Doctoral Dissertation Research: Food-Associated Calls in the Tufted Capuchin Monkey (Cebus apella)

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Food associated calls have been described in several species of primates. These vocalizations serve to attract other group members to the food source but their informational content, adaptive significance, and consequences for foraging animals are poorly understood. The ecological factors and evolutionary forces that led to the important role of intra-group exchange and cooperative foraging activities in human hunter-gatherer societies have been amply discussed, but few data from other primate species exist to provide a comparative framework. Understanding the adaptive significance of apparently cooperative foraging behaviors in non-human primates and other vertebrates will help to address these questions. This proposal is aimed at understanding the informational content and adaptive significance of food associated calls of tufted capuchin monkeys. The vocal repertoire of this species, in terms of acoustic structure and socioecological context of vocalizations, will be obtained from tape recordings of the animals' vocalizations in Iguazu National Park, Argentina. Field playback experiments will be used to understand the informational content of these vocalizations. Food discovery experiments using feeding platforms will be used to evaluate how the food-associated calls are affected by different socioecological contexts, and to explore the possibility of deceptive use of these signals by capuchins. Field experiments with models of predators also will be performed to test the hypothesis that food associated calls are given to reduce predation risk by attracting other groups members to the food source. The predictions of eight different hypotheses on the adaptive significance of these calls will be tested using the tape-recordings of vocalizations and the results of field experiments. The results obtained from this project will help to understand the origin of apparently altruistic behaviors that play an important role in the foraging activities of humans and non-human primates.