Behavioral Ecology and Sociobiology

, Volume 64, Issue 2, pp 247–255

Sex differences in the movement patterns of free-ranging chimpanzees (Pan troglodytes schweinfurthii): foraging and border checking

Original Paper

DOI: 10.1007/s00265-009-0841-3

Cite this article as:
Bates, L.A. & Byrne, R.W. Behav Ecol Sociobiol (2009) 64: 247. doi:10.1007/s00265-009-0841-3

Abstract

Most social primates live in cohesive groups, so travel paths inevitably reflect compromise: decision processes of individuals are obscured. The fission–fusion social organisation of the chimpanzee, however, allows an individual's movements to be investigated independently. We followed 15 chimpanzees (eight male and seven female) through the relatively flat forest of Budongo, Uganda, plotting the path of each individual over periods of 1–3 days. Chimpanzee movement was parsed into phases ending with halts of more than 20 min, during which individuals fed, rested or engaged in social activities. Males, lactating or pregnant females and sexually receptive females all travelled similar average distances between halts, at similar speeds and along similarly direct beeline paths. Compared to lactating or pregnant females, males did travel for a significantly longer time each day and halted more often, but the most striking sex differences appeared in the organisation of movement phases into a day's path. After a halt, males tended to continue in the same direction as before. Lactating or pregnant females showed no such strategy and often retraced the preceding phase, returning to previously visited food patches. We suggest that female chimpanzee movements approximate an optimal solution to feeding requirements, whereas the paths of males allow integration of foraging with territorial defence. The ‘continually moving forwards’ strategy of males enables them to monitor their territory boundaries—border checking—whilst foraging, generally avoiding the explicit boundary patrols observed at other chimpanzee study sites.

Keywords

Chimpanzees (Pan troglodytes)Range useSex differencesFission–fusionIndividual movement patternsBorder checking

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  1. 1.Centre for Social Learning and Cognitive Evolution, School of PsychologyUniversity of St AndrewsSt AndrewsScotland