How to raise woolly bear caterpillars

It made for a memorable Thanksgiving a couple of years ago when we sat down for turkey and all the fixings and a large orange moth seemingly appeared out of nowhere, haphazardly fluttering above our heads.

“Whoa, where did it come from,” I remember asking no one in particular as I stared at it zigzagging around the kitchen table.

“Grandma! It’s our woolly bear,” my daughter, Vayda, erupted with joy.

Indeed, my daughter’s woolly bear had emerged from its cocoon to greet us on Thanksgiving and a short 72 hours later it would be dead. Isabella tiger moths only live long enough to mate, lay eggs and die.

Although our tiger moth never had a chance to mate, hatching in our kitchen, it provided delightful end Vayda’s science project and taught her about the life cycles of caterpillars in a way that can’t quite be captured in a book.

Fortunately, banded woolly bears like the one we raised are considered common all across United States, Mexico and Southern Canada. So it wasn’t a huge hit to the local ecosystem to enjoy the beautiful moth’s company indoors at the end of its life cycle.

Their abundance, wide distribution and flexible diet make banded woolly bear caterpillars an ideal choice for a home school science project. And by knowing even more than we did about their life cycle, you can ensure your caterpillar cocoons at a time that ensures reproduction.

Where to find woolly bears

Woolly bears are relatively easy to find because of their prevalence and willingness to eat any number of low-growing, broad-leafed plants. You might just as easily find one crawling across your lawn as you would in a field, pasture or prairie. So maybe the better question to answer is when to find woolly bears.

There are two generations of woolly bears every year. The first hatches in May, eats during the summer and changes into moths during the fall. The second generation hatches in the fall, eats a little, hibernates over winter, eats some more in the spring and turns into moths. Spring woolly bears can be found where food is plentiful in lawns and fields. Fall woolly bears can also be found in lawns and fields, but may also be found seeking shelter crossing roads or under dead plant debris where they frequently hibernate. Plant debris offers enough protection from the weather for many insects to hibernate.

We have typically found our woolly bears in the yard while raking leaves or under bark that’s fallen off logs near the wood pile and log splitter.

Taking care of your woolly bear

Caring for woolly bear caterpillars is fairly easy in comparison to some other species of butterflies and moths whose larva has limited host plant preferences. For example, monarch butterfly caterpillars only feed on milkweed and are completely reliant on that host to survive and pupate. In contrast to the monarch, woolly bears will feed on a wide variety of plants.

Some of the plants woolly bears feed on include:

• Low-growing, broad-leafed plants. Woolly bears prefer to eat low-growing, seed bearing plants that have leaves instead of blades. These plants include lambs quarters, violets, clovers, dandelions, nettles, burdock, yellow dock, curly dock and many native plants. They will also occasionally feed on leafy garden plants such as spinach, cabbage, other greens, garden herbs and sunflowers.
• Grasses and grains. In the absence of preferred food sources, woolly bears will eat grasses and grains. These plants include wild grasses, as well as, cultivated grains such as corn and barely. Note that they will only eat the leaves, so they will only eat grasses in their leafy green stage.
• Trees. Although woolly bears typically stay on the ground, they can sometimes be found in deciduous trees feeding on their foliage. They prefer the sweeter leaves of maple, elm and birch trees and rarely bother fruit trees and decorative trees.

Aside from providing your woolly bear with fresh food daily, you’ll also need to take its life cycle into consideration if you want to avoid it emerging from its cocoon before the end of winter. When it starts feeding less or even stops, you might consider getting some plant debris – leaves, bark, hollowed out stems and twigs – and piling it in your habitat with the fresh food, so it has somewhere to hibernate. Then move your habitat to a garage, porch, patio or somewhere sheltered but cooler so it can hibernate over winter.

Make sure to check on it frequently to ensure it has access to fresh food when it comes out of hibernation. If everything goes as planned, you’ll get to release a beautiful tiger moth this spring!

Related Content

• How to care for red-striped ‘woolly bears’

Resources

• Iowa State University Extension and Outreach