Jill Pruetz

JILL D. PRUETZ, Texas State University, San Marcos, Texas, received a grant in April 2017 to aid research on ‘How Do Spear-hunting Chimpanzees ( Pan troglodytes virus ) Adjust to Prey Behavior at Fongoli, Senegal?’ Chimpanzees at the Fongoli, Senegal study site are the only non-humans that regularly use tools to hunt. These savanna-dwelling apes fashion “spear” tools to jab into tree cavities to capture nocturnal bushbabies ( Galago senegalensis ) resting there during the day. Research focused on the hypothesis that Galago behavior influences Fongoli chimpanzee hunting. Specifically, the limited rainy season hunting warranted explanation. Data were collected on Galago cavity use across seasons as well as temperatures within branch versus tree trunk cavities. The availability of Galago prey for Fongoli chimpanzees was best explained by rainfall itself. Following storms, chimpanzees were more likely to hunt with tools. As Galago cavities became inundated with water, bushbabies apparently moved to the outer cavity and were easier for apes to capture. An alternative hypothesis related to food scarcity was not supported in that chimpanzees did not hunt with tools more when food was scarce, but they did hunt more when party sizes were largest. Better understanding prey behavior is crucial to providing insight into chimpanzee hunting. This aspect of hunting receives little attention in discussion of the evolution of hunting behavior in our own lineage but has implications for the complexity of ape and hominin behavior.