Department of Anthropology, University of Notre Dame
April 14, 2016 , Atrium Ballroom A/B
Navigating complex social interactions is an important part of life for most primates. Gregariously social behaviors including allogrooming and observational learning are frequent foci for studies of sociality. However, purportedly solitary behaviors exhibited individually may also have social implications. Stone handling is a common behavior in one long-tailed macaque (Macaca fascicularis) population near Ubud in Bali, Indonesia, which is thought to emerge among well-provisioned populations with reduced foraging pressures. Although stone handling occurs at the individual level, stone handling bouts themselves may include several individuals engaging in the behavior in close proximity. The present study explores potential social aspects of stone handling. Preliminary results indicate that social stone handling is particularly important for sub-adult males and juveniles, who engage in stone handling with an average of 0.79 and 0.42 “same behavior” neighbors within three meters per scan sample, respectively. An ANOVA shows significant differences in the average number of “same behavior” neighbors between focal sub-adult males, juveniles, adult males, and females (p <0.001). We compare these results with similar analyses for object handling (including a broader range of edible and nonedible items) as well as allogrooming at two sites in Bali (Ubud and Uluwatu). We also analyze the social context of foraging at Uluwatu to compare with patterns of allogrooming in that group, as well as stone handling at Ubud. Our findings suggest that certain solitary behaviors facilitate social experiences for group members and that focusing on them can help us better understand primate social networks.