The Puss Caterpillar . Don’t let its soft, furry appearance fool you—the puss caterpillar (Megalopyge opercularis) is widely regarded as the most venomous caterpillar in the United States. Covered in what looks like silky, plush fur, this deceptive insect resembles a harmless tuft of cotton or even a small cat—hence its name. But beneath those inviting hairs lie venomous spines capable of delivering an intensely painful sting.
Found primarily in the southeastern U.S.—including states like Texas, Florida, and Georgia—the puss caterpillar prefers warm climates and often hides in shade trees like oak, elm, and sycamore. Though small (typically around 1 inch long), its sting can leave a big impression. When touched, the caterpillar’s venomous spines break through the skin, causing immediate burning pain, swelling, nausea, headache, and even difficulty breathing in severe cases. The sting is often compared to the pain of a broken bone or blunt trauma, with a red grid-like rash appearing around the site of contact.
Encounters with puss caterpillars are most common in late summer and early fall when they’re fully grown and searching for a place to pupate. While their adult form—a fuzzy, dull-colored moth—is harmless, it’s the caterpillar stage that poses a serious threat, especially to children or unsuspecting individuals who brush up against one accidentally.
If stung, it’s important to seek medical attention, especially if symptoms escalate. In the meantime, applying adhesive tape to the area can help remove embedded spines, followed by washing with soap and water and applying cold compresses to reduce pain and swelling.
Despite their danger, puss caterpillars play a role in the ecosystem like any other insect. However, knowing how to identify and avoid them is key to staying safe.
Stay alert, especially around trees in warm, wooded areas—and always look before you touch.
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