RESUMO
Tool use and extractive foraging could be drivers for right hand use preference. The robust capuchins, Sapajus, are more specialized for destructive and extractive foraging than the gracile capuchins, Cebus. Thus, we predicted them to show right-hand preference and higher rates of extractive foraging when compared to the gracile capuchins. We hypothesized that capuchins that evolved in dry habitats are predisposed to show higher rates of extractive foraging and right-hand preference. We employed the tube task (152 individuals) and an extractive foraging task (212 individuals) in seven species of capuchins in captive settings. Data on hand preference and extractive foraging were collected using focal and scan sampling, respectively. Contrary to our hypothesis, S. libidinosus showed significant left hand preference, while S. robustus and S. flavius showed a right hand preference. The species S. xanthosternos, S. flavius, and S. robustus engaged in extractive foraging significantly more often than S. apella, S. libidinosus, and Cebus albifrons. As expected, the gracile capuchins showed significant higher left-hand bias when compared to the robust capuchins. The findings from this study is the first indication of left-hand population level laterality in S. libidinosus, a species that evolved in an environment selecting for increased tool use. Although tool use has been associated with population level right handedness, or a strong trend to use the right hand, our results suggest the link between tool use and right-hand preference is simplistic, at least in Sapajus. The ultimate explanation for the differences in hand preference across species might be due to differences in use of key food resources. We suggest that capuchin monkeys from the Atlantic forest evolved under a stronger selective pressure for high reliance on bimanual feeding and extractive foraging, which requires more sequential actions and planning, than those species from the Amazonia forest and Caatinga/Cerrado dry forest.