefit from their social status by adopting spatial positions in the community that could influence their fitness positively. These results are discussed to improve our understanding of social dynamics in wild primates.

Keywords: Spatial position, primates, socio-ecology, social dynamics.