Do Indoor Ants Leave in the Winter?

By Chris Williams on January 11, 2016.

We had tiny ants in our house all summer and now that it’s gotten colder they seem to be gone. Does that mean that they weren’t nesting in the house after all?

J. R., Boston, MA

That is probably what it means. When you have ants in your house on a regular basis, there are two possibilities: (1) the ants are nesting outside and are just entering your house looking for food, or (2) the ants are nesting inside and are foraging in your house looking for food. In either case, the annoyance factor can be about the same but control options are different.

Ants Nesting Indoors Can Remain Active in Winter

If the ants had been nesting inside your home, you would probably still be seeing them, at least on occasion, because the warm indoor temperatures would keep them somewhat active. If the indoor nest is in a colder area of your home, however, the ants may be fairly quiet until late winter or early spring when they might become active on a warm day.

In winter in our Northeast region, ants that have outdoor nests become relatively inactive. Because ants are not warm blooded creatures, as the outside temperatures drop, so do their body temperatures. Below about 500 F., ants are no longer actively foraging and may move into protected places such as under stones or tree bark. Those with ground colonies may move their nest deeper underground where it’s warmer. They share body heat, keep the queen warm, and often bring a food supply along to help see them through the winter.

Will They Be Back In My House Next Year?

As soon as the weather warms up in the spring, so do outdoor ants. They will reopen the entrance to their nest, become active, and begin foraging again for food. If your ants are from an outside colony, they may forage into your home again next spring, or they may not. It depends on a number of factors including weather, moisture, food supplies, size of colony, etc. It probably also depends on the quality and type of food you are offering compared to what they can get outside!

If ants come back with the seasons, give Colonial Pest a call. Ant control is one of our specialties. A thorough inspection should answer the question once and for all as to whether the ants are nesting inside your home or outside. In either case, we can keep them outside where they belong. Give us a call!

For more on ants and their control, see these blogs:



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