How does the woolly bear caterpillar predict winter weather?

Some people believe the color pattern of a woolly bear caterpillar can forecast the upcoming winter. While only superstition, it is thought that large amounts of black bristle at the caterpillar's head and tail indicate a harsh winter.

Woolly bear caterpillars are covered in wiry hairs, or bristles. They are black at both ends and brown in the middle. Many people believe that more black bristles means a more severe winter.

In reality, the caterpillar's markings have to do with its age and the environment in which it lives. Smaller caterpillars have less black bristles than larger caterpillars. Woolly bears that live in wet environments have more black bristles than those living in dry environments.