# How long do caterpillars stay in a cocoon?
**URL:** https://boards.straightdope.com/t/how-long-do-caterpillars-stay-in-a-cocoon/459909
**Category:** Factual Questions
**Created:** [August 13, 2008, 11:08pm UTC](https://boards.straightdope.com/t/how-long-do-caterpillars-stay-in-a-cocoon/459909 "2008-08-13T23:08:33Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@CC](https://boards.straightdope.com/u/CC)
#### Post date: [August 13, 2008, 11:08pm UTC](https://boards.straightdope.com/t/how-long-do-caterpillars-stay-in-a-cocoon/459909/1 "2008-08-13T23:08:33Z")
My granddaughter and I put a caterpillar into a glass box (covered with Saran Wrap with holes poked into it) with some twigs and leaves and it built a cocoon in about a day. It’s been there for a couple weeks and I fear that life, as we know it, has ended for that little feller, for reasons unknown. However, I really don’t know how long to keep it before I have to dispose of it. It was some sort of furry yellow guy with a few spiky hairs on its back, maybe 2-3 cm long. I haven’t been able to ID it and I can’t find much info on how long they take to metamorphose to adulthood. Any guides? Any ideas? On the southern shores of Lake Michigan.
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### Author:  [@John\_Mace](https://boards.straightdope.com/u/John_Mace)
#### Post date: [August 13, 2008, 11:39pm UTC](https://boards.straightdope.com/t/how-long-do-caterpillars-stay-in-a-cocoon/459909/2 "2008-08-13T23:39:09Z")
Monarchs take about 2 weeks. I don’t know what the range is for all butterflies/moths.
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### Author:  [@jayjay](https://boards.straightdope.com/u/jayjay)
#### Post date: [August 14, 2008, 12:25am UTC](https://boards.straightdope.com/t/how-long-do-caterpillars-stay-in-a-cocoon/459909/3 "2008-08-14T00:25:17Z")
Is [this](http://homepage.mac.com/eceisner/Insects/Moths/c8529.jpg) your guy? If so, [this](http://homepage.mac.com/eceisner/Insects/Moths/m7249.jpg) is what he’ll turn into.
I can’t find pupal durations for that species, though. (Spilosoma virginica, Virginia Tiger Moth…it has a presence on the south shore of Lake Michigan, though)
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### Author:  [@Quartz](https://boards.straightdope.com/u/Quartz)
#### Post date: [August 14, 2008, 11:32am UTC](https://boards.straightdope.com/t/how-long-do-caterpillars-stay-in-a-cocoon/459909/4 "2008-08-14T11:32:50Z")
Paging **Colibri**.
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### Author:  [@CC](https://boards.straightdope.com/u/CC)
#### Post date: [August 14, 2008, 7:17pm UTC](https://boards.straightdope.com/t/how-long-do-caterpillars-stay-in-a-cocoon/459909/5 "2008-08-14T19:17:51Z")
[QUOTE=jayjay]
Is [this](http://homepage.mac.com/eceisner/Insects/Moths/c8529.jpg) your guy? If so, [this](http://homepage.mac.com/eceisner/Insects/Moths/m7249.jpg) is what he’ll turn into.
I can’t find pupal durations for that species, though. (Spilosoma virginica, Virginia Tiger Moth…it has a presence on the south shore of Lake Michigan, though)
[/QUOTE]
Hard to say, but the moth looks familiar, so it could be. In any case, if moths or butterflies stay in their cocoons no more than 3 or 4 weeks, I’m verging on getting rid of it. I just need to know the outside range so that I can safely figure that there will be no metamorphosis here.
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### Author:  [@CC](https://boards.straightdope.com/u/CC)
#### Post date: [August 16, 2008, 5:20pm UTC](https://boards.straightdope.com/t/how-long-do-caterpillars-stay-in-a-cocoon/459909/6 "2008-08-16T17:20:26Z")
Legitimate bump/update:
Two weeks, 4 days. No action. Should I keep it?
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### Author:  [@Pasta](https://boards.straightdope.com/u/Pasta)
#### Post date: [August 16, 2008, 11:16pm UTC](https://boards.straightdope.com/t/how-long-do-caterpillars-stay-in-a-cocoon/459909/7 "2008-08-16T23:16:15Z")
Keep it. When I was a kid, I plucked a cocoon (of unknown age) off a tree and placed it in a old cigar box with foliage of various sorts. I looked at it everyday for a couple of weeks, and then forgot about it. Way later (my memory says well over a month, but I was pretty young, so who knows), I noticed the box in my closet and opened it to find a huge and very lively moth. YMMV.