Distribution

Coastal waters of the Persian Gulf through India and Sri Lanka to Vietnam, southwards to Indonesia, Papua New Guinea and northern Australia. Also often found at river mouths and further upstream.

Biology

Wide area of distribution and high incidence. Prefers shallow water with sandy or muddy bottom. Narrow, elongated head, tapering at the front like a beak (→ "Beaked sea snake"). Sturdy body. Basic colouring of its dorsal side grey to grey-green, lighter towards the belly. Dark cross bands the entire length of the body. Length on average 1–1.2 m.

Enhydrina can open its jaws very wide, which allows it to swallow large prey (primarily catfish), but also to grip firmly when biting in defence. In contrast to most other sea snakes this species is fairly easily provoked and if truly disturbed will bite aggressively. According to reports from bite victims the snakes do not let go after biting and have to be literally pulled or shaken off.

Risk

The venom of Enhydrina is one of the most potent snake venoms. Although usually only a small amount of venom is injected during a defensive bite, or none at all, cases of severe envenoming are nonetheless not uncommon. The group at greatest risk from these snakes are fishermen, who may be bitten while emptying their nets or while laying nets in shallow water.

In northwest Malaysia, between 1957 and 1964, from a series of 81 identified sea snake bites, 55 were caused by E. schistosa. The 7 fatalities in this series were all due to E. schistosa (Reid 1975b).

Literature (biological)

Cogger 1975, 1987, 2000, Dunson 1975b, Gasperetti 1988, Heatwole 1975, Limpus  1975, 1987, Minton 1975, O'Shea 2005, Reid 1975b, Reid and Lim 1957, Sanders 2012