Sea snakes are marine elapids comprising two main groups: the true sea snakes (Hydrophiinae, mostlyfully marine and viviparous) and the sea kraits (Laticaudinae, typically oviparous and coming ashore to nest). Both possess neurotoxic venom, yet most species are non‑aggressive in natural encounters.
Ecology & Biology
Respiration & osmoregulation: an elongated single lung, valved nostrils, limited cutaneous gas exchange and a functional salt gland for life in seawater.
Reproduction: viviparity in most Hydrophiinae; oviparity in Laticauda which must come ashore to lay eggs.
Diet: primarily fishes and eels, with some crustaceans/cephalopods; ambush or active foraging.
Behaviour: common on reefs, lagoons and continental shelves, with pelagic specialists (e.g., yellow‑bellied sea snake).
Identification
Tail: strongly laterally compressed, paddle‑shaped.
Scalation/colour: smooth to weakly keeled; many species show black‑and‑pale banding.
Head: small, flattened; valved nostrils; rear‑facing fangs typical of elapids.
Size & Longevity
Length: typically 60–150 cm, up to ~200 cm in large species.
Life: generally several to 10+ years, species‑dependent.
Range & Habitat
Centred on the Indian and western Pacific from tropical to subtropical waters—reefs, seagrass beds, bays and open‑ocean surface zones. Some pelagic species extend into the eastern Pacific to the Americas.
Conservation & Threats
Threats: fisheries bycatch, degradation of reefs/seagrass, pollution and plastics, and extreme ocean‑warming events.
Measures: gear modifications and safe release, key‑habitat protection, debris reduction and public awareness.
IUCN: this is a group‑level overview spanning multiple genera; statuses range widely (LC–EN). Marked here as Not Evaluated (NE).
