Elapidae Family of Sea Snakes

Yellow-bellied Sea Snake, Hydrophis platurus. A representative of the Elapidae Family of Sea Snakes.

Phylogeny: Sea Snakes are members of the Elapidae Family of reptiles. There are fifty species of Sea Snake in this Family, divided into two sub-families – Hydrophiinae or True Sea Snakes, and Laticaudinae or Amphioxus Sea Snakes. Very familiar snakes such as adders, cobras, coral snakes and mambas are included in this Family. Amphioxus Sea Snakes are more primitive and to come ashore to mate. True Sea Snakes spend their entire lives at sea. They are in the Class Reptilia and the Order Squamata.

Distribution:  The Elapidae are found in tropical and subtropical waters of the Indian and Pacific Oceans with the great majority being found in the Indian Ocean and Western Pacific Ocean. Only one species is found along Mexico’s Pacific Coast. Sea Snakes spend the majority of their lives in shallow water, but can be found at depths up to 100 m (328 feet).

Morphology:  The Elapidae are elongated and legless characterized by having short, fixed, fangs in the front of the upper jaw. These fangs may be weak and break easily, but these animals offset this weakness by being very venomous. Elapids may be aquatic, arboreal or terrestrial. Sea Snakes have vertically flattened tails, valve-like flaps covering their nostrils, and skin that allows for the exchange of gases while underwater. Sea Snakes reach a maximum body length of around 2 m (6 feet 6 inches).

Ecosystem Roles:  Elapidae are carnivorous feeding primarily on fish and fish eggs. In turn they are preyed upon by sea birds, sharks, and other large fish. Some species of Sea Snakes have light sensing skin on their tails to help protect these important tails from predation.

Caution! All Sea Snakes are venomous. Their initial bite is not particularly painful, and it may appear as pinpricks. Within a few hours of envenomation dizziness, muscle pain, muscle spasms, paralysis and vomiting may occur. Within  three  to six hours the involved muscle fibers will break down and release their contents into the blood stream, often leading to reduced kidney function. Approximately 3% of Sea Snake bites are fatal and such bites should be taken seriously.