Discover the Incredible Survival Adaptation: The Caterpillar That Mimics a Venomous Snake

Ladies and gentlemen, the award for best invertebrate mimicry goes to Hemeroplanes triptolemus for its masterful impersonation of a venomous snake!

Photo: Andreas Kay

Native to the rainforests of the Amazon, the snake mimic caterpillar turns into a rather unimpressive moth in the family Sphingidae, but in its larval stage it incorporates an astonishing survival tactic. It needs one too, as without a good defence system in place, sphinx moth caterpillars are essentially energy-rich ‘nom-nuggets’ presented on a bed of leafy greens for the jungle’s predators.

To avoid that fate, the larva of this moth expands and exposes its underside to mimic a snake’s head with black eyes and even light reflections.

Photo: Andreas Kay

It’s not an easy feat though. The caterpillar begins its defensive manoeuvre by throwing itself backwards and twisting its body to expose hidden shades of yellow, white and black on its underbelly. Then, it sucks in air through tiny holes in its sides (known as spiracles) and pumps them to the front of its body. Once the segments are inflated, the caterpillar is truly transformed, having taken on the form of a venomous snake complete with a diamond-shaped “face” and large, black eyes.

If the “deadly” (and rather costly) costume isn’t enough to deter a predator, such as a lizard or a bird, the caterpillar might also strike like a snake to enhance the effect.

Although deflection – a tactic involving using eyespots to draw predators’ attention away from the head – is not uncommon among animals, the snake mimic caterpillar’s false face is actually located on the same end as its real one.

“Deflection might not work well for a caterpillar because the caterpillar probably won’t survive if any part of its body gets pierced or ripped off by an attacker,” explains eyespot expert Dr Thomas Hossie. “This defence is all about intimidating or startling an attacker who will run (or fly) away instead of risk a lethal encounter with a snake.”

Photo: Andreas Kay

Photo: Reinaldo Aguilar

Photo: Andreas Kay

Interestingly, we also know of a moth that camouflages as a snake in its fully developed stage, and for which the price of this kind of disguise is also rather high energy-wise.

But this guy seems to beat everybody else in the animal kingdom in terms of sporting the best snake costume ever.