Social Traditions and Social Networks among Long-Tailed Macaques in Indonesia

The main objective of this study is to determine the impact of distinct social traditions (i.e., cultural behaviors) on sub-adult male long-tailed macaque (Macaca fascicularis) social relationships by comparing two allopatric populations (Padangtegal and Uluwatu) on the island of Bali, Indonesia. Stone handling occurs only within the two study groups at Padangtegal, while “robbing and bartering” occurs only among the two study groups at Uluwatu. In this research I characterize the relative influence of these social traditions on patterns of sub-adult male social behavior at the individual level. Sub-adult males are highly active in both social traditions, and occupy a life history stage characterized by shifting social relations. Data were collected during 15 minute sample periods via focal animal scan and all-occurrence sampling. Scan data were collected every 180 seconds during the sample period and consist of focal animal state behaviors and nearest neighbor identification. Changes in state behaviors, and all event behaviors (e.g., gestural interactions), were recorded throughout the entire 15 minute sample period. These data were assessed via social network analysis to understand individual social behavior in relation to other members of the social group. Such analyses offer specific insight into how individuals utilize particular social relationships to navigate complex social networks. This research offers a distinctive contribution to the literature on the evolution of primate societies by examining the patterns by which social traditions and social networks interface with, and shape, social structures among nonhuman primates.