Material Examined : 7 adults.

Description & Scalation : Body cylindrical. Head slightly distinct than neck. Eye small, with vertical pupil situated high on the head. Nasals separated by a single internasal; frontal much broader than the supraocular. Rostral more than twice as wide as high, scarcely visible from above; 1 loreal about as high as long or little longer than high; 1 preocular reaches upper surface of the head, not touching the frontal; 2 postoculars; temporals 1+2 or 2+2; Scales smooth and subequal, in 17:17:15 rows; supralabials 7-8 ( 4th in contact with the eye ); infralabials 8-9, first 4 touching the first pair of genials; anterior pair of genials longer than the second pair; ventrals 145–155; subcaudals 30-36, paired, ( in 4 speciemens first caudal plate entire ); tail short; anal divided.

Coloration : Uniform brown or gray-olive above; outer three scale rows yellow-ivory; lip scales ivory, edged with brown or gray. Belly scales ivory or whitish-gray, with distinct dark-gray edges, scales under tail nearly uniform dark-gray.

Natural History : A grooved-fanged snake, nocturnal in habits. Mainly found on mudflats in mangrove swamps, also tidal rivers, in the costal areas. Recent study shows this species to rest in lobster holes in the mud, during the day. 13 speciemens were observed on knee deep mudflat at about 2200 hrs in North Andaman, at low tide. All these snakes were sitting on crab holes, with their tails inside the crab holes and within 7-8m apart from each other. This species occurs in the same geographical areas where the other snakes like Cerberus rynchops ( Dog-faced Water Snake ) and Cantoria violacea ( Yellow-banded Mangrove Snake ) also occur. Mainly feeds on soft shell crabs, fish, shrimp and other small aquatic animals & is known to tear the prey apart before swallowing it. Bears live young. Grows up to 53cm.

Distribution - India : Occurs on mainland coastal areas and Andaman Islands. Elsewhere : Coasts of Sri Lanka, Bangladesh, Myanmar, Malaysia and Thailand.

External link : http://reptile-database.reptarium.cz/species?genus=Gerarda&species=prevostiana