Isabella tiger moth

(Pyrrharctia isabella)

Isabella tiger moth
Photo by Bill Reynolds
  Hodges #


Conservation Status
  IUCN Red List

not listed


N5 - Secure


not listed


In its larval (caterpillar) stage, Isabella tiger moth may be the most widely recognized moth in North America. Folklore says that the size of the orange band predicts the severity of the coming winter, with wider bands forecasting a milder winter. This means of forecasting is probably as accurate as the Farmer’s Almanac, though perhaps not as accurate as the National Weather Service.

The adult is less conspicuous but equally distinctive. The adult moth has a wingspan of 1¼ to 2 and a total length of 15 16 to 15 16. The thorax is densely covered with long brown or yellowish-brown hairs. The abdomen is orange with an upper (dorsal) row of black spots.

The forewings are pointed and are uniformly light to medium orangish-brown. On some individuals there is a fringe of reddish-orange hairs on the outer margin. The veins are marked with faint brown spots. There is a series of black spots on the subterminal line and often one or more spots on the antemedial, median, and postmedial lines. The discal spot has a group of 3 to 5 black spots. The hindwing of males are pale orange with a black discal spot and black spots near the margin. The hindwing of females is pale rose but otherwise similar.

The caterpillar is up to 2 long and is densely covered with stiff bristles (setae) from front to back. There are also a few longer, softer hairs extending from the front and back of the body. The setae are in clusters of several and are mostly uniform in length. On most caterpillars the setae are black on the head, thorax, and first few and last few abdominal segments; and orange on the middle abdominal segments. As the caterpillar ages and grows, it sheds its skin and setae (molts) several times. At each successive stage between molts (instar) it becomes more orange. On some individuals all of the setae are blond, brown, rust, or tan. There is a small breathing hole (spiracle) on both sides of each thoracic segment and all but the last abdominal segment. On pale individuals the spiracles are tan or white.




Total length: 15 16 to 15 16

Wingspan: 1¾ to 2½


Similar Species


Deciduous woodlands, prairies




One brood. Early June to late July.




Caterpillars are especially mobile in the fall. When disturbed, they curl up into a ball.

Adults are nocturnal. They are attracted to lights.


Life Cycle


Eggs hatch after about two weeks. Caterpillars overwinter under leaf litter or other debris, where they freeze solid. In the spring they become active and resume feeding. After a few days then spin a cocoon to pupate. Adults emerge in about a month.


Larva Hosts


Deciduous trees and a wide range of low growing herbaceous and woody plants.


Adult Food


Adults do not feed.


Distribution Map



21, 24, 27, 29, 30, 71, 75, 82.




Widespread and common



Lepidoptera (butterflies and moths)  


  Infraorder Heteroneura  


Noctuoidea (owlet moths and allies)  


Erebidae (underwing, tiger, tussock, and allied moths)  


Arctiinae (tiger moths and allies)  


Arctiini (tiger moths)  
  Subtribe Spilosomina  



In 2011 the family Arctiidae (tiger moths and lichen moths) was transferred to the family Erebidae mostly intact but demoted to a subfamily. The former subfamilies are now tribes, the former tribes now subtribes.




Isia isabella


Common Names


banded woollybear

black-ended bear

Isabella tiger moth

woolly bear











The developmental stage of arthropods between each molt; in insects, the developmental stage of the larvae or nymph.



A usually rigid bristle- or hair-like structure on butterflies and moths used to sense touch. Plural: setae.



A small opening on the surface of an insect through which the insect breathes.






Visitor Photos

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Alfredo Colon

    Isabella tiger moth   Isabella tiger moth  
    Isabella tiger moth   Isabella tiger moth  

Greg Watson

    Isabella tiger moth      


    Isabella tiger moth      

Margot Avey

    Isabella tiger moth      


    Isabella tiger moth      

Bill Reynolds

    Isabella tiger moth   Isabella tiger moth  
    Isabella tiger moth      





Isabella Tiger Moth
  Isabella Tiger Moth  

Copyright DianesDigitals

Woolly Bear Caterpillar
Andree Reno Sanborn
  Woolly Bear Caterpillar  

Pyrrharctia isabella (larval form)


adult is the Giant Leopard Moth:

Pyrrharctia isabella (Isabella Tiger Moth)
Allen Chartier
  Pyrrharctia isabella (Isabella Tiger Moth)  



Visitor Videos

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Other Videos
  Isabella Tiger Moth (Erebidae: Pyrrharctia isabella) Caterpillar
Carl Barrentine

Uploaded on Oct 6, 2010

Photographed on a blustery afternoon near Fisher, Minnesota (04 October 2010).

  Run, Woolly, Run!

Uploaded on Oct 14, 2008

A Woolly Bear (the caterpillar stage of the Isabella tiger moth, Pyrrharctia isabella) showed up in the yard, so I recorded it running away. Maybe it thought I was a predator. Boy, I've never seen one move so fast!

  Banded Woolly Bear Caterpillar (Pyrrharctia Isabella)

Uploaded on Jan 23, 2012

Just some quick footage of a banded woolly bear caterpillar I rescued from the pool. They turn into a isabella tiger moth.

  Wooly bear caterpillar (Pyrrharctia isabella)

Published on Oct 4, 2012

Larval form of Isabella's tiger moth. Amherst, VA. Slow speed.




Visitor Sightings

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  Greg Watson

Location: La Crescent, MN

Isabella tiger moth

  Alfredo Colon

Location: Albany, NY

Isabella tiger moth


Location: St. Paul, MN

they are unusual. :)

Isabella tiger moth

  Alfredo Colon

Location: Woodbury, Minnesota

Isabella tiger moth

  Margot Avey

Location: St. Louis Park, MN

Isabella tiger moth


Location: Roanoke VA

Isabella tiger moth

  Peggy Haskin

Hello:  I found a woolly bear caterpillar in my house today.  I thought he was dead, but when I touched him he curled up.  I'd like to save the little critter, but if I put him outside (it's 20 degrees here today), I'm afraid he'll immediately freeze.  I have a small tree planted in a large pot in my house, so I put him on top of the soil.  He's crawling around.  I looked online and saw directions for "overwintering" him, but it said I should collect leaves from outside to feed him. Well, as you know, there are no leaves outside.  Can you give me some advice on what to do with him?  Thanks so much.

  John Valo

Maybe put in in a refrigerator with a potted plant (for it to hang from) in the hope that it will create a cocoon and pupate. The cold may be the trigger it needs.

  Bill Reynolds

Location: Pennington Co. MN

… this fall we had tons of Woolly Bear caterpillars crawling about the yard.

Isabella tiger moth

  Bill Reynolds

Location: Pennington Co. MN

Woolly Worm, the caterpillar stage of the Isabelle Tiger moth.

Isabella tiger moth





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