The Tonkin snub-nosed monkey (Rhinopithecus avunculus), listed as critically endangered, is restricted to a small area in north-eastern Vietnam, and is considered one of the 25 most endangered primates in the world. The goals of this study include documenting the positional behaviour repertoire of adult males and females of R. avunculus and to relate the positional behaviour of this species to the tree species profile and forest structure at Khau Ca area, Ha Giang Province, north-eastern Vietnam. This is the largest known population of this species and consists of more than 90 individuals.

This study will not only provide the first quantitative analyses of the positional behaviour and habitat use of R. avunculus in the wild, but will also identify preferred habitat characteristics for this critically endangered species, information that will help shape forest rehabilitation and expansion plans in the Khau Ca area. Moreover, it will provided continued presence of local research assistants in this forest block ensuring that poaching or other illegal activities will not occur. Methods will follow standard protocol for collecting and analysing positional behaviour.

In addition, forest structure characteristics will be studied in both botanical transects and plots, most of which are already established in this area. Outcomes will include a richer understanding of positional behaviour, habitat use and habitat preference of R. avunculus, information directly relevant to our ongoing forest rehabilitation and expansion plans, and continued presence of researchers (local, national, and international) in the area ensuring ongoing protection of this population.