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Toxic “Toupee”: Explaining the Most Venomous Caterpillar in the U.S.

No warm and fuzzy here—a possible boom in a highly toxic but irresistibly touchable caterpillar is sending people in the eastern U.S. to the hospital.

Young children from Florida to North Carolina are reporting excruciating pain after coming into contact with the most venomous caterpillar in the U.S., the furry puss caterpillar (Megalopyge opercularis), according to news reports. Some have petted the insect; others have been injured when the caterpillars fell onto them from trees.

The puss caterpillar got its name because it resembles a cuddly house cat, said University of Florida entomologist Don Hall. While these insects may look soft, their outer comb-over (which some have compared to a toupee or the coif of Donald Trump) hides small, extremely toxic spines that stick in your skin. (Read more about venom in National Geographic magazine.)

Photo of a puss caterpillar feeding on winged elm leaf.
A puss caterpillar feeds on a winged elm leaf. Photograph by Donald W. Hall, University of Florida

“A puss caterpillar sting feels like a bee sting, only worse. The pain immediately and rapidly gets worse after being stung, and can even make your bones hurt,” Hall said.

“How bad the sting hurts depends on where you get stung and how many spines are embedded in your skin. People who have been stung on the hand say the pain can radiate up to their shoulder and last for up to 12 hours,” Hall said.

Caterpillar Boom and Bust

This species naturally goes through boom-and-bust cycles, and populations can rise and fall dramatically based on weather, food availability, and the number of parasites around, Hall said. (See “How ‘Zombie’ Virus Liquifies Caterpillar Hosts.”)

The furry puss caterpillar population seems to be on the rise, which may explain why so many people are being stung now, he added.

Hall has been stung himself several times, mostly by young caterpillars that he’s raised in his garage—juveniles generally have fewer spines than older, fuzzier insects.

Although there are no defined medical procedures if you do get stung by a puss caterpillar, Hall recommends covering the area with cellophane tape and then ripping it off to remove any spines that remain in the wound, which will help decrease the pain.

Poop Throwers

Female flannel moths (what puss caterpillars become as adults) covers her eggs with hairs from the tip of her own abdomen. “Those hairs are not venomous, but presumably protect the eggs from natural enemies in some way,” Hall said.

They fling their poop away from their bodies. Hall believes that behavior prevents parasites from being attracted to the feces and potentially harming the caterpillars themselves. (Also see “Scat-Firing Caterpillars Elude Predators.”)

A poop-throwing, toupee-wearing caterpillar that can send you to the hospital—what will Mother Nature think of next?

Follow Carrie Arnold on Twitter and Google+.


  1. Kathryn mouton
    Metairie Louisiana
    September 25, 8:45 pm

    These critters have been crawling all over my back porch for a week or so. Didn’t try to touch them, but they still stung me on my nerves arm and inner wrist. Terrible pain, then terrible itching. But even tho the marks are still visible, no more symptoms from these two bites. Then last Thursday somehow they caught me on my palm. Again, pain, then fierce itching. I still didn’t know what they were. Found out from a “bug man” on Friday. I’m still scratching. Using Benadryl stop itching cream and Ice pack.

  2. Liana LeFey
    Austin, TX
    September 22, 11:47 pm

    My daughter found one of these little guys today on a bush by our front walk, and we thought it was so cute we got a jar & took it inside. We both touched it, nobody got stung, she named it, we fed it some leaves…and then I looked it up to see what kind of butterfly it would become. HA! We were very lucky not to get stung. Cute little things, look just like Tribbles, but not something I want to tangle with. Worst part is, I went back out and checked, and the entire bush where we found it is FULL of them.

  3. Charles conder
    September 19, 4:35 pm

    Just found one on a tarp I put over a couch yesterday before the rain. They breath heavily when u blow on them lol. Didn’t know what it was and almost got stung. Decided to look it up first. Wow thank goodness I did that. Did not want to end up in hospital today!!!

  4. Adriana
    Manvel, Texas
    July 28, 10:56 am

    I got stung by one of these yesterday in Pearland and I was getting some branches off a tree for a room DIY and one branch had something that look like this and I had excruciating pain for like 3 hours and then pain just went away. I didn’t cry and I’m only 10

  5. Devin Brooks
    United States
    July 22, 8:08 am

    I was working for a company that installed directv systems in florida some years back and the house I was setting up in had literally hundreds of these things all over it. Nobody knew what they were. Luckly nobody touched one.

  6. Richard Cera
    Friendswood Texas
    July 4, 7:56 pm

    My wife and I were in the back yard and she sat down on our bench, her leg landed on that f@#king bug(3:48 pm 7/4/16) she has been in pain for more then 2 hrs. Her skin welted up, turn reddish, pain that spread from under the thigh to the top and outward,it has also caused leg spasms. The pain she said is like a bee sting but a hundred times worst.There is a mark the shape of the puss caterpillar on her thigh. For treatment I have used: warm shower for opening the pores, tape for the hair/spine, ice for the swelling, Tecnu bite & sting wipe, Extra strength Benadryl cream for allergic reaction and tylenol extra strength for the pain. The pain is really bad for her because she is a small woman. Please note if stung do not move to much it causes the poison to spread faster. She has finally gone to sleep after much crying from the pain and agony (3hr) her spasms have stopped along will the swelling. I hope that it will go a way when she wakes up cross my fingers…..I hope the treatment helps any one that reads this, good luck to all you will need it.

  7. Genny Mikel
    March 29, 6:31 pm

    The sting is just their way of protecting themselves kinda like we use our fists.

  8. Shari Monetta
    November 27, 2015, 11:15 am

    Just got stung, on right palm, playing with my cat, it was on the side of my oak tree.
    Instant pain. Did the Tape, Ice and Benadryl. Dr’s office is closed.

  9. Lana
    November 16, 2015, 10:06 pm

    I touched one multiple times the other day. Was as soft as a kitten. I picked it up to move it to grass and look at it’s tummy. Didn’t sting me at all. Didn’t even know it was venomous until I looked it up online later.

  10. Victoria
    October 29, 2015, 12:26 am

    I found one of these cuties climbing on my pumpkin on the front porch. I had no idea what kind of caterpillar it was, I just thought it was the coolest and cutest caterpillar ever. I decided to pick it up, I took it inside to show my family and then I returned it back outside. While holding him, I decided to goggle what kind of caterpillar it was. Guess what kind of caterpillar it was!? Yep, a Puss caterpillar!! I’m so lucky that it had mercy on me and he never did hurt me. Yikes!!

  11. Melissa
    Manassas, VA
    August 29, 2015, 12:14 am

    Came in contact with one of these things today while doing yard work and it had to be one of the more frightening experiences I’ve had during those sort of chores! Had no idea what the heck bit/stung me until I looked online and noticed the welt on my arm resembled those these things leave.

    Got lucky though, only brushed against it a little so got the welts, the rash and pain but none of the worse symptoms. None of the stingers got stuck in my skin. If you touch one be sure to clean it with water, ice it and take a benadryl. That’s how I kept it from irritating me so I only had to deal with the pain for an hour. After that everything has subsided since then. Be careful!

  12. Denise321
    Nola, Louisiana
    August 26, 2015, 10:40 pm

    Holy cow! I was stung this afternoon by one of these evil things! Why did Mother Nature make these?? Joking, but not really…
    Thought it was a leaf on a chair, so as I grabbed the chair it got me in the palm of my hand. I used the tape trick, washed it, slapped a little antibiotic ointment on, then numbing spray. It felt ‘tolerable’ after an hour or two.
    It actually hurts more now than 4 hours ago. Feels like a throbbing, burning, cramping charlie horse in my hand and down my fingers. Tiny soft ice packs are helping greatly.

    Beware! They blend in very well. We have seen them mostly on our porch table which is wooden. I had never seen these before this year. I’m curious to know if they’ve they always been around or is their presence on the rise, and if they can harm pets.

  13. Joe
    July 31, 2015, 3:08 pm

    I just got stung about an hour ago by one of those little caterpillars and the pain is BAD. in between two of my fingers on my right hand, and the pain goes all the way through my armpit. it is a bone hurt kind of pain. I am not shy to pain and usually am able to work through it pretty well but I assure you those caterpillars hurt

  14. donna santos
    central FL
    July 3, 2015, 11:47 pm

    Andrew Howley, that is exactly what I was thinking! Tiny tribbles! Just saw my first one today on my horse fence… which makes me wonder, can they poison the horses or our puppies if they go nosing around them? Yikes! Just moved to florida and first it was fire ants,not a fan. Then it was huntsmen, wolf, black and brown widow spiders. Also not a fan. Then rattle snakes in the hen house. Not cool. Now poisonous caterpillars… I’m thinking CT snow and ice doesn’t look so bad anymore!

  15. Charlotte Zima
    Kingwood, Texas
    July 3, 2015, 12:58 am

    In Texas we have had them since I was a teen growing up and my sister was stung by one and it almost caused her death as it’s toxin is so poisonous. We call them asps and they are much darker in black mostly or brown black. But everything else about it is the same..

  16. Amber A
    Gaithersburg, MD
    June 28, 2015, 5:44 am

    The caterpillars are in Maryland as well. At least western Maryland. I have been stung by the puss caterpillar that fell out of a tree in Oldtown, Maryland. It was he most intense burning, left the patterned like rash on my hand. It was worse than a wasp sting, even worse than getting your feet bit up by fire ants.

  17. Jhon
    June 11, 2015, 4:26 pm

    i just got stung,on my head!!! the best treatment is to stay in a cold place with ice on the bite part. it reduces the concentration of the bite since the sensation of venom is hot it needs hot environment to hurt more as in the cold it will relieve it.

  18. Robbie
    May 1, 2015, 6:42 am

    Who cares what it is called, “puss or asp”. The point is it is a painfully mean little caterpillar. Knowing what to do when you encounter this creature is what’s important.

  19. rick
    lafayette la.
    December 1, 2014, 2:04 pm

    I accidently had one sing me on elbow last night. I didn’t see it until I felt this tremendous burning sensation on my elbow. Looked down on sofa and saw this little animal. Long story short- the pain lasted for about 4 hours. First hour very intense pain then subsided. Google it and did the treatment and positively identified creature. 59 y.o. and had never heard of this ltitle beast.

  20. Christian
    san Antonio texas
    November 24, 2014, 5:42 pm

    My wife just got stung at the park about 20 min ago when she leaned up against one on the pickknic table. She’s doing OK mainly due to it stinging her through her clothes. I got at ng by a defferant species as a kid on the rest while at the river and let me tell you its in the top three worst pains of my life.

  21. Aries
    November 22, 2014, 10:33 am

    I saw one at a elementary school I volunteared at and I touched it but I was fine afterwards I was tempted to put it somewhere the kids wouldn’t play with it but when I moved some of its hair around I noticed it had a maggot looking body so I just left it

  22. phil
    October 27, 2014, 5:23 am

    Those soft supple leather light tan gardening gloves (with the little red plastic balls on the cuff strings), commonly sold in many stores, are perfect protection against the puss if you have to fiddle with or climb trees. Also good to wear these when grabbing planks around the woodshop where fiddleback spiders may be lurking on the underside.

  23. Pearl
    Atlanta Ga
    October 11, 2014, 12:37 am

    I saw one of these yesterday it was on the side of my house just sitting there, I froze in place when I saw it, it scared the hazelnuts out of me. I’ve never seen or heard of this creature in all the 54 years of my life, and it was huge and extremly furry. It really creeped me out mainly because I didn’t know what it was I took a picture of it and posted it on Facebook a friend of mine informed me of what it was then I googled it to try to learn everything I could about it. Very interesting creature

  24. sooz
    October 7, 2014, 5:17 pm

    I think some people are missing the part regarding which stage is laying the eggs. The statement Mr. Hall made is this, “Female flannel moths (what puss caterpillars become as adults) covers her eggs with hairs from the tip of her own abdomen.” He is stating that the ‘moth’ covers her eggs with hairs, not the caterpillar.

  25. Don Hall
    Gainesville, FL
    September 29, 2014, 10:52 pm

    Obviously I did not make some things clear in my interview with Carrie. If you will go to to my web site on the puss caterpillar, many of your questions will be answered. Also, I have photos of all of the life stages there. The URL is:

  26. Susan
    September 21, 2014, 3:06 am

    Judson, that’s “puss,” as in “Puss In Boots,” not “pus,” like what comes from an infected sore.

  27. Amber
    September 20, 2014, 5:24 pm

    “Puss” as in another word for cat, Judson, not as in infected ooze.

  28. Edgar Ushap
    London Uk
    September 20, 2014, 3:42 pm

    Uy careful with this guy, its pretty dangerous. The lint that is a mask covering his entire body and is covered in hghly venomous barbs. Also living in eastern Ecuador sona practically what the Amazonian area. In large scale can be seen in the summer the place is from June to October. Their diet is vegetable.

  29. Angelo Sastre
    Dumaguete City, Negros Oriental Philippines
    September 20, 2014, 12:18 pm

    LOL.. . It looks like a pokemon 🙂 🙂 🙂

  30. Myra Binnicker
    Central Florida
    September 20, 2014, 7:33 am

    My husband was up in a tree with a chainsaw when one of these fell down his shirt, and it rolled down his back. He had stings from his neck to his waste. He had to immediately shut off the chainsaw and climb down. He said it was intense pain; his stomach was cramping; he was dizzy; he was sweating. There were welts everywhere it had touched. It lasted the rest of the day.

  31. Oscar Fonseca
    September 20, 2014, 1:48 am

    esta oruga le llamamos acá en ecuador gusano pachón o gusano de pollo por temporada de invierno hay muchas si me han picado es muy doloroso.. El bello es muy toxico esa picazon dura un par de días..

  32. Bobbie. Lemley Williams
    Christiansburg, VA
    September 19, 2014, 9:27 pm

    Have any of them made their way into VA? If so, where? From being a “tomboy” as a child, I KNOW I WOULD HAVE PICKED ONE UP. LOL, I sure that it would be one time only. What size are they compared to the wooly ones(black & redish brown) that people use to determine what kind of winter we are going to have?

  33. Dan Boyd
    Nebo, North Carolina
    September 19, 2014, 4:33 pm

    herbs n plants that contain : turpine an cineol is what i have used for the sting of the puss caterpillar. I recommend Tea Tree Oil, Benadryl,after you remove spines with tape.You can buy Tea Tree at most Drug Stores. I believe if Doctors knew this first hand like i do they would have some Essentials Oils in the ER. just saying i hope this post helps someone,and if it is a child God Bless !!!!!!

  34. Gordon Cariveau
    September 19, 2014, 12:01 pm

    You may call them asp but an asp is a small venomous snake from egypt not a furry caterpillar.

  35. Judson bagwell
    September 19, 2014, 10:56 am

    “The puss caterpillar got its name because it resembles a cuddly housecat”, did no one notice this? Puss and cuddles are not similar things.

  36. Bob Bailey
    September 19, 2014, 10:55 am

    I remember them when I was a kid. We called them asp. You can hold them in your palm and pet them with a finger and not get stung.

  37. Terrell Dean
    September 19, 2014, 10:00 am

    By looking at the comments people obviously don’t read…. Read the article and it tells you plain as day what the caterpillar becomes as an adult, geesh… Glad I don’t see these things in my city.

  38. Carrie Arnold
    September 19, 2014, 9:49 am

    Thanks for your eagle eyes on the female caterpillars laying eggs. It’s the adult female flannel moths that do that- I’ve made the corrections in the text.

  39. vincent joseph
    india hyderabad ap.
    September 19, 2014, 9:48 am

    After removing the spines by cellow sticky tapeplace another sticky tape over the wound contact and phone for medical tretement from a docotor or a chemist and see
    A reguar doctor for pian and sweeling along the wound treatment cold or hot water swabs till cured and good luck …..

  40. Barbara Halbert
    United States
    September 19, 2014, 9:29 am

    I thought caterpillars turn into moths or butterflies? How do they lay eggs if they are still a caterpillar?

  41. Must C
    September 19, 2014, 9:27 am

    What, no video of the poop-flinging?! I am disappoint…

  42. van
    September 19, 2014, 8:35 am

    what does the adult look like ?

  43. Jarrod
    Nashville, TN
    September 19, 2014, 8:25 am

    I’m confused… “Female Puss Caterpillars use their spines to protect their eggs from ants and other predators”… I don’t think eggs would be laid until the moth stage, do they still have stinging spines when they’re a moth (called a flannel moth as an adult)?

  44. randy hanson
    September 19, 2014, 7:13 am

    the article says they protect their eggs,…… since when do catapillars lay eggs?

  45. Kelly M
    September 19, 2014, 6:44 am

    “Female puss caterpillars use the spines to protect their eggs from ants and other predators”

    I don’t know what is meant by this statement; caterpillars don’t lay eggs. Adult moths do.

  46. corinna marriott
    September 19, 2014, 5:30 am

    Pretty sure caterpillars don’t lay eggs…that would be the moth/butterfly does that.

  47. Tham Ze King
    September 19, 2014, 4:43 am

    Will all caterpillars turning into butterfly?
    How does the butterfly this one turn into look like?

  48. Bryony Collins
    September 19, 2014, 4:06 am

    We have something similar over here called the Pine Processionary Caterpillar. http://web.cortland.edu/fitzgerald/pineprocessionary.html

  49. Jonathan
    Manila, philippines
    September 19, 2014, 3:45 am

    I was just wondering… What do they become when they grow into adulthood?

  50. CLARIA
    September 18, 2014, 5:36 pm


  51. Frank Cowan
    Denver, co.
    September 17, 2014, 2:31 pm

    In the south they were always called an “asp”. Been stung several times trimming trees like Red Buds.

  52. Andrew Howley
    September 17, 2014, 11:40 am

    And now we finally understand the real trouble with tribbles.