Material Examined : 9 adults.

Description & Scalation : A large cat snake. Body long, compressed. Head distinctly broader than neck. Eye large, with vertical pupil. Rostral twice as high as wide, curved at base, hardly visible from above; internasals much shorter than the prefrontals; 1 loreal; 1 preocular just reaches upper surface of the head, not touching the frontal, ( in few specimens 1 presubocular is present ); 2 postoculars; temporals 3+3 or 2+2 or 3+2. [ Scales smooth, in 31, 29 or 27:21, 19 or 15:17, 15 or 13 oblique rows, as per Das, 1997 ], [ I have examined 9 adults, they are in 23 or 21:21:15 rows ]. Vertebral scales distinctly enlarged; supralabials 8 ( 3rd to 5th or 4th to 6th in contact with the eye ); infralabials 10, first 5 or 6 touching the first pair of genials; ventrals 225–235, strongly angulate laterally; subcaudals 77-107, paired; tail long; anal entire.

Coloration : Yellowish-brown above, each scale with black or dark brown uneven spots, or some scales edged with black, underside uniform bright yellow, with small black spots. Lip scales yellow, head shields blackish or brown, infused with dull yellow. No black stripe behind eye. Juveniles uniform yellowish-brown above, paler below.

Natural History : Nocturnal and terrestrial in habits. Though Cat snakes are arboreal in habits, none was observed on bushes or trees. I have always found them on ground near fresh-water bodies in forested areas. Many individuals were sighted while catching frogs on a hill-top forest, coiled on rocks or small branches, approx 60/70cm over & above water accumulated along road sides. These small pools were full of frogs; this snake was also observed in lowland pandanus swamp. 9 specimens were observed within a span of 2 hrs at around 2100 hrs while crossing the road, with many having missing tail tips. This species occurs in the same geographical areas, where Xenocrophis trianguligerus ( Triangle-spotted Keelback ) occurs. Mainly appears to feed on frogs, according to Nicobarese it enters their huts for chicken eggs. A rear-fanged snake. A man bitten by this species on his leg claimed of large swelling lasting for two days, in other instances, I met one local with an amputated thumb and another had to ampute his leg from below the ankle, due to bite by this species. Not much known about its breeding biology. Grows up to 1.4m.

Distribution - India : Endemic to Southern Nicobar Group of Islands, ( Great Nicobar, Little Nicobar and Pilo Milo Islands. )

External link : http://reptile-database.reptarium.cz/species?genus=Boiga&species=wallachi