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How To Know If You Have Mice or Squirrel in the Attic

February 28, 2021
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Rodents are a large family of diverse animals with different characteristics. Two of the most common species of rodents are mice and squirrels. They climb nearby trees, gutter, and utility lines to get inside the house and build a nest in the attic. But to eliminate them completely, it’s crucial to identify first what pest resides in the attic.

So how can you tell mice and squirrels apart in the attic? The best way would be if they’re seen since mice and squirrels have entirely different appearances. However, the kind of noises, type of entry hole, size of droppings, and track marks are also enough to accurately identify them.

How to Tell if it’s a Mouse or Squirrel in the Attic

About 29% of American homes have already had a rodent problem in their household at least once. While the majority of these infestations are due to mice and rats gaining access to the house, squirrels also become a nuisance when they decide to nest in the attic.

Mice and squirrels invade homes for the same reasons – food and warmth. Mice can die from hypothermia if they’re exposed to cold temperatures. Although squirrels are more tolerant of cold, they still need access to warm shelter and high-calorie food to survive through the winter.

If you suspect a rodent infestation in the attic, here are some of the ways to identify if they’re mice or squirrels:


Mus musculus (or house mouse) are small rodents that commonly infest residential buildings. They have gray fur with cream-colored bellies. They have a rounded-shape body with four legs. They also have pointed muzzles and large ears. Their bodies grow up to 2.5” to 3.75” long with tails that measure around 2.74” to 4”.

On the other hand, squirrels have slender bodies and bushy tails. They are larger than mice but smaller than raccoons. They have four paws, but their hind legs are longer than the front limbs. Their fur color varies between species, but the most common ones are white, gray, brown, and red. Squirrels also have large eyes and small ears.


Mice communicate through ultrasonic sounds that aren’t heard by humans without using special devices. But sometimes, they also make noises that are audible to people, such as high-pitched squeaks. There’s also a chance you’ll hear them scurrying inside the walls or in the false ceilings.

Squirrels produce much louder sounds than mice. They also communicate with other squirrels through a sound range that’s audible to humans. These rodents produce chattering and chirping sounds when communicating. When they’re moving around, squirrels are heard chewing, scratching, and rubbing through pipes and wood beams.

Aside from the kind of noise in the attic, the time of the day you hear them is also a good indicator of what pest is inside. Mice are nocturnal animals so if there are squeaking and chewing noises at night, you might be dealing with these rodents. But if there are scurrying noises in broad daylight, then there’s a good chance that the rodents in the attic are squirrels.

Entry Hole

Mice only need small holes in the size of the quarter to gain access to the house. If they reach the attic, there’s a good chance that they climbed through nearby trees or the gutter. The holes they pass through are also likely to be greasy from all the dirt from their fur.

Squirrels require bigger holes to get inside the attic. If there’s not a gap big enough for them, they chew through the materials. Holes made by squirrels are around 2 inches in diameter with chew marks. Like raccoons, squirrels might also make use of the open doors they spot to gain access to the house.


Mice leave droppings anywhere they go. They’re oblong-shaped pellets that are about a quarter-inch long. Each mouse produces around 50 to 75 pellets per day. Droppings are also a great indicator of the nest’s location – the more the droppings there are and the fresher it is, the nearer you are to the nest.

Squirrels' droppings are similar to how large rat droppings look. They’re barrel-shaped pellets that are smooth and dark brown. The droppings measure around 3/8” with a diameter of 8mm. Aside from the possible health hazards that squirrel droppings bring, their feces also attract flies and smaller insects if left uncleaned.


Mice tracks are quite hard to identify if you only look at their paws. It’s easier to look for greasy tracks at the lower part of the walls or in other areas where mice might pass through. There’s also a chance that there are mice droppings in the place where there are greasy tracks.

If there are muddy tracks in the attic, check for the size of the paws to confirm if it belongs to squirrels. These rodents have five toes on all the paws, but their front paws are smaller than the hind paws. The front paws are around half-inch by half-inch, while hind paws are a bit longer at one inch with a width of half-inch. Squirrels are also considered “bounders” so there might be a foot or two between each set of paw prints.

The Dangers of Mice and Squirrels in the Attic

Although they’re small in size, mice and squirrels are destructive creatures that are capable of spreading severe diseases and causing serious structural hazards. Here are some of the damages they bring to a home:

Structural Damages

Both mice and squirrels have strong teeth that chew through everything. They ruin the insulation in the attic and the water pipes they pass by. They also chew on electrical wiring, which results in broken appliances and possible fire hazards. Although these materials aren’t edible for the rodents, they still chew on them to keep their teeth trimmed.


Rodents like mice and squirrels are carriers of diseases. They transmit viruses, bacteria, pathogens, and other ectoparasites to pets and humans in different ways. Their urine, saliva, and droppings might contaminate the food and water. These rodents might also fight back when cornered; their bites and scratches are also another way to spread diseases.

Carried by Mice

  • Hantavirus – The most common way of hantavirus transmission to humans is when the rodent droppings, urine, or saliva are stirred up and become airborne. People may inhale the contaminated air, which is why it’s important to wear full protective gear when disinfecting rodent nests.
  • Lymphocytic Choriomeningitis – This viral disease is transmitted to humans when they come in contact with the urine, saliva, or droppings of an infected mouse. It’s also transmitted through mouse bites. This disease occurs in two phases: patients experience flu-like symptoms in the first phase, but it might progress to a neurologic disease in the second phase.
  • Plague – The plague was responsible for the death of millions of people around the world during the Middle Ages. Humans might contract the plague if they’re bitten or when they handle an infected rodent.

Carried by Squirrels

  • Tularemia – This bacterial disease attacks the skin, eyes, lungs, and lymph nodes of the host. Tularemia is highly infectious and fatal, but it can be cured by antibiotics after an early diagnosis. There are different kinds of tularemia depending on where and how the bacteria entered the body.
  • Typhus – This is another kind of bacterial disease that’s transmitted when the infected ectoparasites from a rodent bite a human. Some of the symptoms of typhus include rashes, muscle aches, headache, fever, and chills. They’re also cured by antibiotics, but early diagnosis is needed.
  • Rabies – Although it’s a rare occurrence, some squirrels may be rabid. If the squirrel is infected with rabies, it displays out of character behaviors like unprovoked aggression, falling over, walking in circles, lethargy, and paralysis.

How to Get Rid of Pests in the Attic

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Once the rodent is identified in the attic, there are different ways to eliminate them before they start causing more trouble. Here are a few steps to keep the rodents out of the house before calling pest management professionals:

  1. Seal All Possible Entry Points – Rodents won’t have a chance to build a nest inside the house if they can’t get inside in the first place. Inspect the house carefully to check for gaps and holes that the rodent might access. Seal all these entry points with steel wool, caulk, and screens.
  2. Use the Appropriate Trap – Because of their difference in size, usual mousetraps might not work for squirrels. Aside from considering their size, the type of trap to use is also important. Snap traps, live traps, electronic traps, and bait stations have their own advantages and limitations, so make sure to pick one that’s fit for your needs.
  3. Trim Overgrown Plants and Trees Near the Roof – Both mice and squirrels are excellent climbers. Having overgrown trees that are connected to the roof serve as easy access for these rodents to get inside and build a nest in the attic.

Protect Your Home with Rodent Control Services by Positive Pest Management

Here at Positive Pest Management, we guarantee high-quality extermination work that completely eliminates rodents. Our exclusion work includes placing different preventative measures in the house to keep the rodents from returning.

Trust us to provide safe and effective pest management services in residential and commercial buildings around New York City. Feel free to contact us at 1-800-294-3130 whenever the need arises.

Read more: 5 Differences: Field Mice Vs. House Mice

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