Where do ants go in the winter?

Once again, our post has been inspired by a children’s book. This time it is Bugs and Bugsicles:  Insects in the Winter by Amy S. Hansen and Robert C. Kray (illustrator). The authors follow different insects, including pavement ants, as they prepare for winter. I posted a review of this book at Wrapped In Foil and insects in winter activities at Growing With Science.bugs-and-bugsicles

When you see ants and other insects coming out in the spring, you may wonder “Where do ants spend the winter?” The answer is, it all depends on where in the world the ants live, and which of the over 12,000 species you are studying.

Where below-freezing temperatures are common, ants exhibit a number of strategies to get by.

Under the ground:

Some ants, like wood ants (Formica), can adjust the structure of their nests to help regulate the internal temperature. The huge mounds act as solar-collectors, increasing the temperature inside. When it becomes too cold, wood ants retreat to deep underground, below the frost line.


In wood:
Camponotus carpenter ants, live in nests in wood. Although wood is a good insulator, it still freezes inside during the winter. Carpenter ant species that live in temperate climates must have a provision for overwintering. The ants enter a state of slowed metabolism called “diapause.” Generally, the queen stops laying eggs. The workers develop large fat bodies, which can be seen as their gasters swell in size. The workers begin to aggregate more than before. In the two species I studied in upstate New York, Camponotus pennsylvanicus and Camponotus novaeboracensis, the larval stage also overwintered in the nest, but pupae and eggs did not.

Although I kept my laboratory colonies at constant temperatures and light conditions, they still periodically went into diapause. It appeared that colonies required exposure to temperatures below 15° C for about 60 days to exit diapause. Without cold temperatures, the colonies would remain in a suspended state for extended periods.


In acorns:
Acorn ants spend the winter inside acorns on the ground. These tiny ants form small colonies. When Joan Herbers and Christine Johnson took a look at how the colonies did over winter, they found low survivorship overall. Why do the ants stick it out in acorns instead of heading underground? Some evidence suggests that by spring acorns are relatively rare, and by staying inside their prize home over winter, the acorn ants are assured of a summer home. (for acorn activities for kids, see Growing With Science).

Winter ants

One species of ant, Prenolepis imparis, has earned itself the name of winter ant because it is often out foraging in temperatures near freezing. Walter Tschinkel showed that in northern Florida these ants actually are active from November to March and then workers seal up their underground nests  and don’t come out until the following fall. Leave it to a species of ant to do things completely the opposite to most other insects.


Photograph of Prenolepis imparis from antweb.org (No photographer named)

No winter?

Ants that live in the tropics or hot climates don’t tend to react much to winter, although they may shut down temporarily during a dry or wet season instead. Some ants have extensive nests with elaborate ventilation systems, where the environment inside has uniform temperature and humidity year around. Now that’s the way to live.

Are ants active where you live yet?


Joan M. Herbers and Christine A. Johnson. 2007. Social structure and winter survival in acorn ants. Oikos. 116(5): 829-835.

Tauber, MJ, CA Tauber and  S. Masaki. 1986. Seasonal adaptations in insects. Oxford University Press, New York.

Walter R. Tschinkel. 1987. Seasonal life history and nest architecture of a winter-active ant, Prenolepis imparis. Insectes Sociaux. 34(3): 143-164.

56 Replies to “Where do ants go in the winter?”

  1. Just wondering if carpenter ants will survive in the walls of a cabin after a cold northern ontario winter?
    Temperatures range from -5 to -25 , average -10 in the Jan, Feb months.
    If a nest is established in a spring and summer, will it be killed in the winter, or will they survive in the walls.
    The cabin is not winterized but insulated , so it gets very cold inside the cabin.

  2. Carpenter ants enter a state called diapause in the winter to survive the cold. They may stay in the walls or they may go into the soil, depending on environmental conditions. They can definitely survive the winter.

    You probably don’t want to hear this, but the presence carpenter ants indicate that there’s a moisture problem, such as roof leak, pipe dripping or problem with the grade that is allowing water to enter the wood. It often pays to take care of those issues. I remember one lady asking me about carpenter ants in her bathroom. When I told her about water leaks, she said “Oh, we’ve known that tub has been leaking for years.”

  3. I live in a 9th floor apartment in Charlotte NC and when I leave the SLIGHTEST bit of food out the ants come-a-runnin during the summer. They, however, dissapeared in the winter. Where do they come from? Do they climb 9 floors to find my crumbs? There is no ground for them to go into so I’m wondering if they are hybernating behind my stove or something?



  4. James,

    Your visiting ants are most likely living in a neighbor’s potted plants, where they would retreat for the winter. Potted plants are a favorite ant hangout.

    A few ants, like pharaoh’s ants, will live in the walls of buildings. They probably would be less likely to go away in winter, though.

    It is possible the ants could be coming from the ground, too. Some species look for food by climbing trees, so they have a tendency to climb up.

    If you want to learn more, try to catch a few workers when they come back and find out what kind they are. That will give you more information about their lifestyle.

    Good luck!

  5. Hi, I live in Michigan and while turning over a log one winter I found a cluster of ants nested in a jelly like substance. Do you know what this jelly is? How do the ant make it or what is it made from/of?


  6. A lot of things live in logs, and it could be that the jelly-like substance may have been a slime mold taking advantage of the ants being immobile. I am writing a post about slime molds right now. I’ll add a link here when it is published.

  7. It’s warm enough in San Bernardino that ants should be active year around. Many live in the ground. They might be under rocks or in fields. Do you have a picnic area nearby? Ants like to come pick up the crumbs that people drop, so they often live nearby.

  8. Hiya, everyone, HAPPY NEW YEAR TO YOU ALL

    i was just wondering if anyone knows how or where i might find some lasius niger ants during the winter months im currently living in London,

    any help ideas ant lovers??

    many thanks 🙂

  9. Do fire ants bite in the winter? My daughter was covered in what looked like fire ants, but there were no bites.

  10. Really fire ants bite and sting. It is their stingers that inject the materials that cause the stinging sensation.

    There are many types of ants that aggressively defend their nests like fire ants, but lack stingers. It was likely your daughter encountered one of these.

  11. I live in Illinois, it is freezing outside. During the spring and summer we always have tiny little black ants in the kitchen. I thought we were safe during the winter. This year I have found a few ants in our living room and not one in the kitchen. Why do you think they are here? Could they be living in my walls?

  12. Hi I live in PA (poconos)and I have lived in my home for 3yrs now. I have never had an ant problem till now and as we know its winter out here. From one little ant went to an army of ants, I have an infant and I’m losing my mind here. I’ve bought the ant traps mind you they don’t work raid seems to work but I can’t spray it a lot I have an infant. The ants are really tiny my apartment is small as well so my living room is basically in my kitchen and they are in both places. Is there anything I can do I feel like I’m infested . I tried to see where they are coming from but it’s impossible started off in one corner now it’s like everywhere . I have no money to spend on awhile bunch of products I’ve waisted enough buying all these different kinds of ant killers. Pleaseeee HELP!!!

  13. Mandy,

    Ants could be living indoors, which would explain why they are active indoors while it is too cold outside. Generally the ants are simply looking for food or water. Sometimes they will wake up too early in the spring to go outside to look for food, and will look for food inside instead.

    If you are interested in learning more about your ants, I would suggest talking to your local Cooperative Extension (listed in the white pages under county government or at http://www.extension.org/) about possible identification. There are a lot of different kinds of ants and identification is the first step to learning more about them.

  14. Giovanna,

    I am going to give you the same advice as I gave Mandy. The first step to solving an ant problem is finding out what kind of ants you have. If possible, contact your local Cooperative Extension (usually listed with county government or at http://www.extension.org/) about getting a sample identified. Then you can learn more about what to do about them.

    Spraying does little to control ants, because they live in colonies. You kill a few workers, but the rest of the colony survives. Generally baits work better (like ant traps), but it really helps to know what kind they are so you can use the right kind of bait.

  15. Hi there,
    We live in Massachusetts, and all of a sudden in the last few weeks black ants (I think carpenter ants) showed up in our bathroom upstairs. They are migrating to other places but that’s where we first noticed them.

    We’ve never had a problem in the winter before. Usually its in the spring when it starts to warm up.

    How can I figure out where the colony is so I can get rid of the queen and deal with this naturally? Is there something natural I can put out so it will be taken back to the colony?

    Thank you

  16. Hi,
    First, you might want to contact your local Cooperative Extension Service (try county government), and see if you can get the ants identified. BugGuide online has identification guides, too.

    I know people freak out when they see carpenter ants, but usually for the wrong reasons. Carpenter ants don’t eat wood, they nest in it. In addition, they don’t nest in sound, dry wood. They prefer soft, moist wood. If you are seeing carpenter ants it means that you have extra moist wood somewhere in your house. It is usually due to a leak, improper ventilation or some similar issue. Is there a leak around your bathroom? Check outside around the windows,too. They may be a sign you need to take care of those nagging home repairs.

    Typically carpenter ants are hibernating in winter in a condition known as diapause. Have you had some extra warm weather to wake them up early? Otherwise, they might not be carpenter ants.

    Good luck!

  17. I found a queen carpenter ant and would like some info on
    how to keep her happy. Is it possible for her to start a
    colony? What size container do I need? Substrate? Food? etc… Thank you

  18. Dear Lloyd,

    Sorry it has taken me a little while to get back to you. It was finals time.
    One of the easiest ways to keep ants is in a test tube, as I discuss here: http://blog.wildaboutants.com/2011/05/15/test-tube-ant-nest/ There are a number of links about rearing ants at the bottom of that post.
    Ants do well with a mixture of sugar and water, or honey and water, which should be supplied all the time. Most ants will feed on a dead insect, like a cricket, or even a small bit of tuna, even the seed-feeding ones.
    I talk about feeding ants quite a bit in this post http://blog.wildaboutants.com/2010/07/07/feeding-ant-queens/

    You might also want to try the Myrmecology forum at http://antfarm.yuku.com/ for information about raising ants.

    Please let me know if you have any specific questions and I’ll try to get back to you more quickly.

  19. I live in the sate of PA… I see a few ants here and there in my home. I have tried my best to keep them away but nothing seems to work. I use to (and more now) keep my house very very clean. So I don’t know what that are after. I can’t even see a trail or where they are coming from. I have tried vacuuming everyday, mopping with vinegar everyday, keeping house clean, ant spray but nothing keeps helps. I even sprayed my foundation with spray. My entire house is hardwood so not sure how I would use DE and vacuum. Any tips? I am afraid to use ant
    Bait as I feel I will get tons more ants and I will go nuts then (more than now). Any suggestion is helpful. Also, will they leaves house when it cools down in the season? And when does that happens? September? Later? I am so helpless now!

  20. Once again, you should probably find out what kind of ants you have in order to best assess what to do about them. You have a couple of options. If you get a nice, clear close up photograph of some of your ants you should be able to submit it online to BugGuide.net for identification.

    Or call your local Cooperative Extension office to see if they offer identification of insects. Many county offices have Master Gardener volunteers who help with things like that.

    You will probably feel less helpless if you know more about what kind of ants you have and learn more about them.

  21. Do ants come out in the middle of the winter if it suddenly gets very warm outside or do they stay underground?

  22. I had an ant problem and I bought the ant traps and it took a few weeks but I haven’t seen one in about a year. Initially when I set out the traps the ants came in swarms and it just seemed like we were feeding them, but I left the traps because the box said that they take the poison back to their colony and the poison eliminates the ants from the inside out. Sure enough the ants are no longer in my house! It works way better than the spray cause this is getting to the root of the problem.

  23. Oliver, It depends on the kind of ant and where you live. Some ants go into a true diapause, which means they have to stay dormant for a certain period of time regardless of the temperature. Others can become active as temperature permits.

  24. I live in Mass. Do ants here dig any new tunnels in existing nests in the winter? Or does new construction only happen when it warms up in the spring? Thanks

  25. Keith,

    That is a very good question. Whether or not an ant would dig new tunnels depends on the weather, of course, but also the species. The winter ant, Prenolepis imparis, gets its name because it is active during much colder times than other ants. They have their mating flights as early as March in Illinois, and would be active in their tunnels before that.

  26. hmm i live in tropic but i has a colony of Japaneses carpenter ants as pet. do they still enter diapause?

  27. Destman,

    It is likely that Camponotus japonicus would live in areas cool enough to go into diapause. Does anyone know for sure?

  28. Cornelius,

    Well, first of all what kind of fire ants? Do you mean the imported fire ant, Solenopsis invicta? In that case, the ants don’t really hibernate, but for the most part just slow down.

    If you are really interested in imported fire ants, I would recommend Dr. Walter Tschinkel’s book The Fire Ants. It discusses in quite a bit of detail how they are effected by temperature and season. It is heavy reading, though.

  29. I encountered red ants in three separate groups above ground. One group was near their ant hole huddled up the size of a dollar coin, another group huddled in a depression about the same size, and the third group were huddled up in between a 4″ channel iron embedded into the dirt. The channel iron supports an electrical outdoor connector. The ants were in a dirt enclosure the size of 4’x7′ triangular shape surrounded by asphalt and roads. The ants remained there during a snow storm for two days and were still alive the next day. As the days continued on the ants were fewer and fewer and birds began eating them. It seemed that the ants refused to go back into their hole for some reason and rather die outdoors. The red ants are 1/4″ in length and seen them fighting with black ants in the air during the summer months. What drove these ants out of their hole in the ground ?

  30. What an interesting mystery.

    I’m sure there are many explanations for what you witnessed,and without knowing more I can’t be sure. Two suggestions are:

    1. Many ants are sensitive to vibrations in the ground, and those vibrations are often a signal that there is danger around. It is possible the channel iron or something else was vibrating at the right frequency to drive them out and keep them out. You can read about ant sound communication here: http://blog.wildaboutants.com/2010/01/28/ant-stridulation/.

    2. It could be the chambers underground filled with water, maybe during a thaw. Once above ground, the ants were probably too cold to move anywhere else.

    Those are my best guesses right now. Let me know if you see more ants there in the spring.

  31. Hello,

    I have a Pileated Woodpecker drilling a pear tree by my house. Someone said it is eating ants. Much of its holes are high in the tree.I do get carpenter ants in the house during the Spring. My question is, would there be a nest inside the tree in the Winter? I live in Ohio and have had zero degree weather. It is during January. Thanks! They are a beautiful bird.

  32. Jerry,

    Congratulations on finding such an interesting bird.

    Although carpenter ants do readily overwinter inside the wood, I share your skepticism that carpenter ants would be that high in a pear tree in the winter, mainly because of the small size of the branches.

    The woodpeckers do drill after wood-boring beetle larvae as well as ants. A common beetle larva in pear is the flatheaded apple tree borer http://extension.missouri.edu/p/g7190

  33. Thanks Roberta. That is what I thought. The woodpecker also drills an old cherry tree and willow trees. The fruit wood attracts many insects and birds. I am happy to be out in the country and can leave old trees standing.

  34. Hello,

    I have a question and I hope you can help me. I am writing a script for an animation and I wanted to stick to facts regarding ants, as they play a big part in it. The story takes place in the winter, and it’s about two boys who come across an anthill under a tree. Since, ideally, I would like to have the ants on the mound going about their business, I wanted to check if this is something they would do if it is still cold outside, even if not everything is covered in show? Does the snow have to be completely gone for them to start emerging from underground? Thanks in advance!


  35. Goca,

    Here in North America the winter ant, Prenolepis imparis, can be out foraging at temperatures close to freezing. Theoretically, there can be times when the temperatures are well above freezing, but there is still snow on the ground. Ants would not realistically be out if it is below freezing.

    Hope this helps…

  36. Hi I believe that some crazy ants made their way into my car during the summer (in florida) . I have tried different things to kill them, none of which have worked so far. I wanted to know at what temperature crazy ants freeze because I live in the north and I wanted to know if they will freeze off and die

  37. Hi there, I have been bitten twice and my daughter once by an unknown insect but the symptoms and look of the bite match the bite of a fire ant. Problem is I live on the East Coast of Canada…and it’s winter! I’m pretty sure I have never seen fire ants here before but I have seen some ants active around the house recently (not many though). Do you know of any biting ants in this area that would produce the same symptoms? I will keep my eye out for a specimen to identify in the future. Thank you.

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