Reptiles and Amphibians of Thailand

Thailand's Snakes, Lizards, Turtles, and Frogs

Blue-necked Keelback

Rhabdophis rhodomelas

This species is found in Thailand, but not within Bangkok itself
Blue-necked Keelback Blueneck Keelback Water Snake Rhabdophis rhodomelas Macropisthodon งูรังแหหลังศร
Blue-necked Keelback in peninsular Malaysia (© Orion Herp Adventure)

English name: Blue-necked Keelback (aka: “Blueneck Keelback”, “Blue-necked Water Snake”)
Scientific name: Rhabdophis rhodomelas (formerly Macropisthodon rhodomelas)
Thai name: งูรังแหหลังศร (Ngu Rang Hae Lang Sorn)

Description: To 75cm long. Orangish-brown to pinkish-brown with a dark brown or black dorsal stripe bordered by light dots. On the neck the dorsal stripe widens to a dark chevron on top while the sides of the neck are light blue. Indistinct barring can appear on the sides of the body.

Relevant scale counts: scales are strongly keeled and the dorsal row is significantly enlarged.

Similar Species: Red-necked Keelback only shows red coloration behind the head, not blue, and has a less distinct checkered pattern rather than a distinct dorsal stripe.
Speckle-bellied Keelback lacks blue coloration on the neck, has no dorsal stripe, and has a light-colored lip that continues into a chevron joining at the neck.
Orange-necked Keelback lacks blue coloration in the area of the neck and has distinct banding rather than a dorsal stripe.

Range: Indonesia, Singapore, Malaysia, and southern Thailand.

Habitat: Lowland forest near water bodies like streams, swamps, and flooded fields.

Place in the ecosystem: Feeds primarily on frogs and toads. Would be eaten by larger snakes, monitors, and wading birds.

Danger to humans: This is a venomous rear-fanged species that can have significant effects and should not be handled.

Conservation status and threats: No known threats exist, though it is not commonly encountered.

Interesting facts: R. Subaraj, a wildlife researcher in Singapore, was bitten by a 35cm long Blue-necked Keelback in the field and immediately his hand became numb and his head begin to throb. Within a minute of the bite he collapsed and began having difficulty breathing. Though major effects subsided within half an hour, through the next two days he continued to have a headache, slurred his speech and had difficulty completing sentences. Mr. Subaraj weighed around 120kg at the time, and the fact that such a small snake had serious impact on such a large person suggests that a smaller person could potentially suffer a worse fate, especially if bitten by a full-sized adult. Care should be taken around this species and it should not be handled.

References:
Ecology Asia: Blue-necked Keelback
IUCN Red List: Blue-necked Keelback
A personal account of envenomation by a Blue-necked Keelback

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