Florida is home to several fuzzy caterpillar species, and some of them pack a surprisingly painful sting. The most important thing to know: not all fuzzy caterpillars are safe to touch. Several species found throughout the state hide venomous spines beneath their soft-looking hair, and contact can cause anything from mild itching to intense, throbbing pain that radiates up your arm.
Fuzzy Caterpillars That Sting
Stinging caterpillars don’t sting the way bees or wasps do. Instead, they have barbed hairs called urticating hairs that break off easily when the caterpillar is brushed against. These tiny, brittle spines embed in your skin on contact. Many species also release a toxin from glands at the base of the spines, which intensifies the pain and can trigger swelling, rashes, or more serious reactions in some people.
Florida’s most dangerous fuzzy caterpillar species include:
- Puss caterpillar (southern flannel moth): About an inch long, covered in gray to brown fur that completely hides its head. It looks soft and almost cuddly, which is exactly the problem. Beneath that fur are stiff spines attached to poison glands. Contact causes intense, throbbing pain that develops within five minutes. The sting site shows blood-colored spots, and the pain can radiate from the hand or arm up to the armpit. Some people experience headaches, nausea, vomiting, and in rare cases, shock or breathing difficulty. Pain typically subsides within an hour, and the spots fade within a day or so. This is widely considered the most painful caterpillar sting in the United States.
- Tussock moth caterpillar: A small, colorful caterpillar with distinctive white tufts of short hair along its back and an orange head. Florida has three species, with the fir tussock moth being most common, followed by the white-marked tussock moth. Their sting is milder than the puss caterpillar’s. Contact produces welts that appear quickly and usually disappear by the next day, though itching and redness can linger for another day or two.
- Io moth caterpillar: Grows up to about 2.5 inches long. Pale green with white and red stripes running the length of the body. The danger comes from yellow or green fleshy protrusions tipped in black along the back. These hollow spines break off easily and embed deeply in skin, causing sudden burning and stinging followed by redness and itching.
- Saddleback caterpillar: Easy to identify by its distinctive brown and green coloring with a saddle-shaped marking. Stinging hairs line each side of its body and cluster at both ends. The spines embed deeply and contain a toxin that causes intense burning, inflammation, red welts, and potential tissue damage.
- Hag caterpillar (monkey slug): Brown with curved lateral spines of varying length. Toxin glands at the base of the spines release venom on contact, causing burning, itching, redness, and inflammation.
Harmless Fuzzy Species
Not every hairy caterpillar you find in Florida will hurt you. The woolly bear caterpillar, with its familiar bands of black and reddish-brown, is harmless. The hickory horned devil, which is the larval form of the regal moth, looks absolutely terrifying with large horn-like projections but is completely harmless despite its fierce appearance. It’s one of the largest caterpillars in North America.
The oleander caterpillar, bright orange with tufts of black hair, is a common sight on oleander plants across Florida and southern Georgia. It’s a significant defoliator of oleander but doesn’t sting people.
The general rule: if a caterpillar has long, soft, flowing hair or bright warning colors with tufted or spiky projections, treat it as potentially venomous until you can identify it. The caterpillars that look the most inviting to touch are often the ones you should avoid.
When and Where You’ll Find Them
In southern states like Florida, stinging caterpillars typically produce two broods per year. The first appears in spring and early summer, the second in late summer and fall. The second brood is the one people encounter most often, as caterpillar populations have had the full growing season to build up.
Tussock moth caterpillars hatch from eggs in late February or early March, maturing and dispersing cocoons by early April. If you live near oak trees in Florida, you’re especially likely to encounter them. Their cocoons end up on homes, park benches, playground equipment, and other outdoor surfaces. These cocoons are hard to remove and contain shed hairs that can still irritate skin and cause itching and burning even after the caterpillar has moved on.
Puss caterpillars turn up on a variety of shade trees and shrubs. They tend to show up in yards, parks, and school grounds, where they drop from branches or rest on fences, walls, and outdoor furniture.
What to Do After a Sting
If you touch a stinging caterpillar, the first step is removing the embedded spines. Press adhesive tape (duct tape or packing tape works well) firmly against the sting site, then peel it away. Repeat with fresh strips of tape until no more spines pull free. This is the single most effective thing you can do to reduce pain and prevent the reaction from worsening.
After removing the spines, wash the area with soap and water. Ice or a cold compress can help with swelling. Over-the-counter antihistamines and hydrocortisone cream can ease itching and redness. For puss caterpillar stings, the pain can be severe enough to need stronger pain relief. If you develop symptoms beyond the sting site, like nausea, difficulty breathing, or widespread swelling, seek medical attention.
Risks for Dogs and Cats
Pets encounter stinging caterpillars too, usually by sniffing or mouthing them. An animal’s fur offers some protection against skin reactions, so dermal stings are less of a concern than they are for people. The bigger risk is oral exposure. A dog or cat that bites or licks a stinging caterpillar may drool excessively, shake its head, paw at its mouth, and have difficulty swallowing. Irritation to the tongue, lips, and throat is common, and the toxins can cause inflammation in the esophagus and stomach.
If your pet gets into a caterpillar, rinse its mouth with water if you can do so safely. Cold compresses can help with swelling. If spines are visible in the skin or gums, tape can be used to pull them out, just as with human stings. Allergic reactions are possible and may require veterinary treatment with antihistamines or other medications. In rare cases where spines get into a pet’s eyes, thorough flushing is the first step, but persistent irritation may need an ophthalmologic exam.
Keeping Your Yard Safe
The simplest protection is awareness: learn to recognize the species above, especially the puss caterpillar and saddleback, and teach children not to touch fuzzy caterpillars. Wear gloves and long sleeves when gardening or pruning, particularly under oak, elm, and citrus trees during peak caterpillar months from March through May and again from August through October.
If you spot stinging caterpillars on trees or structures, you can remove them mechanically using gloves and a stick or tongs, dropping them into a bucket of soapy water. Check outdoor furniture, railings, and the undersides of play equipment before kids use them. Tussock moth cocoons on walls and benches should be scraped off carefully with a putty knife while wearing gloves, since the shed hairs embedded in the silk can still cause skin irritation long after the moths have emerged.