The comparative socioecology of white-fronted capuchin monkeys (Cebus albifrons) and the ethology of social learning in Cebus

Capuchin monkeys (genus Cebus) -- one of the most widely distributed New World primates geographically -- exhibit a female-bonded social structure that is unusual among platyrrhines. Their broad distribution is generally attributed to how their remarkable object manipulation abilities facilitate their very effective generalist foraging strategy. I studied these two aspects of Cebus biology in a wild setting in Amazonian Ecuador and in captivity at the National Institutes of Health.;I incorporated over 650 hours of activity and ranging data that I collected on Ecuadorian C. albifrons into the socioecological model for Cebus. The results generally support the idea that C. albifrons exhibit highly variable group sizes, large home ranges, substantial home range overlap, and directed movement within the home range between ripe fruit trees.;I conducted a phylogenetic character reconstruction analysis to assess the likely ancestral condition for Cebus courtship behaviors, including behaviors that I newly observed in C. albifrons. The results indicate that a courtship profile more similar to extant tufted capuchin monkeys is the most likely condition for the Cebus ancestor.;Using focal data from Ecuador, I tested whether food interest behavior by C. albifrons could be an adaptation for social learning about food processing. The results support this hypothesis, but they can be explained equally well by selection for effective food scrounging.;Using experimental data from captive C. apella and small amount of data from field experiments, I tested a model of how simple stimulus enhancement social learning could result in durable behavioral traditions. The results suggest that traditions like those observed in wild Cebus can emerge from an interaction of stimulus enhancement learning with reinforcement learning.;Finally, building on methods developed by researchers of C. capucinus , I tested whether variable food processing techniques show traditional patterns in the focal data that I collected on wild C. albifrons. I developed a novel application of cluster analysis and social network analysis to process focal data on intragroup food processing variations. The results indicate that white-fronted capuchins exhibit traditional qualitative variations in food processing techniques.