The Magic of the Woolly Bear

The woolly bear, sometimes called the woolly worm, is a well-known harbinger of weather to come. If you do any sorts of workings involving weather magic, it’s not a bad idea to keep an eye on these crawly critters, which are typically seen during the end of summer and into late fall. Where I live, they’re starting to pop up already — of course, in my neck of the woods, our seasons are Winter, More Winter, Construction, August, and Football (at least during non-Covid years), so take that with a grain of salt.

At any rate, the woolly bear, which is the larval stage of the tiger month, has black on its ends, and a brown section in the middle. According to traditional folklore, you can tell how bad a winter is going to be by the amount of black on the ends of the woolly bear. The more black you see, the colder and longer winter is going to be this year. On the other hand, if you see a lot of brown, and just a bit of black on the tips, you can plan on a more mild winter season.

Some people believe that the darkness of the black bands is significant as well – if the caterpillar’s head is a darker black than the back end, it means winter will be worse at the beginning, but taper off towards the end. On the other end, if the tail end of the woolly bear looks darker, that means winter will start off mild but end with lots of snow, ice, and cold.

As if that wasn’t confusing enough, the woolly bear caterpillar has thirteen different bands on its body, which folklorists say correspond to the thirteen weeks of the winter season.

Scientists, on the other hand, generally disagree with the woolly bear stories. According to the National Weather Service Weather Forecast Office,

“The woolly bear caterpillar’s coloring is based on how long caterpillar has been feeding, its age, and species. The better the growing season is the bigger it will grow. This results in narrower red-orange bands in its middle. Thus, the width of the banding is an indicator of the current or past season’s growth rather than an indicator of the severity of the upcoming winter.”

Not everyone in the scientific community is on the same page with this, however. The woolly bear (and its weather-indicating abilities) was actually scientifically studied in the early 1950s, by Dr. C. H. Curran. Dr. Curran analyzed a group of woolly bears, and examined the colors in their segments. He then used it to predict winter weather, with a pretty decent success rate.

So, scientific debate notwithstanding, people have believed in the magical folklore of woolly bears for centuries. Try watching a few woolly bears, make a note of what they look like, and see if you can spot a connection to the weather patterns this coming winter!

Woolly Bear Caterpillar image by Mike Keeling, 
Creative Commons license (CC BY-ND 2.0), via Flickr