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Ocean Watch Susan Scott |
Sea snakes are gentle
and shy but venomous"Is the yellow-bellied sea snake the most poisonous in the world?" writes Connie, a third-grader from Everett, Wash.
No, and a good thing, because another reader wrote he recently spotted one while snorkeling off South Point on the Big Island. This visitor described the black-and-yellow "eel" he saw to a local friend who knew his marine life. The buddy thought the creature sounded like a yellow-bellied sea snake, but doubted it since sea snakes are so rare in Hawaii.
The friend was right on both counts. Sea snakes are rare in Hawaii, but once in a great while, a yellow-bellied beauty will drift here with a wayward current. This is the only kind of sea snake ever confirmed in Hawaiian waters.
The good news is that worldwide, only one human death has been attributed to the yellow-bellied sea snake.
Still, sea snakes are nothing to mess with, no matter what the species. Their venom contains some of the same chemicals found in cobra venom, only more concentrated. Yellow-bellied sea snakes may not be the most poisonous in the world, but their venom is more toxic than that of Mojave rattlesnakes and king cobras.
But even with 55 species of sea snakes, all venomous, inhabiting the Indian and Pacific Oceans (the Atlantic and Caribbean have no sea snakes), relatively few people suffer bites. That's because sea snakes are gentle, shy creatures that bite only to get a meal or defend their lives.
Sea snakes like warm, tropical waters, but when the water gets too warm, they swim down to cooler temperatures. Transmitters attached to yellow-bellied sea snakes show they can dive to about 150 feet and can stay underwater for more than three hours.
Like seabirds and sea turtles, sea snakes have special glands that collect extra salt from the creatures' blood. Snakes' salt glands lie beneath their tongues. Each time a sea snake flicks its tongue, it is ejecting salt back into the ocean.
Sea snakes eat mostly fish and swallow them whole. This explains why sea snake venoms are so deadly: The poison has to kill quickly. A thrashing fish could either escape or its sharp spines might poke a hole in the snake's stomach.
The yellow-bellied sea snake is the most widely distributed snake of any kind, land snakes included. That's because these snakes drift far out to sea, giving birth to live babies there.
A snake litter contains two to 20 babies, ranging in size from 4 to 9 inches long.
People commonly find yellow-bellied sea snakes in slicks, places where the wind and currents have pushed floating objects, such as seaweed and driftwood, together. There, hundreds, sometimes thousands of snakes gather, waiting for an unsuspecting fish to swim past.
In 1932, a man reported a slick more than 60 miles long containing millions of yellow-bellied sea snakes.
I live for the day I sail into a slick full of these beautiful yellow snakes. But even though I know they probably won't bite me, I don't think I'll go swimming there.
I for sure will never jump into a batch of beaked sea snakes. This species, which ranges from the Persian Gulf to South Asia, carries venom about 100 times as toxic as king cobra venom. One drop can kill three men.
Yellow-bellied sea snake poison is about one-fourth that strong. The beaked sea snake is by far the most poisonous snake in the world.
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Marine science writer Susan Scott can be reached at http://www.susanscott.net.