Among mammals, female reproduction is generally thought to be food limited, and dominance should theoretically afford high-ranking females with access to better food resources. Although the importance of dominance rank among female chimpanzees (Pan troglodytes) has been debated in the past, mounting evidence suggests that rank is very important among females (P. t. schweinfurthii) at Gombe National Park, Tanzania. In this study, we investigated the influence of season and dominance rank on female foraging strategies. We found that high-ranking females spent less time foraging and tended to have a narrower diet breadth and higher diet quality than subordinate females. In this way, subordinate female foraging strategies were consistent with how females in general adapted to periods of food scarcity. The results of this study therefore suggest that low-ranking females may face persistent "food scarcity" as a result of interference food competition. We also provide evidence that subordinates may forage less efficiently because they occupy lower quality habitats or avoid associating with dominant females in shared areas.
Bibliographical noteFunding Information:
We thank Tanzania National Parks, the Tanzania Wildlife Research Institute, and the Tanzanian Council for Science and Technology for granting us permission to work on this project in Gombe National Park. We also thank the Jane Goodall Institute for funding data collection at Gombe, the Gombe Stream Research Center staff, and Dr Jane Goodall for granting us permission to work with the long-term data set. We thank Dr Mark Bee and 2 anonymous reviewers for suggestions on an earlier draft of this article. We thank Dr Paul Bolstad for advice on vegetation sampling and analysis. C.M.M. would also like to acknowledge her field assistants, especially S. Athumani, M. Mlongwe, and M. Msafiri, and Mete Celik for helping to extract dyadic association data. C.M.M. was supported by a grant from Milton Harris, a Dayton–Wilkie Fellowship, and the Graduate School at the University of Minnesota. C.M.M. and A.E.P. were both supported by a grant from the National Science Foundation (NSF # IIS-0431141).
- Dominance rank
- Foraging strategies
- Habitat quality