What You Need to Know About the Southern Flannel Moth—AKA the Country’s Most Poisonous Caterpillar

What You Need to Know About the Southern Flannel Moth—AKA the Country’s Most Poisonous Caterpillar

Ever heard of the Southern flannel moth (Megalopyge opercularis)? It has a distinctive look—so if you ever run into one, you definitely won’t be able to miss it. Its larval form is unique too, and it goes by many names: furry puss caterpillar, asp, woolly slug, and opossum bug, just to name a few. More important than its varied nomenclature? The caterpillar form is also super poisonous; in fact, it is one of the most dangerous bugs in the United States.

Why do you need to know about it? The moth caterpillar resembles a cat, but it is far from cuddly. It is covered in hair that hides poisonous, venom-filled spines. This bug is currently in the news because a 5-year-old child in Texas was recently stung by one while playing outside at daycare. According to NBC Dallas-Fort Worth, the child was hospitalized after the caterpillar’s spines stuck in her arm and led to pain and swelling. Her teachers removed the spines using tape, which was quick thinking. As reported by NBC Dallas-Fort Worth, according to the girl’s mother, Lauren Chambers, “They said if that had not happened it could actually cause her whole body to go numb and start shutting down.”

These extreme pain-inducing spines protect the caterpillars, and once the caterpillars turn into moths, the poisonous spines disappear. Because they are often found on trees and in plants and bushes, keep an eye out if you’re near locations these caterpillars are known to frequent.

Southern flannel moth caterpillars are widespread in the United States and can commonly be found on the East Coast in states stretching from New Jersey to Florida. They can also be found as far west as Texas and Arkansas. For more information, read this fact sheet from the University of Florida Department of Entomology and Nematology.

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Have you ever seen one of these in person? While the moth caterpillar is furry and some say it resembles a cat, it is far from cuddly.