If you’re someone who follows folklore, then you’re likely familiar with the alleged weather-predicting capabilities of the Isabella Tiger Moth.
OK. So maybe the moth’s common name isn’t ringing any bells. We’re actually talking about the moth’s infamous caterpillar – what we all lovingly refer to as the Woolly Bear.
Woolly Bear caterpillars have 13 different body segments. Their typical coloration is black on either end with a mid-section that’s reddish-brown.
The weather-predicting myth of the Woolly Bear has been passed down since colonial times. The folklore holds that when you see a caterpillar in autumn, the thicker the reddish-brown stripe, the milder the winter ahead. If its coloration is dominated by the thicker black bands, then we’re in for a doozy of a winter.
So, the million dollar question is, “Can Woolly Bear Caterpillars really predict the weather?” The answer is both no, and yes.
Despite the popularity of this legend, Woolly Bears cannot predict what the winter ahead will be like.
However, while the caterpillar can’t predict the future, it’s appearance can tell you what the weather, or more accurately the growing season, was like during the past spring and summer.
According to Mike Peters, an entomologist at the University of Massachusetts, there’s evidence that the number of brown hairs on the caterpillar has to do with its age. The older caterpillars started eating and growing early in the spring and therefore have a thicker reddish-brown band.
So yes, a thick reddish-brown band on a Wooly Bear does say something about an early spring, the problem is …it’s telling you about an early end to the previous winter rather than what’s in store for the months ahead.