Wednesday, October 21, 2009

Why Did the Woolly Bear Cross the Road?

By Joann M. Ringelstetter

This time of year, Ruth and I spend a lot of hours traveling the backroads in search of fall color scenes to photograph. And as our tires roll down the road, we see one woolly bear caterpillar after another making its way across the road.

There are numerous species of woolly bear caterpillars. One of them is called the Yellow Woolly Bear or Yellow Bear Caterpillar. Two years ago at the end of September, we had gotten out of the car to get a close-up look at a shagbark hickory tree that was loaded with nuts. Soon I noticed a yellow bear caterpillar clinging to a thin stem that was blowing in the wind.

As I concentrated on getting the yellow bear in focus in spite of the wind, Ruth started laughing and said, “Don’t look now, but there’s a woolly bear on your butt.” I thought she was kidding, but she wasn’t. Woolly bears supposedly cross the road in the fall in search of a place to spend the winter. I guess I should have had a “No Vacancy” sign on my butt!”

The banded woolly bear is the species with which you are probably most familiar. Some say the woolly bear can forecast the severity of the winter by the width of its reddish brown band – if it’s wide, the coming winter will be mild; if it’s narrow, the winter will be severe. In reality, the reddish brown band gets wider as the caterpillar matures. It could also have something to do with the moisture in the woolly bear's environment.

Fall signals the woolly bear to seek shelter, such as underneath plant debris or in an old log or a woodpile. It survives the winter by producing its own anti-freeze. In spring, it begins to move and feed again, and then spins a cocoon, eventually turning into an Isabella Tiger Moth.

When you’re out in autumn, either walking or driving, look down and you’ll probably see a woolly bear crossing the road.

Happy Shunpiking!

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