The pristine forest of Neora Valley National Park (NVNP) in Kalimpong hills, Darjeeling district, which has formed an ecological trijunction with Sikkim and Bhutan, is the last virgin wilderness in West Bengal. It is one of the oldest (1881) reserve forests in India. Since this area has been put under protection and is an unworkable working circle, the high forest remains intact.

Marsh Mongoose Herpestes palustris is the only extant endemic mammal of the East Kolkata wetlands, which has been declared a RAMSAR site in 2002. Since its first description by the scientists of the Zoological Survey of India, the population of this species has dwindled to an alarming state due to reclamation of the Salt Lake City and Rajarhat expansion, as well as from other anthropogenic causes. Recently, during a field survey only a small population of this endangered mongoose was found in a single location.