Dispersal patterns exhibited by group-living animals play an important role in individual reproductive success and survival, as well as population and social dynamics （Greenwood, 1980; Isbell and van Vuren, 1996; Kappeler and van Schaik, 2002）. Dispersing individuals may emigrate voluntarily, or they may be forcibly evicted by other individuals （Pusey and Packer, 1987; Clobert et al. , 2001 ）. One cause of individual dispersal is when an extra-group male compels another male to leave a group of females. This phenomenon has been well documented in primates, especially Old World monkey species （ e.g. Colobus vellerosus ： Saj and Sicotte, 2005 ; Erythrocebus patas ： Ohsawa, 2003 ; Macaca fascicularis ： van Noordwiik and van Schaik, 2001）.
Although there are some reports that have described primates eating animals,it is unknown whether predation on vertebrates exists in herbivorous leaf-eating primates.We have witnessed firsthand wild Sichuan snub-nosed monkeys(Rhinopithecus roxellana)preying on and consuming Eurasian blackbirds(Turdus merula)in the Qinling Mountains of China.This event suggests that R.roxellana,which has previously been described as a herbivorous leaf-eating primate,may be partially carnivorous and the correct classification of this species would be omnivorous.Furthermore,food-share behavior among higher-ranked members occurs in a one-male unit when vertebrate prey is hunted by this species.
