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.
It is these bands that much of the folklore maintain indicate winter weather. After all, much as meteorologists do not always concur, so woolly bear caterpillar predictions vary in agreement. One larval school believes that it is the width of the stripes that determine the severity or otherwise of the winter. If the central reddish-brown band is wide, winter will mild but if narrow it will be severe. Other observers say it is the colour of stripes: they darker they are, the harsher the coming winter.
Then there are those who eschew either theory. They watch for which direction the caterpillar crawls. If southwards, it is said to be escaping the cold.
Sad to say, there is not one iota of scientific support for such caterpillar conjections.
None of this discourages believers of the woolly bears--or municipal boosters. Why should groundhogs have all the fun? Every fall there are festivals aplenty in eastern North America featuring thee celebrity caterpillars along with the inevitable crafts, food, music:
Wes Porter is a horticultural consultant and writer based in Toronto. Wes has over 40 years of experience in both temperate and tropical horticulture from three continents.
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.
