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Marine Animal Encyclopedia

Turtle-headed Sea Snake Emydocephalus annulatus

This Australasian sea snake is highly notable for its color variation, and also for its highly specialized lifestyle as a predator of fish eggs. The color it most commonly takes is a plain blue-gray, which is found throughout its range. A striking ringed form lives in some parts of the Great Barrier Reef, while a rarer, dark or melanistic form is found on isolated reefs farther east in the Coral Sea. The turtle-headed sea snake moves slowly among living corals, methodically searching for egg masses either glued to the coral’s branches or laid directly on the coral sand. When it finds an egg mass, it scrapes the eggs off with an enlarged scale on its upper jaw, which works like a blade. In most cases, parent fish leave the eggs unguarded, so the snakes can feed unhindered, but some species— such as damselfish—guard their eggs aggressively and try to keep the snakes away.


Little is known about this snake’s reproductive habits, apart from the fact that the females give birth to live young. In keeping with their lifestyle, turtle-headed sea snakes have tiny fangs (less than in [1 mm] long) and they rarely try to bite. Their venom is one of the weakest of any sea snake, and instead of striking back at predators, they react to danger by disappearing into crevices in the reef.

Turtle-headed Sea Snakezoom image
  • Order Squamata
  • Length 2–4 ft (60–120 cm)
  • Weight Up to 3 lb (1.5 kg)
  • Habitat Coral reefs and coral sand banks
  • Distribution Indian Ocean and Pacific, from northern Australia to Fiji
Turtle-headed Sea Snake Habitat Mapzoom image