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Wooly Bears 

August Nature Notes: Legions of caterpillars are inching their way through Illinois this month. 
By: Carol McFeeters Thompson 
On crisp autumn afternoons, legions of woolly bear caterpillars inch their way across country roads in an endless parade that travels at the frantic pace of four feet per minute. Multitudes of the short, fuzzy caterpillars scurry in every direction, as if each has some important place to go.          

Woolly bears wear a dense coat of “fur” in three stripes, black at each end with a rusty band in the middle. An insect, larva of the Isabella moth, woolly bears have six true legs with claws, one pair on each of the first three segments. The next four segments have prolegs—fleshy extensions of the body that look like suction cups. There is a single prop leg at the rear. This arrangement gives the bear his lumbering gait.          

The traveling bears have finished feeding for the year and are in search of the perfect sheltered spot to overwinter. Woolly bears spend the winter, not in the pupal stage like most moths, but as caterpillars.          

According to folklore, the beloved bears are able to predict the severity of the coming winter. If the middle band is the narrowest, the approaching winter will be severe. If the middle band is the widest, the winter will be mild.  


Carol McFeeters Thompson is the Interpreter at Weldon Springs State Recreation Area and a regular contributor to OutdoorIllinois.