Population of the endangered Bengal Marsh mongoose Herpestes palustris Ghose, 1965 (Mammalia: Carnivora: Herpestidae), previously considered a subspecies of H. javanicus, is endemic to the swampy southern West Bengal. It is the latest mongoose species in India, distributed in the peri-urban, non-forest, natural or manmade wetlands in Howrah, South and North 24-Parganas districts, situated on both banks of the river Hooghly. Now, only the undisturbed core area (bheries or fisheries) of East Kolkata Wetlands, a RAMSAR site spread over 125 km2, is the last stronghold of this marsh mongoose in the world. Although this typical wetland mongoose was recognized by the Zoological Survey of India forty five years ago, no field studies were conducted to update information on this rare animal until recently. Consequently, the Bengal marsh mongoose remained a poorly known and data deficient species. Recent researches have developed a knowledge-base on this marsh mongoose. This chapter highlights the past and present distributions, morphological features, ecology, behaviour, food habits, reproduction, conservation threats and status of H. palustris. During the field surveys, being conducted since mid-2005, a sizeable population of this mongoose was found only in the largest bheries of Nalban, but probably dwindled in other habitats due to rapid reclamation of its habitats for two new satellite townships, the Salt Lake City (Bidhannagar) and Rajarhat Megacity in North 24-Parganas district, as well as other anthropogenic threats. Immediate conservation measures are required to be taken by the nodal authorities to prevent habitat encroachment and extinction of H. palustris in near future.
Keywords: New native species, piscivorous bengal mongoose, controversial taxonomy, dorsal guard hair identification, peri-urban freshwater wetland, reclamation, habitat loss, population decline, endangered.