Very hairy caterpillars known as woollybears make their appearance in late summer and autumn. The comparison to bears comes from their hairy appearance, wandering habits and the fact that they feed on a variety of plants. But, the caterpillars rarely cause concern because the damage they do occurs so late in the growing season.
The most common species in Colorado are the yellow woollybear and saltmarsh caterpillar. The banded woollybear is the less common of the two, but the best known.Folklore says that the wider the bands are on these caterpillars, the more severe an upcoming winter will be. Little, if any, evidence indicates there’s a connection between band width and future weather.
Yellow woollybear and saltmarsh caterpillars spend the winter in silken cocoons. The banded woollybear spends the winter in its hairy, larval stage and begins to change in spring. Then, all the caterpillars transform into attractive, white moths. Many have a banded pattern leading to the common name, “tiger moths,” for the adults.