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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.
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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!
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Comments
Very interesting. Thanks for
Very interesting. Thanks for the good read & keep on predicting!
hmmm very cool and my
hmmm very cool and my daughter was facinated when i read it to her
This is something I've heard
This is something I've heard all my life, passed down from several generations in my family. I never made the empirical observation myself, but my grandmother did every year, and she swore by it! Some other signs she looked for were the thickness of hulls on hickory nuts and walnuts, and if the garden produced a bountiful crop that summer.
I have to agree some with
I have to agree some with Craig King. I have watched the Wolly Worm for years but have not gotten any answers about the weather. I find the the Quantity of Nuts and wild berries that are produced, the thickness of the shells are a better clue as to the temperature of the winter. Also find that the closer to the ground that the wasps and hornets build their nests in the summer the colder it will be in the winter. I think that folks in different areas have their own special ways of determining how they think the weather is forecasted in that area.
Hardyville,Va
i have heard as a child for
i have heard as a child for weather forcasting the catapiller is quite accurate in priducting the coming winter
I have also heard this all my
I have also heard this all my life and I agree has been accurate to a point. My belief is old sayings from generation to generation have thier reasons to carry on, If they did not believe in knowing what they see to be the truth, which is to predict the coming winter. Good feeling to read this article.
Thank you
I was raised on this way of
I was raised on this way of forecasting the winters. The woolys here in my part of Ky. are showing very little brown. Very large area of black on both ends. Will be interesting to note what kind of winter we end up with. Unusually cold for this time of year and early frost so far...
Very interesting and
Very interesting and informative article. A friend of mine recently told me squirrels were very active this past summer gathering all the nuts they could, which he said they do for in preparation for a long harsh winter. I hope he's wrong!
I believe in the woolly bear.
I believe in the woolly bear. I have seen several in my area this year, and the squirrels has been very busy this fall. I'm looking for a long cold winter this year in East Central Kentucky.
We too were brought up on
We too were brought up on looking at the wooly bears for how cold the winters would be. We were told that the blacker they were the colder it would be.
Personally, I hope they are wrong, this year's are mostly black. Like most everyone else, the squirrels are very busy collecting this years bumper crop of nuts.
This is the first time I hear
This is the first time I hear this about the Woolly Bear Caterpillar although I've been seeing them my whole life! Thank you!
I knew of wooly worms in
I knew of wooly worms in Nebraska but here in Denver, Colorado I don't find the wooly worms. Do you know what areas the worms do not ive in? and why?
Interesting article -- but
Interesting article -- but what does it mean when up here in central New York, neither I nor my family have yet to SEE even one woolly bear this Fall? It's the first time I can recall that happening in my 73 years up here.
I grew up in PA. One year I
I grew up in PA. One year I showed my Mom one I found, she said"Oh No are they all like that?" I told her yes, she said, we're in for a bad winter" Well those wooly bears were right, it was a terrible winter. this past fall in West TN the wooly bears were black and so far we have had 17 inches of snow when a normal total snowfall for the season may be 1 to 2 inches. I have lived here for 14 years and this is the first time I ever saw the wooly bears all black and I would definitely say they were right! So much for science ha!ha! GOD BLESS!
Our woollies have always had
Our woollies have always had thick dark bands on them. yesterday I saw two without a single band....they were both a dark orange, very furry and quite large. what does this mean for this winter in southern Wisconsin?
Our wooly worms/bears are all
Our wooly worms/bears are all orange also! Here in central southern michigan. What does it mean?!
Here in S.W. Missouri, as far
Here in S.W. Missouri, as far back as when I first came here in 1965, all the old folks predicted the winter as to how black looking they were. When lighter, a mild winter, when dark, a harder winter.
Wooly bears, Acorns and ice
Wooly bears, Acorns and ice in the Northeast.
This year there are so many acorns I cant walk a step in the back yard without stepping on three. The wooly bears are all orange though. This combination usually means that when we have precipitation we will see little snow, a lot of ice and the winter will be longer than normal. We are collecting the acorns for the deer due to the ice build up on trees will make it nearly impossible for them to get a decent meal in late february. Signing off in the lower hills of the Berkshires
NJ wooly bears are all orange
NJ wooly bears are all orange this year too! I thought I was imagining it, but then I found this article. I wonder what is going on?
Georgia wolly worms/bears are
Georgia wolly worms/bears are all orange this year as well.
I have seen all black ones
I have seen all black ones then some with black on each end and brown in the middle. What does that mean?
I live in the southwest part
I live in the southwest part of Virginia (the mountains) and I've seen two caterpillars, barely the tinest of black on each end and 99% brown/orange in the middle. Never seen one that wasn't striped at all---interesting to see what kind of winter this will be.
I live in Western NC about an
I live in Western NC about an hour west of Boone, NC. This year the Woolly Worms here are mostly black with very little red or either all black.
I live in Fayetteville, NC.
I live in Fayetteville, NC. Just saw a wooley worm for the first time! I had to look it up just to know what it was. I was so surprised at how big it was. I took pictures with my finger for comparison :) No brown/red at all. Completely black. It will be interesting to see what the weather is like here!
Fortunately, the woolly bear
Fortunately, the woolly bear caterpillar I had just found late last week was almost entirely reddish-brown, with hardly any black whatsoever. I sure could use a mild winter here in Northern Virginia. Last winter was hellacious, with a three foot snowfall in one weekend last February. I am soooo not looking forward to a repeat of that. Thank you ~ (•8-D
All Black here in Salvisa. Ky
All Black here in Salvisa. Ky from North Carolina and have always seen striped in NC! I think the solid colors mean a solid winter!!
They are all black here in
They are all black here in Springfield Twp, NJ too. Have never seen them all black!
I agree, all that I have
I agree, all that I have found here in North East Ohio, 2 miles from Lake Erie are also all black. Not boding well for a smooth winter at all.
Here in Toronto Ontario I
Here in Toronto Ontario I have seen off white and totally gray ones:-) Interesting! Two one the off white and the other one was silver gray.
Stay away from these, the
Stay away from these, the bristles are infectious.
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