showed that the larvae of a related moth, Grammia incorrupta (whose larvae are also called 'woollybears'), consume alkaloid-laden leaves that help fight off internal parasitic fly larvae. Based on the caterpillars' wide range of food plants, this moth could be found almost anywhere that plants grow. This species is a generalist feeder, consuming many plant species, including herbs and trees. Handling larvae is discouraged, however, because their sharp, spiny hairs may cause dermatitis in some people. Larval setae do not inject venom and are not urticant they do not typically cause irritation, injury, inflammation, or swelling. It survives being frozen by producing a cryoprotectant in its tissues. First its heart stops beating, then its gut freezes, then its blood, followed by the rest of the body. The banded woolly bear larva emerges from the egg in the fall and overwinters in its caterpillar form, when it literally freezes solid. The isabella tiger moth can be found in many cold regions, including the Arctic. Adults are generally dull yellowish through orangish and have robust, scaly thoraces small heads and bright reddish-orange forelegs. In direct sunlight, the brown hair looks bright reddish brown. The thirteen-segment larvae are usually covered with brown hair in their mid-regions and black hair in their anterior and posterior areas. It was first formally named by James Edward Smith in 1797.

Pyrrharctia isabella, the isabella tiger moth, whose larval form is called the banded woolly bear, woolly bear, or woolly worm, occurs in the United States and southern Canada.

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