Woolly bear bands: Winter fact or fiction?

Q. I saw a black woolly bear caterpillar. I’ve heard this means a bad winter. Is this how the Farmers’ Almanac predicts our winters?

Sally from Berlin Center

A. Every year I get questions about these intriguing caterpillars. Mostly the questions relate to the ability of these caterpillars to predict our winter weather. As the tale goes, the black band on the woolly bear caterpillar will expand to predict bad winters with heavy snows and be almost nonexistent in the fall before a mild winter.

This is just a tall tale. It never fails that I get into an in-depth conversation each fall – answering questions and explaining how this is good fun, but it really means nothing.

According to our entomologist, Dave Shetlar, the woolly bears are the caterpillar stage of medium-sized moths known as tiger moths.

There are eight or more species of woolly bear caterpillars. The most common in Ohio are the banded woolly bear, the yellow woolly bear and the salt marsh caterpillar.

The one most commonly mistaken for foretelling our winters is the banded woolly bear, of which the adult is the Isabella moth. Dave says the coarse hairs of the banded woolly bear are black at both ends and reddish-brown in the middle. The black bands can be wider on some caterpillars, leading some to talk about the black bands expanding.

Research has debunked this legend by showing the amount of black varies with the age of the caterpillar and the moisture levels in the area where it developed.

Actually, the all-black caterpillars aren’t even a woolly bear caterpillar at all. It is most likely the caterpillar of the giant leopard moth, which looks all black until it curls up and then you can see red stripes on its sides.

So, why do we suddenly see these caterpillars this time of year? October and November are the months when these woolly bear caterpillars search for a location to over-winter.

To read more, visit go.osu.edu/woollybear

Eric Barrett is the Ohio State University Extension Educator for Agriculture and Natural Resources in Mahoning County. Call the hotline at the office on Mondays at Thursdays from 9 am to noon to submit your questions at 330-533-5538.

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