From August 2007 to June 2008,the diet and social structure of a group of gray snub-nosed monkeys(Rhinopithecus brelichi) were studied at Yangaoping in Fanjingshan National Nature Reserve,Guizhou.The results revealed that the gray snub-nosed monkey mainly fed on leaves,buds,fruits and flowers,accounting for 33.5%,29.1%,24.3%,and 6.9% of their diet,respectively.Besides those main food items,bark,calyxes and insects were also recorded.The social unit of the species is multi-female,single-male units,and these social units(or families) often ranged and rested together in large,semi-cohesive bands.At least one all-male unit,which was composed of 2-5 adult and sub-adult males was found on the periphery of the bands.The adult sex ratio(male vs female,excepting the all-male group) was 1∶2.5.These bands displayed a temporary fission-fusion phenomenon.In summer and autumn the bands form large aggregations of over 400 animals,but in winter the bands split up temporarily into several small groups with 50-200 animals.
