Substrate and tool use by brown capuchins in Suriname: Ecological contexts and cognitive bases

Brown capuchins (Cebus apella) at Raleighvallen Nature Preserve in Suriname have recently been discovered to exhibit object manipulation abilities in foraging, specifically frequent substrate use and a remarkable episode of tool use. The food items being processed with these exceptional skills are numerous species of morphologically diverse, thickly husked fruits, with fruit walls impenetrable even to the powerful jaws of C. apella. These fruit taxa, many in the Lecythidaceae, the Brazil nut family, are rare in Western Amazonia and Central America, regions in which capuchins have been most often studied. Based on extensive qualitative observations, we provide a preliminary description of this phenomenon within a natural history perspective. The manipulative skills of brown capuchins in Suriname are poised to upheave current understandings of tool use and object manipulation in capuchins. Moreover, the implications of these findings for the cognitive evolution of human and nonhuman primates are significant. The capacity to use tools is considered one of the major achievements of our species and figures deeply in explanations for the origin of human intelligence and behavior. Many hold that tool and object manipulation, language, social skills, and morphology are linked in primate evolution. Given that unusually complex social and communication skills are not evident in capuchins, the proposed connection between the evolution of tool use, language, and social skills in human evolution is thereby weakened. Instead, our observations in Suriname support a paradigm premised on the concept of functionally and evolutionarily distinct brain modules.