ABSTRACT
Foraging animals are usually simultaneously both predator and prey. This simple truism dictates that many animals face a profound conflict between predator avoidance and efficient food intake, because behavioral decisions minimizing the risk of predation are often antithetical to efficient food intake. This conflict and ensuing tradeoff have been the subject of several behavioral studies over the last 20 years. This chapter examines these studies and the conclusions drawn from them; a major theme throughout is that the present interpretation of anti-predatory vigilance is perhaps more a function of human intuition than of a critical examination of the processes thought to underlie observed behavior. It focuses on four main areas in the study of antipredatory vigilance: the effect of group size, cooperative vigilance, the scanning process itself, and the role of mathematical modelling. The chapter outlines several topics in need of further research, many of which can be approached experimentally.
