The Nilgai or Blue bull (Boselaphus tragocamelus) is the largest Asian antelope. The Nilgai has been associated with Hindu mythology since the Vedic period, 1500–500 BC. However, Nilgai or Blue bull is actually not a cow but an antelope. The other antelopes found in Nepal are Black buck (Antilope cervicapra), Four-horned Antelope (Tetraceros quadricornis) and Tibetan Antelope (Pantholops hodgsonii). A good population of Blue bull is seen in the reserve.
The Nilgai is listed on the Appendix III of CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora). The Nilgai is categorised as Least Concern by the IUCN. In Nepal, this mammalian species has not given legal status as tiger, rhino, elephant, and snow leopard have.
Habitat destruction, habitat alteration, retaliatory killing, absence of predators, are some conservation issues to this species. The reserve’s authority has been conducting habitat restoration and conservation education campaign.