Glossy marsh Snake - Gerarda prevostiana
Photo : Kunal Salunkhe
Glossy marsh Snake (Gerarda prevostiana)
English- Cat-eyed Fishing Snake, Cat-eyed Water Snake, Gerard's Water Snake.
Distribution - Found in all coastal areas, mangroves and tidal rivers.
Status - Common in its distribution areas.
Length- Adults measure approx. 55cm, but can grow up to 90cm.
Dorsal body- - Body shape cylindrical with very shiny smooth scales. Body colour black, gray, brown, reddish brown or olive. From upper lip to tail side colour whitish or yellowish white upto 3rd dorsal row on each side.
Ventral body- Belly scales gray at edge, also many times gray stripe runs along the belly at the center and surrounded by yellowish-white striped near the dorsal scale row. Subcaudal scales paired in a zigzag manner, their color is darker than belly scales.
Head- Head scales smooth and very glossy; slightly broader than neck. Upper lip colour white with blackish edge many times. Small eyes have vertical pupil. Tongue colour blackish behind and whitish in front.
Tail- Tail length shorter and little thicker than typical snake's tail and ends with pointed tip.
Key characters for identification-
Look alikes- Crab-Eating Snake, Smooth Scaled Water Snake and other mangrove snakes.
- Looks like typical snakes, have uniform brown, black or gray colour with very glossy scales.
- Tail scales are larger than other dorsal scales and looks reticulated in light coloured individuals.
Head- 7 or 8 Supralabials; 4th touches eyes; 1 Preocular; Loreal 1; 2 Postocular; Temporals 1+2 or 2+2, only single Internasal found.
Dorsal- Scales smooth with 17/17 in front body and 15 or 13 in posterior body.
Ventral- 144-157; Anal divided.
Subcaudal- 29-36; paired in Zig-zag manner.
Behavior- Glossy Marsh is a nocturnal snake and often seen during day time in coastal areas. It remains hidden in holes situated in mud. Lives in mangroves, estuaries and coastal parts. Can also be seen a few kilometers away from the sea coast. Feeds on a variety of aquatic animals like freshly moulted Crabs, Fishes, Mud-skippers etc. Often observed catching its prey in their mound or holes. This is one of the few species in the world who feeds on selective parts of its pray. If a Crab is bigger and hard to eat entirely, it breaks the Crab's limbs and chooses the nutritious middle body part only. It is a gentle species and chances of getting bitten is very less. When encountered, it always tries to escape in encounter.
Reproduction - Mating is not much known, its an oviparous snake and gives birth to 5-6 new ones.
Rescue Situations -
Seen very rarely in rescues as it inhibits mud areas, mangroves and estuaries. May enter human house but this species should not be bagged or any attempt of keeping it after rescue. It is dangerous as it lives in wet surrounding only. So if found in rescue, it must be released immediately.