The banded woolly bear caterpillar is the larval form of Pyrrharctia isabella, the Isabella tiger moth. Typically, the bands at the ends of the caterpillar are black, and the one in the middle is brown or orange, giving the woolly bear its distinctive striped appearance.
Woolly bears do not actually feel much like wool; they are covered with short, stiff bristles of hair. Banded woolly bear caterpillars are active during the day and when they are threatened they curl up in a ball.
Legend has it that the banded woolly bear caterpillar, also called woolly worm and fuzzy worm, has the reputation of being able to forecast the coming winter weather. Whether this is a fact or folklore, it is all about how you “read” the worm.
In some parts of the world, it is believed that the severity of the winter can be predicted by the intensity of the black on the Isabella tiger moth’s larvae (caterpillar). In some parts of the United States, it is believed that if the woolly worm has more brown on its body than black, it will be a fair winter. If the woolly worm has more black than brown, the winter will be harsh.
The furry banded woolly bear can be spotted during the fall months in great numbers inching along the ground. While you will notice them in great numbers during the fall months, the woolly worm actually has two life cycles, so they can also be found inching around in June and July.
Woolly worms may look small, but these dazzling creatures have 13 segments and three sets of legs. They have tiny eyes, but they make their way around mostly by feeling around and touching. Mature woolly bears search for overwintering sites under bark or inside cavities of rocks or logs. (That’s why you see so many of them crossing roads and sidewalks in the fall.)
Prior to settling in for the winter, the woolly worm will survive by eating a variety of plants such as cabbage, spinach, grass, and clover. And to protect itself from predators, the woolly worm will curl up into a ball, exposing only its bristles, which can be quite irritating to the skin.
If you want to see the banded woolly bear in action, don’t seek them out at night. Remember, worms are nocturnal for the most part, not caterpillars. The woolly worm is very active during the day in the fall. It is not uncommon to spot them in groups of multiple individuals, all of them with one common goal — to find a place to hide.
In some places in United States, the banded woolly bear worm has a pretty good weather prediction rate. Scientists would prefer not to acknowledge it, but the woolly worm, according to some authors, has an 80-85 percent accuracy rate for predicting the winter weather. The worm has held its record for accuracy for more than 20 years.
However, most scientists discount the folklore of woolly bear worm predications as just that, folklore. So, if you come across a local banded woolly bear worm, observe the colors of the bands and what they foretell about your winter weather. If you have difficulty in reading the banded woolly bear you may consult the Farmer’s Almanac or turn to your local weather station for the weather forecast.
Explore the outdoors and all of its creatures. Enjoy the beauty of Boundary County!