Behaviour 2019
Social Influence on the Expression of Stone Handling Behavior in Balinese Long-Tailed Macaques
Lilah Sciaky1,2, Richard Weil2, NoŽlle Gunst2, IN Wandia3, Jean-Baptiste Leca2. 1Columbia University, New York, New York, United States; 2University of Lethbridge, Lethbridge, Alberta, Canada; 3Udayana University, Denpasar, Bali, Indonesia

Animals use social information, available from conspecifics, to learn and express novel behaviors. Response facilitation is a social learning mechanism whereby observing a demonstrator performing a behavior temporarily increases the probability that the observer will perform the same behavior. We focused on “stone handling” (SH) behavior, a form of object play routinely displayed by free-ranging long-tailed macaques (Macaca fascicularis) in Ubud, Bali, Indonesia. We tested whether the expression of SH was subject to response facilitation. We compared video-recorded focal samples of witness individuals immediately after they observed a SH bout performed by group members, and matched-control focal samples of the same witnesses in the absence of any surrounding SH bouts. We found converging evidence that SH was at least partly triggered by response facilitation. SH occurred significantly more often in the witness condition than in the control condition. A monkey initiated SH more rapidly in the former than in the latter, and this facilitation effect mainly occurred during the first two minutes after witnessing SH. These results support the cultural nature of SH in macaques. †