any of three species of highly venomous snakes (snake) (family Elapidae (elapid)) found from Australia to the southern edge of New Guinea. Taipans range in colour from beige to gray and pale brown to dark brown. Some taipans also experience seasonal colour changes. The coastal taipan (O. scutellatus) is the largest Australian elapid. Its maximum length is 2.9 metres (9.5 feet); however, most range between 1.8 and 2.4 metres (6 and 8 feet) in length. The fierce snake or inland taipan (O. microlepidotus) is smaller and can grow up to 1.7 metres (5.5 feet) in length. A third species, O. temporalis, was discovered in the central mountain ranges of Western Australia in 2006; its life history and habits await more detailed study.

O. scutellatus and O. microlepidotus are mainly rodent eaters and are moderately common in sugarcane plantations or other areas harbouring large populations of rats (rat) and mice (mouse). Taipans are also egg layers. During the breeding season, O. scutellatus deposits clutches of between 7 and 17 eggs, whereas O. microlepidotus lays between 12 and 20 eggs.

Taipans are quick to defend themselves if disturbed. Their venom is very potent and usually injected in amounts sufficient to kill a human within hours if medical treatment is not available. The venom of O. microlepidotus is widely known as the most toxic of any terrestrial snake in the world.