Household Pests: Deer Mice

The world is home to many species of rodents. One type, the mouse, has several species of its own. Some are kept as pets, while others are considered pests and can infest your land and home. One type of mouse considered a huge problem and commonly found throughout homes is the deer mouse, or Peromyscus maniculatus. 

But what are deer mice, anyway?

What Are Deer Mice?

Deer mice are only one species of mice and rodents. They are native to North America and can be found throughout the United States, Canada, and Mexico. Deer mice produce rapidly, thanks to their ability to become pregnant shortly after giving birth. Typical litters have 4-6 offspring but can vary from 1-11. 

Deer mice are usually nocturnal, meaning they’re most active at night. They’re often found on the ground and in low-lying areas but are good at climbing, so they can often be found in higher places, too. Deer mice are a social species that gather in small groups. One mature male dominates the group, consisting of mature females and many young offspring. During colder months, individual deer mice and small groups may come together to form nests and conserve heat. 

Deer mice have excellent senses of touch, hearing, vision, and smell. Their senses help them keep an eye on their surroundings, avoid predators, and scavenge for food. Deer mice communicate through tactile, visual, auditory, and chemical signals. They’re close-knit and provide each other with grooming services. 

Deer mice often use scent to mark their territories through pheromone emission. They can be territorial toward strange deer mice and show this by quickly drumming their front paws against solid surfaces. 

Night-time predators like owls, snakes, and other carnivorous mammals often hunt deer mice.

What Do Deer Mice Look Like?

If you want to identify deer mice, it’s important to understand what deer mice look like. 

Deer mice get their name from their fur, which is similar to that of a deer. They have a small framed body similar to a typical house mouse. Their bodies are round and slender. They can reach a length of between 119-222 mm and a weight of between 10-24 grams. Tail length varies but is usually around 44-105 mm. Deer mice found in the woods are larger, with longer tails and bigger feet. Prairie forms are smaller with shorter tails and smaller feet. 

Deer mice have a small head with a pointed nose and big, black, and beady eyes. Their eyes have some fur that covers them. Deer mice have long hind limbs but short forelimbs. They’re typically grayish or reddish brown white undersides and bicolored tails. Like deer fur, their fur is short, dense, and soft to the touch. 

Where Do Deer Mice Live?

Deer mice favor rural lifestyles over urban living. As such, deer mice can commonly be found in open grasslands, forests, and pasturelands. They may also be found in building structures such as: 

• Sheds
• Vacation homes
• Homes near forests and woodlands 

Deer mice build nests in fence posts, tree hollows, and other debris. They will also find shelter underneath decks and in log piles. In colder months, deer mice find their way into homes, garages, and sheds, and can even nest in vehicles. Inside homes, deer mice will inhabit storage boxes, wall voids, and cracks and crevices. They prefer tight spaces often found in basements and attics.

What Do Deer Mice Eat?

Deer mice are omnivores and commonly feed on seeds, beetles, and other insects. However, they are not limited in their diet and will eat anything available, including fungi, fruit, and carrion.

Their feeding habits change with the seasons and depend on what is readily available. They scavenge for food, especially in holes, tree cavities, and bird nests. They hoard food in the fall in preparation for the colder months. 

Deer Mice Lifespan 

Deer mice have been known to live eight years in captivity. Wild deer mice have a much shorter lifespan, typically less than a year. This can be due to several factors, including starvation during the colder months, human interference, and being preyed upon.

Are Deer Mice Dangerous?

While deer mice might look cute and harmless, they’re not. If you wonder, “Are deer mice dangerous?” the answer is yes. Deer mice can carry and transmit diseases through bites and feces. 

When deer mice infest your home, they leave behind bacteria-infested feces. The feces can spread bacteria which can contaminate food, cause allergic reactions, and even spread diseases and viruses to humans who encounter the droppings. 

Commonly transmitted diseases and viruses from deer mice to humans include: 

• Bubonic plague: The bubonic plague is historically known as the Black Death. It’s a highly contagious and extremely fatal disease. In the Middle Ages, the bubonic plague was responsible for one-third of the European population dying. The plague is spread when a flea bites an infected rodent and then into a human host. Symptoms include fever, headache, and lymph nodes that are painful and swollen.
• Hantavirus: The Hantavirus is another life-threatening disease, primarily transmitted to humans through the white-footed deer mouse. Infection occurs after a human has been exposed to contaminated droppings, urine, or salvia. Common symptoms include fatigue, fever, and muscle aches, but can also include headaches, chills, dizziness, and abdominal issues.
• Rat-bite fever: Rat-bite fever often occurs after coming into contact with an infected rodent, such as an infected deer mouse, and usually after getting bitten. Despite the name, rat-bite fever can also be transmitted through contaminated food. Rat-bite fever can be fatal. Symptoms occur 3-10 days after exposure and include headaches, muscle pain, fever, vomiting, and a rash.
• Salmonellosis: Unlike the other diseases mentioned, salmonellosis is a type of food poisoning. Symptoms include fever, abdominal pain, and diarrhea. Salmonellosis is contracted when a person eats contaminated food.

If you have come into contact with contaminated food, droppings, or deer mice, and are experiencing any unusual symptoms, consult with your doctor to discuss testing and treatment options.

Deer Mice Prevention

Many homes become infested with deer mice and other rodents during the colder months. Deer mice try to flee the cold and take shelter in warm homes, often causing destruction in their wake. Not only do they chew on wires, which can increase the risk of a house fire occurring, but they can also leave a mess of feces and urine in their wake.

Deer mice prevention begins with inspecting your home for signs of infestation. You should inspect your home and property on a routine basis. Look for signs such as feces, gnaw marks, and damaged food. If applicable, check basements, attics, and outbuildings for signs of deer mice.

Other preventative measures include: 

• Seal cracks and crevices around your home 
• Replace mortar and weather stripping, especially around the basement and windows 
• Place food in sealed, rodent-proof containers 
• Keep your home and outbuildings clean and dry
• Ensure all garbage is disposed of regularly 
• Keep clutter to a minimum 
• Cut down tree branches and shrubs 
• Avoid keeping pet food and bird seed in outbuildings 
• Routinely check basements, attics, and outbuildings 

How To Get Rid Of Deer Mice

If you suspect you have a deer mice infestation problem, you may wonder how to get rid of deer mice. You may want to consider contacting a professional pest control company or contractor. These professionals will have the tools, knowledge, and licenses to remove deer mice from your home safely. 

If you decide to try and tackle the problem on your own, there are many traps available to use. Some traps are considered inhumane, such as those trapping mice by their feet, tails, or snouts, or glue-based traps. Others are harmless and considered humane, like those that trap mice inside a long tube. 

Regardless of your choice, it’s important for your health and home to eliminate these pests from your property.