Sex and age differences in the organization of behavior in wedge-capped capuchins, Cebus olivaceus

Abstract

I studied behavioral variability across age and sex classes in a group of wedge-capped capuchin monkeys (Cebus olivaceus) living in a deciduous tropical forest in Venezuela. Variability was analyzed in terms of proportions of time devoted to various activities, position in vertical space, and dynamic aspects of temporal organization. Adult males spent less time foraging, more time in vigilance, and more time on or near the ground than did other age/sex classes. Juveniles spent more time foraging and less time scanning than adults. Infants moved and socialized more and foraged less than other classes. No class or individual exhibited a clear relationship between the duration of an activity and the interval between bouts of that activity. Females foraged in more bouts per unit time, and in longer bouts, than males; males rested more frequently than females. Sequential patterning of activity, evident in all age/sex classes, varied significantly across ages. Differences between juvenile males and juvenile females in time budgets, use of space, bout and interbout durations, and patterns of transitions were along the same lines as between adult males and females. Similar age and sex differences in vigilance behavior and manipulative activity are evident in other free-ranging populations of capuchins and in captive capuchins, indicating that they are not dependent (in the short term) on the time needed for foraging or the risk of predation. The findings indicate the importance of intrinsic characteristics in molding nonsocial aspects of behavior, in juveniles in particular, in directions consonant with the species's behavioral ecology.