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Woolly Bear Winter Forecast
October 09, 2019 by Haya Aldoori

As the temperatures begin to fall, some familiar fuzzy orange and black nature friends are appearing all over, and in great numbers. The Woolly Bear caterpillars of High Park are on the move and are busy searching for a safe place to settle down for the winter!

Woolly Bear caterpillars, also known as a Banded Woolly Bears, Fuzzy Bears, or Woolly Worms, are the larval stage of Isabella Tiger Moths. This caterpillar has long been thought off as a predictor of the coming winter weather. According to folklore, the amount of black fuzziness on the caterpillar in the Fall, varies proportionately with the severity of the coming winter, specifically in the region in which the caterpillar was found. The longer the fuzzy black bands, the longer, colder, snowier, and more severe the upcoming winter will be. Similarly, if the fuzzy brown band in the middle is longer, this indicates a winter that is milder.

The position of the longest of the two black bands, is also thought to be an important factor in predicting which part of the upcoming winter will be most intense. If the black at the head of the caterpillar is longer, the beginning of winter will be more severe. If the black at the tail of the caterpillar is longer, the end of winter will be more severe.

As with most folklore, there can be more than one version of this story. Another version says that the Woolly Bear caterpillar’s overall fuzziness indicates how severe the winter will be. So, if they are extra fuzzy, it will be an extra cold winter. A third version of this story relates more to the caterpillar’s direction of travel. If the Woolly Bear is crawling in a southerly direction, they are trying to escape intense upcoming winter conditions. On the other hand, if they are crawling north, the upcoming winter might be milder.

Woolly Bear caterpillar

The truth is that this little caterpillar can’t actually predict how severe the upcoming winter will be. Rather, the colouring on the caterpillar’s body varies based on factors like how long it has been feeding, or its age.

All the different stories about Woolly Bears, and other things, can connect people to nature in a memorable and engaging way. With that in mind, we encourage you enjoy the nature stories that speak to you but also to dig a litter deeper, and uncover what is behind them.

On your next Fall visit to High Park, keep a careful eye out for Woolly Bear caterpillars wandering by your feet!

FUN FACT: When picked up or disturbed, Woolly Bear caterpillars will curl themselves up into a tight bristly ball and “play dead.”

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