No, Woolly Bears aren’t large, furry mammals like black, brown, panda, or polar bears.
The Woolly Bears I’m referring to are insects.
They’re the adorably fuzzy black-with-rust-band caterpillars that appear throughout the U.S. and parts of Canada and Mexico every autumn, usually in September. I remember being delighted spotting them as a child growing up in western Washington state. If I touched them while they were still on the ground, or gently picked one up to hold in my palm, they would slowly curl into a tight, furry ball. Once they felt safe in my hand, though, they would open up and start crawling again. They have fourteen tiny “feet” that tickled ever-so-lightly when moving across my skin.
I don’t remember having a particular name for them then. I just called them caterpillars.
Now I know they have the perfect name: Woolly Bears. Their scientific name is Pyrrharctia isabella, and in the spring they become the beautiful orange Isabella Tiger Moth.
Even more than the cooler temperatures and shorter days, for me it’s leaves turning color and these banded caterpillars appearing that announce the arrival of autumn. (This year, autumn officially starts tomorrow, September 22, 2021.)
As the boys and I were finishing our walk this morning, I saw this Woolly Bear crossing the road, right on schedule.
Most mornings I take my dogs for an easy-paced stroll of a couple of miles through the neighbors’ fields and forests. Finn is doing great, with a slight head tilt the only sign he was dealing with vertigo a few weeks ago. But he’s an old man, so we go at an old man’s pace. I rather enjoy that pace because I have more time for photos. We go early, maybe an hour after sunrise, so there’s often some mist on the ponds, or fog hovering over the fields, and on clear days, early sunlight filters through the leaves and limbs of the tall maples and birches.
The leaves are starting to turn in Vermont. One young maple we pass regularly, deep in the woods, is already entirely on fire with brilliant vermilion leaves.
The chokecherry trees along the fields’ edges started their transition weeks ago, turning a deep reddish purple, but their leaves are small and they’re a fairly short tree, so their visual impact is muted. It’s the older maples and birches, rising high above their neighbors, that will put on the real show over the coming weeks.
Closer to the ground there’s plenty of autumn to see. While the abundant Goldenrod and Milkweed flowers have recently gone to seed, Asters – both white and purple – continue to add brightness to the landscape, blooming abundantly on the edges of woodland paths and roads.
Tourists who come to New England to view the autumn colors are referred to leaf peepers.
Well, I’m not a tourist in Vermont, but I’m such a recent transplant that I will fully embrace my leaf peeping status this autumn. I’m looking forward to the next several weeks, watching the hillsides all around me change until they’re exploding with variations of yellows, oranges and reds before finally dropping their leaves for winter.
Once all the leaves are on the ground, dried and crunching underfoot as the air turns frigid and smells of snow? That, I’m told, is called “stick season” in Vermont. The transition from fall to winter.
But wait, what about that adorable Woolly Bear caterpillar I mentioned at the start of this post?
You know me. Intrigued by the one I saw this morning, I couldn’t resist learning more about them.
Also known as the Woolly Worm in the south (though decidedly not a worm), it turns out Woolly Bears are so heavily associated with autumn that here in the Northeast they have inspired winter-weather-predicting folklore going back generations. And they have a strange and fascinating sort of anti-freeze in their blood that allows them to withstand incredibly cold winters in a state of hibernation.
They’re also known as the Hedgehog Caterpillar for their habit of curling into a tight ball as a defense mechanism, something I found charming as a young girl.
Woolly Bear caterpillars hatch in summer from eggs laid by the female Tiger Moth. In autumn, they leave the plants they’ve been munching on all summer (grasses, weeds, nettles, dandelions) and are seen crossing roads and sidewalks in search of a winter hiding place under bark or in the cavities of rocks and logs, where they hibernate. The following spring they’ll spin a fuzzy cocoon – I remember as a child seeing the cocoons on the side of our house, snug in corners, usually on brick, where they were well protected from weather – eventually emerging as a Tiger Moth.
What follows is information about Woolly Bears found on the U.S. National Weather Service website. Yes, the Weather Service, proving the strength and longevity of the folklore about Woolly Bears predicting winter weather.
According to folklore, the amount of black on the woolly bear in autumn varies proportionately with the severity of the coming winter in the locality where the caterpillar is found. The longer the woolly bear’s black bands, the longer, colder, snowier, and more severe the winter will be. Similarly, the wider the middle brown band is associated with a milder upcoming winter. The position of the longest dark bands supposedly indicates which part of winter will be coldest or hardest. If the head end of the caterpillar is dark, the beginning of winter will be severe. If the tail end is dark, the end of winter will be cold. In addition, the woolly bear caterpillar has 13 segments to its body, which traditional forecasters say correspond to the 13 weeks of winter.
As with most folklore, there are 2 other versions to this story. The first one says that the woolly bear caterpillar’s coat will indicate the upcoming winter’s severity. So, if its coat is very woolly, it will be a cold winter. The final version deals with the woolly bear caterpillar’s direction of travel. It is said that woolly bears crawling in a southerly direction are trying to escape the cold winter conditions of the north. On the other hand, woolly bears crawling on a northward path would indicate a mild winter.
Even though it is widely believed that the woolly bear caterpillar can predict the upcoming winter’s severity, the truth is that this caterpillar can’t predict what Old Man Winter has in store for us in the upcoming winter. The woolly bear caterpillar’s coloring is based on how long the caterpillar has been feeding, its age, and species. The better the growing season is, the bigger it will grow. This results in narrower red-orange bands in its middle. Thus, the width of the banding is an indicator of the current or past season’s growth rather than an indicator of the severity of the upcoming winter. Also, the coloring indicates the age of the woolly bear caterpillar. The caterpillars shed their skins or molt six times before reaching adult size. With each successive molt, their colors change, becoming less black and more reddish. In addition, there are approximately 260 species of tiger moths (the adult of the woolly bear caterpillar) in North America, and each species has slightly different color patterns and hair coverings. As a result, some of the color and hair variations that we see each fall are a result of these different species.
As far as the story about the woolly caterpillar’s coat, this is how Mother Nature helps it survive winter. The fur is called setae and it isn’t there to protect them from the cold weather. Instead it actually helps them to freeze more controllably. Here is something truly remarkable. Once settled in, the caterpillars hibernate, creating a natural organic antifreeze called glycerol. They freeze bit by bit, until everything but the interior of their cells are frozen. These interior cells are protected by the hemolymph. Woolly bears can – and do – survive to temperatures as low as -90F. This ability to adapt to cold shows up particularly in the Arctic, where the woolly worms live in a strange state of slow motion. Most caterpillars live for two to four weeks before becoming moths. The Arctic woolly worms, however, spend at least 14 years in the process! The woolly bear caterpillar has even been known to survive an entire winter completely frozen in an ice cube.
This myth [of predicting winter] has been around since colonial times. However, it grew in popularity after Dr. Howard Curran (curator of entomology from the American Museum of Natural History) did a small study in 1948. He went out to Bear Mountain, New York with a reporter, his colleagues, and their wives. He counted the brown bands on 15 different specimens. He then made a prediction for the winter. This news story was published in the New York Herald Tribune. It was picked up by the national press and the rest is history.National Weather Service
Feature photo: Conall waiting for me and Finn to catch up before leaving the fields for home. He’s wearing his orange Do Not Hunt Me vest because, well, it’s hunting season again. At least it’s not legal to hunt wolves in Vermont, so it’s slightly better than Idaho, but not much. Behind Conall, chokecherry leaves make a red band close to the ground while the taller maple is just showing hints of fall color. September 20, 2021.