Stone Centipede

2008 May 31

If you turn over any given rock in Michigan, you are likely to find one of these:


This is a “stone centipede”, order Lithobiomorpha, so called because that’s what they live under[1]. They run like water, flowing around obstacles and into holes in a way that’s very much like the way a stream of water flows, and are kind of hard to catch. On top of the speed, they are slippery, and their dozens of legs are very good at forcing them through crevices, or out from between your fingers. Even their antennae have a disturbingly fluid nature, flowing over surfaces and contorting in a way that is more like what you would expect from tentacles than from antennae.

That first picture was low-magnification because the whole centipede is much too long to fit into a single high-magnification image. Here’s a few showing it in more detail:

Front end

In the picture of the head end, you can see two bulges on the sides of the head. These are the “poison claws” that they use to grab their prey. Here’s a (somewhat blurry) picture showing the claws opened and looking very ominous:


Getting back to the body, here is the midsection:


While stone centipedes do have lots of legs, they don’t have a hundred legs. This one would have had 30 legs, except that it is missing one of the rear ones. There is one pair of legs per body segment, even though some of the legs look like they are coming from the junctions between segments. This is because the body segments are wildly variable in size, with some of them being practically nonexistent. I’m not sure why that is, I would have expected all the body segments to be about the same size.

Rear end

The last few sets of legs point almost straight back, which doesn’t seem like it would be all that helpful for walking. Maybe they are used to push forward? Mostly, it just seemed to drag them around.

While stone centipedes are reputed to be able to “bite”, once again I can’t confirm that. I was picking this one up and pushing it around, and it was doubtless pretty annoyed with me, but it didn’t let me have it with the poison claws. I understand that some of the big tropical centipedes have pretty painful bites, but as I’m sure everyone has gathered by now, Upper Michigan is hardly the tropics[2].

Anyway, stone centipedes are pretty aggressive predators, preying on the other things that live under rocks like woodlice, worms, springtails, grubs, and who knows what else. They are easily the fastest-moving things you are likely to find under a rock, and their thin body shape makes it easy for them to squeeze quickly into crevices.


They are pretty stong, too. I had this one in my photographing dish with a glass slide over it, and it was strong enough to muscle the slide aside and crawl out. Then it was off like a shot, and I had to scramble to catch it again (this was when it had a really good opportunity to bite me, but didn’t take it). I ended up having to hold the cover slide down with my finger to keep it from getting away again.

[1] I was looking at the “categories” list on the sidebar, and noticed that while I had multiple specimens for the other major classes of arthropods I’m likely to find around here (arachnids, crustaceans, and insects), for the myriapods there was only this one, lonely millipede. So, Sam and I went out flipping over rocks to find some more myriapods to fill out the list a bit.

[2] The term “subarctic” comes to mind[3], although I guess it is officially classified as a “humid continental” climate. I know a faculty member at the University who was visiting the Soviet Union (back when there was a Soviet Union), and mentioned where we were located. The Soviet professor he was talking to was convinced that our university must be the US Government’s equivalent of Siberia for exiling politically-disgraced scientists. I dunno. Maybe it is.

[3] The Keeweenaw Peninsula was just about the last place in Michigan to come out from under the ice at the end of the last ice age: the glaciers from the “Marquette Readvance” didn’t melt off until about 9,900 years ago, several thousand years after the lower peninsula of the state had melted off completely. Even then, a lot of the U. P. was periodically inundated for the next several thousand years until the lake levels stabilized. That sounds like a long time for wildlife to recolonize the area, until one considers that wingless arthropods like centipedes had to walk about a thousand miles to get up here since the ice melted. A mile every 10 years or so doesn’t sound that hard to us, but to critters less than an inch long that can’t fly, it’s a pretty fast clip. The centipedes move fairly briskly, so they probably got here comparatively quickly (maybe 5000 years ago), but things like woodlice must have had a hard slog of it (unless they hitch-hiked on birds or something). Some of the slower creatures, like earthworms, didn’t make it up here at all until they were carried up by human activities (earthworm eggs in mud stuck to tires, or abandoned fishing bait, for example). So, even though a lot of the things that live in the soil in, say, Ohio could probably live just fine up here, they just haven’t gotten this far yet.

29 Responses
  1. May 31, 2008

    That is one fine looking creature! Love your blog.

  2. MRL permalink
    June 2, 2008

    I love your blog, truly I do, but…I should have realized that if you kept it up, you would have to eventually come to one of the very few multi-legged critters that truly do freak me out.

    Bloody centipedes…

  3. June 3, 2008

    Mike: Thanks!

    MRL: Sorry about that. There will be at least one more species of centipede in a few weeks (a “soil centipede”) that we found under the same rock, and probably another millipede or two later. But other than that, we are pretty short of myriapods in this region, so that might be about it. After that, it’s going to be just things with 14 legs or less. I’ve never seen a “house centipede” around our property, so you’re probably safe from that one at least.

  4. MRL permalink
    June 3, 2008

    Heh, no need to say “sorry” – I’m rational enough to know that it’s an irrational fear. Weirdly enough, I loved the millipede, I’m looking forward to any more you find!

  5. Sandy permalink
    June 3, 2008

    (From wife of author): A common refrain around the house is, “It could have bit me, but it didn’t.” One of these days the luck will run out, I just hope we don’t end up in the emergency room trying to explain poison claws and phyllum to the nurses and doctors. More importantly, I hope innocent bystanders don’t become the test cases for these critter bites.

  6. November 19, 2008

    I was looking up this bug, because i was laying on my living room floor, when i felt something on my ankle, thinking it was my pants leg, i just used my other foot to brush my jeans down, about 5 min later i felt something climbing up my knee, and knew it was a bug, ran to my room, and jumped out of my jeans ASAP! Then shaking my jeans out came across, was what(im pretty sure)this bug!

    My questions is are they often found in flordia, how would it get in my house, and is it poisonousness enough to kill by bitting???

  7. November 20, 2008

    1. Given how many of them I see in Michigan, I would expect that they are probably fantastically common in Florida.
    2. They can get through even the tiniest crevices, so if they are determined to get into the house they can squeeze under doors, through cracks in the foundations, around windows, you name it. The question isn’t so much how do they get in, as whether there is any practical way to keep them out.
    3. They certainly aren’t poisonous enough to kill a person, or even make anyone sick. I don’t actually know anyone they have bitten, and the way this one was scrabbling away at my fingers without injuring me, I’m not so sure that they are even strong enough to break the skin. Their poison (if any) is evidently more suited for killing and eating small insects. There are some (usually much larger) tropical centipedes that might be dangerous, but all things considered I don’t think that this is one of them.

  8. sam permalink
    May 21, 2010

    cool blog. You can also find them in Banbury where i live. i found 2 of them.

    If you can find out any more facts on habitat and mating,
    Please let me know.

  9. May 23, 2010

    Sam: Thanks!

    At first, I didn’t know which Banbury you meant (it turns out there are about a dozen Banburys in North America), but then I saw that you have a UK email address, so I expect you mean the one in the UK. Yes, stone centipedes are pretty widespread, they live pretty much anywhere that there are rocks to hide under. The most common European species is Lithobius forficatus, so that may well be the particular species that you have.

    It turns out that they live in pretty much any reliably moist environment (they need moisture because they don’t have the waxy coating that most insects and spiders have, and so they dry out quickly). Since the undersides of rocks is pretty reliably moist, that’s where you find them. It’s only one habitat, but it is a really widespread one. As for mating, it sounds like the males just drop a sperm packet on the ground, and then try to get a female to pick it up.

  10. natasha permalink
    June 26, 2010

    my last apartment was infested with those things i never knew what they were called until now. yes they do bite and yes it hurts and they bite hard enough to just break the skin. i had gotten bit several times in my attempts to catch them and throw them outside, but im still alive so obviously they are not poisonous enough to kill a human.

  11. Amanda permalink
    October 12, 2010

    I live in Southern Indiana and have found several of these in my basement! They DO bite and according to my husband, it HURTS!!! How can we keep them out? I have young kids and have told them NOT to touch them if they see one! Any suggestions?

  12. October 12, 2010

    Amanda: I think the best way to keep them out is to eliminate moisture. They dry out quickly without a source of water. Moisture also gives their prey someplace to live. If you have moisture in your basement, try to get everything up off of the floor so that air can circulate under it. A dehumidifier might help, as long as you don’t have too much humidity. If there are cracks where the walls meet the floor, the centipedes and their prey probably live in there too, so sealing them up might help.

  13. Della3 permalink
    October 12, 2010

    During my college years I once lived in a place where the head of my bed was underneath a hole in the ceiling. It was a basement bedroom. One morning, I had just picked my head up from my pillow, turned around, and down plopped a very beautiful, transluscent, green and blue centipede. Something told my “very poisonous” and I freaked out for a second. Luckily, I moved out soon after that. Years later I read (or saw video in a nature movie) that only the most poisonous and deadly ones are so beautifully colored, and that they can excrete poisons from their feet. I’ve never seen a picture of the one I saw, so I’ll never know if it really was one of those types, but I shudder every time I think of it. Cameras were not so prevalent back then, so of course I don’t have any pictures – just the one in my head. Maybe I’ll check and see if I can find anything similar.

  14. Della3 permalink
    October 12, 2010

    I just did some internet surfing for centipede pictures. I haven’t finished, but I came across this very informative site:

    So far, they have the best info. on the subject. I’m surprised there aren’t more pictures on Centipedes seem to come in a great deal of variety. The small, brown ones are the most common, but there are many very colorful ones out there! The one I described earlier was transparent. The fluorescent light green and teal or sky-blue (stripes going down its length?) were also transparent. I haven’t seen any pictures that come close to this description yet. I’ll keep looking.

  15. Della3 permalink
    October 12, 2010

    I found another very informative spot on centipedes:

    It seems to indicate that even if there is venom secreted from the legs of certain types of centipedes (not the typical house centipedes), the venom will only cause a trail of irritation down the path that the centipede crawled on a person’s skin. Centipedes do not typically carry enough venom to do real harm to most human beings. It’s also nice to know that most centipede bites are compared to bee stings, and that any very rare fatalities would occur from those people that are allergic to centipede venom. This last information was found on another site. (Sorry, I didn’t keep track of which site it was.) The allergic reactions would also be similar to the reactions of those with allergies to bee stings.

  16. Della3 permalink
    October 13, 2010

    Sorry about this third post, but I really got into trying to I.D. the centipede I’d seen so long ago. It must have been a very rare variety. I’ve surfed for over an hour, and I’ve just finished looking thru over a thousand photos on Flickr. Most of the centipedes are brown. A few have black and red colors. A much smaller number of photos showed blue colorations. Most just had blue legs. A few were blue all over. The blue ones were in Taiwan, Chile, Malaysia, Mexico and Australia. They usually had the same teal-blue color I saw on my centipede. None of them had the green. Some had transparent (or transluscent) blue legs. But all had opaque bodies. The only ones with transparent bodies were yellowish or tan in color. So where in the heck did my very beautiful transparent blue and green-bodied one come from? I was living on the U.S. East Coast at the time. Why would something so exotic be there?! Anyway, the search was fun, and I found a really cool pic:

    See how much you inspire in your followers, Tim? If you ever find a blue one, let me know!

  17. October 13, 2010

    Thanks for all the links, Della3!

    You know, it occurs to me that your mystery centipede might not actually have been native – could somebody above you have been keeping exotic centipedes as pets?

    Or, for that matter, it might have been a more typical centipede infected with an iridovirus – I don’t know if these viruses infect centipedes, but when they infect pillbugs and woodlice they turn them bright blue.

  18. Della3 permalink
    October 13, 2010

    No one in the family I was renting from had any affinity for insects, and they did not have any pets at all. The ceiling of the basement was at ground level in a very moist climate. It seemed that there was a space between the ceiling of the basement and the floor of the level above. This was probably a good breeding/gathering space for all sorts of critters. The hole was about the size of my head, but the owners were in no hurry to fix it, and the bed could not be moved, thanks to a lot of built-in shelves and desk space. For other reasons, I could not sleep with my head on the opposite end of the bed. I tried covering the hole, but everything just kept falling off, and I was not handy with tools back then.

    The centipede scampered away as soon as it oriented itself, and seemed quite healthy. The pillbug picture you reference is interesting, but my bug did not have this type of coloration. The pillbug is completely blue and the wrong color of blue. As you can see from the pictures of other blue centipedes, the blue color they usually use is a beautiful lighter teal color — the same color of blue on my centipede. Its blue legs looked exactly like the blue legs on the pictures I’ve found. It’s just that there was a lot of the same blue and some green on the body as well, and the body was translucent, just like the legs. The blue and green seemed to be in stripes down the entire body, which would also be unusual for a centipede, since they tend to exhibit colors that alternate in bands on different segments, or they have a solid-color body, with legs and/or head of a different color. It’s possible that it had a red head, but I’m not sure. I just remember that it was extremely colorful and I wished it would have stayed still longer and that I could have taken a picture of it. It was maybe one and a half inches long, or less. The legs were short and somewhat uniform in length (compared to the common american brown house centipedes), such as those on other blue-legged varieties. I have wondered if the blue coloration had something to do with a cycle or phase that the centipedes go thru, but I would think people would find quite a few more blue ones if that were the case. Also, one could speculate that the blue color could result from what type of food they are eating. But after seeing all the different photos of red, red and black, brown, yellow, and blue centipedes, I’m thinking the colors have more to do with camouflage, or “keep away, I’m poisonous”, or “hey, I’m beautiful, come get my sperm sac and make my babies”.

    It seems that centipedes have not been researched that extensively yet. I’m surprised by this, because I find them quite fascinating. I’m also surprised that so many bug fanciers find this particular bug too creepy to deal with. But thanks for rekindling my memories of this amazing experience, even if it was a little scary.

  19. Roberto Granados permalink
    May 3, 2011

    We’ve got these in N. California as well.I *have* been bitten by these centipedes,and it hurts very badly.I was first bitten by a 4″ Lithobiid when I picked it up,thinking that it was a Millipede.The bite feels like a burn,but I don’t remember the pain lasting for more than a couple of hours.Nowadays when I pick up any large centipede(over 1″),I grasp it at the base of its head and hold on.I’ve been lucky to have not bitten again,as the handling method I just described is very risky.Here’s an easy,safer method:

    1)Hold the centipede’s head down(gently)with your left thumb.
    2)Slide a piece of stiff paper underneath the centipede(don’t release your grip on the centipede’s head)
    3)Slide your left hand fingers under the paper,and lift the paper and the centipede up so that the paper protects your fingers from the centipede’s claws

  20. mallerie braud permalink
    July 27, 2011

    We just moved to gautier mississippi and we’ve spotted centipedes and yes we’ve been bitten they’re small but gross! As a matter of fact I have like 12 bites on my bck that at firdt I chalked up to a mosquito bite at first, then the bite dosent look anything like a mosquito. And I see sentipedes goin up nd down my wall only in the bed room. We had just moved in and weren’t told of this problem. So now its va. Allll over again there we moved into an apt. W bed bugs and that’s worst cause they only comeout at night when u r asleep! How can I get rid of theese centipedes?

  21. July 28, 2011

    Mallerie: I’m surprised that you’d have more than one centipede bite. They don’t suck blood, they normally only bite a person if they are being picked up or squashed. Having 12 on your back would imply that you’ve been laying on a whole bunch of centipedes, which seems like the sort of thing you would notice. Have you actually seen a centipede bite you? Are you sure that they aren’t bedbug bites, or any of the hundreds of other bloodsucking insects that live in warm places?

    I think it is likely that you are being bitten by something else, that actually wants your blood. And the centipedes are most likely eating the things that are really biting you (and are in the bedroom because that’s where the other bugs are).

  22. Ariesgirl411 permalink
    May 4, 2012

    My sister just found one of these in her laundry room she lives in the hills of Castro Valley ,Ca. We are alittle freaked out because she has a dog and a cat. Please let me know more about the pets situation. Thanks

  23. May 5, 2012

    Ariesgirl: I expect that the cat is likely to play with them and eat them. The dog will probably ignore them. Neither of them is in any danger from the average centipede. As far as I know, the only centipedes that are at all dangerous are the big tropical ones that are as long as your arm, and that’s only because of the sheer quantity of venom they can produce. The ones in North America that are big enough to bite may be painful for a few hours, but are not dangerous.

  24. Sonja permalink
    May 24, 2012

    I live in Alaska and just found one of these little buggers running across my driveway. I’m SO confused! I thought we didn’t have anything like this, I was born and raised here and had no idea and can’t find much info. Do you know anything else that would look identical to this but live in Alaska? Or if this does in fact somehow thrive here, is it dangerous?

  25. May 24, 2012

    Sonja: It is quite possible that these centipedes are just now moving into Alaska following the end of the last ice age. It looks like the ice barrier between Alaska and the rest of North America lasted until at least 10,000 years ago, and the centipedes would have had to walk the whole way from somewhere around Oregon – something on the order of 2000 miles just to get to Anchorage. Given the distance, they probably didn’t walk there themselves, they most likely hitched rides on vehicles or in shipping containers.

    They certainly are in at least the southern parts of Alaska, in any case: here’s one on BugGuide that was found in Sitka County.

    Once they are there, they should do OK in that climate as long as you aren’t in a permafrost region. They need to burrow down below the frost line for the winter, which they obviously can’t do if the soil is frozen all the way down. They do fine here, and our climate is not wildly different from the coastal regions of Alaska.

    And no, they aren’t dangerous. A bite is possible if you are handling them roughly, but even if they do bite the venom is nothing special.

  26. Brea permalink
    March 11, 2013

    I live in Eagleriver Alaska
    I have found two brown centipedes in my home .
    could you tell me If the legs have poison in them? my childrens rooms are where i found them and they are both alergic to beeing stings .????? yuck !

  27. March 12, 2013

    Brea: The only venom is from the two “poison claws” near the head. I’ve never had any problem from just the legs, in spite of letting them run over my hands any number of times.

    Centipedes are so distantly related to bees that I doubt that their venom has much (if anything) in common with bee venom. And if yours are the same kind as ours, it’s practically impossible to goad them into biting. So I wouldn’t worry about them.

  28. Wax Scraper permalink
    April 11, 2015

    I think centipedes use those backward pointing legs to grasp prey- when I bring small stone centipedes indoors and feed them, their back pair of legs twitch excitedly when they sense prey. Then when they bite it, they bend their tail forward and hold on with the rear legs. Other times they don’t even use the poison pincers, they almost rear their tail up like a scorpion and flip their whole body forward and grab it with their back legs. ( though the prey usually escapes when they do this.) also, if the centipede it held by their head (by fingers or a spider) they use the back legs to jab at their captor and force themselves free.

  29. November 5, 2016

    Omg just got home from the ER. Stepped into my shower earlier and felt something sting my leg. I have bad veins and there always breaking, so i thought my vein broke . Then again a harder bite and i thought ” what the hell” . I looked down and not being able to see good it thought it was a roach. I knocked it off and it grabbed my finger. I screamed and jumped out. Anyway my leg begain to hurt bad. My husband took me to ER because im allergic to bee stings and have heart problems. By the time i got there. My bp was high, bad headache, and chest pain. They gave me something for pain, and something to lower my bp. And i was having anxiety attacks. They may not be deadly but he scared the crap out of me. I can tell you the pain is bad.

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