Hydrophiinae

Hydrophiinae is a subfamily of venomous snakes within the family Elapidae. In many taxonomic treatments it includes the majority of sea snakes and, depending on the authority, the sea kraits of the genus Laticauda; some classifications place Laticauda in its own subfamily Laticaudinae. The group is distributed in warm tropical and subtropical waters of the Indian and Pacific Oceans, from coastal areas and coral reefs to open seas. Laticauda species are amphibious and return to land to lay eggs, whereas most other Hydrophiinae are highly adapted to a marine lifestyle and give birth to live young at sea.

Morphology and adaptations common to Hydrophiinae include slender, dorsally compressed bodies and broad, paddle-like tails that aid in swimming. They possess relatively large lungs that extend well along the body, enabling prolonged dives. Their nostrils, eyes, and sensory systems reflect adaptations to aquatic life. Venom apparatus is well developed, with fangs capable of delivering potent venom.

Ecology and diet focus mainly on fish and eels. Most species hunt underwater, using their venom to immobilize prey before consumption. Reproduction is variable within the subfamily: many sea snakes are ovoviviparous or viviparous, giving birth to live young at sea, while Laticauda sea kraits lay eggs on land.

Venom is highly potent and primarily serves prey capture; envenomation of humans can be dangerous, though encounters are relatively uncommon and outcomes depend on species and bite circumstances. Antivenoms are available for some sea snake bites.

Conservation status varies among species. Habitat degradation, coastal development, pollution, and bycatch in fisheries threaten several Hydrophiinae species, while others remain widespread or data deficient. Taxonomic arrangements continue to evolve with molecular studies, shaping how the subfamily is circumscribed across different authorities.