Grouping Patterns and Competition Among Female Pan troglodytes schweinfurthii at Ngogo, Kibale National Park, Uganda

Article

Abstract

In mammals, access to mates is probably the most important influence on male reproductive success, whereas foraging efficiency is probably the most important influence on female reproductive success Emlen and Oring (Science 197:215–223, 1977). Male chimpanzees (Pan troglodytes) are highly gregarious and form cooperative relationships with other males. In contrast, female social relationships vary within and between populations. Females in most East African populations, e.g., Gombe, Mahale, Kibale-Kanyawara, are less gregarious than males and spend most of their time alone or with only their dependent offspring. Researchers have attributed low female gregariousness to the high potential for feeding competition. I provide the first data on association patterns and agonistic interactions of female chimpanzees (Pan troglodytes schweinfurthii) from the unusually large Ngogo community, Kibale National Park, Uganda. Ngogo females were less gregarious than males, but spent a mean of 64% of their time in association with ≥1 other females and as much time in all-female parties as they did alone. Further, female dyads associated nonrandomly and they formed associative cliques. Association levels within cliques were similar to those among the relatively gregarious West African chimpanzee females at Taï (Pan troglodytes verus) and among bonobo (P. paniscus) females. Agonistic interfemale interactions were extremely rare, and monthly mean party size and the numbers of anestrous females per party do not correlate significantly with fruit availability. Thus, Ngogo females maintained relatively high levels of gregariousness, but avoided detrimental feeding competition by preferentially associating with a small subset of other community females.

Keywords

association patterns female socioecology Ngogo Kibale National Park Uganda Pan troglodytes schweinfurthii party size 

Notes

Acknowledgments

I thank the Uganda Wildlife Authority, Uganda National Council for Science and Technology, and Makerere University for permission to work in Kibale National Park. I thank J. Lwanga for logistical support in Uganda. A. Magoba, G. Mbabazi, L. Ndagizi, and A. Tumusiime provided invaluable assistance in the field. S. Amsler, R. Bribiescas, J. Mitani, and K. Potts all provided valuable discussions and advice in the development of the manuscript, which benefited from the comments of 2 anonymous reviewers. I thank A. Pusey and M. Emery Thompson for organizing this special issue and for inviting me to participate. Finally, a special thanks to my advisor, D. Watts, whose continued support and guidance has made my research possible. My field research was supported by the L.S.B. Leaky Foundation, National Science Foundation Graduate Research Fellowship and travel grant, Yale Institute for Biospheric Studies, and grants from Yale University Graduate School of Arts and Sciences.

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© Springer Science+Business Media, LLC 2008

Authors and Affiliations

  1. 1.Department of AnthropologyYale UniversityNew HavenUSA

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