What Do Woolly Bear Caterpillars Eat? Helpful Tips

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Planning to keep a woolly bear as a pet but don’t have the answer to “what do woolly bear caterpillars eat?” Don’t worry; all the information is just a scroll away.

As harmless as it is small, a woolly bear is not actually a bear but a small caterpillar. They were named so by James Edward Smith, a botanist, and curator of insects. 

James named them after their fuzzy appearance and interesting fur pattern with bands of black, brown, and black on their backs. 

These fuzzy, harmless caterpillars are found in abundance all throughout the American continent, including the US, colder areas of Canada, and warmer Mexico.  

 

What Do Woolly Bear Caterpillars Eat

 

You can often find them feeding on garden plants, ivy, plantain, dandelions, clover, nettles, and other such shrubberies. 

In this article, we learn more about what these caterpillars eat and the proper care they need to survive in captivity.

What Is a Woolly Bear Caterpillar?

It is the juvenile stage of the Isabella tiger moth (Pyrrharctia Isabella).

Woolly bears can be distinctly identified from other caterpillars by their fur, which is brown and capped by black at the ends. 

Their body is formed of 13 segments, but if threatened, they curl into a uniform, round ball and play dead. 

There runs a tale that the colors of woolly bears signify the severity of the coming winter season based on how much of their bodies are brown and black. A more brown caterpillar signifies a mild winter. 

However, these are all myths. In fact, their color depends on how large the caterpillar is and its age. 

Moreover, there is a wide variety of these creepy crawly’s, with nearly 260 species being found in North America alone. 

Each has its own coloring pattern, so it is hard to tell anything by its color alone. As an adult moth, they have a wingspan of 1 ½  to 2 inches with black dots on them. 

 

Woolly Bear

 

Yellow Woolly Bear Caterpillar Diet

Woolly bears are a generalist species that can survive on a wide variety of native plants. Their dietary preference is very varied. They snack on almost any leaf and can survive without water. 

Woolly caterpillars are herbivorous and feed on fruit trees, herbs, grass, grains, nettles, and more. 

They are more inclined to leafy plants (as opposed to those with blades) such as goldenrod, dandelion, spinach, clover, and cabbage. 

Mostly, they feed on low, ground-dwelling plants. They show minor interest in fruits but have been known to, on occasion, feed on sunflowers. 

Among trees, they prefer elms and maples. They are also known to ingest poisonous plants like foxglove! 

In the adult form, isabella tiger moths mainly survive on nectar from flowers and survive only a week. 

What To Feed Them As a Pet?

Due to their non-toxic nature, woolly bears make great pets for kids. They are also available aplenty all across the US. 

As a pet, make sure you give them a fresh and new leaf pile every day. This includes leaves such as those of lambs’ quarters, violets, and clovers.

If you have a garden, you can store and feed them weeds such as ground ivy, plantain, and dandelions. 

 

Woolly Bear Caterpillar

 

For grass, make sure you give them the young, fleshy grass instead of the mature grass, which has turned into blades. 

Apart from feeding, once your pet woolly bear is ready to form a fuzzy cocoon, make sure you give them appropriate barks and branches to hang from. 

Do woolly bear caterpillars need water?

Woolly bears do not drink water. They source their water from the plant content they eat. 

Hence, if you keep one as a pet, you can simply mist the container from time to time instead of setting out a separate petri dish for water. 

How long can woolly bear caterpillars go without food? 

In caterpillar form, wooly bears are aggressive eaters and eat for months. However, once in the cocoon stage, they go into a chrysalis and stay without food for the entire duration. 

During these few months, they will not eat anything at all. 

In general, we know that caterpillars cannot survive without food for too long, and some, like the Monarch caterpillar, enter can starve in as little as 24 hours. 

What Eats Wooly Bear Caterpillars?

The thick hair helps these caterpillars survive some of their predators, such as yellow jacket wasps. 

However, common predators include mantids, flies, and birds such as the American crows, thrashers, and towhees and catbirds. 

As an adult, their main predators are bats and spiders. Despite this, woolly bears are aplenty, and their global conservation status is rated as G5. 

This means that they are not declining in numbers and are existing across multiple localities healthily. 

 

Woolly Bears

 

Frequently Asked Questions

How do you keep a wooly bear caterpillar alive?

It’s best to keep a woolly bear in a well-ventilated jar with plenty of fresh, misted leaves. 
Make sure to give them a dark space to hide in as well. Before going into a cocoon, give them a branch to cling to. 

How long do woolly worms live?

In a warm climate, the caterpillar stage lasts only two weeks, after which they enter into a pupa. 
In cold areas, they use their dense fur to freeze themselves (by controlling the temperature of their body) and pupate after winter. In short summers, the caterpillar stage may even last years. 

Is it safe to hold a woolly bear caterpillar?

Woolly bears are completely safe to hold, despite their bristly and spiky appearance. 
However, their hairs may cause allergic reactions in people with sensitive skin and irritation in pets (if they happen to eat the wooly bear). 
Usually, on being touched, they pretend to be dead and turn into a coil. 

How can you tell how old a wooly bear caterpillar is?

A woolly bear will molt six times over the course of its caterpillar stage. After every molt, more brown hairs are added. 
Hence, by seeing how long the brown patch is, one can gauge how long it has been alive. 

Wrap Up 

Woolly bears have been long been a fascination among children. In fact, Ohio even holds a Woollybear Festival every Fall where everyone dresses up as these caterpillars. 

If you’re planning on keeping a woolly bear as a pet, make sure you give them a diet full of juicy, soft leaves and mist their tank every day.

Thank you for reading. 

 

 

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Authors

  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

    View all posts
  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

    View all posts
Tags: Woolly Bear Caterpillars

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28 Comments. Leave new

  • Is it typical of woolly bear pupae to have that sparse hair-like cocoon? I saw something stuck to the inside of one of our umbrellas that looked awfully similar. Hopefully I can get some decent pictures of it tomorrow.

    Reply
    • Woolly Bear Caterpillars shed their hairs and incorporate the hairs in the spinning of the cocoons. It is often possible to see the pupa through a thinly spun cocoon.

      Reply
  • daniel white
    May 12, 2014 3:59 pm

    im 13 and i study bugs and i noticed this site when i was looking for more info however that is not a silver spotted tiger moth cause 1 off it is no venomous 2 off it has no read but it could be a relative of one

    -Daniel

    Reply
  • daniel white
    May 12, 2014 3:59 pm

    im 13 and i study bugs and i noticed this site when i was looking for more info however that is not a silver spotted tiger moth cause 1 off it is no venomous 2 off it has no read but it could be a relative of one

    -Daniel

    Reply
    • We maintain that the image of the caterpillar of a Silver Spotted Tiger Moth, Lophocampa argentata, that is posted to BugGuide matches the individual pictured in this posting. BugGuide also states: “Note of Caution: Like several kinds of wooly-bear-type caterpillars, these have venomous, stinging hairs, which can cause a burning sensation and/or a rash in sensitive people- look, but don’t touch!”

      Reply
  • i have studyed these guys for almost a month now.And have held multiple specimons and they are
    most certainly not poisounis

    Reply
    • Thanks for providing your personal observations and experience.

      Reply
    • Jessica pannell
      May 26, 2017 11:03 pm

      One crawled on me today and it has felt like glass under me skin for hours

      Reply
    • I agree with u I have raised 1 before and 3 right now 4 in total and not once have I had issues like poison if they were they would attack us with those hairs right away as soon as they crawl on our finger they are not poisonous or I’d be dead right now from touching 4 or more of them

      Reply
  • i have studyed these guys for almost a month now.And have held multiple specimons and they are
    most certainly not poisounis

    Reply
  • does anyone know what the moths eat? I, like Daniel, am a teen who likes to raise them. I don’t know if they are like some other species of moths, and don’t eat anything, or if they actually have a food source.

    ~safire

    Reply
  • does anyone know what the moths eat? I, like Daniel, am a teen who likes to raise them. I don’t know if they are like some other species of moths, and don’t eat anything, or if they actually have a food source.

    ~safire

    Reply
  • I am currently writing a blog on this species if you need more information.

    Reply
  • Stephanie Anderson
    July 10, 2014 6:54 pm

    Oh I apologize! I thought I put the link on here.

    http://cycnia.tumblr.com/

    Reply
  • catch-a-moth
    June 25, 2015 10:33 am

    They are poisonous, but it only effects sensitive people. I too have been handling them all my life, and have not been effected in any way. That doesn’t mean the experts are wrong. It simply means that I am not sensitive to the hairs.

    I had two of my cocoons hatch, and I am happy to say that I now have two dozen eggs.

    Reply
  • catch-a-moth
    June 25, 2015 10:33 am

    They are poisonous, but it only effects sensitive people. I too have been handling them all my life, and have not been effected in any way. That doesn’t mean the experts are wrong. It simply means that I am not sensitive to the hairs.

    I had two of my cocoons hatch, and I am happy to say that I now have two dozen eggs.

    Reply
  • I happened to find a silver spotted tiger moths caterpillar a month and a half ago and within 12 hours of having it, it started pupation. Does anyone know how long it usually takes before it emerges as a moth? I’m worried that the little guy didn’t make it.

    Reply
  • adie miller
    June 4, 2018 4:42 pm

    What do they eat?

    Reply
    • According to BugGuide, caterpillars feed on “Douglas Fir (Pseudotsuga menziesi) but not uncommon on other conifers. There are also a few reports of them eating a wide variety of other plants.”

      Reply
  • I don’t beleave ppl who say it’s poisonous I have raised 4 or more and had them crawl on my hand and not once felt what ppl say u feel and I never got a rash and I’m one person who has sensitive skin and I would be dead by now with how much I hold them each day so I don’t beleave a word some of u say

    Reply
  • I’ve been collecting these caterpillars for a week or two, feeding them to see what the cocoons will look like. (I had no reaction to gently scooping them up in my hand.)
    Yesterday I finally found a cocoon in their container–with an obliging caterpillar modeling adjacent to the cocoon.
    Coos Bay, Oregon, USA
    (I’d post a photo if I could remember how to do that… Guidance?)

    Reply
  • I’ve been collecting these caterpillars for a week or two, feeding them to see what the cocoons will look like. (I had no reaction to gently scooping them up in my hand.)
    Yesterday I finally found a cocoon in their container–with an obliging caterpillar modeling adjacent to the cocoon.
    Coos Bay, Oregon, USA
    (I’d post a photo if I could remember how to do that… Guidance?)

    Reply
  • Tacocat99999
    May 27, 2022 8:48 pm

    I have held many of them no rash or anything like that. from my research from other sources the “venom” or hairs only hurt those with sensitive skin.

    Reply

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