Diet, activity, habitat use, and ranging of two neighboring groups of food-enhanced long-tailed macaques (Macaca fascicularis).

We conducted observations of two neighboring groups of food-enhanced long-tailed macaques (Macaca fascicularis) over a period of one year. We examined their diet, behavior, habitat use, and ranging and how within-population variability reflected differential utilization of anthropogenic food resources. The group that consumed more anthropogenic food spent less time feeding on wild fruits and flowers, less time resting, and more time locomoting. They used forest habitats less often, and had a larger total home range and mean monthly home range. Some of these results contrasted with previous studies of food-enhanced primates which reported that food-enhancement resulted in smaller home ranges, shorter daily ranges, less time traveling and feeding, and more time resting. These contrasting patterns may relate to the nature of anthropogenic foods. In most studies of food-enhanced primates, anthropogenic food resources were abundant and concentrated but the macaques in this study used anthropogenic foods mainly from a few refuse sites where they had limited access, and from dispersed and irregular human provisioning. The group consuming more anthropogenic food therefore showed more spatially dispersed feeding activity and home range use, an effect that was likely further enhanced by lower natural food resource availability within their home range. The Singapore macaque population shows small-scale variability in feeding and ranging behavior, contributing to the complexity of their adaptive variability in a human-altered habitat. Our findings could have important implications for mitigating human-macaque conflict as measures applied at a higher spatial or population level may achieve highly inconsistent results, intensifying the challenges for wildlife managers.