Ranging behavior is an important aspect of animal behavior that researchers use to investigate ecological influences on individual behavior.We collected data on the ranging behavior of one group of François’langurs(Trachypithecus francoisi)between August 2003 and July 2004 in a limestone habitat within Nonggang Nature Reserve,China.We evaluated the influences of food availability,water resources and sleeping sites on ranging behavior.During the study period,the total home range size for the study group was 64.5 or(69.3 ha if the lacunae within the borders in which langurs were not observed were included),and the mean daily path length was 541 m.These are well within the range of variation reported in Trachypithecus species.The monthly range size was between 9.8 and 23.3 ha,and monthly range size correlated negatively with young leaf availability.The langurs tended to use a larger range size during young leaf-lean periods.The langurs did not use their home range uniformly,and 74%of their activities occurred within 35%of their home range.The most heavily used quadrats in the home range were located near the most frequently used sleeping sites,suggesting that sleeping sites have a significant influence on the ranging behavior of François’langurs in limestone habitats.