April 12, 2005

Woolly Bears

Whilst out walking with my sons recently, we've several times spotted "woolly bear" caterpillars. I explained to the boys that these caterpillars would eventually turn into either a butterfly or a moth, but that I didn't know which one. They not unreasonably asked me to find out. So I did a Google search, and to my surprise this is what I found:

A wooly bear caterpillar is black at both ends of its body and has one reddish brown stripe in the middle.

 The wooly bear caterpillar, which turns into the tiger moth, Isia Isabella, is the source of a common superstition. Some people believe that the coat of a wooly bear caterpillar can be used to predict how bad the coming winter will be. There are many wooly bear caterpillars in the United States and Canada. They can be seen anytime from May to October.

They believe that if a wooly bear caterpillar's brown stripe is thick, the winter weather will be mild and if the brown stripes are narrow, the winter will be severe.

Now this rather surprised me, because I've never seen a two-toned woolly bear like the one in the picture, nor have I ever heard of the related bit of folklore. Almost all of the woolly bears I've ever seen here in Southern California have been all black; on rare occasions I've seen ones that were all brown.

Wikipedia comes to the rescue. It turns that there's an entire taxonomic family of tiger moths:

Many species have hairy caterpillars which are popularly known as woolly bears. The scientific name refers to this (Gk. αρκτος = a bear). The caterpillars are usually active during the daytime. If disturbed, they will roll into a tight spiral. Colonial superstition has it that the forthcoming weather can be predicted by the amount of black on a woolly bear caterpillar.

So the local varieties are just a different species than Isia Isabella, but they definitely moths.

Posted by Will Duquette at April 12, 2005 08:35 PM

Deb said:

You need to move UP NORTH where we keep an eye on wooly bears, how the squirrels are putting away thier cache of nuts, how soon the geese fly south and other scientific predicters of the coming winter weather.

Will Duquette said:

"North"? What is this "North" of which you speak?

Deb said:

If you look at a map of the US and can read the writing on it, it's towards the top. Duh!

Will Duquette said:

What? You mean those places are REAL?