Spooky Nature: Hickory Horned Devil Caterpillar

The hickory horned devil looks pretty creepy with bright colors, huge eye-spots, and gigantic horns. But this caterpillar turns into the lovely regal moth.

Happy October! The countdown to Halloween is on, and it’s time to celebrate spooky species including ravens, bats, spiders and more. First up, the hickory horned devil (Citheronia regalis), the larva of the regal moth. As assistant curator of a butterfly exhibit, I handle a lot of caterpillars on a regular basis, and I can easily say that none of them are quite as alarming on first sight as these freaky creatures.

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hickory horned devilJill Staake

Are Hickory Horned Devils Poisonous?

Despite the fearsome look of these caterpillars, they are actually entirely harmless to humans. For potential predators, though, their bright colors, huge eye-spots, and gigantic horns are a clear sign to stay away. After all, those horns look like quite a bit to swallow, and bright colors often signal toxicity in the animal world. And if that’s not enough, when disturbed these caterpillars will rear back and vibrate, creating a buzzing noise that’s startling in and of itself.

Oh, and did I mention that these caterpillars can grow up to six inches long, and get as fat as a hotdog? Their sheer size is enough to scare most people, even without the horns and spikes.

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Hickory horned devils are not poisonous
Hickory horned devils are not poisonous

Facts about Hickory Horned Devil Caterpillars

  • This species lives in the Eastern United States, from New York south to central Florida.
  • As the name indicates, the caterpillar hosts on hickory, plus walnuts, persimmon, sycamore, sweet gums and a number of other trees.
  • The caterpillar pupates underground in an earthen chamber. They will remain there until the following spring. They they will emerge as the regal moth, sometimes also called the royal walnut moth.
  • The adult moth is in the silk moth family, and does not feed—it actually has no mouth parts. It will live off its stored fat reserves for a few days while it mates, and then die very quickly.
  • The regal moth is one of the largest moths in North America, with a wingspan of as much as 6 inches.
A regal moth sitting on a wooden railing.Courtesy of Stephanie Perry
Regal moth

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There are plenty of other freaky caterpillars out there (tomato hornworms and flannel moths come to mind). But these are the craziest I’ve ever personally come into contact with.

Next, learn how to tell the difference between a moth vs a butterfly.

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Jill Staake
Jill lives in Tampa, Florida, and writes about gardening, butterflies, outdoor projects and birding. When she's not gardening, you'll find he reading, traveling and happily digging her toes into the sand on the beach.