| Abstract: | We studied the locomotor behaviour of white-headed langurs Trachypithecus leucocephalus and Fran(c)ois' langurs T.fran(c)oisi to test two hypotheses: (1) these monkeys have evolved locomotor ability to support their activities on limestone hills,and (2) Fran(c)ois' langurs have evolved more diverse locomotor skills than white-headed langurs. Data were collected from 1996 - 1998 and in 2005 in Fusui Nature Reserve,Guangxi,and showed that the two species had similar locomotor types,but Francois' langurs had more locomotor modes (26) than white-headed langurs (12). Quadrupedal walking and leaping were two major types,and white-headed langurs were more arboreal than Fran(c)ois' langurs. We suggest that,while keeping their ancestral locomotor types,the two species have evolved new types allowing them to live on limestone cliffs. Compared to white-headed langurs,Francois' langurs have more diverse locomotor modes that probably have allowed them to live in more habitat types. As an evolutionary outcome,Fran(c)ois' langurs have a larger distribution range. |
