Woollybear Caterpillars

The woollybear is a common and well-known caterpillar. Though most people have one kind of woollybear in mind, there are 8 or more species in the U.S. that could legitimately be called woollybears because of the dense, bristly hair that covers their bodies. Woollybears are the caterpillar stage of medium sized moths known as tiger moths.

The best-known woollybear is called the banded woollybear. It is black at both ends and reddish-brown in the middle. The adult is called the isabella moth. The banded woollybear is found throughout the U.S., Mexico and southern Canada but not the rest of the world. There are 2 generations of caterpillars each year (May and August) The second generation is the one noticed in late fall when the woollybears are crossing the roads, usually in great haste as if they have someplace special to go. In fact they are only scurrying to find a sheltered location under dead plant debris, etc. where they will spend the winter as a larva. In the spring they will feed briefly before changing into a cocoon and eventually a moth. Eggs laid by the female moths start the cycle over again.

The adult moth of the banded woollybear has white wings with scattered black spots. Wingspan in about 2 inches.

The banded woollybear is the species mentioned in winter-prediction folklore that claims longer the black at the ends of the body, the more severe will be the coming winter. As you might expect, science 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.

This doesn't stop the good folks of Vermilion Ohio (west of Cleveland) from holding an annual "Woollybear Festival" -- claimed to be the largest one-day festival in Ohio. Festivities include a parade, woollybear races and an "official" analysis of the woollybears and forecast for the coming winter.

This article originally appeared in the November 9, 2001 issue, p. 122.


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