Having a mouse infestation is always a worry for a homeowner. As the cold weather draws in, you may be wondering if you can expect to see them around your home or yard. Or do mice hibernate in the winter?
Wild mice do not hibernate in the winter months. Mice do not have the biological ability to remain dormant for long periods of time. As mice remain active during the winter, they need to make adaptations to survive. In winter mice will make physical, dietary, and behavioral changes to stay warm and save energy.
If you want to know more about the changes that mice make during winter then keep reading. This guide will take you through everything you need to know about the changes that mice make to remain active and survive the winter season.
Let’s jump in.
Can Mice Hibernate?
Winter is a challenge for all wild animals due to bitter cold weather and food scarcity. Hibernation is a state of dormancy that many animals use to conserve energy during this time.
Hibernation allows animals to reduce their heart rate, breathing, and metabolism to the minimum. This is so the animals stay alive, whilst saving as much energy as possible. Being dormant prevents animals from needing to use up precious energy to move, find food or pass waste.
The process of hibernation is controlled by hormones and chemicals in the animal’s body. Seasonal influences such as reducing sunlight and lower temperatures will trigger these hormones. Once these factors are present the animals will start to slowly enter hibernation. These animals also need to have the ability to build large fat stores in summer and fall, which their body uses throughout hibernation.
Mice don’t have the required hormones or body structure that hibernating animals need. Due to this mice need to stay active to find food, shelter, mate, and eliminate waste. Yet the winter conditions make this much harder for mice, and so they need to make several changes to ensure survival.
What do mice do in the winter?
Conditions in the winter months are a challenge for small mice. First, there is a lot less food to go around, and second, harsh weather can be life-threatening.
For mice to survive they need to make adjustments to their lifestyle to help them adapt to these changes in conditions. Like any wild animal, the mice need to keep themselves warm, safe, and well-fed.
Let’s look at how they can do this.
1. Build nests
Mice need shelter all year round. Yet in winter their shelter needs to provide a bit more cover and warmth than other times of the year.
For urban mice, Homes are often a good place for mice to try and invade during winter. That’s because homes are warm and can keep out larger predators.
Once they gain access to your home the mice will often bite, chew, and scratch to gather materials to build a nest. Cardboard, paper, insulation, and packaging can be used as nest material for mice in winter. They’ll try to stay in low-traffic areas such as wall cavities but will come out at night when all is quiet. Kitchen areas are ideal for mice as they have food and heat from cooking appliances.
For rural mice, they will usually try to burrow or build nests in sheltered and secluded areas. They will use grass, twigs, bark, leaves, and moss to create insulation. Mice will normally stay in these nests until it is discovered or disturbed by predators. Creating new burrows can be difficult when the ground is frozen or covered in snow.
Mice are highly social animals and will mate throughout the winter. This means they will share their nests with other mice. This helps them to survive by sharing body heat.
Mice are very adaptable creatures and they learn to make changes quickly. This includes them recognizing that food is a lot scarcer during the winter seasons than at other times of the year.
To prepare for these times, mice learn to store away caches of food during summer and autumn. These stores can be used as a natural pantry for mice to come back to when supplies are low during the cold weather.
A mouse’s diet is mainly made up of seeds, grains, and nuts, and this is what they’ll stash away. These foods store really well without going off. They keep their nutrients and provide the mice with a good energy supply.
Usually, a mouse will store their food within 10 ft. of their nest. This allows the mouse easy access to a food source without having to travel too far. This tactic of short travel can be life-saving as it protects them from predators and cold weather conditions.
One thing to look out for in the near winter is that your bird feeders are being emptied quickly overnight. This can be a sign that mice are using your feeders and storing them in caches in or near your home.
3. Fatten up
When food is plentiful in summer and autumn some species of mice will try to eat as much as possible. Eating more than they need for energy means that they will lay down a small fatty layer. This fat can be used as energy during the winter.
Think of this fatty layer as an emergency energy supply. The mice won’t rely on it, but it can be used when weather conditions are too dangerous for them. The fat layer can be broken down for heat and energy to last a very short period of time.
If the mice use up too much of this fatty layer then they run the risk of starving to death. This is why mice need to remain as active as possible during the winter. Foods high in protein and fats help provide mice with the energy they need to remain healthy and support their fast metabolism.
4. Reduce Activity
Reducing activity is a survival tactic mice will use in winter. Although it’s probably safer to say they reduce their outdoor activity rather than all activity.
Staying in sheltered areas rather than roaming around will keep mice protected. The biggest threats are unpredictable winter weather and low temperatures. Mice are also much more vulnerable to hungry predators in winter, so keeping a low profile is a good idea.
Mice can sleep for longer periods of time during winter and then use their food caches to keep their activity low. They usually won’t breed when supplies are too low. This means the mice don’t need to worry about eating more for pregnancy, nursing, or feeding baby mice.
The mice can use their emergency fat supplies to lay low for a day longer than they normally would. They’ll do this if temperatures drop too low, where it would be dangerous for them to go out and forage. Some species enter a state of torpor which allows them to rest for a prolonged period of time whilst saving energy.
Where do mice go in winter?
There are many species of wild mice that have differing behaviors. This is usually due to the challenges they face in the winter months. Urban mice have a better chance of survival than rural mice do. That’s because urban mice can rely on humans for providing shelter, warmth, protection, and food.
There are over 1000 species of wild mice. Let’s take a look at where some of the most common mice species will go in winter.
Deer mice are the most common type of rural mouse. They usually live in raised nests situated in hollowed-out trees. Deer mice are solitary through the majority of the year. In winter they will share nesting spaces with more than 10 other deer mice. Deer mice largely remain outdoors in the winter. They are more likely to have short periods of torpor when outdoor temperatures dip below freezing.
House mice are the ones that are most likely to invade your home during the winter. They will build their nests in areas of low traffic but plenty of warmth and shelter. House mice will build nests in basements, attics, garages, and wall cavities. This species will remain indoor though most of the winter, and usually remain active throughout.
House mice can live in large colonies of around 100. The males will often move on to find new territories but the females usually stay in the same place their whole life.
Western harvest mice
Harvest mice can be found in large grasslands. They will normally build their nests from grasses or use rock crevices at the edge of fields. Harvest mice will stay close to the ground in winter. They will use small burrows in the ground to ensure cover.
Harvest mice have a much higher mortality rate than other mouse species. This is because they can’t store large fat levels. This means they find it harder to withstand cold winter temperatures and will be at greater risk of predators when searching for food.
The cactus mouse is well adapted to living in dry and hot conditions most of the year. Cactus mice will usually make nests in burrows or rock crevices. Winter can be a struggle for this species which is why they have adapted to using periods or torpor. The cactus mouse will usually go into this state when food supplies are too low or the temperature is too cold.
White-footed mice are quite adaptable to living in both urban and rural areas. They will usually look for nesting sites that are warm and dry. Hollowed-out trees and disused bird nests are ideal for the species.
If given the chance white-footed mice will make their nest in your home or property. Family units of white-footed mice will nest together over winter.
Are mice worse in Winter?
Mice are no more active in winter than they are at any other time of year. The only difference is that you may notice them more in winter if they have built a nest in your home.
House mice will usually stay within the confine of a home during the winter. This can make them more of a pest as they will explore your home at night for food sources, and leave trails of urine and feces.
Mice that nest in your home can cause damage to your property. This may be physical damage from chewing, but also health concerns from their waste. Mice feces and urine are known to carry various diseases which can cause you or pets to become unwell.
To prevent these issues check out my guide on how to keep mice out of your house.
Do Mice Migrate?
Mice are not migratory animals. They may travel a short distance to find a suitable nesting place for winter. Mice can also slowly migrate closer to human dwellings to be closer to shelter and food sources.
Mice won’t migrate seasonally to warmer climates. In fact, mice are well adapted to surviving in the wild. They adjust well to winter by finding good shelter and keeping food stashes for when they can’t forage.
Mice don’t hibernate during winter. Yet they need to learn to adapt to the harsh conditions and low food supplies during this season. Mice will find good sheltering places and create food stockpiles that they can use throughout the winter.
This helps mice to slightly reduce their activity to keep themselves safe and well-fed. Each mouse species will adopt its own wintering behaviors depending on its environment. Mice are resilient creatures who can survive wintertime without hibernating or migrating.