Sleeping Site Selection in a Wild Group of Moor Macaques (Macaca maura) in Sulawesi

Abstract In primates, sleeping behaviour and the selection of sleeping sites with specific characteristics are hypothesised to represent adaptative strategies to diverse evolutionary pressures within their habitats. However, for many species, it remains unclear how these factors influence the selection of sleeping sites. We examined the impact of range defence, predator-, risk-, and parasite-avoidance on the sleeping behaviour and choice of specific sleeping trees in a group of wild moor macaques ( Macaca maura ) inhabiting a savannah forest in South Sulawesi, Indonesia. From March 2023 to June 2023, we collected data on the spatial distribution and physical characteristics of the sleeping trees used by the study group and on their behaviour before entering and after leaving the sleeping trees. During the study, the group used 19 different sleeping trees, located in seven different sleeping sites, and primarily chose large Ficus trees in the central area of their home range, which they often reused on consecutive nights. Macaques often emitted vocalizations when entering the sleeping trees at sunset. These results partially align with the predator avoidance hypothesis and with the risk avoidance hypothesis, but not with the range defence and parasite avoidance hypotheses. While limited to a twelve-week period, our study suggests that predator avoidance and the risk of intergroup encounters likely affect sleeping site selection by moor macaques.