ONH

Woolly Bear Caterpillars

  • 1635
  • 3303
  • 3946
  • P1260481
  • 1941
  • 1945
  • 1952
  • 3736
  • 3465
  • P1560701
  • 1635
    1 - Banded Woolly Bear, Pyrrharctia isabella.

    09/27/2008 Dungeness National Wildlife Refuge, Washington

  • 3303
    2 - Banded Woolly Bear, about 3 centimeters long.

    09/27/2008 Dungeness National Wildlife Refuge, Washington

  • 3946
    3 - Banded Woolly Bear.

    10/05/2005 Heart O' the Hills Area, Olympic National Park, Washington

  • P1260481
    4 - Banded Woolly Bea, adult Pyrrharctia isabella on Bluebells of Scotland Campanula rotundifolia.

    Sunrise Ridge Trail Olympic National Park, Washington

  • 1941
    5 - Yellow Woolly Bear, Spilosoma virginica.

    09/22/2006 Heart O' the Hills Area, Olympic National Park, Washington

  • 1945
    6 - Yellow Woolly Bear.

    09/22/2006 Heart O' the Hills Area, Olympic National Park, Washington

  • 1952
    7 - Yellow Woolly Bear, crawling head downward, showing several pairs of soft prolegs.

    09/22/2006 Heart O' the Hills Area, Olympic National Park, Washington

  • 3736
    8 - Yellow Woolly Bear.

    09/22/2006 Heart O' the Hills Area, Olympic National Park, Washington

  • 3465
    9 - Yellow Woolly Bear, an uncommon darker variant.

    9/06/2005 Heart O' the Hills Area, Olympic National Park, Washington

  • P1560701
    10 - Yellow Woolly Bear, an uncommon darker variant.

    9/08/2022 Upper Wolf Creek Trail, Hurricane Ridge, Olympic National Park, WA

The caterpillars commonly called woolly bears are the larvae of two moth species the Banded Woolly Bear, Isabella Tiger Moth, Pyrrharctia isabella, and the Yellow Woolly Bear, Vestal Tiger Moth Spilosoma virginica.

Like all caterpillars, they have six jointed true legs in the front and several pairs of soft prolegs in the rear (slide 6).

Photos of the adult moths and photos of other variant colorations are in Insects of the Pacific Northwest, by Peter Haggard and Judy Haggard and on bugguide.net.