Can a caterpillar predict coming winter weather? Since the 1600s, North American folklore holds that the larvae of the Isabella Tiger Moth, Pyrrharctia isabella, can do just that. But be warned: the sharp hairs of woolly bear caterpillars, as they are popularly called, while not poisonous may cause dermatitis in sensitive people.
The moth is native to southern Canada and the United States. Its larvae, a couple of inches long, forage on a wide range of trees and plants such as burdock, clover, dandelions and nettles. In the garden they may be found feeding on asters, green vegetables, herbs, sunflowers and violets, amongst others. The covering of spiny hairs may fluctuate in colour, although generally blackish at either end dividing a reddish-brown middle stripe.