Abstract # 4397 Poster # 161:

Scheduled for Friday, June 22, 2012 07:00 PM-09:00 PM: Session 22 (Gardenia) Poster Presentation


NUT-CRACKING IN WILD BEARDED CAPUCHIN MONKEYS: SOCIAL INFLUENCES ON LEARNING TO USE TOOLS

Y. Eshchar1, B. Dogo de Resende2, P. Izar2, E. Visalberghi3, K. M. Laity1, M. Verderane2, C. E. Carvalho2 and D. M. Fragaszy1
1University of Georgia, Athens, GA, USA, 2University of Sao Paulo, SP, Brazil, 3Consiglio Nazionale delle Ricerche, Rome, Italy
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     Adult bearded capuchins (Sapajus libidinosus) use stones to crack palm nuts on anvils. Meanwhile, juveniles spend years engaging ineffectively with nuts and stones. We are conducting a longitudinal study at our field site in Piuaí, Brazil, to determine the influence of others’ percussive activity, including auditory signals and physical remains of cracking, on juveniles’ behavior with nuts. We report data from our first period of data collection. We recorded activities of 11 juveniles (3 to 54 months) in one wild group, and concurrently the activities of other group members, over an 8 week period. Manipulation of nuts increased with age (R2=0.78, N = 11, P<0.001), but manipulation of other objects did not (R2=0.17, N = 11, P=0.214). The subjects were significantly more likely to manipulate nuts near anvils, where remains of nut cracking can found, than elsewhere (P<0.01). Manipulation of nuts alone occurred significantly more often than expected when two or more group members were engaged in nut-cracking, and manipulation of other objects was significantly less frequent (P<0.01). Our preliminary findings indicate that young monkeys’ general activity with nuts is supported by the behavior of others in the group. Future analyses will examine behavioral synchrony between specific adults and juveniles and the influence of hearing others crack and of encountering remains of cracking. Supported by the National Geographic Society. * University of Georgia, Athens, GA, USA