Eyed Cat Snake ( Boiga siamensis Nutaphand, 1971 )

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Scientific Name: 
Boiga siamensis (Nutaphand, 1971)
Regional Names: 
Thai Cat Snake, Gray Cat Snake
Found in almost whole of North-east region from North Bengal. Also found in Bangladesh, Bhutan, Cambodia, Malaysia, Myanmar, Thailand and Vietnam.
Venom Type: 
Characteristics for identification: 

Morphologically it can be identified by checking grayish-brown (in adults) or reddish-orange (in juveniles) dorsal body marked with dark patterns on top and white patches on side dorsals touching belly.


Average length- 100cm.
Maximum length- 170cm.

Dorsal -
Long body of moderate thickness laterally flattened body. Scales smooth and long in shape; top dorsal scales along vertebra larger than adjacent scales. Dorsal color distinct in two life states. Adults: Neck and start of mid-body yellowish-brown with series of oblique or V shaped markings on top; rest of dorsal body grayish-brown with light and dark spots or cross-bands, gradually becoming faint on posterior side. Juveniles: Color bright reddish-brown or orange with patterns similar in adults. Regular white color patches found on side dorsal touching belly in all life stages.

Ventral -
Belly color grayish-brown in adults while reddish-brown in juveniles which have a demarcating boundary with dorsals by having series of white spots and darker color between them. Subcaudal scales paired in zig-zag manner.

Head -
Head triangular with blunt snout and rounded edges of jaws; clearly broader than neck. Top of the head patternless with color similar to dorsal in respective life stages. A thick postocular streak of black color found from eye to angle of head. Two parallel streaks of same color run transversally on neck. Upper lip yellow to white depending upon life stage, usually yellowish-white or light brown in adults and bright yellow in juveniles. Eyes brown in adults or reddish-orange in juveniles with vertical pupil.

Tail -
Long and thin tail typically like other tree snakes with a pointed tip. Dorsal body patterns found usually in faint form.

Supralabial 8; 3rd to 5th in contact with eyes; loreal 1; preocular 1; reaches to upper surface of head but not in contact with frontal; postocular 2; anterior temporal 2.
Smooth scales in 23: 23: 15 rows. Vertebral distinctly larger than adjacent scales.
247-270; anal undivided.
Sub Caudal: 
116-129; paired.
Widely distributed in many kind of forests including mixed, moist deciduous forest, rainforest etc. Lives in low to to high elevations of North-east region and eastwards countries of Asia. Choose tree holes, low to moderately high vegetation, dense bushes etc. for roosting and hiding.
Natural History: 
Thai Cat Snake is a nocturnal and arboreal species. Prefers low heights and sometimes seen during evening time also. Behavior elusive, shy and usually non-offensive. On threatening it throws much of forebody into loops with inflates or puffs and open mouth, often hisses. Juveniles are found to be more nervous than adults and often go aggressive on disturbance. Oviparous. Female lays eggs during summer months in tree holes, cracks at heights etc.
Feeds on lizards, rodents, birds, frogs, eggs, other snakes etc.
In India direct threats are killing due to confusion with venomous snake like Pit Vipers and road kills. Population of this species is depends on protection of dense forest of North-east region.
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