Skip to Content

If You See One Mouse How Many Do You Have?

Spotting a mouse in the house may be a sign of an infestation. The time of the day and the location of the mouse are important indicators that show if you’re dealing with a rare occurrence or with an infestation.

A mouse will move into the house for food and shelter. Mice reproduce at a fast rate with up to 10 litters per year which means there are always high risks of a larger number of mice indoors when spotting only one.

Key facts

  • Spotting a mouse during the day may mean there are no others around
  • One or multiple mice spotted at night may signal an indoor nest
  • More than 10 fresh droppings signal the presence of multiple mice

How do you know there’s a mouse in the house?

Confirming the presence of a mouse is not difficult. From spotting one to hearing one or discovering its traces, a mouse always makes its presence felt.

Spotting a mouse – this is the confirmation a mouse is indoors and a sign you need to check for other mice indoors.

Hearing mice movements – movements and sounds such as rattling and scratching at night are a good indication there’s at least one mouse in the house.

Finding chewed-through materials and foods – chewed foods, cardboard, or power cables are an indication of at least one mouse in the home.

You only have one mouse when

There’s only one mouse in the house when you spot it out during the day while multiple mice are present when you see at least one in common areas at night. Mice activity during the day may be the result of the rodent trying to escape a predator or cold weather while nocturnal activity signals the high risk of a colony presence.

Here are some of the instances which may only involve a single mouse in your home.

You spot a mouse during the daytime in a high-traffic area

Mice are nocturnal and rarely move around during the day. They seek out the safety of nighttime for movements without as many predators or human activity nearby.

Spotting a mouse during the day is an indication the rodent is escaping a predator such as a cat. It might also be escaping cold weather outdoors and seeking shelter. A mouse running around during the day is also an indication of its nest being destroyed somewhere nearby.

There are only 4-6 mice droppings around the house

You can estimate the number of mice in a room, garage, or basement, by the number of confirmed droppings around.

Up to 6 droppings are normal for a single mouse in the area. Spotting more than 10 droppings is already a confirmation of an established nest.

Mouse droppings appearance: mice droppings are small and cylindrical with pointed ends. They have a size of up to 0.5 inches and a brown color when fresh with a dry grayer color when old.

You may have more mice indoors when

Mice found in homes always live in colonies. They create nests and multiply multiple times per year.

A female mouse can get pregnant 5 to 10 times per year with a gestational period of up to 21 days.

A serious home infestation may have new litters of up to 14 pups even every 25 days.

Female mice can give birth to dozens of pups and remain pregnant soon after having a new litter.

This being said, there’s always a risk of having more mice indoors when you spot only one. Here’s how you can confirm the presence of more indoor mice.

You spot a mouse at night 

Mice are naturally moving at night. Spotting one at night or even hearing the mouse scratching or moving around the house at night is an indication there’s a nest and mice are casually coming out for food.

There are more than 10 mice droppings around the house 

Using a flashlight, you can investigate all floors, furniture, and areas of the spotting to count droppings. More than 10 fresh droppings are an indication of having more mice indoors.

When you hear scratching in the walls at night 

Mice build nests in walls, corners, and other remote dark areas that are difficult to access. Hearing them inside walls means this is their selected area for nesting.

When cats become alert for no apparent reason 

Cats may stare at the wall for no apparent reason. In reality, they can pick up the scent or the movements of mice behind walls, particularly when there’s more than one.

Signs of chewing 

Mice chewing signs on food, cardboard, drywall, cables, or furniture are among the typical signs there’s more than one mouse in the area.

Visual signs of a large mice infestation

While you can always hear scratching and rattling at night, not all of these noises come from mice as other bugs and animals may be found indoors. Some of the visual signs that confirm their presence in higher numbers include.

Multiple droppings around food – stored grains, and open food such as fruit with droppings around them indicate the presence of at least several mice.

Chewed-through materials – it’s unlikely a single mouse can chew through cardboard, power cables, or drywall in a short period. This is a sign of multiple mice and their damage over a longer period.

Places to look for other mice to confirm higher numbers

Mice prefer to nest in dark undisturbed areas of the house. Enclosed spaces such as wall voids, old cardboard boxes, or inside furniture are ideal places for them to lay litter and nest in. You may only confirm the presence of more mice indoors when you find their nest. Here’s where to check


Look for wall voids for signs of mice activity. This area gets no traffic and is an ideal place for mice to build nests.


Dark, filled with old boxes and rarely visited, basements are ideal places for mice to nest. They can escape basements and be spotted individually inside the house.


Low-traffic areas such as attics are also ideal places for mice to live in.


Mice may nest in the garage and be spotted in the house as they move around looking for more food or when their nest is destroyed by humans or animals such as cats.

Inspect all areas of your property for mice, especially dark crevices


Mice prefer to live in colonies and they multiply rapidly. Spotting a single mouse is the first sign there are more of them around.

Some of the exceptions when there’s truly only one mouse in the house is when you see one moving around during the day as this is an indication of a disturbed nearby nest or of a mouse running indoors after being chased by a cat or a predator.

There’s more than one mouse in the area in most cases, particularly when you spot the mouse at night or when you hear it moving around the house at night. A pregnant female lays an average of 6-8 babies and it may remain pregnant again immediately after laying the litter.

With a short gestation period, a female mouse can lay up to 10 litters each year with an average of 60 to 80 mice adding up each year from a single female.

There’s always a chance there are at least several other mice in the house when you spot one at night as they have short gestation periods and since they multiply rapidly at a rate of almost once every month.