Food unpredictability drives both generalism and social foraging: a game theoretical model

Resource predictability can influence foraging behavior in many ways. Depending on the predictability of food sources, animals may specialize on a few food types or generalize on many; they may aggressively defend feeding territories or nonaggressively share food with others. However, food defense and diet breadth have generally been studied separately. In this paper, we propose that variation in resource predictability could drive both of them together. We construct a game theoretic model to test whether situations in which resources are unpredictable might favor both generalism (the ability to use multiple food types) and nonaggressive social foraging. Our model predicts that the proportion of social generalists is highest when resources are unpredictable, whereas a predictable resource distribution favors territorial specialists. We discuss our result within the context of animal cognition research, where diet breadth and social foraging are associated with the 2 dominant views of the evolution of cognition: the "ecological" and the "social brain" hypotheses. Our results suggest that social and dietary demands on cognition might be less independent than is often assumed. Copyright 2008, Oxford University Press.