Abstract # 1901 Poster # 166:

Scheduled for Friday, August 18, 2006 07:00 PM-09:00 PM: Session 17 (Regency West 1/3 ) Poster Presentation

Stone handling in Japanese macaques (Macaca fuscata): a 10-troop comparative study about a behavioral tradition

J. B. Leca1, N. Gunst2, C. A. Nahallage3 and M. A. Huffman3
1Equipe d'Ethologie des Primates, Institut Pluridisciplinaire Hubert Curien, Departement Ecologie, Physiologie et Ethologie, UMR 7178 CNRS-ULP, 7 rue de l'Universite, Strasbourg 67000, France, 2Institute of Ecology, University of Georgia, Athens, USA, 3Section of Ecology, Primate Research Institute, Kyoto University, Inuyama, Japan
     Stone handling is a form of solitary object play, consisting of manipulating stones by performing various behavioral patterns. Previous findings from one group of Japanese macaques showed that this behavior is socially transmitted across generations as a tradition. This study aimed at investigating the roles of the demographic, social, and ecological factors influencing the diffusion and maintenance of stone handling in Japanese macaques. We conducted a comparative study among 10 troops within Japan: 4 captive groups (Primate Research Institute, and Japan Monkey Centre, Inuyama), and 6 free-ranging provisioned populations at Arashiyama, Koshima, Shodoshima, and Takasakiyama. Our standardized observation procedure consisted of continuous video-recorded focal-animal sampling interspersed with instantaneous group activity scans. We found important inter-troop differences in the frequency (from 0.02 to 1.49 bouts/hour), prevalence (from 0.0 to 13.6% of scan-sampled individuals), rate of diffusion (from 7.7 to 95.7% of group members), demographic distribution (from one to all age classes), and form (from 10 to 45 patterns) of stone handling. Diffusion rate differences were not significantly correlated to group size, and stone availability did not account for stone handling prevalence (Spearman correlation tests, p>0.05). In free-ranging troops, stone handling mainly occurred just after feeding time, whereas it was not directly connected to feeding activity in captive groups. Activity budget and social factors may partly explain some of these differences. Supported by a Lavoisier grant.