Coral snake

Coral snakes are a large group of elapid snakes that can be subdivided into two distinct groups, Old World coral snakes and New World coral snakes. There are 16 species of Old World coral snake in three genera (Calliophis, Hemibungarus and Sinomicrurus), and over 65 recognized species of New World coral snakes in three genera (Leptomicrurus, Micruroides, and Micrurus). Genetic studies have found that the most basal lineages are Asian, indicating that the group originated in the Old World.

North American coloration patterns

Coral snakes in North America are most notable for their red, yellow/white, and black colored banding. (However, several nonvenomous species have similar coloration, including the scarlet snake, genus Cemophora; some of the kingsnakes and milk snakes, genus Lampropeltis; and the shovelnose snakes, genus Chionactis.) In some regions, the order of the bands distinguishes between the non-venomous mimics and the venomous coral snakes, giving rise to quite a few mnemonics along the lines of "Red and yellow, kill a fellow. Red and black, venom lack." Another helpful mnemonic, is "Yellow, Red, Stop!" referencing the order of traffic lights. In any case, remembering that yellow touches both other colors can indicate a cause for caution. However, this reliably applies only to coral snakes native to North America: Micrurus fulvius (Eastern or common coral snake), Micrurus tener (Texas coral snake), and Micruroides euryxanthus (Arizona coral snake), found in the southern and western United States. Coral snakes found in other parts of the world can have distinctly different patterns, have red bands touching black bands, have only pink and blue banding, or have no banding at all.