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EmailThe woolly bear caterpillar—with its 13 distinct segments of black and reddish-brown—has the reputation of being able to forecast the coming winter weather.
Here are the history, facts, and lore about this legendary caterpillar.
How the Woolly Bear Became "Famous"
- In the fall of 1948, Dr. C. H. Curran, curator of insects at the American Museum of Natural History in New York City, took his wife 40 miles north of the city to Bear Mountain State Park to look at woolly bear caterpillars.
- Dr. Curran collected as many caterpillars as he could in a day, determined the average number of reddish-brown segments, and forecast the coming winter weather through a reporter friend at The New York Herald Tribune.
- Dr. Curran's experiment, which he continued over the next eight years, attempted to prove scientifically a weather rule of thumb that was as old as the hills around Bear Mountain. The resulting publicity made the woolly bear the most recognizable caterpillar in North America.
What is the Woolly Bear?
The caterpillar Curran studied, the true woolly bear, is the larval form of Pyrrharctia isabella, the Isabella tiger moth. See and share this picture of a woolly bear!
Here is more background:
- This medium-size moth, with yellowish-orange and cream-colored wings spotted with black, is common from northern Mexico throughout the United States and across the southern third of Canada.
- As moths go, the Isabella isn't much to look at compared with other species, but its immature larva, called the black-ended bear or the woolly bear (and, throughout the South, woolly worm) is one of the few caterpillars most people can identify.
- Woolly bears do not actually feel much like wool—they are covered with short, stiff bristles of hair.
- In field guides, they're found among the "bristled" species, which include the all-yellow salt marsh caterpillar and several species in the tiger moth family. Not all are 'woolly bears!'
- Woolly bears, like other caterpillars, hatch during warm weather from eggs laid by a female moth.
- Mature woolly bears search for overwintering sites under bark or inside cavities of rocks or logs. (That's why you see so many of them crossing roads and sidewalks in the fall.)
- When spring arrives, woolly bears spin fuzzy cocoons and transform inside them into full-grown moths.
- Typically, the bands at the ends of the caterpillar are black, and the one in the middle is brown or orange, giving the woolly bear its distinctive striped appearance.
Do Woolly Bear Caterpillars Forecast Winter Weather?
According to legend, the wider that middle brown section is (i.e., the more brown segments there are), the milder the coming winter will be. Conversely, a narrow brown band is said to predict a harsh winter. But is it true?
- Between 1948 and 1956, Dr. Curran's average brown-segment counts ranged from 5.3 to 5.6 out of the 13-segment total, meaning that the brown band took up more than a third of the woolly bear's body. As those relatively high numbers suggested, the corresponding winters were milder than average.
- But Curran was under no scientific illusion: He knew that his data samples were small. Although the experiments popularized and, to some people, legitimized folklore, they were simply an excuse for having fun. Curran, his wife, and their group of friends escaped the city to see the foliage each fall, calling themselves The Original Society of the Friends of the Woolly Bear.
- Thirty years after the last meeting of Curran's society, the woolly bear brown-segment counts and winter forecasts were resurrected by the nature museum at Bear Mountain State Park. The annual counts have continued, more or less tongue in cheek, since then.
- For the past 10 years, Banner Elk, North Carolina, has held an annual "Woolly Worm Festival" each October, highlighted by a caterpillar race. Retired mayor Charles Von Canon inspects the champion woolly bear and announces his winter forecast.
Most scientists discount the folklore of woolly bear predictions as just that, folklore. Says Ferguson from his office in Washington, "I've never taken the notion very seriously. You'd have to look at an awful lot of caterpillars in one place over a great many years in order to say there's something to it."
Mike Peters, an entomologist at the University of Massachusetts, doesn't disagree, but he says there could, in fact, be a link between winter severity and the brown band of a woolly bear caterpillar. "There's evidence," he says, "that the number of brown hairs has to do with the age of the caterpillar—in other words, how late it got going in the spring. The [band] does say something about a heavy winter or an early spring. The only thing is . . . it's telling you about the previous year."
What do you think? Do woolly bears predict winter weather? What other signs of the seasons tell us about coming weather?
If you're interested in winter weather predictions, be sure to check out The Old Farmer's Almanac, too!
Comments
In September, I saw 4 all
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By Southern NH
In September, I saw 4 all black wholly bears. Now in October, all the wholly bears I have seen have about 1/4 black on each end and brown in the middle. Also, we can't step out in our backyard without walking on acorns. So, I have a feeling it is going to be a long cold winter, with the ice and snow having fun with us. But I guess we will have to wait and see.
I saw my first one of the
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By Blue Liner
I saw my first one of the season about 15 minutes ago just outside my garage & it was ALL black. I'm just outside Gloversville, NY, bordering the Adirondacks in Upstate NY. I know people think they're a myth but almost every year I've seen them they've matched. Funny one year I saw all white & thought oh boy; we're probably going to get tons of snow & we barely got any. We've had an easy winter last year & the one before wasn't too bad. So my guess (along with my fellow black buddy) is cold times ahead.
I have a wooly winter-over in
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By Mary Tonks
I have a wooly winter-over in my barn every year. Last year's visitor had a very wide brown band and winter was mild. This year, however, my visitor is nearly all black!
I have never in my lifetime,
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By mccbaby102
I have never in my lifetime, I'm 61, ever saw a pure white wooly bear. It had a pinstrip, very small down the middle of its back. I saw 3 of them in less then 1 week. I only saw 1 woolly bear that had the usual brown with black on the tips of both ends. A WHITE WOOLLY BEAR!!!!!! I can't believe it what does it mean. Today someone in a pizza shop saw one too and is alittle afraid about what the future
holds.....Please respond asap> TY. can't wait to hear from you..............Mccbaby
mccbaby - the one and only
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By luci
mccbaby - the one and only time I ever saw a pure white woolly was a few years back when we had an enormous amount of snow. It wasn't a particularly cold winter but we had above average snowfall.
Awesome observations and so
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By katie regan
Awesome observations and so different-from one part of the country to the other . The ones I've spotted here in northern new york where I've lived all of my life, are 98% golden/reddish/brown with very little black, if any. Never before have I seen this. Also the hair was so much thinner than its usual thick make up. Possibly a mild, warmer winter. I am a wolly bear believer. Regardless, the change of seasons in the northern regions is awesome.
Time to bundle up folks,,,happy winter.
Katie
Sept. 27,2012 Saw two woolly
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By Ithaca, NY
Sept. 27,2012
Saw two woolly bears in the last few weeks,
both were light orange, no black on them, hum.
Ithaca, N. Y.
Erie-saw a woolly bear
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By pam-s
Erie-saw a woolly bear caterpillar this morning with NO brown on it...a bad winter ??
It is sept 24th and all I
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By Libby streeter
It is sept 24th and all I have seen this year for wooly bears are all black. I really cant wait to see what this winter has in store for us. Im getting a generator for sure. I live in spencer, mass.
The photo you have is not a
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By rnhowl
The photo you have is not a wooly bear caterpillar! It's a spotted tussock moth caterpillar. At least try to get the photo right.
and the real experts tell us
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By luci
and the real experts tell us that it's also known as the "yellow woolly bear"...
Syracuse NY .... I just saw
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By Jessica t
Syracuse NY .... I just saw one on my door it was tanish red no dark brown at all... Wierd. I've never seen them like that before
The one a friend of ours
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By crdhld
The one a friend of ours found had almost no black, very little on each end...been a lot of yellow jacket nest this year............will just have to wait and see.......
I don't understand, one
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By myknj
I don't understand, one person in NJ commented all orange, yet another said completely black.
have not seen a single wooley bear yet in nj, anyone else?
I have seen many of them that
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By Jennylmoon
I have seen many of them that are all black this year. I live in Maryland. Every year they are different....this is the first I have seen so many all black....we will see..
I haven't seen one yet this
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By muench
I haven't seen one yet this year, but last year I saw a few and they all had huge rust bands, we had a very warm winter!
I saw one today that was
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By vermontjd
I saw one today that was completely orange/brown, no black at all, in Vermont. So I'm hoping for a mild winter since I have a broken ankle and I'm not looking forward to walking thru snow with crutches. Anyone else in VT/NH seen any?
9-13-2012. Last wknd, I saw
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By Zuza
9-13-2012. Last wknd, I saw several Woolies in my back yard. Some were cream colored, some were light-brown/orange, and some were all black. None appeared to have bands. They were hiding in the thick grass between stuff. I was thinking that maybe they get darker as they mature in age. I hope this winter is a bit colder than last though -the bugs are real bad this summer in Chesapeake, VA.
Just found a Wooly bear
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By Deb Lee
Just found a Wooly bear caterpillar on the front walk here in mid southern Ontario Canada just outside of Sarnia. All orange. Hopefully that means a mild winter. Don't want a repeat of two years ago when the 402 highway was shut down because of the huge snowfall.
It is Sept. 1st today in the
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By Peacefulcreek
It is Sept. 1st today in the Rocky Mtns. of Colorado. Twice in the last week, I have seen the "wooly worms" crawling across my pavement. Both were good sized worms and both were entirely black in color....no brown bands on either of them! If the folk lore remains true, we will be in for a severe winter this year...which is good because we have been so dry from past winters hence our summer of forest fires here in Colorado. I sure hope it is a very snowy cold winter here in the Rockies!
We found many black and
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By Jeanne46
We found many black and yellow/orange ones in Austin, NV today. My 4 year old is fascinated by them and wants to see them change into moths. Will they survive in a water jug with holes and cottonwood leaves?
August 27, 2012 and we still
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By Chey
August 27, 2012 and we still have not seen one single Wooly worm this year. Last year, we saw many that were almost completely blonde or very light brown and we had an unusally warm winter. This year, we are not seeing ANY anywhere. (southeast Ohio). has anyone else seen any this year?
Mostly, if not all brown here
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By salmonid74
Mostly, if not all brown here in Maine
I saw a wooly bear a few days
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By rebecca rebecca
I saw a wooly bear a few days ago Aug 25, 2012, it was all black. Just to let you know.
thanks,
All black ones here in
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By Cox
All black ones here in Fairview tn
I have watched them for many
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By Anonymous in maine
I have watched them for many years and it holds pretty true, last year 2011 was a wide band and we had a mild winter, I just saw some with no band, hope this is not true of the worst winter ever. Get ready folks
Ours appear to be all black
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By AnonymousSherry
Ours appear to be all black with an under shadowing of orange. We will see what this winter brings.
I live in central Wisconsin,
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By echo
I live in central Wisconsin, and have seen three Woolly Bear Caterpillers Between April 12th and 15th. They are crawling, look big and fat. How come I am seeing them now? I am a road/walker and see a lot of nature.
Hi, Echo, In northern
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By Almanac Staff
Hi, Echo,
In northern climates, there are usually 2 generations of banded woollybear (isabella tiger moth) per year. Overwintering caterpillars emerge around May. They eat a bit and than pupate. Adult moths emerge in early summer. These will then produce another generation that emerges around August. These caterpillars will overwinter, starting the cycle again.
The fall-generation caterpillars are perhaps more noticeable because they are searching for a good place to overwinter, so they travel about more.
In southern areas, there could be three or more generations. Hope this helps!
i love to explore and find
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By Addie
i love to explore and find bugs. When i do look for bugs the 1 that i try to look for the most is the Woolly Bear Caterpillars. I love caterpillars so much. I look for them every day and I'm always asking my mom if i can order some but she says NO!!!! I'm in 2 grade and i have a sister that is in 3 grade. I have a mom named Sasha. I have a dad named Andy and i have a dog named Howie he is just a baby!
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