Preliminary investigation of the habitats of Presbytis françoisi and Presbytis leucocephalus, with notes on the activity pattern of Presbytis leucocephalus.

In this paper the habitat structure and ecology of Presbytis françoisi and Presbytis leucocephalus are compared. Observations were made of the two langur species in areas of southwest Guangxi province in which the langurs occur but are not sympatric. The results showed that the habitat of P. leucocephalus differs from that of P. françoisi and that the habitat in western areas was different from that in eastern areas in terms of vegetation and other criteria. P. françoisi was limited in its distribution to localities at higher altitudes, in contrast to P. leucocephalus. This may be due to human activities such as crop cultivation and logging. With respect to its activity pattern, P. leucocephalus spent 51.8% of its day in the trees and 48.2% on the rocky substrate. The results of this study suggest that Presbytis may best be regarded as a semiarboreal form.