Introduction
Three species of otter occur in the Indian sub–continent: the Eurasian otter, Lutra lutra Linnaeus, the smooth–coated otter, L. perspicillata Geoffroy, and the original small–clawed otter, Aonyx cinerea Illegar. The smooth–coated otter is distributed throughout the Indian sub–continent, from the Himalayas southward. Outside the Indian sub–continent, its range extends to Mynamar, Indonesia, Kampuchea, Laos People's Republic, Malaysia, Vietnam, southwestern China and Brunei, with an isolated race, L perspicillata maxwelli, in the marshes of southern Iraq (Pocock, 1941: 265–312; Prater, 1971; Mason & Macdonald, 1986). Despite its wide distribution, no detailed ecological studies on this species have been undertaken so far. It is listed as insufficiently known in the IUCN red data book (Groombridge, 1994) and is protected under Schedule II of the Indian Wildlife (Protection) Act, 1972. Previous work on Indian otters involved observations on captive animals (Desai, 1974; Acharjyo & Mishra, 1984) with occasional notes on their occurrence from different parts of the country (e.g. Hinton & Fry, 1923; Pocock, 1939; Chitampalli, 1979) and a few studies on their feeding habits (e.g. Wayre, 1978; Foster–Turley, 1992; Kruuk et al 1994).
It is believed that the existing populations of all the three Indian species are rapidly declining due to loss of habitat and intensive trapping (Hussain & Choudhury, 1997). Because of limited knowledge on the ecology of Oriental otter species, practical conservation measures are difficult to develop.