How To Read A Woolly Worm?

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Last Updated on January 9, 2023 by Urska

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.


What do the colors on a wooly worm mean?

The colors of the wooly worm are very interesting. They are in fact, not so much a matter of color as of pattern. Each of these is actually a worm with its own particular color pattern. The colors are actually a result of the different parts of the worm that it has in it. For example, a wooly worm might have one head and two tails.

In this case, the head would be white, the body grey, and the two tails black and white. If you look at the photo of a wooly worm, you will see that it has a series of bumps on it. These bumps are actually the heads of the worms. The worms' bodies, or the rest of their bodies, is covered by their heads.

When the worms are young, the pattern on their bodies will be very simple. They will have just a few colors, but as they grow up, their bodies will become more complex. As the worms grow up, they also get bigger. When the worms are fully grown, they will be about the size of an inch long. Wooly Worms can live for a long time. They will continue to grow until they reach a certain age. Once this has happened, they will begin to die off. Wooly worms can live for about six months in the wild. But in the wild, most of them do not survive for more than a few weeks.

What happens if you touch a wooly worm?

You get a little shock. That’s the experience of the worm. The worm has tiny hairs on its skin that send out electrical signals to warn other worms about the danger posed by you. That’s why it’s called a “wet dog” — because when you touch a worm, you get a little shock. But this is no ordinary wet dog.

Do caterpillars need water?

Caterpillars are not dependent on water for their survival, but they do use it as a food source. Most caterpillars have some sort of water storage organ that holds moisture for them to use. The amount of water stored varies by species and may depend on the time of year. Some species of caterpillars can also make use of the water in their food source (their food plant) to help them survive.

How long does it take a woolly bear to turn into a moth?

It's a common myth that if you leave a woolly bear in the sun for a few hours, it will slowly shrink and become a moth. The truth is that it takes a woolly bear about a week to turn into a moth. The myth is based on a misunderstanding of the life cycle of the woolly bear caterpillar.

A woolly bear caterpillar needs to be protected from the sun for a long time so that it can grow and mature as a chrysalis. If it is kept in the shade or in a cool room, it will eventually turn into a moth.

What is caterpillar's favorite food?

Caterpillars eat a variety of plants. However, one plant they particularly like is the oak leaf (maple). The caterpillars chew off the leaves of the oak trees, then use their mouthparts to absorb nutrients from the damaged tissue.

Once the caterpillar has consumed all of the nutrient-rich tissue, it spins a cocoon and becomes a chrysalis.


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?

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