Can woolly worms actually predict winter weather?
Todd Bush
Tethered loosely on 3-foot-long strings, a row of brown-and-black caterpillars lines up on the stage to compete in individual heats for a chance to predict whether the upcoming winter will be mild or harsh, or a little of both. Inch by inch, the fuzzy competitors steadily race to the finish line at the annual Woolly Worm Festival in Banner Elk, North Carolina, a tradition since 1978, when a local resident created a way to decide which woolly worm would become the next Punxsutawney Phil-type prognosticator in this quaint mountain town. Each year, the champion wins the coveted title of official forecaster.
According to woolly worm fans throughout the Blue Ridge states, the caterpillar’s 13 bands of fur represent the 13 weeks of winter. A brown band allegedly indicates a mild week, while a black one signals cold, ice and snow. In some parts of the country, the width of the band, not the colors, signifies the severity of the upcoming season.
This time of year, the curious-looking critters—they are actually the larvae of the Isabella tiger moth—are frequently seen crossing the road or feeding on grasses and goldenrod as they wander around looking for places to hibernate beneath logs, rocks or debris. What many people don’t realize is that the autumn woolly worms actually belong to the second round of a group that initially emerges from cocoons in the spring. After the moths come out of the pupae stage, says Stewart Skeate, a biology professor and wildlife biology program coordinator at Lees-McRae College in Banner Elk, “they actually go through an entire generation in the summer, but we don’t really notice them. And then they go through this whole thing again with the larvae, cocoon and adult and they lay eggs again.”
Their legendary status as foretellers of the future began in 1948 when Dr. C. H. Curran, curator of insects at the American Museum of Natural History in New York City, studied the woolly worms in a small area for a short period of time, determined that winter would be mild if the caterpillars sported more brown segments than black, and published his findings in the New York Herald.
What the hues really show, according to Skeate, is how old the worms are. “When they’re really little, they’re almost completely black and as they grow, the rusty or red hairs replace the black hairs,” he says. “It’s kind of like as we get older, we get more and more gray hair that replaces the black ones. As to why [the woolly worm] does that, we’re not really sure. That’s kind of a mystery, but maybe it discourages predators.”
The long, stiff hairs probably help keep them warm, Skeate adds. “One of the reasons they’re so widespread and do so well up here in the mountains is that they can withstand freezing temperatures. … Its scientific name ends in ‘arctica,’ which indicates that it’s capable of surviving in really, really cold, cold weather.” It accomplishes this by freezing solid when the temperature drops; the cryoprotectant (a.k.a. “antifreeze”) in their tissues protects their bodies until the spring thaw.
“There is a little bit of science possible in this [folklore],” Skeate says with a laugh. “If it’s a cold and wet summer, the caterpillars don’t grow as much and as a result, they have less red and more black. So maybe by having a colder summer, you’re going to have a colder winter. But there’s really not a whole lot of science involved. It’s more of a fun type of thing.”
Appreciating a Festival, Whether it Happens This Year or Not
As we go to press, the announcement comes that the 43rd Woolly Worm Festival will not take place this autumn.
Over its first 42 years the festival, featuring racers like Patsy Climb and Dale Wormhart, has raised some $1.4 million for children in Avery County.
We hope you will take this opportunity to put the festival on your list for future travels. Learn more here: WoollyWorm.com
The story above appears in our September / October 2020 issue. For more like it subscribe today or log in with your active BRC+ Membership. Thank you for your support!