The socioecology of Cat Ba Langurs (Trachypithecus poliocephalus)

Cat Ba langurs are a Critically Endangered Asian colobine endemic to Cat Ba Island, northeastern Vietnam. There are less than 75 Cat Ba langurs globally, which has placed this species on the Top 25 Most Endangered Primates list since 2000. They are restricted to limestone karst hill habitat, which is quickly being lost, degraded, and fragmented. It is imperative that we learn as much as possible about this understudied species in order to document how they are being affected by these anthropogenic changes. This 11 month study uses scan sampling to explore the socioecology of two breeding groups within the wild population. This includes an examination of activity, diet, postures, locomotion, home range, habitat use, sleeping sites, social behaviours, and infant development. Initial results show that behaviours, diet, postures, locomotion, and home range size fall within the range of similar species. There is variation in habitat use due to the nature of a vertical karst landscape. The Cat Ba langurs use slightly more sleeping sites per group but for fewer consecutive nights than similar species. Females are attracted to young and will huddle together when one is part of the same huddle, whereas males avoid being in proximity to young. Pelage change seems to occur slower for Cat Ba langurs than other similar species. It is hoped that these results will provide a baseline of behaviours and development, so that their responses to ever-increasing anthropogenic interactions and habitat modification can be quantified to better improve conservation goals and management. Rebecca has studied and worked with primates for the past nine years to satisfy her deep curiosity in why we – as primates – do what we do, including what shaped our evolution. She has an MS in Primate Behaviour (Central Washington University, USA) and is currently working on her PhD in Biological Anthropology (ANU).