Choice and Characteristics of Sleeping Sites in a troop of Central Himalayan Langurs (Semnopithecus schistaceus)

Abstract

Arboreal primates spend about half of their lives at sleeping sites; hence, selection of sleeping sites is crucial for individual survival, and data concerning them is important for conservation efforts. We collected data on sleeping sites for a group of Central Himalayan Langur (Semnopithecus schistaceus) around Mandal village at the southern fringe of Kedarnath Wildlife Sanctuary from August 2018 to mid December 2018. In the mixed broadleaf forest at the southern fringe of Kedarnath Wildlife Sanctuary, Central Himalayan Langur, Semnopithecus schistaceus, used 306 trees to sleep in, out of which 73.6% trees were used to sleep more than once. The species were chosen according to their frequency in the forest area with the highest usage observed for Quercus leucotricophora. Compared with random trees, sleeping trees had higher average diameter at breast height (DBH), higher basal diameter, and higher average height. They chose to sleep on trees with exposed crown more than expected from the distribution in the forest. The study troop also used crevices on a cliff face as their sleeping site. The troop showed alertness and vigilance while entering and occupying sleeping sites. The langur troop usually slept in close proximity to the last feeding spot. The troop left the sleeping sites later in the morning and entered early in the sleeping trees in the cold season. These behavioral responses suggested that predation risk, thermoregulation, and foraging constraints could be the main determining factors in the selection of sleeping sites.