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.
HOMEWORK:
Identify a species that is both venomous AND poisonous.