Animals In Your Car

    Animals In Your Car

    February 2017

    Winter Home Invasions, Part 2: Stowaways in Vehicles

    By: Levi Price and Dr. Nicki Frey

    squirrel nest in car

    Nobody likes to be cold, not even our furry friends. During the winter months we turn our home and car heaters up. While humans seek shelter from the biting cold, the animals around us seek out warm places to live and sleep for their survival. Sometimes those warm places are our homes, sheds, and other similar structures. Other times they find shelter inside of our vehicles. These animals are not intentionally trying to cause problems, but anytime an animal invades our space problems can occur. When animals try to share our space, it may result in property damage, but health risks are also a concern because some animals can transmit disease. In this article we present the information about the potential dangers animals can pose when they inhabit our vehicles and how to prevent damage.

    Cars are an ideal shelter for wild animals. The small, compact spaces in an engine block are a great refuge from winter weather and predators. An engine also stays warm for a while after it has been shut off, and this heat can entice animals to climb into your engine. Sometimes these unwanted visitors will enter and leave without you ever knowing, but other times they can inadvertently cause damage that can be obvious and severe. Additionally, as an engine starts it can cause injury and death to an animal that is using it for shelter. Mice, rats, and cats are some of the animals that are common stowaways. Here are some common problems an animal can cause to a vehicle and ways to prevent it.


    Rodents can cause extensive damage to your vehicle. In addition to winter shelter, these animals can be attracted to cars that are infrequently used at any time during the year. Mice, rats, and squirrels have been known to build their nests inside vehicles. These unwanted residents can cause electrical, air condition, heating, and sanitary problems. Some common damage caused by rodents include:

    mice in engine
    • Electrical shorts caused by wires being chewed
    • Nests blocking air vents
    • Nests and food unbalancing the heater fan blade
    • Interior carpets and seats being chewed
    • Feces and urine can increase chance of disease transmission.

    Rats, and possibly mice, store bring food into the vehicle, often near their nests. The food is a health risk to humans during cleanup, when humans are at risk for coming into contact with rodent saliva. Additionally, uneaten food can spoil and grow mold. When nests are located in ventilation systems, they can cause health issues if not cleaned up properly. Fungal spores and bacteria that become airborne when a person starts the heater and ventilation can cause Hantavirus, Salmonellosis, and Leptospirosis, just to name a few. At the very least, airborne dander (sloughed skin particles) can cause respiratory illness or distress (Herkewitz, 2016).

    rodent feces in the air filter

    Part of a rodents’ natural behavior is to chew on wires, wood, and upholstery. Because rodents chew through wires in random spots it can be very difficult to find and replace the broken wires. If they chew through the right wire it can prevent your car from starting. The damage caused by rodents can cost thousands of dollars to repair.

    Its important to remember that rodents can enter vehicles throughout the entire year so the problems they cause are not limited to the winter months. Any vehicle that is not used regularly may be seen as an attractive location for a nest or temporary shelter. The following prevention tips for rodents can save you money, time, and aggravation year-round.


    • Park your vehicle inside a well-kept garage. Ensuring that you have mouse and rat proofed the garage will significantly reduce the possibility of a rodent entering your vehicle and home. If you cannot park in a garage park away from brush and areas rodents tend to inhabit.
    • Store dog food, cat food, bird food, and grass seeds in a secure location away from your vehicle. This reduces the readily available food that rodents could bring into your vehicle.
    • Keep the interior of your car clean. Many urban rodents such as rats and squirrels are scavengers. Leftover food and snacks can be smelled by animals outside yoru car and entice them to gain entry into the vehicle. Any food you leave inside your car becomes a nice meal for them.
    • Block small entrances to your engine compartment with wire mesh. If they can’t get in they can’t make your car their home.
    • Place traps around your vehicle and on top of the wheels if it is parked or in storage for a length of time..
    • Open the hood of your car when you park it in personal garage or other storage area for more than a couple nights. This gives the perception that the area under your hood is “open”, and not a quiet, secure place to build a nest or rest for a while. It also lets more cold air into the engine compartment eliminating the warmth they are seeking. Additionally, when you enter the garage and the lights are turned on, this lets light enter the engine compartment; mice and rats prefer to nest in dark environments.
    • Turn on or drive your vehicle regularly. This allows you to see if any damage has been done.

    Depending on the circumstances in the area you live you may want to apply some or all of these tips year-round to keep rodents out of your vehicles. If you have a high density of rodents in your area or house other steps may need to be taken to protect yourself from damage. Last month’s article on Deer Mice has some great tips for removing a mouse infestation in your house.

    Cats and Other Mammals:

    woodrat nest in car

    In the winter, stray or lost cats and other cat-sized mammals are attracted to vehicles when they are looking for warmth and shelter from the environment. They can be seriously injured or killed when the engine is started. If they survive the engine starting, they could fall off your car as you are driving and be injured. Jane Harrell, Editor-in-Chief of Pet Health Network, said, “I’ve been in the pet industry for thirteen years, and every year there is a story that comes up about a cat that’s gotten trapped in a car [engine] (Carr, 2016). I personally have friends whose cat died when they started their engine while it was sleeping inside. This sad experience is fairly common and it is worth taking a few simple preventative measures. While cats are the most common victim, any wild animal may also view your car or truck as a safe haven. I’ve even had a ground hog climb into the hood of my truck while I was taking a fall hike. The following preventative measures will also help prevent other wild animals from accidentally being injured when they venture inside your car.


    • If you own a cat keep it inside as much as possible during the winter. This will reduce the need for a cat to seek out warm places.
    • If you own a cat make sure you know where it is before starting and driving your vehicle.
    • Park your car inside a closed garage. If cats and other animals can’t reach it they can’t climb inside it.
    • Look under your vehicle for any animals hiding or sleeping underneath. This is a good year-round practice to prevent an animal from being run over. During the winter, you can take advantage of snow and mud to determine if any animals have left prints near your vehicle. If so, look under your hood before getting into and starting your car or truck.
    • Rattle your keys and bang on the hood as you enter your car. This should wake the animal up if it’s asleep and encourage it to exit the vehicle. You can also honk your horn a couple times. However, if it is a wild animal, honking and banging may cause it to crawl into a tighter, “safer”, spot inside the hood.
    • After making plenty of noise wait a little bit to allow the animal enough time to leave before you start and drive your car. If you know that it is a wild animal or stray (not tame) cat in your vehicle, you may need to walk away for a few minutes because the animal will not leave while you are near especially not if you are IN your vehicle.
    • If you know that a cat (tame) is inside your hood, you may lift the hood and try to remove the cat.

    What not to Do:

    • It is not recommended to open the vehicle hood to remove a stray cat or wild animal. Stray and wild animals will react in 1 of 2 ways: they may crawl into a smaller, tighter spot and take longer to eventually leave the vehicle or they may attack you, causing physical injury to yourself and the animal.
    • If you have opened the hood of the vehicle and found a wild animal, DO NOT prod the animal or attempt to remove it. Instead, leave the hood open and walk away from the vehicle for a few minutes. You may also try to honk the horn, if it appears that the animal is eager to get out of the vehicle.

    These tips are not a sure fire way to prevent animals from entering your car, but they can reduce the likelihood of it happening. Despite our best efforts, animals sometimes get by our preventative measures. If they do we adapt and find another solution. Preventative measures can help us reduce damage caused by animals and help us live together.

    Works Cited

    Carr, Jason. “Cats and Cars in Cold Weather.” Pet Health Network, Accessed 23 December 2016

    Frank, Rochelle. “How to Keep Mice, Rats, and Other Rodents Out of Your Car Engine.” Axle Addict,

    Jones, Matt. “Winter Pests: Keeping Rodents out of Your Vehicle.” Smart Motors, Accessed 23 December 2016

    Herkewitz, William. “What Happens When a Rat Decides to Live in Your Car.” Popular Mechanics, Accessed 23 December 2016.