Stokes's Sea Snake

Stokes's sea snake is a large sea snake of the family Elapidae, sometimes placed in its own genus, Astrotia. The belly scales are enlarged to form a distinct keel, frequently broken into two wart-like tubercles. It is highly variable in colour, from cream to brown to black, often with broad black bands or rings (Wikipedia, general species account).

It is distributed from India, Pakistan and Sri Lanka to the South China Sea and the Strait of Taiwan. The snakes sometimes form migrating groups in the thousands, drifting in slicks a metre long in the Strait of Malacca. They give birth to live young, in small broods of five each mating season. The Reptile Database lists the coast of Kerala.