woolly bear
woolly bear, the caterpillar of any of several species of tiger moth.
One of the most well-known species is the banded wooly bear, which is the larva of the Isabella tiger moth (Pyrrharctia isabella), known as the banded woolly bear, is brown in the middle and black at both ends. The width of the black bands is purported to predict the severity of the coming winter: the narrower the bands, the milder the weather will be.
The Editors of Encyclopaedia Britannica This article was most recently revised and updated by Melissa Petruzzello.
Citation Information
Article Title:
woolly bear
Website Name:
Encyclopaedia Britannica
Publisher:
Encyclopaedia Britannica, Inc.
Date Published:
19 November 2025
Access Date:
November 14, 2026