Chapter 7 Food as a Selective Force in Primates

PRIMATES MUST EAT to survive; the acquisition of food resources is thus among one of the most signifi cant selective pressures affecting their biology. The necessity of fi nding food to meet nutritional requirements must be balanced with avoiding predation and securing mates, and thereby infl uences primate physiology, ecology, activity, movement, and social relationships. All animals, including primates, should typically avoid expending energy through unnecessary travel, and should eat the most nutritious foods available to them. In a classic study of baboons (Papio cynocephalus), Altmann found that the closer an individual’s foraging approached the optimal amounts of protein and energy (Pyke 1984), the higher its fi tness (Altmann 1991; Altmann et al. 1993; Altmann 1998). Because of the importance of food as a selective pressure for so many aspects of primate biology, it is not surprising that primate feeding ecology has received considerable attention in the literature over the past 25 years (CluttonBrock 1977; Milton 1980; Cant & Temerin 1984; Rodman & Cant 1984; Hohmann et al. 2006). Here we examine the feeding problems primates encounter and the strategies they employ to satisfy their nutritional needs. We also consider the consequences of adopting specifi c strategies. Our goal is to evaluate what is known about primate diets and to stimulate research on primate foraging strategies by identifying new ways to interpret diet and feeding data. We start by reviewing primate nutritional requirements, diets, and digestive strategies. We then address three central problems in the study of primate feeding biology: how do foraging strategies infl uence primates with respect to their (1) ecology and distribution, (2) movement and ranging patterns, and (3) behavior and social organization. For each problem, we present basic information and an illustrative example. We conclude with a summary of how feeding and foraging biology impacts the conservation potential of a species.