Two movies at the top of the U.S. box office charts, "Snitch" and "Identity Thief," involve people taking on false identities. Faking out predators and prey by mimicking another specie has been a plot line in nature for millions of years.
A dangerous example of look-alike animals is the copy-cat coloration of the harmless Mexican milk snake (Lampropeltis triangulum annulata, left) and highly venomous Texas coral snake (Micrurus tener, inset). The two species look similar, inhabit the same areas and even share a taste for dining on their fellow serpents. However, although the docile milk snakes are common pets, the coral snake is a relative of the cobras and injects a potent nerve venom, or neurotoxin, with its bite.
How can herpetologist avoid a deadly case of mistaken identity? Both snakes have a combination of red, black and yellow bands, but in a different order. The rhyme, "Red next to yellow, kill a fellow...red next to black, poison lack," accurately describes the difference in coloration and danger of the two species.
Predators don't have humans' skill at remembering life-saving rhymes, so they tend to avoid both reptiles. This type of mimicry, called Batesian, allows a harmless species to bluff their way to survival. The odd thing is, in this case, how could a predator ever learn to avoid red, black and yellow banded serpents if the coral snakes killed any predator that tried to make a meal of them?
Evolution may have embedded the fear of coral snakes in some predators. An experiment published in Science found that some birds will instinctively avoid red-and-yellow ring patterns, although they will readily attack red-and-yellow stripes or green-and-blue rings. Birds aren't the only animals leery of serpents. Primates, including humans, seem to have evolved an ability to rapidly develop a fear response to snakes, according to numerous studies. However, these instinctual fears can be overcome by conditioning or, in the case of humans, education.