The all-time predictor of the winter to come is the Wooly Worm, also known as  Fuzzy Bear, Hedgehog Caterpillar or Woolly Bear (approved name by the Entomological Society of America). This is the larval stage of the Isabella Tiger Moth, an orange-yellow moth with a wing span

of 2”.

Woolly Bear Caterpillars are usually seen in the fall as they search about for a perfect place to curl up and spend the winter, which is usually under bark, a rock, a log, etc. Their heavy coats, along with producing natural organic antifreeze, help them over-winter. They can actually survive -90 degree F temperatures!

In the spring, they warm back up, begin to feed for a while and then form a cocoon, pupate and emerge as the Isabella Tiger Moth. Fertilized female moths lay their eggs on a variety of plants including birch, elm, maples, asters, sunflowers, spinach, cabbage, grass,  and plantain, where the eggs hatch. The small caterpillars begin to feed on their host plants and the process starts all over again. There are usually 2-3 generations each year and it’s the last generation that over-winters as the Woolly Bear Caterpillar.

Woolly worms have very tiny eyes and a limited range of sight. They pass through up to 6 larval stages before reaching the stage most see in the fall; during which the color and size of its bands on the 13 body segments may change. It is those 13 bands that folklorists use to help predict the weather. According to folklore: 

   -  The amount of black in the fall varies proportionately with the severity of the

       upcoming winter

   -  The longer the black bands, the longer, colder, snowier and more severe the winter will be.

   -  And the position of the bands indicates which parts of winter will be the coldest.

   -  If the head is dark, the winter starts out severe

   -  If the tail is dark, the end will be cold

   -  Since the Woolly Bear has 13 body segments, folklorists believe that each segment

       corresponds to one of the 13 weeks of winter. So reading each band could conceivably

       forecast each week of the winter.

Other signs include thicker coats meaning colder winters and if they seem to be traveling south, they are trying to escape the cold conditions of the north. If they are traveling north, however, it indicates a milder winter.

Through the years, research has shown us that the Woolly Bear caterpillar’s coloring is actually based on how long the caterpillar has been feeding, its age and, of course, the species. The better the growing season, the bigger it will grow and this results in a narrower red-orange band in its middle. So, the width of the banding is really an indicator of the current or past season’s growth, rather than an indicator of the severity of the upcoming winter. And as these caterpillars may molt as many as 6 times before reaching adult size and the colors will change with each molt, they become less black and more reddish.

Source: www.rwilson@natorp.com; www.backyardwildlifehabitat.info/index.htm

Fuzzy Bear Caterpillar

Isabella Tiger Moth

Flight June-August in the North, February-November in the South.

Habitat Meadows, pastures, uncultivated fields, and road edges.

Range Throughout North America, except northern Canada.