CLARKSBURG, W.Va. (WBOY) — In the last couple of months you may have seen these white-looking “woolly” caterpillars inching across lawns or parking lots. Urban myth suggests that these fuzzy little critters warn of impending snow, similar to how other woolly caterpillars are said to predict the severity of the upcoming winter.
Video courtesy of Tina Corcoran
The woolly worm you are probably most familiar with is the Isabella Tiger Moth Caterpillar pictured below. Although they don’t really predict the severity of upcoming winters, the brown band in the middle can be an indicator of how old the caterpillar is. The older it gets, the longer it grows, making the rust-colored section appear smaller in comparison to the black parts on both ends of the caterpillar.
While you may think the hairs on its body are to help keep it warm during the winter, it’s actually the opposite. These hairs, called “setae,” help the Isabella Tiger Moth freeze itself without dying in a type of hibernation that uses a kind of organic antifreeze. By keeping all but the inside of their cells frozen, these caterpillars can survive temperatures as low as minus 90 F, according to the National Weather Service.
The white caterpillar in the video above is a different species altogether – a Hickory Tussock Moth caterpillar. These caterpillars always appear white and black, regardless of the week’s weather forecast, however, they are in the same Erebidae family as tiger moths. The hairs on this caterpillar can detach and act as a defense mechanism that can cause a rash or itchiness in humans. These hairs are also used to help make the caterpillar’s cocoon which helps protect it from predators as it transforms into a moth.
What about all-black or all-brown caterpillars?
Similar to the Tussock Moth caterpillars, any all-black or all-brown fuzzy caterpillars you see are a different species than the Isabella Tiger Moth, and are not real indications of future weather, but all of the species talked about here can be found in West Virginia.
The fuzzy all-black woolly worms are Giant Leopard Moth Caterpillars, but unlike the Tussock Moth Caterpillars, their hairs do not detach. However, the Missouri Department of Conservation advises caution when touching fuzzy caterpillars with your bare hands if you are unsure about your sensitivity to possible skin-irritating toxins. These caterpillars can grow up to 2 to 3 inches long, with a wingspan of around three inches when they turn into moths. Just like the Leopard Moth Caterpillars, The Virginian Tiger Moth or the “yellow woolly bear” caterpillars are not poisonous and their hairs do not detach, but its bristles may still cause irritation to sensitive skin.