Deer mice are tiny rodents that can be found across North America. At first glance they may seem harmless, but these little creatures can actually pose some serious health risks to humans. Learning about the dangers of deer mice can help you stay safe if they invade your home or property.
An Introduction to Deer Mice
Deer mice (scientific name Peromyscus maniculatus) are small rodents that are common across most of North America. They typically grow to about 2-3 inches in body length with tails that are 3-4 inches long.
Some key facts about deer mice:
- They have brown or gray fur on their backs and white undersides. They also have large eyes and ears.
- Deer mice are nocturnal and most active at night. They build nests in enclosed spaces like woodpiles, attics, and crawlspaces.
- An agile climber, the deer mouse can fit through very small openings less than 1/4 inch wide.
- Deer mice are omnivores that eat a variety of foods including seeds, nuts, fruits, insects, and fungus. They may also scavenge in garbage cans and compost piles.
- Females can produce up to 10 litters per year with average litter sizes of 3-6 babies. This allows deer mouse populations to grow rapidly under ideal conditions.
- Deer mice are prey for many animals including snakes, birds of prey, foxes, coyotes, and house cats. Even with many predators, deer mice thrive nearly everywhere in North America.
Why Deer Mice Can Be Dangerous
While deer mice may seem cute and harmless, they do pose some health risks that you should be aware of:
1. Deer Mice Can Carry Hantavirus
Deer mice are natural carriers of hantavirus, a rare but dangerous virus that humans can contract through contact with mouse droppings, urine, or nesting materials.
Hantavirus does not make deer mice sick, but it can cause a potentially fatal respiratory disease in humans called hantavirus pulmonary syndrome (HPS).
Early symptoms of HPS are similar to the flu including fever, muscle aches, headaches, nausea, vomiting, and fatigue. After a few days, infected persons develop severe respiratory problems that can be fatal. There is no vaccine or cure for hantavirus infections in humans.
Outbreaks of hantavirus infections have been linked to cleaning vacated sheds, cabins, and other enclosed spaces where infected deer mice had been living. Disturbing and stirring up deer mouse nests and droppings is the primary way the virus is transmitted to humans.
2. They Can Contaminate Food and Surfaces
Deer mice droppings and urine may contain disease organisms including salmonella, E. coli, and leptospirosis that can contaminate surfaces or foods.
If deer mice have access to cupboards, pantries, or storage containers, they can transmit these diseases by contaminating food supplies. Any surfaces the mice contact should also be considered contaminated and cleaned thoroughly.
3. Bites May Cause Infections
While not common, deer mice will bite if threatened or handled. Their sharp teeth can introduce bacteria deep under the skin causing painful wound infections.
Deer mouse bites are a concern because the mice may be carrying infectious diseases. Seek medical care for any deer mouse bites to determine if antibiotic treatment is needed.
4. They May Damage Property
Chewing and nest building behaviors of deer mice can also damage insulation, wiring, and stored items in homes and outbuildings. They will chew through containers to reach food supplies.
Their gnawing and digging habits can cause costly repairs if they establish nests and colonies inside buildings. Keeping deer mice out of structures is key to preventing this property damage.
Preventing Deer Mouse Infestations
Here are some tips to keep deer mice out of your home and workplace:
Seal All Possible Entry Points
Deer mice can squeeze through tiny openings less than 1/4 inch wide. Seal any gaps or holes on the interior and exterior of buildings using steel wool, caulk, foam sealant, or other weather-stripping materials. Pay close attention around the foundation, roofline, windows, doors, and where utilities enter the structure.
Clear Out Clutter
Deer mice seek shelter in enclosed spaces with clutter they can build nests in. Keep areas around buildings clear of woodpiles, tall grass, brush, and debris. Store seldom used items in sealed plastic or metal containers. Remove trash and food waste frequently.
Use Traps
Live traps or snap traps can help remove deer mice that find a way inside. Bait traps with peanut butter, chocolate, or bacon grease. Place them along baseboards and in corners where there are signs of mice.
Keep Food in Sealed Containers
Any pet food, bird seed, or human food left out can attract deer mice. Keep all foods sealed tightly in plastic, glass, or metal containers that deer mice cannot chew through. Clean up any spills or crumbs right away.
Cut Off Water Sources
Fix any leaks and avoid leaving standing water from leaks, pets, or plants. Deer mice need a fresh water source to survive, so eliminating leaks and drips removes an attraction.
Use Repellents
Peppermint oil, fox urine granules, or ultrasonic pest repellers may help deter deer mice to some degree. However, removing food and sealing entry points is more effective.
Get a Cat
Cats can be excellent hunters of mice. A feline presence may scare deer mice away or reduce populations around your home. Make sure cats are properly vaccinated for diseases mice can transmit.
Call a Professional Exterminator
For serious deer mouse infestations, the help of a professional pest control company may be warranted. They have industrial strength traps and exclusion methods not available to homeowners.
How to Safely Clean Up Deer Mouse Contamination
If you find deer mice or their droppings in your home, shed, cabin, or other buildings, use extreme care in cleanup to avoid hantavirus transmission:
- Ventilate the space by opening doors and windows for at least 30 minutes before starting cleanup. This allows any virus particles in the air to disperse.
- Wear personal protective equipment including gloves, goggles, respiratory mask, and coveralls. Avoid stirring up dust.
- Lightly spray nesting areas and droppings with a disinfectant or 10% bleach solution. Let soak for 10 minutes.
- Use disposable rags, paper towels, or a vacuum with a HEPA filter to clean up debris. Double bag any waste before disposing.
- Disinfect any surfaces mice contacted like countertops, floors, and shelves. Steaming hot water also kills hantavirus.
- Wash hands thoroughly after cleanup and shower once finished. Machine wash clothing worn.
- Avoid sweeping or vacuuming nests and droppings without disinfecting first, as this can stir up contaminated dust.
Contacting a professional cleanup or restoration company is recommended for large-scale deer mouse infestations. They employ specialized disinfecting methods to neutralize hantavirus risks.
Deer Mouse FAQs
How can I tell if I have deer mice?
Signs of deer mice include small rodent droppings around the home, tiny burrows, gnaw marks, rustling noises at night, and the mice themselves. Look for the large ears and eyes and white underside unique to deer mice. Also inspect for rub marks along commonly traveled routes.
Where do deer mice nest?
Deer mice build nests in enclosed spaces with available cover and materials to chew. Common nest sites include attics, crawlspaces, sheds, woodpiles, behind walls, under appliances, and in openings around pipes or vents. They prefer higher locations.
What smells deter deer mice?
Strong odors that may deter deer mice include peppermint oil, cayenne pepper, garlic, and fox or coyote urine. Mothballs may also repel mice to some extent. However, eliminating food sources and sealing entry points is more effective.
How do you kill deer mice?
Snap traps, electronic traps, or glue boards can humanely kill invading deer mice. Place traps along baseboards, in corners, or areas with signs of activity. For safety, have a professional handle large infestations. Poisons are not recommended since mice may die in hard to reach spots.
Do cats keep deer mice away?
Yes, the presence of an outdoor cat may deter deer mice around the home by preying on them or scaring them off with their scent. Indoor cats may also kill and dispose of any mice that find their way inside. Make sure cats are properly vaccinated for any diseases mice can transmit.
Can deer mice climb walls?
Yes, deer mice are excellent climbers thanks to their strong claws, toes, and tails. They can scurry up vertical surfaces like walls, trees, pipes, poles, and fences. Deer mice use their climbing skills to access nesting sites and search for food.
Conclusion
While tiny, deer mice can transmit harmful diseases and cause property damage if they invade homes and buildings. However, through proper exclusion techniques, sanitation, and population control, the risks posed by these small rodents can be minimized. Learning to identify signs of deer mice and taking prompt preventative action is key to staying safe from the dangers they can potentially cause. With vigilance and appropriate prevention measures, deer mice do not need to become dreaded intruders.