Yellow sea snake (Hydrophis spiralis)
The longest of the true sea snakes (Hydrophiids), the yellow sea snake (Hydrophis spiralis) has a striking yellow or yellowish-green body, boldly marked with 30 to 60 narrow, black rings. The head is also yellow in adults, but in young individuals it is blackish with a distinctive yellow, horseshoe-shaped mark on the top. The jaws bear small, fixed, tubular fangs, which are used to administer powerful venom.
Like most sea snakes, the tail of this species is flattened and paddle-like, helping to propel the snake through the water. Other adaptations for living in water include nostrils placed on the top of the snout, so that breathing can take place without exposing the body to aerial predators. The nostrils are also valved, and close when this species is submerged.