Status and Distribution of the Eastern Hoolock Gibbon (Hoolock leuconedys) in Mehao Wildlife Sanctuary, Arunachal Pradesh, India

Abstract

A field survey was conducted in 2008–2009 in the Mehao Wildlife Sanctuary in Arunachal Pradesh, India, to investigate the status and distribution of the eastern hoolock gibbon there. The data were collected using line transects (trails covering all representative areas of the sanctuary) and by registering calling groups. We recorded 157 groups of gibbon in the sanctuary, of which 28 were directly sighted and 129 groups were registered by their calling. Of the 88 individuals seen, 61.4% were adults, 22.7% juveniles and 15.9% infants. Average group size was 3.14, with an adult sex ratio of 1:1. The survey also confirmed the presence of capped langur (Trachypithecus pileatus), Assamese macaque (Macaca assamensis), rhesus macaque (Macaca mulatta) and slow loris (Nycticebus bengalensis) in the sanctuary. We identified encroachment, jhum cultivation, horticulture, selective logging and inadequate infrastructure as being the major threats for the hoolock gibbon and other wildlife in the sanctuary. Although the gibbons were not hunted, hunting was evidently a threat to other wildlife in the sanctuary.