Enhydrina schistosa

Environment and physical characteristics:

The beaked sea snake is responsible for the bad name of the other 31 known species of sea snakes. It is responsible for more than half of all sea snake bites against humans and 90% of fatal attacks. It can be found in shallow waters from the Persian Gulf to the northern coast of Australia, and especially likes to hang out at the mouths of strong rivers. It is one of the larger kinds of sea snake; males are about 1.2 meters long and females about 1.5 or more. Some are colored an even pale grey-green, while others have alternating dark grey rings. Its head curves down at the snout, which along the way caused someone to think of a beak; thus it acquired its present name. Its nostrils are essentially at the top of the head, allowing the snake to come up for air while exposing as little flesh as possible to airborne predators. When underwater, the nostrils' shut-off valves prevent water from leaking through. In body shape, the only significant difference between any sea snake and their landlubber cousins is that the sea snake's tail tapers out into a powerful paddle shape, allowing it to re-adapt to life underwater.


Most sea snakes have a diet heavy on eels, since their mouths are often too small to get completely around bigger fish, and it would be a waste of energy to chase the small ones all day. This leaves plenty of fish, especially those with wider heads, for the beaked sea snake, which is better able to accommodate them. He will swim slowly along the ocean floor, enshrouded in mud drifts, and wait for a catfish, puffer fish or some other prey deserving of his attentions. When one approaches overhead, he will seize it from the side and immediately paralyze it. Once lunch is limp, he turns his head into the current, and the onrushing stream of water helps him get the whole meal down, often tail-first. A salt gland on the floor of his mouth will help insure that he does not ingest too much sodium.


Beaked sea snakes will come together in large numbers during breeding season, often in shallow water, and this is also when they are most dangerous. Females will lay their eggs on the shore, and produce an average of about 10-30 live young apiece. Newborns stay in shallow water for several months, then head out to sea.


Although the beaked sea snake is the most deadly of sea snakes, with an LD50 of 0.14 milligrams per kilogram it is not the most venomous. (That honor goes to the olive sea snake, whose LD50 is 0.04 mg/kg). However, it is widely recognized that it is the most easily upset, and it moves across land much easier than other sea snake species. Most of the deaths from sea snake bites occur among fishermen in southeast Asia, where access to antivenom is scanty or nonexistent, and where the snakes are trapped by some groups for their skins. If you get a live one in your net, and it hasn't wasted all of its venom chewing through the rope, a single fully loaded bite could kill 52 grown men.

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