At least 32 species of sea snake have been recorded in northern Australian waters and some species are also found in the southern waters off Victoria, Tasmania and South Australia. Sea snakes are readily identified by their flattened tails and valvular nostrils. They are, of course, excellent swimmers and divers, feeding on fish and eels. They shed their skins much more frequently than land snakes, as often as every two weeks. The young are born alive at sea, except for those of the banded sea krait (Laticauda colubrina), which comes ashore to lay its eggs. All sea snakes are venomous.