Belcher’s Sea Snake

1 Overview

Belcher’s sea snake (Hydrophis belcheri) is considered the most toxic snake known – far more toxic than land snakes. It lives mainly in the Indian Ocean.

SOURCE NOTE: family is Elapidae (sea snake subfamily Hydrophiinae). Despite extreme toxicity it is notably docile and bites only when strongly provoked (often when fishermen pull nets). Its small fangs deliver little venom, so it is not considered highly dangerous in practice – but still handle with care.

2 Appearance

The most toxic snake known, many times more toxic than land snakes. Sea snakes are fully marine venomous snakes; nostrils upward with closeable valves, can close and dive 10 min; scales over thick skin prevent seawater entry and water loss; a salt gland under the tongue expels excess salt. Small ones about 0.5 m, large about 3 m; live in coastal shallows, especially brackish river mouths, eating fish. Body like land snakes but with a laterally flattened oar-like tail; head usually oval (not triangular) like non-venomous land snakes.

3 Conservation & Aquaculture

Sea-snake venom is valuable (medicine, food, industry). Belcher’s is the most toxic but docile; bites usually occur when fishermen handle nets. Because fangs are weak and venom yield low, it is not rated highly dangerous – but still be careful. Sea-snake farming or aquaculture is underdeveloped; scaling it up could be lucrative.

4 Distribution & Environment

Common in the Indian Ocean; also Philippines, New Guinea, Thailand coast, Australian islands, Solomon Islands; especially Ashmore and Cartier Islands in the Timor Sea. A bite is often painless, sometimes no swelling; symptoms start mild but worsen – slight anxiety, dizziness, light ‘drunk’ floaty feeling, tongue swelling causing difficulty swallowing, muscle weakness progressing to paralysis.

5 Diet & Feeding

Most live off north-west Australia’s Ashmore Islands; observed eating fish. Docile, preferring shallow water around shelves and islands, rare in open water deeper than 100 m. Some like sandy or muddy turbid water, others clear water around coral reefs. Sea-snake farming or aquaculture is underdeveloped; scaling it up could be lucrative.