Banded Woolly Bear

Fuzzy, reddish brown caterpillar with a black anterior end. Usually, they have black posterior and anterior bands, but the colors change as they molt to successive instars, and they become more reddish brown with age. The woolly bear's setae are not urticating, so they do not usually cause irritation or injury from being handled. However, their setae may cause dermatitis in some susceptible people.

According to folklore, the length, thickness, and color of a woolly bear's color bands can be used to forecast how severe the winter weather will be. This myth dates back to colonial American folklore and is still widely believed today. However, the truth is that these caterpillars can't predict the weather. In reality, a woolly bear's coloring is based on how long the caterpillar has been feeding and its age. The width of the banding is simply an indicator of that current season's growth. Woolly bears molt six times before pupating, and with each successive molt, their colors change, becoming less black and more reddish brown - this is completely independent of the weather. The last point to address in debunking this myth is the reason for the woolly bear's "coat". The thickness of its setae has nothing to do with predicting severe weather. Rather, their setae helps them to freeze more controllably, and once the caterpillars begin hibernation, their bodies create a kind of natural antifreeze called glycerol. This ability to freeze gradually helps protect them during the cold winter months. So, it would seem that woolly bears have unwittingly gained status as being weather forecasting prophets and there is no scientific evidence to prove that they are actual prognosticators of winter weather.