Reptiles and Amphibians of Thailand

Thailand's Snakes, Lizards, Turtles, and Frogs

Blue Bronzeback

Dendrelaphis cyanochloris

This snake is found in Thailand but not in Bangkok
Blue Bronzeback Wall's Bronzeback Dendrelaphis cyanochloris งูสายม่านฟ้าเขียว thailand khao sok
Blue Bronzeback in Khao Sok National Park (Thai National Parks / CC BY-SA)

English name: Blue Bronzeback (aka: “Wall’s Bronzeback”)
Scientific name: Dendrelaphis cyanochloris
Thai name: งูสายม่านฟ้าเขียว (Ngu Sai Man Fa Kiao)

Description: To 140cm long. An extremely slender snake with a narrow neck which enlarges as a threat display. Body is bronze with blue or greenish-blue skin between the scales which show brilliantly when enlarged. Head is copper with a black eyestripe that continues well onto the neck. Eye is moderate is size. Belly is yellowish towards the front becoming pale green further back.

Relevant scale counts: 15 rows of midbody scales with enlarged vertebral scales. First sublabial touches more than two infralabials. 189-206 ventrals and 137-156 subcaudals.

Similar Species: Elegant Bronzeback has three black stripes on the back third of the body and an extremely large eye.
Kopstein’s Bronzeback has a reddish neck (most visible when inflated) and a narrower black eyestripe which ends at the jaw.
Nganson Bronzeback is more robust, drab in color below, and has brown mottling on the body.
Sawtooth-necked Bronzeback has black saw-tooth pattern on the neck.
Banded Bronzeback has a yellowish neck (most visible when inflated) and a short eyestripe that transitions to black oblique bars on the neck
Painted Bronzeback has distinct white stripe on its bottom flank.

Range: From northeast India through southeast Asia to Singapore.

Habitat: Forests and agricultural areas.

Contribution to the ecosystem: Feeds on lizards, birds, and frogs. Eaten by birds of prey and larger snakes.

Danger to humans: This species is not dangerous to humans.

Conservation status and threats: No known conservation issues.

Interesting facts: The “blue” in the Blue Bronzeback’s name comes due to a combination of the color of the edges of its scales and the color of its skin. Most bronzebacks when threatened will expand their narrow necks, causing the skin between the scales to show. This brightly-colored skin (blue in most species, yellow or red in some) may serve as a warning to the predator, either leading it to assume the snake is more dangerous or threatening than it had appeared, or simply surprising it such that its plan to attack the snake is interrupted. While many bronzebacks display this blue color when threatened, it is especially brilliant in the Blue Bronzeback and often shows to a degree even under normal conditions.

References:
Ecology Asia: Blue Bronzeback
Dendrelaphis cyanochloris, the Blue Bronzeback
Thai National Parks: Wall’s Bronzeback
A new species of Dendrelaphis from Southeast Asia
A new species of Dendrelaphis from Java, Indonesia
A Field Guide to the Reptiles of South-East Asia

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