English name: Bocourt’s Water Snake
Scientific name: Subsessor bocourti (formerly Enhydris bocourti)
Thai name: Ngu Zi, Ngu Leuam-ao
Description: To 110cm long. The largest, most robust of the water snakes in Thailand. Head is large and blunt. The smooth-scaled body has large brown blotches/bands with black borders that narrow on the sides, with yellow bands in-between that broaden correspondingly. Brown areas sometimes have thin tan-to-orange line in the center. Both the light and dark coloration becomes more indistinct as the snake ages. Head is reddish-brown with a cream upper lip and red eyes. Underbelly is yellowish-white.
Similar Species: Jack’s Water Snake has keeled dorsal scales, is usually not as robust, is lighter in color, and has a distinct dark face mask.
Jagor’s Water Snake has simple dark blotches rather than the more extensive dark pattern.
Habitat: Found in swamps, ponds, shallow lakes, rice fields, and other stagnant waters in lowlands. Is highly aquatic and usually stays near water, but will travel over land during rainy nights. Conceals itself among logs in or near water during the day.
Place in the ecosystem: Eats fish and frogs. Is eaten by larger snakes, large fish, monitors, and wading birds.
Danger to humans: Though Bocourt’s Water Snake is a rear-fanged species its venom is not a threat to human. It is not aggressive, but if restrained its large size and sharp teeth allow it to give a nasty, painful bite.
Conservation status and threats: There are no known serious threats to its Thai populations. However, Bocourt’s Water Snake is harvested for its meat and skins in several countries. In Cambodia’s Tonle Sap Lake, extended overharvest has led to the species being rarely found and it now comprises only a small proportion of the annual snake catch. There have also been declines due to overharvest in Vietnam. Much of the hunting of snakes in both countries has been constrained, but enforcement is minimal and there are concerns that many snake populations are collapsing.
In some areas Bocourt’s Water Snake has begun to be farmed in large numbers, which could relieve pressure on wild populations.
Interesting facts: Like many water snakes, Bocourt’s Water Snake releases a foul-smelling musk and feces when handled.
IUCN Redlist: Enhydris bocourti
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