Rank changes in female chimpanzees in Tai National Park


The social life of female chimpanzees (Pan troglodytes) differs between subspecies, with females in East African field sites often described as avoiding association to avoid competition, while females in Taï have been shown to be more gregarious, spending most of their time in close contact with each other, probably to avoid predation. This close association leads to increased levels of direct competition for resources, possibly increasing the benefit of having a higher dominance rank and challenging dominant group members. Female chimpanzees in Gombe have been shown to queue for rank rather than challenge others. Here, we show that female dyads in Taï do at times change their dominance rank, with at least six clear rank changes recorded in the Taï North and South community. We discuss life events that could facilitate rank challenges. The increased flexibility in the female dominance hierarchy potentially adds a level of complexity not seen in East African chimpanzees.

The Chimpanzees of the Tai Forest: 40 Years of Research