The 84th Annual Meeting of the American Association of Physical Anthropologists (2015)

The ecology of fear and savanna resource limitation in western chimpanzees (Pan troglodytes verus) at Fongoli, Senegal


1Anthropology, Iowa State University, 2Ecology, Evolution, and Organismal Biology, Iowa State University

March 28, 2015 , Gateway Ballroom 2/3/4/5 Add to calendar

A chimpanzee’s home range includes not only the base layer of desirable, consumable resources, but is also composed of a second layer that comprises the chimpanzee’s perception of its risk of mortality due to predators of various species. These layers contribute to the spatio-temporal patterns of costs and benefits that the chimpanzee might expect to encounter across its home range. In this study, we assessed how resources and risk concomitantly shape the foraging behavior of western chimpanzees (Pan troglodytes verus) at Fongoli, Senegal. As desired resources were in risky areas of their home range, particularly near anthropogenic landmarks, we hypothesized that males would avoid these areas unless the benefits outweighed the costs. Food intakes and intake rates of males (N=11) were compared to risky areas of their home range and behavioral indicators of perceived risk. Furthermore, we compared feeding behavior to habitat and proximity to surface water. Males increased intake rate in open habitats (Kruskal-Wallis χ2=6.35, df=1, P=0.01) and consumed less food as the distance to drinking water increased (Spearman’s ρ= -0.23, P<0.05). Such adjustments might offset the metabolic cost of feeding in exposed areas, or reduce the risk of dehydration, respectively. Individuals displayed antipredator behavior towards people but rather than truncate a feeding bout, adult males ingested more food (Kruskal-Wallis χ2=6.58, df=1, P=0.01) and increased foraging party size (Spearman’s ρ=-0.26, P<0.05). Although people rarely hunt chimpanzees in Senegal, we show that they perceive humans as predators and adjust their behavior in response to this risk.

This research was supported by the Leakey Foundation and the Rufford Foundation.