Dog-faced Water Snake ( Cerberus rynchops Schneider, 1799 )

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Name
Scientific Name: 
Cerberus rynchops (Schneider, 1799)
Regional Names: 
English: 
Dog-faced Water Snake, Asian Bockadam, New Guinea Bockadam
Kannada: 
ನಾಯಿ ಮುಖದ ಹಾವು
Marathi: 
Shwanmukhi sarp
Hindi: 
Ubhareshalka jal saap
Gujarati: 
Shwanmukhi jal saap
Photographs: 
Full Body Shot
Distribution: 
In India this species is found in all coasts on mainland, also found in Andaman & Nicobar Islands. Coasts of Gujarat are its western most limit.
Family: 
Characteristics for identification: 

Can be identified by checking brownish dorsal surface marked with darker bands or blotches. 

Description: 

New born- 15-25cm.
Average length- 60cm.
Maximum length- 100cm.

Dorsal -
Body thick, robust and covered with highly keeled scales arranged in striated manner. Dorsal color gray-brown with faint or dark cross bands of gray-black color.

Ventral -
Belly white or cream with or without dark blotches which may extends to first few dorsal rows.

Head-
Head elongated, depressed and broader than neck. Eyes with vertically elliptical pupil. Upper head scales fragmented. Color similar to dorsal body with upper lip whitish. A dark streak exist behind eyes. Nostrils and eyes at height and slightly protruding.

Tail-
normal length tail, laterally compressed with color similar to dorsal.

Scalation
Head: 
Head: Internasals usually divided; usually in contact with loreal; frontals partially and parietals completely broken into small scales; supralabial 8-10, last two horizontally divided; loreal 1 or 2; 1-3, 1-4 (rarely 2-3, 2-4) supralabials in contact with loreal; preocular and postocular usually single; 1-3 subocular.
Dorsal: 
Strongly keeled scales in 23-27: 21-25: 16-20 rows.
Ventral: 
135-152, rounded; anal divided
Sub Caudal: 
56-67 (Male), 48-59 (Female); paired.
Habitat: 
Found in marine coastline, mangroves, tidal rivers, brackish estuaries, mudflat, paddy fields of both marine and fresh water. Choose crab holes, under rocks, under root of aquatic vegetation standing on bank, dense aquatic vegetation etc. as roosting site.
Natural History: 
Dog-faced Water Snake is a nocturnal species which shows few activity at dim light and daytime also. Mostly aquatic and shows prone activity in mud and water both. Behavior active and alert in aquatic environment; usually non-offensive. Viviparous. Female directly gives birth to young individuals (6-30) from post winters to most of summer months. New born individuals may stay with mother for few days but no other association found between them.
Diet: 
Feeds actively on various fishes, eels, crustaceans, tadpoles and frogs.
Threats: 
Direct threats like killing and road kills are not much affecting this species but it regularly comes in fishing net and got killed or deeply injured many times. Due to conversion or modification of mangrove lands into agricultural fields and salt farms this species is facing threat of permanent vanishing from a particular area. Climate change will affect its population status as it inhibits mainly in mangroves which are under verge of extinction in upcoming decades.
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