West Bengal is a state with variable biogeographic characteristics. Starting from high Himalayan alpine zone down to coastal areas including world famous mangroves of Sunderbans, the entire area harbours bewildering array of genera and species of plants and animals. In fact West Bengal offers a wide variety of habitats ranging from temperate Himalayan type to moist tropical forests of northern Bengal including Savana woodlands, Gangetic alluvial zones of Central Bengal, the lateritic dry zones of coppiced sal forests of southwestern Bengal and the vast estuarine mangroves of Sunderbans.

MUSTELIDS

Eighty five percent of the area of the state is non-forest but contains numerous wetlands, which provide habitat for otters. Three species are said to occur: Eurasian otter Lutra lutra, smooth-coated otter L. perspicillata and small-clawed otter Aonyx cinerea. Past records reveal collections of common otters as far back as 1886 (Anderson 1879) and Pocock (1941) reported both Eurasian and smooth-coated otters as occurring near Calcutta. Jerdon (1867) recorded small-clawed otters from Salt Lake and Sunderbans to the east of Calcutta. Trade in otter skins was once common in Bengal (Anderson 1879). Since 1972 this has decreased but the very nature of the vast wetlands of Gangetic Bengal make law enforcement very difficult.

Presently the Eurasian otter is widely distributed in the districts of Howrah, 24 Parganas (N) and 24 Parganas (S) (Sanyal 1991). In the Howrah district, Panchla and Shyampur areas sustain about 50 km2 of wetlands and canal inundated areas with vast beds of Typha angustata, Phragmites karka and Sclerostachya fusca. These areas are flooded by both tidal canals of Hooghly river as well as by the freshwater canals from the river Damodar. Thus the area is one of paddy fields interspersed with Typha and reed beds.

The area was surveyed for signs of otters. The plant species present in the area were identified. Since otters sometimes take fish from the bamboo fish traps set by local people, food preference was studied in the wild.

The salinity of the water in Ganges/Damodar canals, measured in the driest season (June) never exceeded 0.4 ppt. The sides of the canals were lined with Typha angustata. Another 15 plant species were identified and the presence of species like Otelea and Salvinia demonstrates that salinity levels remain low in spite of tidal flooding via the Hooghly river.

There were about 20 fish traps in the study area. Footprints revealed that Eurasian otters visited the traps frequently and took some of the fish. In past 2 years the local people had killed and eaten 4 otters.

A study on the diet of Eurasian otters showed a preference for small prawn Metapenaeus spp. the non-scaled fish Glassogobius gigures and the highly predatory "Boal" fish Wallago attu. Wallago attu is menacingly predatory and efforts are being made to impress upon the local people the advantages of otters preying upon it. The inter-tidal zone between Calcutta and Sunderbans now harbours a good population of Eurasian otters.

By contrast, the smooth-coated otter population of Sunderbans appears to be restricted to the mid and inner estuarine zone only. Good populations may however occur in the riverine forests of north Bengal, in Gorumara and Jaldapara Sanctuary where communal sprainting sites are found along the rivers Torsa and Murti.

It is possible that the small-clawed otter still survives in the Himalayan region of north Bengal as well as in the mangroves of Sunderbans delta, but further surveys are required to ascertain this.

The other lesser known mustelids of West Bengal found in the higher elevations are yellow-bellied weasel Mustela kathiah, Siberean weasel M. sibirica, back-striped weasel M. strigidorsa, beech marten Martes foina, yellow-throated marten M. flavigula, hog badger Arctonyx collaris, large-toothed ferret badger Melogale personta and small-toothed ferret badger M. moschata (ZSI 1992, Chaudhury 1999). In the plains, occassionaly, ratel or honey badger Mellivora capensis has also been observed (ZSI 1992).

VIVERRIDS

Three species of viverrids are common in West Bengal namely, the small Indian civet Viverricula indica, the large Indian civet Viverra zibetha and the common palm civet Paradoxurus hermaphroditus.

Amongst these species common palm civet is very common even within the city of Calcutta and its outskirts particularly in old buildings. It often becomes a problem in hospital kitchens where the wildlife department has to intervene and trap a few animals to redress the difficulties of kitchen authorities. In the reclaimed Sunderbans over an area of nearly 5,000 km2 the common palm civets are often sighted. They are also found to be addicted to village sweet shops in this region.

The large Indian civet is quite frequent in the moist tropical forests of north Bengal. In Buxa Tiger Reserve, innumerable pairs of eyes are visible during summer nights on the fire lines, when the large Indian civets come out to feed. Local people in West Bengal, i.e. in the lateritic districts of Midnapore, Purulia, Bankura, Birbhum and parts of Burdwan often hunt the small Indian civets. For the tribal population of Bengal, small Indian civets are highly palatable.

The other lesser known viverrid of West Bengal, the masked palm civet Paguma larvata was once common but is now rarely sighted (ZSI 1992).

HERPESTIDS

Four species of Herpestes are found in West Bengal namely Indian grey mongoose Herpestes edwardsii, small Indian mongoose H. auropunctatus, marsh mongoose H. palustris and crab-eating mongoose H. urva (Pocock 1941, ZSI 1992, Choudhury 1999).

Indian grey and small mongoose are quite common all over Bengal and are often a menace to the poultry (ZSI 1992). A good population of Herpestes species is found in the outskirts of Calcutta. Marsh mongoose is particularly endemic to the east Calcutta wetlands where it was first reported (Ghose 1965). Its population has however decreased in recent times owing to continuous anthropogenic interference in the east Calcutta wetland ecosystem where its habitat is shared by both the species of mongoose as well as by the Fishing cat Prionailurus viverrinus and Eurasian otter.

The crab-eating mongoose occurs in north Bengal in the Darjeeling and Jalpaiguri districts (Wroughton 1916). Its present status is not known.

REFERENCES

Anderson, J. (1879) Anatomical and zoological researches compromising and account of the zoological results of 2 expeditions to western Yunan in 1868 and 1875 and the Monograph of cetacean genera. Platanista and Orcella. Vol-I, 209. London.

Choudhury, A.U. (1999) Conservation of small carnivores (mustelids, viverrids, herpestids and one ailurid) in north Bengal, India. Small Carnivore Conservation, 20, 15-17.

Ghose, R.K. (1965) A new species of mongoose (Mammalia, Carnivora, Viverridae) from West Bengal. Proc. Zool. Soc. of Calcutta, 18, 173-178. 

Jerdon, T.C. (1867) The Mammals of India. Roorkee.

Pocock, R.I. (1941) The Fauna of British India including Ceylon and Burma. Vol-II, London.

Sanyal, P. (1991) Otters of West Bengal, India, with special reference to a study area near Calcutta. Habitat. No 6. Hankensbuttel. Germany.

Wroughton, R.C. (1916) Bombay Natural History Society’s mammal survey of India, Burma and Ceylon. Report No. 23. Sikkim and Bengal Tarai. J. Bombay nat. Hist. Soc., 24, 468-493.

ZSI (Zoological Survey of India) (1992) Fauna of West Bengal. Part I, Zoological Survey of India, Calcutta.