2024 December 28

   Marie O’Shaughnessy writes: I was at Maber Flats with Carla on Christmas Eve December 24th and during our walk we found a Banded Woolly Bear caterpillar crawling along the dirt pathway. I thought it was so surprising to see the larva of the Isabella Tiger Moth in December. Is this sighting unusual?

When I researched this caterpillar I was fascinated to find it is featured in the old Farmer’s Folk Lore Almanac.

It is reputed (!) to be able to forecast the winter weather, based on the width of the orange/rust coloured middle band. The more of this colour the milder the winter weather, and the more black each end of the caterpillar , the harsher the weather.   So it is said, anyway!

Jeremy Tatum writes:  The Banded Woolly Bear (which, as Marie, says, is the caterpillar of the Isabella Tiger Moth) spends the winter as a caterpillar.  We generally see lots of them in October, and then we see them again in March or April as they come out of winter hibernation.  Mild mid-winter may cause them to wake up and wander around.  Whether this is good for them is questionable – it may be better for them to sleep undisturbed throughout the winter.

And yes, the width of the central brown band is indeed reputed to forecast the severity of the winter.  This is, of course, total nonsense – the width of the band has nothing whatever to do with forecasting winter.  But it persists as part of folklore, and it is remarkable that there are still people who believe it to be true.

Banded Woolly Bear Pyrrharctia isabella (Lep.: Erebidae – Arctiinae)
Marie O’Shaughnessy