The small-headed sea snake (Hydrophis macdowelli), also known commonly as McDowell's sea snake, is a species of venomous snake in the subfamily Hydrophiinae of the family Elapidae. The species is native to waters off northern Australia.
The specific name, macdowelli, is in honor of American herpetologist Samuel Booker McDowell Jr.
Hydrophis macdowelli is found along the northern coast of Australia, the south central coast of Papua New Guinea, the Loyalty Islands, and New Caledonia.
The preferred natural habitat of Hydrophis macdowelli is shallow ocean waters with sandy bottoms, at depths of not more than .
As one of its common names implies, Hydrophis macdowelli has a small head in relation to its body size. The species grows to a total length (tail included) of up to 1 metre (39 inches).
Hydrophis macdowelli preys upon eels and other elongate fishes.
Hydrophis macdowelli is ovoviviparous. Litter size is 2âÂÂ3 young.
Hydrophis macdowelli possesses a powerful venom, and its bite is dangerous to humans.