The hickory tussock moth caterpillar, also known as the hickory tiger moth caterpillar is a beautiful creature that looks soft and furry. It's appearance almost invites one to pick it up or to touch it to see if it is as soft as it looks. But doing so can cause a severe reaction due to the venom and barbs at the end of its hairs.
The long black hair tufts at the ends of the caterpillar are connected to venom glands that secrete poison when the hairs are touched. Unsuspecting people who come in contact with the caterpillar will usually experience a rash like poison ivy or nettle stings. This can cause a burning sensation, swelling and pain. In extreme cases, a serious allergic reaction and nausea may occur. Medical attention may also be required, if the reaction persists.
The hickory tussock moth caterpillar concentrates toxins from the host plants that it eats, allowing it to develop this chemical defense. Nature will often provide small, or otherwise vulnerable creatures with a means of discouraging predators. The tussock moth caterpillar is one of those creatures.
The caterpillars eat oak, ash, hickory, walnut, and elm leaves, and although they can be found in large numbers, the caterpillars are not likely to defoliate a plant enough to cause an issue for the plant.
In fact, the caterpillar's venom is not sufficient to be a serious threat to most people, and even in extreme cases, the effects are not long lasting or life-threatening. This did not stop the spread of "caterpillar terror" in Ohio in 2016, however. A well-meaning mother posted on social media about her experience with the caterpillars when her daughter licked one of them in 2016 and suffered a painful reaction. Her point was to warn other parents so that they would educate their children about the hazards of touching the creatures. But the result was an over reaction that caused widespread concern, and even fear.
The caterpillars are actually an essential part of the diet for chickadees and other songbirds that inhabit Canada and the eastern United States of America. They have been around far longer than humans and they are an important part of our ecosystem.
As with all animals, avoiding unnecessary contact is always wise, for our own health, as well as for the animal's health. There is a saying that if we leave them alone, they will leave us alone. This is certainly true for the hickory tussock moth, or any other caterpillar. All they want to do is eat, avoid being eaten themselves, and turn into a cocoon for the winter. Enjoy them from a respectful distance. They are a beautiful and fascinating little animal.