How to Tell the Difference Between a Rat and a Mouse

Rodent infestations are common in Massachusetts during the fall season. As the outside temperatures begin to cool, rodents—such as mice and rats—begin coming indoors in search of food and warmth. Rodents can not only create many problems with the structure of your home, but they also pose a health risk as they can spread bacteria, contaminate food sources, and trigger allergic reactions. Your local rat exterminators at F&W Pest Control has over 75 years of experience protecting your home from rats, mice, and other rodents. We’ve put the following information together to help you tell the difference between rats and mice, as well as provide helpful advice.

The Difference Between Rat and Mouse

Even though they’re both very common pests, rats and mice do have several key differences that will allow you to tell them apart and fully understand the type of infestation you’re dealing with. Below is a list of traits that can help you identify the difference between rats and mice.

Below is a list of traits that can help you identify the difference between rats and mice.

Rat vs Mouse Size & Appearance


  • Mice tend to be significantly smaller than rats
  • Mice have a thinner tail that is covered in hair.
  • Weigh no more than 20 centimeters in length.
  • Weigh no more than 30 grams.
  • Typically are white, gray, or brown.
  • Have rounded snouts and long whiskers.


  • Rats up to 40 centimeters long.
  • Weigh twice as much as mice.
  • Have a much thicker tail that is usually hairless.
  • Variation of shades of brown, black, gray, or white.
  • Have flatter snouts.

Rat vs Mouse Attitude & Behavior

Now that you know what they both look likes, it’s easier to study their attitudes and behaviors to know if you’re reading with a rat or mouse. They do have a few things in common, such as they are both nocturnal and excellent swimmers. While they are both able to climb structures, mice climb with more ease as their smaller size makes them more athletic and agile.

The biggest difference between a rat and a mouse is that a rat is more cautious, so they will typically make an effort to avoid unfamiliar places, while mice are curious and will always explore. Other ways to tell mice apart are by their fast scurrying and their ability to squeeze through extremely small openings.

Rat vs Mouse Lifestyle & Breeding Habits

What do rodents eat?

  • Mice will eat most of the same foods that humans enjoy, which is one reason why an infestation can create such a hassle.
  • Mice chew their way through unopened containers of food, contaminating the entire contents.
  • Rats will eat any type of food, but they have a clear preference for meat and fresh grains.

Why and how do rodents get inside?

  • Mice enter a home mostly to search for food or a warm place to birth a litter of babies.
  • Rats come inside to search for water in addition to food.
  • Mice will chew through whatever is in their way rather than dig.
  • Rats burrow their way under obstacles.

When can you expect litters, and how many are in each?

  • Both rodents primarily breed and bear offspring in the springtime.
  • Rats can have as many as six litters each year. Each litter can have up to 12 babies.
  • Mice can have between five and 10 litters each year, averaging six babies per litter.

What do different rodent droppings look like?

  •  A rat produces 20 to 50 droppings daily, but a mouse produces twice that number.
  • Mouse droppings are normally about 0.25 inches long and are pointed on each end.
  • Rat droppings are usually three times as long.
  • Mouse droppings are typically found in a pile, but rat droppings are often spread over a wider area.

The Similarities Between Rats and Mice

In spite of these three key areas of differences, it is true that rats and mice also have some similarities. Aside from the fact that they are both mammals of the rodent classification, they both also breed very quickly and can adapt well to many different types of environments. They both like to seek out the warmth provided in homes, particularly in the fall and winter months. Since they can easily birth large litters, they will often create beds in quiet areas of the home in which to have their babies. Therefore, it is common for homeowners to find both rats and mice in basements and attics. 

What do I do When I Have a Rodent Infestation?

Both house mice and rats are very common pests in the Boston area during the cooler part of the year. If you see droppings or other evidence of a rat or mouse infestation, please contact F&W Pest Control right away. Remember that both mice and rats can easily chew through the electrical wiring in your home, as well as clothing and paper. This can result in much structural damage to your home. Additionally, both rodents and mice have been known to carry various diseases that can be passed on to humans, creating a potential health hazard in your home. For these reasons, it’s imperative to get professional rodent control as soon as you have an inclination that you may have an infestation! F&W Pest Control offers real solutions to your rodent problems, so contact us today for a free thorough inspection of your home.

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