Preliminary Report on Golden Langur (Trachypithecus geei) Winter Sleep Sites

Abstract

Golden langurs (Trachypithecus geei) in Bhutan have received little research attention in the anthropic environments where most of the population lives. We recorded group sizes and compositions and documented sleep sites for 24 golden langur groups living in a biological corridor (N = 9) and near a human settlement (N = 15) in central Bhutan. We used scan sampling to document behaviors and direct observation and camera traps to record potential predators, and we recorded occurrences of mortality, including two cases of electrocution, one case of roadkill, and one langur skull recovered from a possible leopard prey cache. Golden langur groups were on average significantly larger near human settlements (13.73 individuals) than in the biological corridor (9.55 individuals), and the adult sex ratio was greater near human settlements. The golden langurs usually slept in more than one tree, and our preliminary results indicated rare re-use of the same sleep site. Golden langurs in our study area most often slept in Sapium insigne trees. Sleep trees’ mean DBH was 51.58 cm and the mean height was 19.37 m. We intend for our preliminary data to establish the foundation for future research on the behavior and ecology of golden langurs in Bhutan.