Hiker's Notebook: Woolly Bear Caterpillar

Common Name: Woolly Bear, Woolly Worm, Black-ended Bear

Scientific Name: Isia Isabella, Isabella Tiger Moth (larval form)

The most recognized of the caterpillars since Colonial times, the Woolly Bear is most frequently found crossing roads, paths and trails in the late Fall.

Potpourri: The alternating black-brown-black bands of the Woolly Bear Caterpillar are reputed to provide a forecast of the severity of the on-coming winter. According to this legend, the wider the brown section in the middle, the milder the winter. In actuality, the amount of black increases with age, so the width of the brown segment is an indication of how late in the spring (i.e. how harsh the previous winter) that the caterpillar got moving.

The stiff black and brown hairs of the Woolly Bear protect it from being eaten, as they contain a stinging chemical.

After hatching in warm weather, the larvae feed on grasses and forbs (small herbaceous non-woody plants). The mature Woolly Bears then set out in search of over wintering sites. That is why you often see them crossing trails.