We studied a free ranging provisioned group of the Sichuan snub-nosed monkey in their natural habitats. Group members spent 14% of their daytime on the ground, 53% in the low stratum and 33% in the canopy. Use of forest strata differed among age-sex classes. Adult males spent 27% of daytime on the ground, 20% of their foraging time on the ground and 29% of their resting time on the ground, all of which were significantly longer than the other classes. They traveled frequently on the ground (53%) but rarely in the canopy (15%). To cross canopy gaps they preferred to grasp the branches on both sides and then shifted themselves in one direction, however, they often descended to the ground to avoid leaping the gaps. In contrast, subadult females and juveniles foraged and rested mostly in the lower stratum and/or canopy. Subadult females and juveniles spent significantly more time traveling in the canopy than adult animals. They rarely foraged or rested on the ground and tended to cross the canopy gaps by leaping. Juveniles were at a greater risk of falling from trees than adults. Factors such as body weight that affected their spatial distribution and locomotion were also examined[Acta Zoologica Sinica 52(3):429-436,2006].
Keywords：Snub-nosed monkeys,Rhinopithecus roxellana,Forest utilization,Tree crossing mode