Ecological factors influencing habitat use by chimpanzees at Ngogo, Kibale National Park, Uganda.

Abstract

Although numerous ecological and social factors influence range use in vertebrates, the general assumption is that ranging patterns typically accord with principles of optimal foraging theory. However, given temporal variability in resource abundance, animals can more easily meet nutritional needs at some times than at others. For species in which sociality is particularly important for fitness, such as chimpanzees (Pan troglodytes) and other group-living primates, the influences of social factors can be particularly strong, and likely interact closely with ecological factors. We investigated home range use by a community of chimpanzees at Ngogo, Kibale National Park, Uganda, to determine whether range use corresponded to energy-based optimality principles. Chimpanzees were particularly attracted to areas of the home range where individuals of Ficus mucuso (a large but low-density resource) were found, but only if those areas also offered other preferred or important resource classes. The aggregation of large foraging parties at F. mucuso crowns (frequently seen year-round) facilitates a number of socially beneficial activities for both males and females. Because chimpanzees apparently seek out F. mucuso in areas where other high-quality feeding opportunities exist, these social benefits likely do not come at the expense of fitness benefits accrued from feeding on high-quality resources. Am. J. Primatol. 78:432-440, 2016. © 2015 Wiley Periodicals, Inc.