Sea snakes are very poisonous cousins of the cobras and are well adapted for swimming and living in the water. Many of the 70 or so kinds of sea snakes are very brightly colored. This is believed to be a warning color pattern, like the stripes on a skunk, so other animals can know to avoid them. Sea snakes tend to be flattened from side to side for swimming. In fact, their muscles are so specialized for swimming that it is difficult for these snakes to move on land. Many seafaring people have learned that these flabby snakes cannot curl upward to bite if held by the tail. Sea snakes are usually quite tame and will rarely strike out at humans.
Sea snakes mainly eat fish. Divers frequently see sea snakes looking into crevices, cracks, and holes in the reef, searching for fish. Some sea snakes have bodies with thin heads so that they better fit into the burrows of eels and other slender fish. One kind of sea snake eats only fish eggs. Since they must drink salty sea water to live, they also have a salt gland next to their tongue. The gland helps them get rid of the extra salt taken in when they drink.
Most sea snakes give birth to living young. The pregnant females often come into rocky areas or mangrove forests to give birth. These areas provide protection for the young until they can fend for themselves. A few sea snakes go into rocky areas to lay eggs.