Creature Feature: Banded Sea Krait

The banded sea krait is an amphibious species of snake, closely related to the Asian cobra, that spends most of its life at sea but comes to land to digest its food, shed its skin, and to reproduce (able to spend up to 10 days at a time on land). Sea kraits are often spotted along the coasts of the eastern Indian Ocean, east through Malaysia, Indonesia and Papua New Guinea to islands of the south-western Pacific, and north to Vietnam, southern China, Taiwan, and the Ryuku Islands, Japan. Occasionally you may see them in the waters off Australia and New Zealand, or as far as the western coast of Central America. The banded sea krait is usually found hunting for food in shallow tropical waters surrounding coral islands, coral reefs and mangroves, to depths of around thirty feet (but some species may dive up to 100 feet). Some species prefer hard bottoms (corals), while others prefer soft bottoms (mud or sand) in which to hunt their prey. Most sea snakes feed upon fishes of various sizes and shapes, including eels.

The sea krait's body has evolved to adapt to its curious semi-aquatic lifestyle. Like its brothers the terrestrial snake, it has larger scales on its underbelly and a cylindrical body shape to aid in climbing onto land and in low trees, but its tail is paddle-shaped to help it speed through the water. With valved nostrils to keep out saltwater while diving, the sea krait has a large lung capacity so that it may stay under for extended periods of time, and glands under its tongue that expel excess salt. The head looks similar to the tail in order to confuse predators and draw them to attack the tail which is less likely to inflict fatal injuries.

On land, the sea krait finds shelter in vegetation, under beach rocks, in caves and crevices. It is in these limestone caves and crevices where they go to lay their eggs; generally a deposit of 1 to 10 eggs. Males come ashore early in the evening and eagerly await the arrival of a female at the high tide waterline. Upon her arrival, several males will wind themselves around the female and escort her to shore. The female can be distinguished as being heavier and around a third longer in body size than the male. A sea krait's average length can range from 3 to 4.5 feet.

Although their venom is the most potent of all snakes, human fatalities are rare because sea snakes are not aggressive, their venom output is small, and their fangs are very short. The longest living sea krait in captivity on record lived to be seven years old.

[1] ARKive: Images of Life on Earth, http://www.arkive.org/banded-sea-krait/laticauda-colubrina/

[2] Britannica Online Encyclopedia, http://www.britannica.com/EBchecked/topic/530726/sea-snake