What are the woolly bear caterpillar predators in the wild, and how do they protect themselves from these hunters? Read on to learn about the fascinating defense mechanisms of these tiny creatures
Tiny caterpillars are easy prey for hunters in the wild. This happens because they are easily accessible and full of protein.
But these tiny caterpillars have evolved a defense system of their own that helps them to steer clear from the dangers of the wild.
In this article, we will talk about the woolly bear caterpillars, what hunts them, and how they protect themselves from such dangers.
What Are Wooly Bear Caterpillar?
The woolly bear caterpillar is the larval form of tiger moths. there are several species of Tiger moths, such as Giant Leopard moths, Isabella tiger moths, Eastern Tiger moths, and so on.
These worms are known for the thick coat of bristle-like hair on them. In fact, there is a myth surrounding their hair that says that one can predict the upcoming winter by looking at them!
They have a black-colored body with a rustic brown band in the middle. However, the color of the body keeps changing with age and the feeding capacity of these insects in the caterpillar form.
The woolly bears can be found across different parts of North America, Mexico, and Southern Canada. Being herbivorous in nature, they actively eat leaves from small plants and leaves of elm, maple, and more.
Who Eats Them?
One of the main predators of woolly bears is birds that hunt hairy caterpillars.
Brown thrashers, American crows, and rufous towhees are some of the ideal examples of birds that prey on woolly bear caterpillars.
Apart from birds, they are also hunted down by mammals like raccoons, red foxes, deer mice, coyotes, and other larger mammals.
Insects like parasitic wasps (such as yellow jacket wasps) and flies are also dangerous for them.
Since they have a lot of predators, woolly bears have their own defense mechanism to protect themselves.
Wooly Bear Caterpillar Defense Mechanisms
Woolly bears usually curl up like a ball and play dead whenever they feel threatened. They lie motionless (or rather play dead) in this position until the threat has passed.
There are other techniques and traits that these insects use to keep themselves protected against the cold and predators. Let us look at them in detail in the sections below.
Surviving Extreme Cold
Usually, it is tough for caterpillars to survive the extremely cold winters, but the woolly bears can survive in temperatures that go way lower than the 0 degrees F.
During such times, they produce a substance in their body called glycerol. Glycerol prevents the inner body parts from getting frozen.
Thus the caterpillar slowly freezes during the winter, but they still remain alive as its internal organs are intact and working correctly.
They can survive temperatures that are as low as -90 degrees F. At times, they survive the winter inside an ice cube. Fascinating, isn’t it?
They also search for warmer places, like crevices in the rocks, abandoned logs, etc., to hibernate throughout the cold season. Thus they can easily survive tough to mild winters.
Bristles To Defend Against Large Predators
The stiff hairs or bristles on the body of these caterpillars are extremely important to save them from larger predators like raccoons and red foxes.
As mentioned above, these worms curl up like a ball when they sense danger. When they curl up, the bristles get pointed outside and provide protection to the internal organs of the body.
Since these bristles are dangerous for insects like wasps, they usually refrain from attacking.
When it comes to larger predators, if they try to swallow the caterpillar, the bristles will get stuck in the throat, causing gagging, coughing, and irritation.
This is also one of the main reasons why you should keep pets like dogs and cats away from the woolly bear caterpillars.
Self-Medication Against Parasitic Larvae
Apart from the large predators, there are some parasites that attack these worms from the inside.
To deal with such predators, they have developed a unique “self-medication” technique.
When parasitic flies lay eggs on these caterpillars, they start consuming plants with bitter compounds, which keeps the parasitic larvae away from them.
Interestingly, the caterpillars don’t normally consume these plants as they contain pyrrolizidine alkaloids which can affect their growth. They only do it when faced with parasites.
What Do They Eat?
Wooly bears are herbivores, and they mainly feed on plants, herbs, leaves, and more. They usually like to eat herbaceous plants that are low-growing and bear seeds.
Usually, they prefer eating fallen leaves rather than grass or plants. Clovers, curly dock, and dandelions are some of their favorites.
They also eat leafy vegetables like spinach, cabbage, and more. If there are no fresh leaves to consume, they will consider eating blades of grass, maize, barley, and more.
Frequently Asked Questions
Do woolly bear caterpillars turn into a butterfly?
No, woolly bear caterpillars in adult form become tiger moths. These insects are way different from butterflies.Â
The adult moths are orange-yellow in color, and they have a 2-inch wingspan. You won’t find any clear markings on the wings, but you will notice three rows of black dots on the abdomen.
How do I get rid of black woolly bear caterpillars?
To remove woolly bear caterpillars, you can use a soapy solution. Just add some liquid detergent to a bucket of warm water and stir the mixture well.Â
Once it is settled, wear some gloves and find the woolly bears in your garden. Carry them out and drop them into the solution. This will kill the worms.
What happens if you touch a wooly bear caterpillar?
Woolly bears are poisonous in nature, and they do not sting or bite humans, but still, you shouldn’t touch them without wearing gloves.Â
This is because the bristles on their body can break past your skin and cause severe irritation and redness.
Can you keep them as a pet?
Since woolly bears are not poisonous, they can be kept as pets, but there is a constant danger of you touching them, which will cause problems.Â
Also, these worms are in the larval stage of tiger moths, and when they grow up, they will probably fly out. Also, having moths around the house is not a pretty sight.
Wrap Up
Being small worms, the woolly bears fall at the bottom of the food chain, but despite this, it is fascinating to see the tiny tricks they use to keep themselves safe from predators and the weather.
We hope that you found the article informative and it answered your questions as much as possible. The unique defense mechanisms of these bugs make them even more interesting than the legends and myths that surround them
Thank you for reading!
Reader Emails
Our readers have often been enamored with these cute and cuddly caterpillars, asking us questions about how to keep them safe and protect them from the elements and predators.
Read on to learn more about these discussions and some strategies that they have been following to keep woolly bear caterpillars safe.
Letter 1 – Grammia Tiger Moth
This was seen on the beach on Tangier Island on the Chesapeake in mid-October of this year.
Roberta Wallace, Manlius, NY
PS Great site. I’ve learned a lot browsing through old queries. Thanks in advance for identification.
Hi Roberta,
We do not have the skill to take this Tiger Moth to the species level, but it is in the genus Grammia. Just a peek on the BugGuide site will show you how similar the various species in the genus are. If we were gambling, we might say Parthenice Tiger Moth, Grammia parthenice.
Letter 2 – Geometrid, not Unknown Tiger Moth from Oaxaca
Dear Bugman,
You were recommended to me as someone who might be able to help me identify this beauty. I took this picture in Oaxaca, Mexico on 10/30/2005. The closest thing I have found on the net are tiger moths… but nothing with these exact markings. In it’s resting pose the moth was approximately 2.5" wing tip to wing tip.
And I echo the sentiment, you have a wonderful site!
joAnn
Los Angeles, CA
Hi joAnn,
The best we can do at the moment is that this is a Tiger Moth in the family Arctiidae. We will contact an expert in the family, Julian Donahue, to see if he recognizes the species.
Update: (05/26/2008)
Dear Daniel,
It is not an Arctiid. It is a Geometrid (Subfamily Ennominae). Pantherodes unciaria Guen
Letter 3 – Wheel Bug eats Wooly Bear
Hi Bugman. I think this is the dreaded "wheel bug". I’ve never seen one before, but I was able to identify it (at least tentatively) through your website. Thanks for a great resource–wish you’d do a print version I could keep in my pocket so that when I encounter these beasts, I’d be better prepared. 😉
Misty Doy
Hi Misty,
it is ironic that a few minutes ago we responded to a reader who was nervous that an Assassin Bug was going to eat the Anise Swallowtail Caterpillars she was raising, that we couldn’t recall seeing images of Assassin Bugs feeding on caterpillars. Your documentation of a Wheel Bug feeding on a Wooly Bear is wonderful. We have toyed with the idea of a book, but first we must find an interested publisher. Also, we doubt that our book would make a very good field guide. We strongly recommend Eric Eaton’s Kaufman Guide.
Letter 4 – Nevada Tiger Moth, we believe
Letter 5 – Why is a Brazilian Tiger Moth in Missouri????
Letter 6 – Figured Tiger Moth, we believe
Letter 7 – Donovan’s Tiger Moth from Australia
Hi there, I have found this post and I am wondering… this moth, too, seems Cymbalophora pudica to me. Please check this image http://www.entomologiitaliani.net/public/forum/phpBB3/download/file.php?id=136276
In the same site you can find many posts about that same moth.
Arctiinae, Idalus sp. Some call it clown faced moth.
But, when I googled it to find a species macth, I found it on Raddit:
https://www.reddit.com/r/mildlyinteresting/comments/3ck6sb/a_white_moth_with_a_chicken_face_on_its_back/
And then here
http://imgur.com/gallery/F77q69f
Maybe the same person?
Thanks for the correction Cesar. It seems that Shana “lied” about taking the image or about the location of St Louis, Missouri. We based our original response on not finding a similar looking Tiger Moth on BugGuide.
Arctiinae, Idalus sp. Some call it clown faced moth.
But, when I googled it to find a species macth, I found it on Raddit:
https://www.reddit.com/r/mildlyinteresting/comments/3ck6sb/a_white_moth_with_a_chicken_face_on_its_back/
And then here
http://imgur.com/gallery/F77q69f
Maybe the same person?
Hello Bugman, In my opinion, this moth is certainly of the genus Idalus.
Hugs from Brazil, Marcelo Brito de Avellar.
Thanks
Hello Bugman, In my opinion, this moth is certainly of the genus Idalus.
Hugs from Brazil, Marcelo Brito de Avellar.
I forgot to say, they are known as clown face moth!