Abstract: From November 2006 to March 2007, we studied the winter diets of the Yunnan snub-nosed monkey (Rhinopithecus bieti) found living at Mt. Longma, Yunnan Province. Fecal components including their relative proportions were quantified by micro-morphological analysis. Phytochemical components of 15 primary food items (including two species of Usneaceae) and 10 secondary food items of R. bieti were analyzed. Winter diets of the Yunnan snub-nosed monkey included 45 plant species of 26 families. Fargesia papyrifera Yi (19.78 %), Usnea longissima (10.28 %), Usnea florida (L.) Wigg (8.37 %), Qiongzhuea rigidula Hsueh (4.93 %), and Fargesia pallens Hsueh (4.46 %) were the main components of the winter diet, totalling47.99% of all utilized plants. Young leaves of woody plants and herbaceous plants constituted 75 % of the total quantity of forage. R. bieti preferred to choose food items with high PΠF ratios and low tannin content in winter. It was also noted that primary food items used by R. bieti had less fibire ( P < 0.01) and tannin ( P < 0.05) than secondary items.

Key words: Rhinopithecus bieti; Food habit; Microhitological analysis technology of feces