This mnemonic (red on yellow, kill a fellow; red on black, venom lack) is used to remember which colors usually differentiate a coral snake from a similarly colored but non-venomous snake. Although this snake bite injury is less common than rattlesnake bites, envenomation can occur with deleterious tissue sequelae.
There are three species of coral snake that are clinically important in the United States – Eastern coral snake (Micrurus fulvius fulvius), Texas coral snake (Micrurus fulvius tenere) and the Sonoran coral snake (Micrurus euryxanthus).
Coral snakes are marked by red, yellow, white, and black rings on their bodies with black mouth parts. They are small-bodied with non-triangular heads and they lack facial pits. They are generally non-aggressive and have relatively small fangs.
Red on yellow, kill a fellow. Red on black, venom lack.