Mertensian mimicry in tri-colour snakes

    Coral snakes, including the Eastern Coral snake (Micrurus fulvius), are highly venomous, and have a distinctive red /  yellow / black colour pattern that serves as an aposematic (warning) signal to advertise this fact. Potential predators avoid snakes with this pattern. Other, non-venomous snakes, such as the Scarlet King Snake (Lampropeltis elapsoides), have evolved a similar red / black / yellow colour pattern. [NB: It is not obvious why the two species have evolved similar but not identical alternating patterns. The patterns may be constrained in development].

    Notes: Where the two species occur in sympatry in the southeastern United States, people use the rhyme "Red next to black, friends to Jack; Red next to yellow, kill a fellow." New teachers in rural schools are often tested with a king snake in their desks.

    Biology 101: Remember that coral snakes, rattlesnakes, and other snake species are venomous, meaning they deliver venom through their bites. They are not poisonous, meaning you can eat their flesh without danger. Rattlesnakes are venomous and not poisonous; not unexpectedly, they taste like chicken.  Fugu fish of the sushi trade are non-venomous but poisonous.