Elapidae is a family of venomous snakes characterized by their permanently erect fangs at the front of the mouth. Many members of this family are also recognized by their threat display of rearing upwards while spreading the neck-flap. Elapids are endemic to tropical and subtropical regions around the world, with terrestrial forms in Asia, Australia, Africa, and the Americas and marine forms in the Pacific and Indian Oceans. Members of the family have a wide range of sizes, from the 18 cm (7.1 in) white-lipped snake to the 5.85 m (19 ft 2 in) king cobra. Most species have neurotoxins in their venom which is channeled by their hollow fangs, while some may contain other toxic components in various proportions. The family includes 55 genera with some 360 species and over 170 subspecies.
Terrestrial elapids are found worldwide in tropical and subtropical regions, mostly in the Southern Hemisphere. Most prefer humid tropical environments, and so are not found in the Sahara or Middle East, although some can be found in Mexican and Australian deserts. Sea snakes occur mainly in the Indian Ocean and the south-west Pacific. They occupy coastal waters and shallows, and are common in coral reefs. However, the range of Hydrophis platurus extends across the Pacific to the coasts of Central and South America.