Influence of group size on home range and habitat use of white-headed langurs

Group size is one of the key factors influencing home range and habitat utilization in primates. However, whether group size affects the home range and habitat utilization in folivorous primates remain unclear. From September 2017 to August 2018, we studied four groups of white-headed langurs (Trachypithecus leucocephalus) in the Banli area of Chongzuo White-headed Langur National Nature Reserve, Guangxi. We systematically collected data on home range, daily travel distance, and habitat utilization to investigate the effect of group size on home range and habitat use in this species. The results showed no correlation between the home range of white-headed langurs and group size, possibly due to high population density of langur groups and low availability of high-quality sleeping sites, which may limit the expansion of their home ranges. However, the average daily travel distance of larger groups was significantly greater than that of the smaller ones. While small groups preferred to rest on cliffs and forage on slopes and hillfoot, larger groups used hill feet habitats significantly more and correspondingly decreased use of hilltop and cliffs compared to smaller ones.