The distribution and population structure of two macaque species in Xizang, China

Xizang, China, has complex alpine ecosystems and supports a diversity of primates. However, systematic survey data on the current distribution and population characteristics of the white-cheeked macaque (Macaca leucogenys) and the Arunachal macaque (Macaca munzala) in Xizang remain limited. To determine the spatial distributions and troop sizes of the two macaque species, line-transect surveys and camera-trap monitoring were conducted in Shannan City and Nyingchi City, Xizang, in 2025. The surveys recorded 11 troops of Arunachal macaques in Himalayan fir forests and forest-edge habitats at elevations of 2,000-3,000 m in Cona City, Shannan City and 10 troops of white-cheeked macaques in habitats, ranging from evergreen broad-leaved forest to mixed coniferous-broad-leaved forest at elevations of 1,395-2,700 m in Gedang Township and Damu Township, Medog County, Nyingchi City. Average troop size was approximately 14 individuals for the Arunachal macaque and 17 individuals for the white-cheeked macaque. Troops of both species included adults, subadults and infants and the presence of infants indicated normal reproductive activity. This study provides the first systematic documentation of the current distribution ranges, habitat preferences and social structure of these two macaque species in Xizang, thereby providing baseline data for subsequent conservation assessments and management decisions.