Large-Headed Sea Snake

The large-headed sea snake, also called the bighead sea snake, is a marine elapid noted for its relatively large, wide head compared to its body, a feature reflected in its common name. It occurs in coastal waters of the Gulf of Thailand and adjacent parts of Southeast Asia.

Like other Hydrophis species, it is fully aquatic and rarely encountered on land, relying on its neurotoxic venom to capture prey and a paddle-shaped tail for propulsion through the water column.

• Distinctly broad, large head relative to a moderately stout body
• Pale grey to olive-brown coloration with dark crossbands or blotches along the length of the body
• Bands may break into blotches or spots toward the belly
• Smooth body scales arranged in overlapping rows
• Laterally compressed, oar-like tail typical of sea snakes
• Adults generally reach 0.7-1.1 m in length

Found in shallow, muddy coastal waters, often near river mouths and estuaries in the Gulf of Thailand and parts of the South China Sea. Prefers soft-bottomed habitats where it can forage among sediment for bottom-dwelling prey, typically in waters less than 30-40 m deep.

Forages primarily along the seabed for small fish, using its broad head and jaws to seize prey before subduing it with venom. Activity patterns include both diurnal and nocturnal foraging depending on local conditions. Reproduction is ovoviviparous, with live young born in the water.