Shared space use and avoidance among groups of wild non-territorial Assamese macaques

Between-group competition in territorial taxa is evident in patrolling and avoidance behaviors. In non-territorial animals, signs of competition are more subtle, and little is known about how neighbors use their shared space. We investigated space use in four groups of wild, non-territorial Assamese macaques ( Macaca assamensis ). Using locational data collected over six years, we quantified group ranging patterns to identify factors influencing home range size and daily travel distances, and investigated spatial relationships among neighboring groups by examining the patterns of shared use of space and sleeping trees. We found that daily travel distances were positively affected by group size and day length, but not fruit availability, while home range size was not influenced by any of the examined variables. Despite considerable home range overlap between groups, we found evidence for spatial and temporal landscape partitioning. Groups used their core areas more exclusively than entire home ranges and preferred to sleep within the core areas. Additionally, home ranges overlapped less when assessed over shorter time scale (annual vs. 3-month intervals). The analysis of spatial dynamics between simultaneously tracked groups demonstrated that patterns of avoidance or attraction were influenced by demographic history and possibly by the distribution of food resources. These findings show that space use in Assamese macaques is influenced by between-group competition and feeding needs. Our study suggests that even in the absence of territoriality, non-territorial species can maintain some exclusivity in their space use via avoidance behaviors to reduce competition with neighbors.