Giant Hickory Horned Devils Are Emerging From Trees in Southeastern States

The hickory horned devil is one of the largest caterpillars in the U.S., and they are starting to descend from trees en masse as they prepare to pupate.

Images of an "impressive" hickory horned devil were shared by the Alabama Wildlife and Freshwater Fisheries Division after a member of the public found one in Jefferson County.

The caterpillars are the larvae of the regal moth, Citheronia regalis, one of the country's largest flying insects, with a wingspan of up to six inches, according to the Missouri Department of Conservation.

Log into Facebook to start sharing and connecting with your friends, family, and people you know.

The caterpillars can grow up to 5.5 inches long, and their appearance is truly bizarre. They are blue-green in color, with big orange spikes on their heads and black patches at the front of their heads.

The species is found largely in deciduous forests in the southeastern United States where they feed on a variety of tree species including walnut, persimmon and, of course, hickory.

Historically, they could be found as far north as Massachusetts, but in recent years their numbers have been declining, thanks largely to increases in pesticide application.

Hickory horned devil
Photo of a Hickory Horned Devil. The caterpillars come down from the trees when it is time to pupate. Alabama Wildlife and Freshwater Fisheries Division

The caterpillars eat continuously for about 35 days before crawling down from the trees to pupate in the soil. This is when they are most likely to be spotted.

"This is the time of year to look for these stout gents in any deciduous woods, and if you meet one don't worry, their prickly hardware is harmless," the Alabama Wildlife and Freshwater Fisheries Division said in a Facebook post.

Their bright green-blue coloring is meant to ward off any would-be predators, such as yellow-jackets and birds, and, when disturbed, they throw their bodies from side to side like writhing baby dragons.

They are most active between July and October, gorging themselves up in the treetops before it is time to pupate. The pupae remain in the soil throughout the winter until the adult moths are ready to emerge in early summer.

Regal moth
Stock image of a regal moth. The adults only survive for about a week before dying of exhaustion. Diane079F/Getty

Like most other members of the giant silkworm moth family, the adults do not have functioning mouthparts so cannot eat.

They survive for about a week before dying of exhaustion.

Although they might look fierce, the hickory horned devil is completely harmless. If you should find one crawling across the pavement or your lawn, you can help it out by moving it into an area with softer soil where it can more easily burrow for pupation.