Abstract # 3209 Event # 17:

Scheduled for Saturday, September 17, 2011 10:15 AM-10:30 AM: Session 4 (Meeting Room 410) Oral Presentation


J. Biswas1, D. Jayanta1,2, S. Anjan1,3 and P. C. Ray1,3
1Primate Research Centre NE India, House No - 4, Byelane No - 3, Ananda Nagar, Guwahati, Assam 781 012, India, 2Wildlife Areas Development and Welfare Trust, 3Gauhati University

The Hoolock gibbon under the genus Hoolock have two species, eastern Hoolock gibbon (Hoolock leuconedys) and western Hoolock gibbon (Hoolock hoolock), was earlier thought to be separated by the river Chindwin in Myanmar. But a recent finding reveals their presence in small part of eastern Arunachal Pradesh, India. To know the status and distribution of eastern Hoolock gibbon in India, a detailed survey was conducted in eastern Arunachal Pradesh within the known range of Hoolock gibbons using modified line transect and call count method from March 2009 to July 2010. We observed 521 individuals of eastern Hoolock gibbons in 162 groups (average group size: 3.2 ± 0.65, range: 2 - 6) of which, 3 were lone individuals. Of these, 62.5% were adult, 7.7% were sub-adult, 15.4% were juvenile and 14.4% were infants. We also recorded 327 calls from 18 different forests, from which 46 counts were deducted being observed, calculating 1450 individuals of Gibbons from Dibang Valley and Lohit district of Arunachal Pradesh, India. From these observations, estimated population of eastern Hoolock gibbon in India would be between 2500 – 3000 individuals. We also outlined the zoo-geographic distribution range of eastern Hoolock gibbon and suppose the possible eastern and western races / variety of eastern Hoolock gibbon (Hoolock leuconedys) from India. Rapid habitat loss, fragmentation, habitat alteration and degradation are the major threat to the gibbon population in Arunachal Pradesh.