1. Anthropologisches Institut und Museum, Universitt ZürichIrchel, Winterthurerstr 190, 8057 Zürich, Switzerland; 2. Tibetan Plateau Institute of Ecology, Qinghai Normal University, Qinghai 810008, China
The utilization of caves is a rather rare phenomenon in nonhuman primates, found almost exclusively in those members of the genus Trachypithecus that share a preference for forest on limestone (karst) hills in Vietnam and southern China. Here we report a new case of usage of caves as overnight sleeping shelters by François' or black langurs (Trachypithecus françoisi) at Mayanghe National Nature Reserve in Yanhe County, Guizhou Province, China. We tentatively address three possible hypotheses that may account for the use of caves in François' langurs at Mayanghe: shelter against climatic conditions, acquisition of minerals and protection from predators.