Pan the Hunter: Ecological Explanations for Chimpanzee Predation

As frequent predators (relative to other apes), and one of our closest living relatives, chimpanzees are a valuable point of reference for investigating why meat consumption increased so dramatically throughout human evolution. Although chimpanzees primarily eat plant-source foods, they consume vertebrate prey with great excitement, attesting to its nutritional value. Indeed, meat is a concentrated source of easily-digestible macro- and micro-nutrients that chimpanzees should consume whenever they can. However, meat comprises a small percentage of chimpanzee diet. What limits predation frequency in this species? In a discussion of how habitat, party size, diet quality and individual differences in risk aversion affect chimpanzee hunting decisions, I argue that the considerable variation in predation frequency within and between social groups is driven by the energetic costs and physical risks that hunting entails. Chimpanzees take advantage of low-cost opportunities to capture prey.