Feeding Ecology of Sloth Bear (Melursus ursinus) in Chitwan National Park, Nepal

Abstract

Feeding ecology of species directly affects the reproductive success, ranging patterns and other behavior, therefore understanding the dietary composition is important to assess its distribution and habitat use. Feeding ecology of Sloth Bear (Melursus ursinus) was assessed in Chitwan National Park(CNP), Nepal to determine the diet composition,seasonal variation of diets and factors affecting diet selection. Entire study area was divided into grids(n=79), each measuring with 4×4 Km vii 2 and 40% grids were randomly selected for field survey.A total of 143 scats collected in the grids as well as along fire lines, trails and around the Machans. Diet composition was estimated and presented in terms of frequency of occurrence and percent dry weight, as well factors affecting the Sloth Bear’s diet selection in the study area were observed. Kruskal-Wallis Rank Sum Test was used to find the significant difference in the diet composition of Sloth Bear in two different seasons. Six types of plants, termites, ants, honey bees, wax, as well as mammalian hair were identified in bear scats. Although variation was observed, there was no significant difference in the diet composition between two different seasons(X =0.8586, df=1,p=0.3541, α=0.05). Overall, insects dominated the composition, occurring in 100% of the scats followed by the plants (39.16%) and mammalian hair (3.49%). Termites and ants were the major and stable components. Termites (90%), Red ants (65%) and Aegle marmelos(35%) were important food for Sloth Bear in summer season but the utilization of plants was very low. During winter, insects were heavily utilized by the bear. The utilization of termites (93.97%) and Ziziphus species (14.45%)was higher in comparison with summer season. Utilization of fruits in this season was negligible. Overall, on percent dry weight basis also, insects (78.98%) dominated Sloth Bear diet,followed by plants (20.99%) and mammalian hairs (0.04%). Similar types of result were also found in both the seasons. Factors like human presence, forest fires, uncontrolled cattle grazing, insect mould distributions, seasons were found to affecting the diet selection of the species in the study area.