Hook-Nosed Sea Snake ( Hydrophis schistosus Daudin, 1803 )

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Name
Scientific Name: 
Hydrophis schistosus (Daudin, 1803)
Regional Names: 
English: 
Beaked Sea Snake, Common Sea Snake
Kannada: 
ಕೊಕ್ಕೆ ಮೂಗಿನ ಕಡಲ ಹಾವು
Photographs: 
Distribution: 
Found in all coasts from Gujarat to West Bengal of Indian mainland. Also found in coasts of Australia, Bangladesh, Iran, Malaysia, Myanmar, Oman, Pakistan, Papua New Guinea, Seychelles, Sri Lanka, Thailand, Vietnam and United Arab Emirates.
Family: 
Characteristics for identification: 

It can be identified by checking indistinct bands on light ground color and beak shaped snout which is not found in other Sea Snakes of its range. 

Description: 

New born- 21-24cm.
Average length- 100cm.
Maximum length- 158cm.

Body -
Less slender anteriorly, clearly compressed on posterior. Dorsal body gray, bluish-gray, olive green with yellowish-white side and belly. About 46-60 moderately dark bands found dorsally, broadest on top, tapered on side and absent underside. Old individuals have more or less uniform dorsal because bands get fused with ground color. Tail laterally compressed and oar like.

Head –
Head moderate, scarcely broader than neck and covered with fragmented shields. Foremost scales of snout curved downwards and give appearance of “beak” and so the name “Beaked Sea Snake”. Moderate eyes with rounded pupil.

Scalation
Head: 
Head shields entire; 7-8 supralabial, 3rd & 4th or 4th alone in contact with eyes, last 2-3 very small; 1 preocular, 1-2 postocular; usually 1 anterior temporal; mental scales small.
Dorsal: 
40-52 (Male), 42-55 (Female) rows around the neck, 49-60 (Male), 51-66 (Female) around the mid-body; scales imbricate or subimbricate with a short central keel.
Ventral: 
239-322 (354), distinct throughout.
Habitat: 
Lives in tropical coasts. Prefers activity in shallow water, river mouth, mangrove waters, estuaries, fresh water lakes etc. Use sand and mud for activity on land.
Natural History: 
Activity both diurnal and nocturnal Spends most of life underwater and occasionally comes on land where it becomes helpless. Behavior usually non-offensive, still it is considered to be one of the most aggressive Sea Snake. Viviparous. Female maturity reaches at 18 months. Gravid females seen during winter to summer months. Directly gives birth to 4-33 young from late winters to monsoon.
Diet: 
Feeds on ariid and plotosid catfishes.
Threats: 
Direct threats are killing in fishing operations. Several individuals get trapped in fishing nets and fisherman kill them before taking them out of net. This species is exploited for its venom and skin in many East Asian countries. As this species lives in costal water, pollution in such areas can be a population declining factor.
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