How to Identify the Hook-Nosed Sea Snake (Identification Guide)
The Hook-Nosed Sea Snake is identified by its distinctive upturned, hooked snout, banded pattern, and small, slender marine body.
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Key identifying features
The Hook-Nosed Sea Snake (Enhydrina schistosa) gets its common name from its most obvious field mark: an upward-curving, hook-like projection on the tip of the snout. This unique rostral shape, combined with a relatively small head and banded body pattern, makes it identifiable among sea snakes found in coastal and estuarine waters of the Indo-Pacific.
Coloration & pattern
The body is typically pale gray, olive, or yellowish-white with a series of darker gray-brown or blackish crossbands running the length of the body. These bands are often more distinct toward the tail and may become faint or broken on the forebody, giving mature individuals a somewhat mottled appearance. The belly is usually paler than the back.
Head, eyes & scales
The head is small and only slightly distinct from the neck. The hooked snout is the standout feature, formed by an enlarged, upturned rostral scale. Eyes are small with round pupils, typical of sea snakes. Body scales are keeled rather than smooth in adults, giving the skin a somewhat rough texture compared to smoother-scaled sea snake species.
Size & body shape
This species has a moderately stout body for a sea snake, though it is generally smaller than large reef species, with adults typically reaching 0.5 to 1.2 meters. The tail is flattened into a paddle shape for swimming, while the forebody is comparatively slender, giving the snake a tapered profile from a thicker middle to a narrower head and tail.
Range & habitat where you'll see it
The Hook-Nosed Sea Snake favors turbid coastal waters, river mouths, and estuaries throughout South and Southeast Asia, extending to northern Australia. Unlike reef-associated sea snakes, it tolerates murky, muddy-bottomed habitats and brackish water, often found near river deltas and shallow bays rather than clear coral reefs.
How to tell it apart from look-alikes
The upturned hook-shaped snout is unique among common sea snakes and is the single most reliable identifying feature. Its banded gray-and-dark pattern combined with keeled scales also helps separate it from smoother, plain-colored species like the Olive Sea Snake. Its preference for murky estuarine water rather than clear reef habitat is another useful clue when comparing habitat overlap with other sea snakes.
Frequently asked questions
What is the main identifying feature of the Hook-Nosed Sea Snake?
An upward-curving, hook-shaped projection at the tip of the snout, unlike the rounded snouts of most sea snakes.
What habitat does this snake prefer?
Murky coastal waters, estuaries, and river mouths rather than clear coral reefs.
Are the scales smooth or rough?
The body scales are keeled, giving the skin a rougher texture than smooth-scaled sea snakes.
What color pattern does it have?
Pale gray to olive with darker crossbands, more distinct toward the tail.
How big does the Hook-Nosed Sea Snake get?
Typically 0.5 to 1.2 meters, smaller on average than large reef-dwelling sea snakes.