Aggression rates increase around seasonally exploited resources in a primarily grass-eating primate

Research reveals that aggression in geladas (Theropithecus gelada), primarily grass-eating primates, intensifies around seasonally scarce underground storage organs in Simien National Park, Ethiopia. Despite their diet being dominated by non-monopolizable grasses, female geladas exhibit strict dominance hierarchies and heightened aggression when competing for belowground resources during the dry season. The study analyzed rank, season, and feeding context to determine that aggression peaks during belowground feeding, particularly in high-ranking females usurping lower-ranking individuals. This suggests that underground storage organs, though less frequently consumed than grasses, play a critical role in social dynamics, possibly due to their energetic significance or competitive value. Further investigation is needed to confirm whether this behavior directly influences resource access.

Jarvey, J. C., Low, B. S., Azanaw Haile, A., Chiou, K. L., Snyder-Mackler, N., Lu, A., Bergman, T. J., Beehner, J. C., & Schneider-Crease, I. A. (2023). Aggression rates increase around seasonally exploited resources in a primarily grass-eating primate. Behavioral Ecology, 35(1). https://doi.org/10.1093/beheco/arad079