Rats do not hibernate. When the nights turn cold, they do not disappear: they move. And the warm, dry, food-filled place they are looking for often looks a lot like your house. Here is where they go once winter arrives, and how to make sure they don’t end up inside your walls.
Where rats spend the winter
Outdoors, rats live in burrows under sheds, decks, woodpiles and dense shrubs, close to a food source. In summer, that is enough. As temperatures drop, food gets scarce and the burrows get cold, so they look for shelter that is warmer and closer to something to eat.
The usual winter destinations are predictable:
- Garages and sheds, especially if they store pet food, birdseed or garbage bins.
- Crawl spaces and basements, where pipes and furnaces keep things warm.
- Attics and wall voids, reached by climbing along pipes, wires or overhanging branches.
- Behind and under kitchen appliances, where the motor of the fridge or the dishwasher gives off heat.
Fall is when they start scouting. By the time you hear scratching in the ceiling on a cold night, they have usually been around for a while.
The signs to look for now
Droppings along walls or in cabinets, gnawed food packaging, dark greasy marks along baseboards, shredded paper or insulation, and scratching noises at night. Pets staring at a wall or a cabinet for no reason can also be a clue.
How to keep them out this winter
The most effective method is not a trap or a repellent: it is closing the door. According to the San Luis Obispo County public health department, a rat can get through an opening about the size of a quarter, and a mouse through a hole the size of a nickel.
- Walk around the house and check the foundation, vents, gaps under doors and the holes where pipes, cables and gas lines enter.
- Plug small holes with steel wool held in place with caulk. Rodents chew through foam and plastic, not steel.
- Cover larger openings with hardware cloth, metal sheeting or cement.
- Add door sweeps to exterior doors and the door between the garage and the house.
- Store food in sealed containers, including pet food and birdseed in the garage.
- Keep firewood stacked away from the walls and off the ground, and trim branches that touch the roof.
Inside, check under the sink, behind the stove and fridge, and where the floor meets the wall: those gaps lead straight into the wall voids.
What won’t work on its own
Scents and natural repellents can help discourage a curious mouse, as we explained in our article on the leaf mice avoid, but no smell will keep a hungry rat out of a warm house with an open door. If you already see fresh droppings every day, or hear activity in several rooms, call a pest control professional.
The same fall routine also works against other winter guests, like the stink bugs that move indoors this time of year. And if you burn wood, choose your firewood well, then keep the pile far from the house.
Steel wool, a tube of caulk and a walk around the foundation. That’s the trick.
