Olive Keelback ( Atretium schistosum Daudin, 1803 )

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Scientific Name: 
Atretium schistosum (Daudin, 1803)
Regional Names: 
Olive Keelback Water Snake
ಆಲಿವ್ ಬೆನ್ನೆಣುಹಾವು
Found in patched form in most of the parts of Central to Eastern peninsular India and Southwards to it. Not found in North-east region and Western India.
Characteristics for identification: 

With number of combination of colors of belly and dorsal body it is confusing for layman to identify it quickly.


Average length- 50cm.
Maximum length- 100cm.

Dorsal -
Body slender with keeled scales. Color olive brown, greenish with or without two red color faint lines running longitudinally. Side dorsal rows of same color which is found in bely.

Ventral -
Belly white, yellow or orange which extends to first two dorsal rows.

Head -
Head covered with smooth scales with rounded snout; slightly broader than neck. Top of head patternless with color similar to dorsal.

Tail -
Tail of typical length, with a pointed tip. Subcaudal scales paired in zig-zag manner.

Supralabial 8 (3rd & 4th touches eyes) or 9 4th & 5th touches eyes); preocular 1; loreal 1; postocular 2-3; temporal 2+3.
Keeled scales in 19:19:17 rows
129-160; anal divided.
Sub Caudal: 
53-85; paired.
Habitat includes paddy fields, wet agricultural lands, swamps, ponds etc. Hides in dense vegetation adjacent to water bodies.
Natural History: 
Olive Keelback is a diurnal and aquatic species which shows activity around water bodies. Locomotion usually slow in serpentine manner. Behaviour calm and rarely bites. On threatening inflates its forebody and try to escape after getting chance to swim away or hide in aquatic vegetation. Oviparous. Female lays upto 30 eggs from winters to most of summer months.
Feeds mainly on fishes, frogs and toads.
Major threats are road kills and destruction of paddy fields, wetlands and wet vegetation from water bodies. It is also done by poisoning and pollution in water bodies which affects its diet. Killing due to misidentification is also possible because of its variations in morphology.
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