Ale, Purna Bahadur2023-06-182023-06-182010https://hdl.handle.net/20.500.14540/17961The study was carried out in the month of Feb, March, July and August of 2007 and 2008. A total of 149 Highland Langurs Semnopithecus entellus were encountered which were living in 6 groups within the total visually accessible area of 32 km² in Langtang National Park. The mean group size was found 24.83 (Range 7-48) individuals. The group density was found 0.18 groups / km² with a population density of 4.65 individuals/ km². Among the total counted monkeys, 29.53% were adult female, 12.08% adult male, 8.05% sub-adult male, 13.42% sub-adult female, 21.42% Juveniles and 15.43% infant during the study period. The adult sex ratio (male to female) observed during the study period was 0.40 (40 males per 100 females) i.e. 1:2.5 (Range 1:1.88-1:3.57). Birth rate (infant to female ratio) was found 0.52 (52 infants per 100 females) during the study period. The average group size was 24.83 (Range 7-48) in the study area. In systematic plots, the highest IVI (49.40) was recorded for Quercus semicarpifolia followed by Ilex dipyrena (29.02), Alnus nepalensis (27.52), recorded for Leucosceptrum canum. In Langur encountered plots, the highest IVI (88.29) was recorded for Queccus semicarpifolia followed by Cotoneaster frigidus (42.31), Rhododendron campanulatum (33.36), Castanopsis indica (31.27), Dodecadenia grandifloria (20.78) and Ilex dipyrena (19.72). Similarly the lowest IVI (12.36) was recorded for Euonymus grandiflorus. There are significant difference in the diversity index, dominance index and evenness of tree community between systematic and Langur encountered plots (t=4.645682, P= <0.05). Index of similarity value for tree species was 41.025% between systematic plots and Langur encountered plots. Among the four types of behavior (Moving, resting, foraging and grooming), foraging was found as maximum (54%) which was followed by moving (26%), resting (12%), grooming (4.5%) and other social behaviors (3.5 % ). Future work on seasonal diet analysis, niche overlapping and inter-troop competition of the species would be additive to lay out the in-depth knowledge in ecology which may answer the question: how are highland Langurs fit and ecologically adapt in such narrow range of habitat and harsh climatic condition along Trishuli river?en-USSemnopithecus entellusLangtang national parkThesis