Vince_Condella's Blog

With the cooler weather for Milwaukee this week, the feeling of autumn is truly in the air.  And that means the Banded Woolly Bear is on the ground.  You may see this little caterpillar frantically crawling along the sidewalk or roadway on its way to a safe shelter for the winter months.

The woolly bear caterpillar has captivated people for many years because of its so-called predictive powers.  Weather folklore claims that the area of black banding on the woolly bear determines the severity of the upcoming winter.  More black means a harsher winter.  Cute story, but not true.

The woolly bear is the larva of the isabella tiger moth.  Larvae from the same clutch of eggs can vary in color from nearly all reddish brown to nearly all black, even when raised under the same conditions.  This natural variability cancels any predictive power.  The amount of winter cold and snow is due to other forces above the ground, like the jet stream and other variables of the atmosphere.

The larvae emerge from the cold of winter after the little woolly bear survives some pretty harsh conditions.  The caterpillar emits a cryoprotectant to protect its tissue from freezing conditions.  In spring, it "wakes up", eats as much grass and leaves as it can, pupates, and then becomes the adult phase, or isabella tiger moth.

Isabella Tiger Moth

The banded woolly bear caterpillar has evoked many festivals celebrating its life and lore.  Since 1973, Vermillion, Ohio has their Woollybear Festival.  There are two Woolly Worm Festivals each year: one in Beattyville, KY (began in 1987) and another in Banner Elk, NC (started in 1977).

Matching shirts at the Woollybear Festival in Vermillion, Ohio

Logo from the Woolly Worm Festival

That's pretty impressive for a little bi-colored fuzzy critter.  When you see one during the next month or so, make sure it stays safe and gets to the other side of the road or sidewalk.  It still has a difficult job ahead: surviving the cold winter months.