Ranging behaviour and sleeping sites in Macaca fascicularis at Bali Barat National Park, Indonesia

Ranging behaviour and sleeping site selection are important aspects of primate ecology in their adaptation to the environment. Several non-exclusive factors have been suggested to explain sleeping site selection in primates: predation avoidance, food resources proximity, interactions with conspecifics, physical comfort, and parasite avoidance. We tested the role of some factors in a group of Macaca fascicularis living in a human-modified landscape in Bali Barat National Park, during 3 months from April-June 2011. Despite the large area of available forest, the group’s home range was centred around human-settlements (park headquarters). The home range size, as well as the average daily range and daily travel, decreased over the study months. These results correlated with the increase of human presence inside the park over the corresponding months. Regarding sleeping sites, the use pattern also seemed to be influenced by the attraction to human settlements. Indeed, macaques slept more than expected close to human-settlements and this tendency increased over the months. 75% of the 56 observed nights were spent inside the core area, an argument for the role of intergroup competition avoidance. In contradiction with the predation avoidance assumption, the DBH and the height of sleeping trees were not significantly greater than those of control trees. On the other hand, most of sleeping trees had no liana on the trunk and a high arboreal connectivity with surrounding trees. Also, the rate of consecutive sleeping site reuse was very low (12%), minimizing the detection by predators. We conclude that the main strategy of this M. fascicularis group could be sleeping not too far from humans because it is advantageous for predator avoidance and proximity to human food, but that additional influences should not be neglected.