Why do we think that the colors of a woolly caterpillar (the larval stage of Pyrrharctia Isabella, the Isabella tiger moth) can predict the severity of a coming winter? It started back in 1948, when Dr. Howard Curren, the curator of insects at the American Museum of Natural History in New York City, collected a sample of these black and brown caterpillars from Bear Mountain, NY and put forth the theory that large amounts of brown predicted a mild winter. The following winter WAS mild in NY, and Dr. Curren’s research was published in the New York Herald Tribune. It became accepted among the general public, despite the fact that (1) the sample size was tiny, (2) the location was extremely limited, and (3) he was not able to replicate an accurate prediction despite repeating it for the following eight years. Skeptical people (me) will put as much trust in the woolly worm as weatherman as we do in Punxsutawney Phil.
The woolly worm’s body consists of 13 segments, which are postulated to correspond to the 13 weeks of winter. They are black at either end, with a midsection of orangish brown. Legend says a black band predicts a week of below average temperatures, a brown band predicts average temps, and a light brown band indicates above average temperatures. More scientific minds say that the colors are a reflection of the age of the caterpillar and perhaps the temperatures during its development.
The Isabella tiger moth lays her eggs on the broad-leaf plantain, a weed found in many lawns. The hatchlings feed on the plantain’s leaves. They mature in summer. We usually take note of them in fall as they are waddling about, looking for a safe leaf pile as a winter haven. Woolly worms can withstand extreme cold winter temperatures without physical damage. In spring, they emerge from their winter homes and spin a cocoon about themselves. After two weeks or so in this silken cocoon, they emerge as winged adults and start looking for dandelion, nettle, or plantain to eat and as a place to lay eggs for the next generation. There is a marvelous YouTube video showing the spinning of the cocoon. View it by clicking here.
Banner Elk, North Carolina hosts a Woolly Worm Festival each year. The festival has been held for 46 years. For 2023, there were 1,400 worm contestants with owners from 21 states and six countries. There are 25 heat races, then semifinals, with a grand finale race between the semifinal winners. I can scarcely describe the enthusiasm among the crowd as we watch the contestants (adults and children) cuddle their worms, softly blowing warm air on them to keep them comfortable during the crisp October temperatures of the festival. Excitement builds as the worms are placed on their racing strings and encouraged to scramble to the top at a rapid clip. Children are just as likely to win as adults. The 2023 winner worm was picked up in a parking lot just prior to the beginning of the race.
My favorite part of the festival is hearing contestant names. Yes, each worm is named by its owner/sponsor. My favorites: Wormzilla, MerryWeather, Patsy Climb, Dale Wormhardt, and Taylor Swiftworm. Winner of the Banner Elk contest for 2023 was a worm named Jeffrey; for 2022, Porta Potty took the $1,000 prize.
It’s all good fun. Just don’t rely too heavily on their seasonal predictions.
A gloriously woolly worm. Photo by Sheila Sund. Used under cc-by-2.0 license.
A mature Isabella tiger moth. Photo by Andy Reago and Chrissy McLarren. Used under cc-by-2.0 license.