How To Read A Woolly Worm

How To Read A Woolly Worm?

Do you know how to read a woolly worm, or are you like many of us who have heard about this mysterious caterpillar and want to know more? Here we will learn all about it.

If you want to forecast the upcoming winter, you may have heard that you should look at a woolly bear caterpillar and get it all sorted.  This same caterpillar is known as the Wooly worm in the Southern United States.

This caterpillar is known in many different names, with most people calling it a hedgehog caterpillar because it curls up into a tight bristly ball and plays dead when disturbed or disabled.

Whatever name you call them, these caterpillars are found in the autumn after they have left their food plants searching for a dark and sheltered place to hibernate as larvae all through winter.  Their food sources include dandelion, plantain, grasses, weeds, and nettles.

So What’s A Woolly Worm?

The woolly worm or woolly bear is a fuzzy brown and black creature, which is the larval form of the tiger moth (Isia isabella).

These worms appear in early fall to feast on common plants, hibernate during winter, and emerge in spring from the pupa stage as moths.  These worms have a reputation for forecasting the winter weather and have been believed to do so for many years.

If their rusty band is vast, the winter will be mild, but if it’s black, then the winter will be severe.  How true this is remains a mystery that most people are not able to decode.

So What’s A Woolly Worm

Did you know the “woolly worm” is not a worm at all?  It’s a caterpillar- specifically the larva of the Isabella Tiger Moth. The caterpillar has13 distinct segments of either black or rusty brown. In other cases, it is black on both ends with rust-colored details in the middle, although it may mostly look black or rust.

Woolly worms are generalist feeders – this means they will eat a wide variety of nature’s goodies, but they favor leaves. Throughout the summer and fall months, they eat a wide variety of greenery from native plants, mostly from herbs like dandelion, nettle, plantain, tree leaves, and other foliage.

In their caterpillar form, woolly bears tend to be nocturnal – they eat at night and sleep during the daytime.  They sleep under the fallen leaves or in other hidden spots. When winter strikes, these worms make their way to hiding places where they will stay during winter.  That is the time we sight them meandering slowly about during the day.

How Does The Woolly Worm Behave During Winter?

As the winter sets in, this worm or bear caterpillar goes into hibernation, choosing a secluded area, maybe inside a fallen log, under a stone, or any other good winter hiding place.  Interestingly, these caterpillars might be the only nature’s ultimate survivors.

Did you know woolly bears produce a kind of antifreeze that safeguards their organs and other soft tissues while the rest of the caterpillars freeze to death in winter?  These caterpillars are able to survive temperatures as low as -66 degrees Celsius!

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Which People Use Woolly Worms The Most?

For the longest time, North Carolina’s Mountain people have relied on the woolly worm’s markings to predict the upcoming winter. They have a strong belief that the coloration of the woolly worm’s coat matches the harsh and mild periods of the winter.

For example, the 13 bands on the caterpillar’s body that are colored black and brown correspond to the 13 weeks of winter.  The darker the band, the harsher the winter in that particular week.

Another version says that the dark color symbolizes a hard winter is upcoming, and most brown bands predict a mild winter.

Read more about Keeping Your Patio Warm In Winter Months

How To Read The Black Woolly Worm

Now that we know what a woolly worm looks like, what it eats, and its behavior in winter, let’s look at how to read it.

Caterpillar winter prediction is a popular fall fun pastime in the North Carolina Mountains.  They go as far as hosting an annual Woolly Worm Festival at which the main events are the woolly worm races, funny ha!  Whoever thinks of racing worms?  Unknowingly and untrained, these caterpillars race on three-foot strings in heats until a champion is found.  And the winning woolly worm is the one to be used for the upcoming winter’s prediction.  Maybe you should plan to attend this exciting and mysterious competition.

The Center for Woolly Worm Studies at Appalachian State University in Boone is serious about these worms. It holds annual studies of about 500 woolly bear caterpillars as a scientific attempt to predict the winter weather.

Next time you come across this worm in the fall, take a close look at them.  There are two generations of these worms.  Some appear in June and July while others in September.  The September ones are the weather forecasters using their wooly bear color meanings.

Once you find these worms, start observing the colors of their brand and what they predict about the winter weather. If the rusty band is wide, the winter will be mild, but it will be more severe if it’s dark.


We cannot decide if these people are right or wrong because we have not seen the worm ourselves.  But based on the claims we have read across the internet, most North Carolina people swear by the predictions of these worms.

They have clearly defined the weather prediction from this worm, most of which has turned out as they predicted.  You never know; science could exist even in things we have no idea of.

Besides, nature itself is science, and it has a lot of predictions it gives us.  If we only learn how to take care of Mother Nature and its unique creatures, we would have a better world to live in, and our food would be healthy.

The internet has some great resources about this caterpillar.  Have some fun looking up information about how to read a woolly worm and its exciting facts, won’t you?