Hickory Horned Devil Caterpillar: Harmless Despite Fearsome Appearance

The hickory horned devil (Citheronia regalis) is the largest caterpillar in the United States, reaching impressive size with prominent horns and spines. Despite its intimidating look, it is completely harmless to humans.

Life Cycle

After hatching from eggs laid by the regal moth, the caterpillar grows through several molts over weeks. When mature, it burrows into soil to pupate, spending fall, winter, and spring underground. The following summer, it emerges as the regal moth—an orange moth with gray markings. Though large, the adult moth is smaller than expected given the caterpillar's size.

Ecology and Safety

Birds readily eat these caterpillars, so few survive to adulthood. The "horns" serve as visual deterrents against predators. The caterpillar only "bites" the leaves it eats (host plants include hickory, walnut, and persimmon). No control measures are needed or recommended.

If found, simply observe and appreciate this remarkable native insect.