Sea snakes are venomous snakes that, as their name implies, spend all or most of their lives in the water.
Almost all sea snakes reside in marine or brackish environments.
Some occasionally swim up rivers for several miles and two species are found exclusively in fresh-water lakes (one in the Philippines and the other in the Solomon Islands).
Sea snakes are found in warm tropical waters of the Indian Ocean and the western Pacific.
They are common in the Persian Gulf, but rare in the Red Sea.
While sometimes found on the west coast of the Americas between Mexico and Peru, they do not inhabit the Atlantic Ocean.
Sea snakes are so adapted to their aquatic environment that most are unable to move on land.
They lack gills, but their lungs can extend for almost their entire body length, allowing them to remain submerged for up to four hours.
Adults generally grow to between four and five feet in length, but one species, found from Australia to Southeast Asia, can reach almost ten feet.
Almost all sea snakes are ovoviviparous, with the female giving birth to live young.
Most sea snakes feed on fish.
Their venom is extremely potent, immobilizing or killing their prey shortly after biting.
Humans, though, are not at high risk.
First, sea snakes are not generally aggressive and seldom bite anything other than a potential food source unless provoked.
Secondly, the fangs of most sea snakes are small and can penetrate the human body only with difficulty.
It is thus rare for much venom to be injected into a human.
Native fishermen frequently find sea snakes in their nets.
They grab the snakes with their bare hands and throw them back into the sea.
This practice is not recommended, but does illustrate the point.