Evaluating social influences on food-processing behavior in white-faced capuchins (Cebus capucinus)

Interpopulation variability in patterns of food processing, similar to what is described as "traditional" or "cultural" variation in chimpanzees (Pan troglodytes) and orangutans (Pongo pygmaeus), was identified in white-faced capuchins (Cebus capucinus). However, recent comparisons of food processing in capuchins were conducted only at the population level, with relatively little attention given to variability among groups, age/sex classes, or individuals. This paper examines variability in the processing of specific food types within the context of various social networks (i.e., patterns of association, rank, and kinship) among free-ranging Cebus capucinus at Santa Rosa National Park in Costa Rica. We collected data on two groups of white-faced capuchins in 2001, identifying rates of "food interest" for each individual, as well as forms of processing for specific food types. Juveniles exhibited the most interest in the food-processing behavior of other group members, and food interest was directed most frequently toward adult females. We identified distinctive processing techniques for several food items (Luehea candida pods, Sloanea terniflora fruits, and caterpillars) that facilitated comparisons among individuals within groups. Food-processing techniques for Sloanea fruit and caterpillars appeared to vary independently of the social networks examined in this study. However, we found evidence that variation in Luehea candida processing is to some degree linked to both patterns of association and social rank. The potential influence of these variables on observed food processing patterns warrants further scrutiny.     

Variability in food-processing behavior among white-faced capuchins (Cebus capucinus) in Santa Rosa National Park, Costa Rica

Observed patterns of variability in the food-processing behavior of white-faced capuchins (Cebus capucinus) across populations may reflect foraging traditions. However, there has been relatively little attention given to intrapopulation variability in food processing among groups and age/sex classes, making recent cross-population comparisons difficult to interpret. In this paper, we provide data on patterns of object use in foraging that we observed at Santa Rosa National Park, Costa Rica, for comparison with published data from a neighboring research site, Palo Verde National Park. We also describe the techniques used to process two food items consumed by Cebus capucinus at Santa Rosa, and discuss the factors that may underlie observed variability. We conducted a 6-month study on two groups of capuchins in 2001, and collected data on general activity and feeding patterns, rates and forms of object use, and distinctive processing techniques employed for two specific foods (Sloanea terniflora and Luehea candida). Rates of object-use behavior at Santa Rosa were considerably higher than those reported for Palo Verde and showed significant variation between groups and age/sex classes, as did patterns of Sloanea and Luehea processing. Observed differences in feeding rates between groups may reflect food availability or relative profitability, whereas variation between age/sex classes seems to reflect differences in the physical capabilities, foraging strategies, and the relative experience of mature and immature animals. Further research is needed to identify how a social context may influence the acquisition of food-processing techniques in juveniles and the development of foraging traditions in social groups.