The day range and home range of the Eastern Hoolock Gibbon Hoolock leuconedys (Mammalia: Primates: Hylobatidae) in Lower Dibang Valley District in Arunachal Pradesh, India

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Kuladip Sarma
Awadhesh Kumar


This paper presents the findings of a study conducted on the Eastern Hoolock Gibbon Hoolock leuconedys in Mehao Wildlife Sanctuary and outside to the south of the park, Arunachal Pradesh, India investigating the daily path length (DPL) and home range used by the species in two forest areas with different disturbance gradients.  The four habituated groups of H. leuconedys in fragmented and contiguous forest areas, two groups in each of the forest types, showed considerable variation in their DPL ranging from 6.59m to 1019.01m with a mean distance of 192.75m (SE = ±26.48) in 73 full day observations.  Although the mean DPL was recorded with very little variation across the seasons in both the forest types, it was significantly different from fragmented forest.  Similarly, the home range size also varied among the groups and was estimated as the maximum for Group D (24.62ha) followed by Group E (16.28ha) in contiguous forest and Group B (2.49ha) and Group A (1.09ha) in fragmented forest.  Also, there was a distinct seasonal pattern of home range used by all the study groups with largest seasonal home range in monsoon  and pre-monsoon season in fragmented and contiguous forest respectively.  The DPL and home range of H. leuconedys in Arunachal Pradesh has been highly affected by forest fragmentation and/or canopy discontinuity which makes the species vulnerable to hunting, predation by feral dogs and hawks and ultimately local extinction.  Thus, the findings of the present research evoke the question of long term survival of the species in fragmented forests.


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Author Biographies

Kuladip Sarma, Department of Forestry, NERIST, Nirjuli, Itanagar, Arunachal Pradesh 791109, India Present address: Centre for Animal Ecology & Wildlife Biology, Department of Zoology, Gauhati University, Guwahati, Assam 781014, India

Dr. Kuladip Sarma has completed his doctoral research on ecology of eastern hoolock gibbon from Department of Forestry, NERIST and currently pursuing his post-doctoral research from University of Gauhati. He is interested on ecoloical conservation of threatened mammals of northeastern India. 


Awadhesh Kumar, Department of Forestry, NERIST, Nirjuli, Itanagar, Arunachal Pradesh 791109, India

Dr. Awadhesh Kumar, an Associate Professor, Department of Forestry, NERIST has been working on primates and other threatened mammals of northeastern India. His interest lies in ecological processes related to wildlife and forest management under the umbrella of forestry research.



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