SEX-DIFFERENCES IN DIET AND FORAGING BEHAVIOR IN WHITE-FACED CAPUCHINS (CEBUS-CAPUCINUS)

I examined sex differences in diet and foraging behavior in two groups of white-faced capuchin monkeys (Cebus capucinus) in a tropical dry f orest at Santa Rosa National Park, Costa Rica. I tested three hypothes es: sex differences in diet and foraging behavior are best explained b y (1) sexual dimorphism, (2) the energy demands of pregnancy and lacta tion for females; and (3) avoidance of competition between the sexes. Sexual dimorphism offered the best explanation of sex differences in t he diet and foraging behavior of C. capucinus, accurately predicting t hat males do more strenuous foraging activity, make less use of small foraging supports, and spend more time on or near the ground. Females spent more time foraging than males did but probably obtained a lower protein yield per unit foraging time. Females exploited more small and embedded invertebrates, while males ate more large invertebrates and vertebrate prey. Pregnant and lactating females spent more time restin g and less time foraging than other females did, increasing their fora ging return by focusing on foods requiring little handling. There was little evidence of competition avoidance between the sexes.