Reptiles and Amphibians of Thailand

Thailand's Snakes, Lizards, Turtles, and Frogs

Black-banded Keelback

Rhabdophis nigrocinctus

This species is found in Thailand, but not within Bangkok itself
Green Black-banded Keelback Black-striped Rhabdophis nigrocinctus thailand khao yai
Black-banded Keelback in Khao Yai NP ( © Ross McGibbon)

English name: Black-banded Keelback (aka “Black-striped Keelback”, “Green Keelback”)
Scientific name: Rhabdophis nigrocinctus
Thai name: งูลายสาบเขียวขวั้นดำ (Ngu Lai-saab Khieo Kwan Dam)

Description: To 95cm long. A slender keelback with greenish front body turning grayish-brown in the back with narrow black crossbars. Head is gray to brown above, lighter on the sides, with distinct black streaks coming down off of the eye. Juveniles have a pink-to-orange blotch on top of the neck.

Relevant scale counts: 17-19 midbody scale rows, dorsal scales are keeled.

Similar Species: Red-necked Keelback has red coloration on the sides of the neck and has a less distinct checkered pattern rather than clear banding.
Speckle-bellied Keelback has a light-colored lip that continues into a chevron joining at the neck.
Blue-necked Keelback has blue coloration in the area of the neck and a prominent dorsal stripe.

Range: Eastern Myanmar, southern China, Thailand, Laos, Vietnam, and Cambodia.

Habitat: Mountain forest near streams and other damp areas from 600m to 1000m elevation.

Place in the ecosystem: Feeds on frogs and toads, likely fish and lizards as well. Would be eaten by larger snakes, monitors, and birds of prey.

Danger to humans: This is a venomous rear-fanged species. Though no specific danger to humans is known, other related species are dangerous and one should be careful around it.

Conservation status and threats: It is common in its habitat, but logging could be a threat to its continued existence in some places.

Interesting facts: The Black-banded Keelback is one of several closely related snakes (including the Red-necked Keelback and Orange-necked Keelback) which have poison-filled organs called “nuchal glands” in the skin of their neck. Incredibly, scientists have discovered that the poison in these glands is not manufactured by the snake, but actually comes from poison in the toads the snakes eat, which is somehow removed by the snake’s body and stored in the glands. When the snake is under attack, it exposes its neck to the attacker and the glands burst, spreading the toads’ poison over the surface of the skin and thereby making the snake both distasteful and potentially dangerous for the attacker.

References:
Snakes of North Thailand: Rhabdophis nigrocinctus, the Green Keelback
IUCN Red List: Black-banded Keelback
Evolution of nuchal glands, unusual defensive organs of Asian natricine snakes
A Field Guide to the Reptiles of South-East Asia

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