Harmless Caterpillar Mimics Menacing Snake Head to Fool Predators

By Sumitra on June 12th, 2015 Category: Animals

Meet the Dynastor darius darius, a harmless caterpillar with astounding survival skills. In order to avoid being attacked by predators during its pupal stage (when the larvae transform into butterflies or moths), the helpless creature takes on the form of a rather menacing snake!

Native to Trinidad, the shape-shifting D. darius often mimics the head of a Gaboon pit viper, successfully fooling even the toughest of its predators. After it sheds its final layer of skin, the caterpillar enters its pupal stage, and its chrysalis takes the shape of a viper’s head. The transformation lasts 13 days, during which time this mimicry is its only line of defense. To make the appearance even more believable, the scary-looking chrysalis hangs on the underside of forest leaves at a carefully selected angle.

Photo: Andreas Kay

We’ve seen caterpillars mimic snakes before, like the Hemeroplanes triptolemus that copy the deadly creatures and also snap at potential predators, but the D. darius pupa is something else. Apart from its realistic impression of an alert viper, this creature has another trick up its sleeve – it is able to sense the world outside and react appropriately from inside its cover. So when a predator approaches, the pupa can sense movement and swing its shell back and forth, creating the illusion of a moving snake that’s ready to attack.

Photo: Andreas Kay

“The explanation may be that the predator itself turns and flees after suddenly coming face-to-face with a realistic ‘snake’ that waves violently back and forth, as does the pupa of Dynastor Darius when disturbed, ” Annette Aiello and Robert Silberglied wrote in Life History of Dynastor Darius in Panama.

Photo: Andreas Kay

According to Earth Touch News, “These elaborate defenses are not really all that surprising when you consider that caterpillars are pretty much just juicy protein sausages whose main life function is to become even bigger, juicier protein sausages. These voracious feeders are preyed upon by everything from birds to people and require powerful defenses if they are to have any hope of surviving.”