Theses and Dissertations

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    Assessing Habitat Use and Activity Pattern of Hoolock Gibbons (Hoolock hoolock) in the Mosaic Landscape of Garo Hills
    (Wildlife Institute of India, Dehradun, 2025) Passah, Betwonsaoo; Lyngdoh, Salvador; Kumara, H.N.
    Primates react to environmental disruption in a variety of ways. Their home range and activity pattern are often linked with anthropogenic disturbance of the landscape. This study focuses on Hoolock Gibbons (Hoolock hoolock) in Garo Hills, Meghalaya, which is a highly arboreal primate and the only ape in India. Hoolock gibbon’s habitat in the Garo hills is being degraded due to the increase in the conversion of forest land into plantations. As most of these forests where the gibbons are located are managed by the community, these forests face overexploitation, which threatens the endangered Hoolock Gibbons habitat. This study aims to establish a baseline Hoolock Gibbon Ecology in the community-managed forest and protected area in the mosaic landscape of Garo Hills, Meghalaya, by examining their habitat use and activity pattern. The main objective is to determine the Gibbon's habitat use within its home range and examine their activity patterns in different forest types. The study is conducted in Daribokgre CR (a continuous forest patch adjoining Nokrek National Park), Dura Kalakgre CR (a small strip of CR which is surrounded by abandoned jhum and active jhum), and an Areca nut plantation which is located in Rensengre close to Selbalgre CR. In each area, one group is chosen and tracked for 20 days. Geo-coordinates and behavioural data were collected, with vegetation sampling and disturbances within a 1 ha cell size grid, which was overlaid on the location points. QGIS was used to map habitat use based on the geospatial data, and the Generalised Linear Model (GLM) was used to check the influencing factors. The activity budget was calculated to understand the behaviour patterns. Across the three studied groups, the habitat types were different group in Daribokgre (Forest group) is dominated by forest patches, the group in Dura Kalkgre (Jhum group) was dominated by abandoned jhum, and the group in Rensengre (Plantation group) was dominated by plantation, and their home range size were 24 hectares, 30 hectares, and 23 hectares, respectively. GLM reveals a significant effect only for the group in the disturbed habitat on the intensity of use. Overall, habitat use patterns and activity patterns varied across the groups, reflecting in behavioural and habitat preference.
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    Social Behaviour and Duetting in Hoolock Gibbons in Gibbon Wildlife Sanctuary, Assam
    (Wildlife Institute of India, Dehradun, 2009) Sankaran, Sumithra; Rawat, G.S.; Kumar, R.S.
    The hoolock gibbon (Hoolock hoolock), only anthropoid primate found in India, is a pair-living, territorial species, which duets extensively. Various hypotheses regarding the function of this behaviour in monogamous primates include territory advertisement, pair-bonding, mate defense, resource defence and group cohesion. This study aimed to understand the nature of social behaviour of this species, and how duetting fits into the repertoire of social behaviour seen in this animal. Three groups of Hoolock gibbons were habituated and studied intensively over a three month period. Relationships between the different group members were explored, alongside time budgets of various activities of the adult pair, the synchrony in their behaviour and frequency and nature of all affiliative and agonistic behaviours. Relationships between territory sizes, group sizes, frequency of duetting and nature of other social interactions have been examined in detail. A considerable amount of individual difference were found between the different study animals in their interactions with other group members. These animals display complex affiliative interactions with rare displays of aggression. It was found that although the proportion of time spent in social interactions was comparable between the three groups, the proportioning of this total time among different social interactions may vary considerably. The primary difference was found to be in allogrooming interactions with the proportion of time time spent increasing with increase in group size. The study also found considerable evidence for the possible existance of male-care in this species.
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    Food selection and ranging in hoolock gibbon (Hylobates hoolock Harlan 1834) in Borajan reserved forest, Assam
    (Wildlife Institute of India, Dehradun, 1997) Kakati, Kashmira; Sathyakumar, S.
    This study on food selection and ranging in the hoolock gibbon (Hylobates hoolock ,Harlan 1834) was carried out between December 1996 and April 1997 in Borajan Reserve Forest, a disturbed and fragmented patch of remnant tropical evergreen forest in Upper Assam, India. The hoolock gibbon is a primarily frugivorous species, confined to closed-canopy evergreen forests of North-east India, Bangladesh and Burma. This type is highly endangered in its entire range. Threats to the continued existence of the hoolock are from large-scale destruction of its habitat and hunting. Two troops of gibbons were followed intensively for four months and behavioural data were collected by continuous focal animal observations. Data were also collected ad libitum on a third troop. Data on the structural components of the vegetation and on the availability of food resources in the Intensive study area were collected systematically. The results of the study show that food availability influenced the diet, movement patterns, home-range sizes and behaviour of hoolock gibbons. Gibbons were selective in their diet using only forty-three plant species out of the more than two-hundred species present. Figs constituted important keystone resources for the gibbons. In months of low fruit availability, the gibbons had a predominantly folivorous diet. Home ranges were small (10.4 ha and 5.4 ha) and habitat degradation represents the greatest threat to the gibbons