Ants from cool climates spend the winter in a resting state called diapause. Ant keepers copy this with a controlled winter rest. Done well, it keeps the queen healthy and the colony strong.
Which species need it?
Species that come from regions with a cold season usually need it. Species from tropical regions do not.
- Needs a winter rest: Lasius niger and the European harvester ants Messor barbarus and Messor structor.
- No winter rest: tropical species such as Dinomyrmex gigas and Atta cephalotes, which ant-keeping sources describe as active all year.
- Unclear: for some species, such as Myrmecocystus mexicanus, the sources do not agree, so check the species page and ask us.
How cold and for how long?
The figures reported by ant-keeping sources:
- Lasius niger: about 5–10 °C from roughly late October to early March.
- Messor barbarus: about 10–15 °C for a few months. Sources give two to five months, and one source calls it beneficial but not mandatory for young colonies.
- Messor structor: a cool rest of a couple of months. Sources differ on the temperature (about 10–15 °C) and the length.
Follow the guidance for your species, and when sources differ, choose the milder option.
How to do it safely
- Prepare in autumn. Feed the colony well while it is still active, then let it slow down naturally.
- Cool gradually. Move the nest to a cooler room or a cellar over several days, not hours.
- Keep the nest slightly moist, not wet. Check the water reservoir every few weeks.
- Stop feeding or feed very little. The ants are barely active, so uneaten food only grows mould.
- Avoid frost and big swings. The nest should stay cold but not freeze.
- Warm up gradually in spring and resume feeding when the ants become active.
What if you skip it?
Ant-keeping sources warn that a cool-climate colony without a winter rest can weaken, and the queen can be worn out the following spring. If you cannot provide a cool place, choose a species that does not need a rest.
Frequently asked questions
Can I hibernate a founding queen?
In many species a founding queen is kept cool in her first winter. Check the species notes first.
Should I feed during hibernation?
Not normally. Offer water access only and watch for mould.
My ants are still active in winter. Is that normal?
It can be, if the nest is warm. Active ants in a warm nest usually need to be fed.
Not sure which colony is right for you?
Tell us about your experience, your space and the climate at home, and we will suggest species that fit. You can also explore the Ant Atlas or browse the shop.