Grammia Tiger Moth Caterpillar
Back on March 30, there was a rare sunny, not-quite-freezing day, and we took the opportunity to take a walk down the road. On the shoulder of the road, right next to our yard, we spotted this caterpillar:
It had obviously overwintered as a caterpillar, it certainly hadn’t gotten that big in the approximately 3 above-freezing days that we’d had at that point. It looked it, too – a bit weathered, kind of scruffy, not moving very fast. It’s certainly a caterpillar of some type of tiger moth, in the family Arctiidae. These are pretty large moths that have fuzzy caterpillars, like the well-known Woolly Bear caterpillar. This one isn’t a wooly bear, but I think it is the caterpillar of one of the moths in the tribe Arctiiini. BugGuide is kind of short of caterpillar pictures here, but from Wagner’s book I was originally inclined to think it was either the Great Tiger Moth, Arctia caja, or the St. Lawrence Tiger Moth, Platarctia parthenos. Unfortunately Wagner’s picture of the St. Lawrence Tiger Moth caterpillar doesn’t look quite right either.
The head is black, too, instead of brown
And the setae (hairs) come out of a kind of warty tuft instead of being spread uniformly over the body
So, on balance, I’m leaning towards the St. Lawrence Tiger Moth, but in either case, the caterpillars are pretty similar as far as habits. They overwinter as partially-grown caterpillars, and then eat a bit more in the spring before pupating and emerging as adult moths. They aren’t very fussy about their food, eating grass, legumes, and pretty much any other low-growing plants that are available. Wagner refers to them as the “musk oxen” of caterpillars, because they are big, hairy, and shrug off the cold. They are also rather long-lived, the St. Lawrence Tiger Moth can take two years to get to adulthood, overwintering twice.
Update: I have been advised by Roar on BugGuide that this is most likely in the tiger moth genus Grammia, so it isn’t either the Great Tiger Moth or the St. Lawrence Tiger Moth, because the hairs are too bristly. As it happens, I have recently gotten pictures of the most common Grammia tiger moths around here, so this is probably what it grew up to look like.
Drhoz!:
overwinters twice? cool!
21 June 2008, 8:24 pmJP:
I just found one of these today out in my yard…he also is all black, although this guy has no brown on him. He is very hairy, and also has curled up into a ball. I found him today December 27, 2008. In Virginia where the weather has been up and down. Freezing just a few days ago, and 60 degrees Farenheit today.
27 December 2008, 12:54 pmKevin !:
I found one in my yard after watering it. It was living under my sidewalk part of it in a large dark hole. I’m thinking of keeping it in a box or something and I was looking for what it eats. So like this web says i’m going to feed it like grass.
9 March 2009, 6:27 pmTim Eisele:
Cool! If you get it to mature into a moth, could you let us know how it comes out?
Hailey:
My friend found one of these caterpillars. Well at least it looks like it. We are not sure what kind of tiger moth it is, but she is under the impression that it will turn into a butterfly. Just wondering, is the tiger moth ACTUALLY a moth, because in the pictures i found, it looks like a butterfly. Also, what do tiger moth caterpillars eat?!?!?
12 March 2009, 6:30 pmTim Eisele:
The “tiger moth” family is pretty large, and some of them do look more like butterflies than moths. This particular one would grow up to look like a moth, though. According to what information I’ve been able to find, the caterpillars eat grass, although I expect that they like green, growing grass better than dry grass.
Marcie:
We found the black and orange “wooly bear” in our garden April 5 2009 after a winter with 5 feet of snow in the garden. We brought him indoors and hope to see him through to moth stage. I home school, so this is a bit of a project for the kids, trying to recreate his natural habitat in a 2.5 gallon tank with screened lid.
6 April 2009, 3:11 pmJo MYnott:
13.6.09, 1030am. I saw two tiger moth caterpillars this morning on Gwithian Towans in Cornwall. One was trying to climb up the sandy slopes and falling down when the going was too steep. The air temperature was about 20C, no wind and sun most of the time. Would the sandy towans have been his natural habitat? .
13 June 2009, 11:23 amBrooke:
i found on on my white birtch tree
14 June 2009, 4:32 pmEliza:
I dont know if the caterpillar I found was a Tiger Moth. It looks like one, but then a saw a picture of one that looked just like it and it said it was poisonous… I’m not going to touch it just in case it kills me and I die (if that makes any sense). So, I guess I’ll go feed it grass and hope for the best!
This was from the prospective of a curious 13 yr old.
15 June 2009, 8:09 pmTim Eisele:
Eliza: A lot of the furry caterpillars have hairs that are at least irritating to the skin, so it is a good idea not to handle them too much. Up here in Michigan, we can afford to be a bit careless because none of the local species are really toxic, but I understand that some of the southern species (particularly the “puss caterpillars”) are downright venomous. Still, it’s not as if they are going to attack you like a wasp might, so keeping one should be OK as long as you don’t pet it.
Brittanie:
This cutie looks alot like one I found at camp once.
I love these things. So any updates on the fellow?
10 October 2009, 3:04 pmTim Eisele:
No updates on that particular one, we let it go after getting the pictures. We’ve seen a few more from time to time since then, so they’re fairly common here.
Jeremy:
I believe it could be a “Giant Leopard Moth ” – Ecpantheria scribonia -check out http://en.wikipedia.org/wiki/Giant_Leopard_Moth
19 October 2009, 3:26 pmTim Eisele:
Jeremy: Thanks for the comment. All the pictures of giant leopard moth caterpillars on BugGuide show them having rather prominent orange bands between their body segments, though, so I don’t think that’s it.