Do Mice Hibernate in Winter?

three mice sitting

Do mice hibernate in winter? Far from it; they hustle. While in rare cases they can briefly slip into a temporary sleep called torpor to save energy, mice are mostly on a non-stop quest for food and cozy places to stay warm. 

Let’s dive into why mice don’t hibernate in winter, how they cope with the cold, and if they ever do take a break, how and when that happens.

When Do Mice Hibernate?

Mice, regardless of the species, don’t hibernate —ever. Unlike some of their rodent cousins, like dormice or groundhogs, mice can’t store energy to last them through times when food is scarce. Due to their small size, they lose body heat quickly, and their high metabolic rates mean they need to eat frequently. 

The result? Mice stay active all year round, including both summer and winter. In the summer, they’re happy outside, but as the weather cools down, they start looking for warmer spots with plenty of food. However, they don’t migrate long distances like birds. Instead, they move a short way from where they usually live to find the best place, which often leads them straight to our homes. This is why you might notice more mice inside your house during winter

What Do Mice Do in the Winter?

Mice activity levels can fluctuate depending on the severity of the winter and their access to food and shelter. Their winter behavior is also influenced by the specific needs of their species. However, they all want the same basic things: warmth, food, and safety. 

Here’s what mice do when the cold sets in:

Seek Shelter

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First on mice’s winter checklist is securing a cozy hideaway. Their perfect spot has to be warm, hidden from predators, and close to a steady supply of food and water.

House mice are particularly fond of garages, attics, wall voids, and basements. You might also find them sneaking behind kitchen appliances, under floorboards and sinks, or even tucked away in utility rooms and cluttered closets. 

Wood mice often set up their winter homes under garden sheds, in compost heaps, beneath wooden decks, or amidst piles of leaves and sticks. Sometimes, they find shelter inside unused equipment or tools left outside.

Deer mice are pretty good at finding quiet spots, like unused corners of garages or even old cars, to spend the winter. 

Harvest mice are less likely to invade your home, but if your property borders natural fields or wooded areas, you might find them venturing close. They’re attracted to dense vegetation and tall grasses where they can hide and find food.

Some of these species, like wood and deer mice, also like to dig tunnels under the snow. These tunnels offer them protection from predators and easy access to food sources like roots and seeds during the winter — which means they can munch on garden plants and mess up your yard. 

Build Insulated Nests

Mice start working on their nests when it starts to get cold, but before winter really hits. They gather materials bit by bit, making several trips to collect everything they need. House mice make their nests kind of loose and round, while wild mice’s nests are more compact to keep out the cold better.

House mice are particularly creative, using whatever materials they can find around the house. You might find nests composed of shredded paper, fabric scraps, bits of insulation, or even pulled-apart soft materials like cotton balls.

Out in nature, mice pick natural stuff like dried leaves, grass, feathers, and small twigs to build their homes. Harvest mice weave tight, round nests out of grass that look almost like a small, natural soccer ball, and hang them up in bushes or tall grass to stay off the ground.

Feed

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Mice eat just about anything they can find, but they really like seeds, grains, and nuts. When winter rolls around, each type of mouse has its own way of making sure they keep their bellies full.

House mice raid pantries and kitchens, nibbling on stored grains, pet food, and any accessible edibles. If available, they go straight for foods packed with protein, fat, and sugar —think treats, cheese, or bits of meat.

Meanwhile, wood, and harvest mice act like little collectors, gathering up seeds and nuts in the fall and hiding them away in their nests and burrows. This way, they make sure they have enough to eat all winter long. Now, if their supplies start running low, they don’t just sit back and wait for spring. Instead, they turn to whatever is available and eat stems, twigs, bark, leaves, and even insects and small invertebrates.

Breed

If house mice find a nice spot to live in your house, they’ll keep breeding even in winter. Other mice species also continue to have babies through the colder months, although not as much as when it’s warmer.

Jaw-dropping fact: Female mice can have 5 to 10 litters of pups in a single year, with each litter averaging 5 to 6 pups. What’s more, they can get pregnant again just 24 hours after giving birth. A mouse’s lifespan is relatively short, but they can have many pups.

Enter Torpor

Wild mice, like deer mice, might enter torpor during the coldest parts of winter. This helps them survive when it’s freezing outside and food is hard to find. Torpor is like taking a short nap that saves them energy. During torpor, a mouse’s body temperature drops, and its heart rate slows down, helping it save energy without going into full hibernation.

Cause Damage

When mice move into your house in winter, they tear apart insulation, paper, clothing, and even bits of carpeting to line their nests. They also have strong little teeth that never stop growing, so they chew on things to keep them from getting too long. 

They can easily bite through wood, plastic, and metals like aluminum or copper, which makes electrical wires, drywall, soft vinyl, rubber hoses, and even some types of wall siding a prime target. While mice can’t chew through harder metals, such as steel, they often find or create small openings around these materials to gain entry into new areas of your home.

In addition, mice carry diseases that can be harmful to us. For instance, they can transmit Hantavirus Pulmonary Syndrome (HPS), which you can catch by inhaling dust that’s mixed with mouse droppings or urine. Other examples of diseases they spread are salmonellosis and leptospirosis.

Common Signs Mice Have Moved in for Winter

While you can take several steps to rodent-proof your house, mice will still try to sneak in during winter to survive the cold. Identifying if they’ve managed to make their way inside is crucial to prevent an infestation that can be costly, stressful, and eventually dangerous.

Here’s what to keep an eye out for:

droppings of mouse on the floor
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  • Droppings: Mice droppings are dark, about the size of a grain of rice, and have pointed ends. They can be scattered along walls, under sinks, or inside cupboards. You can also find them in kitchen cabinets, drawers, pantries, or near food sources like pet food bowls.  
  • Gnawing: Look for gnaw marks on electrical wires, furniture, or food containers and packages. 
  • Scratches on walls: Mice climb walls to find entry points or just reach higher areas, like countertops or shelves, leaving scratch marks or tiny claw marks along your walls or even on furniture close to the walls.
  • Strange noises: At night, when mice are most active, you might hear scratching, scampering, or rustling sounds within walls, above ceilings, or under floors. 
mouse track on snow
Photo Credit: Bryan Alexander / Flickr / CC BY 2.0
  • Footprints and tail tracks: In less-traveled, dusty areas of your home, you might spot tiny footprints or tail drag marks left by mice. You’ll typically see them near the edges of rooms, in the basement, or the attic.
  • Unpleasant smells: A strong, musty odor, similar to ammonia, is often associated with mouse infestations. This smell comes from mouse urine and can get really strong in areas where mice frequent or nest.

Do Mice Go Away After Winter?

Mice don’t have a seasonal migration pattern. Once house mice find a safe, warm spot with steady food, like in your home, they’re likely to stay, even after winter. Mice living outdoors, like field and wood mice, usually stick close to their winter homes if they can still find plenty of food nearby. However, they may venture out more, exploring further and being more active as the weather improves. 

FAQ About Mice During Winter

Do mice like the cold?

Mice don’t enjoy the cold. Due to their small size, they are prone to rapid heat loss, so they’re most comfortable when it’s between 64 to 79 degrees Fahrenheit. Now, they can survive colder weather and are very adaptable. However, there isn’t a clear-cut lowest temperature they can withstand. It largely depends on their ability to find food and create warm shelters to ride out the cold.

Do mice become more aggressive in winter?

No, mice aren’t typically aggressive with people. In winter, they’re mainly focused on looking for food and a warm place to stay. So, most of the time, they’ll try to stay out of your way. However, you might notice them more at night because that’s when they’re busy exploring and humans are usually asleep or not moving around much.

Is it safe to release live mice outdoors in winter?

Releasing live mice outside during winter isn’t totally safe for a couple of reasons. First, if you release them too close to where they were caught, they can easily find their way back into your property, looking for warmth and food again. Second, if the mice are adapted to the comfort of your house, placing them outside in the cold without their usual food sources can be a significant shock, and they might not survive

Hire Professional Help for a Mice-Free Winter 

Mice view our homes as perfect winter getaways. Instead of hibernating, they slip through the smallest cracks, set up camp in the quiet corners of your house, and even bring health risks into your living spaces. While you can do a lot to keep them out, like sealing up entryways and storing food properly, it’s tough to cover all your bases on your own.

Hiring a pest control professional is your best move to get peace of mind and enjoy a mice-free winter season. Pros have the expertise to identify entry points, suggest effective prevention strategies, and, if necessary, safely remove any mice already inside.

Main Image Credit: Pixabay

Tatiana Barrie

Tatiana Barrie is a seasoned writer and a DIY enthusiast. Over the years, she's collected practical tips and insights on tackling tricky home improvement projects: from repurposing unused spaces to mastering essential maintenance tasks. Now, she uses her writing and newfound skills to help others avoid their own household calamities.