Mouse vs Rat: 5 Main Differences Explained

Written by AZ Animals Staff
Published: June 19, 2021

At first glance, mice and rats look very similar. They both have a face with tiny dark eyes and twitching whiskers. But, there a lot of differences between these two rodents. We have looked at the differences between mouse vs rat.

The biggest difference is their size. A mouse is much smaller than a rat. In fact, a large mouse is still about half the length of an average rat. Secondly, rats have longer tails than mice. Furthermore, a rat’s tail is thicker than a mouse’s tail. Another difference between these two animals has to do with the size and shape of their poop.

Learn more about the differences between a mouse and a rat so you can recognize one when you see it.

Comparing Mouse vs Rat

Size12 ounces to 1.5lbs.0.5 ounces to 3 ounces
HabitatAttics, inside walls, sewers, cellarsHomes, garages, burrows under trees, beneath decks
DistributionUrban areas in the midwestern and eastern part of the United StatesRural areas of the mid-western and eastern United States
BodySmall ears and a large head, coarse dark brown or multi-color (white, gray, black) furA small face and head with large ears, pointy, triangle-shaped nose, smooth fur in gray, brown or black
PoopDroppings are black and shaped like elongated ovals. They measure around ¾ of an inch. These rodents leave behind 20 to 50 droppings at one timeSimilar to black grains of rice measuring about ¼ inch long. They leave behind up to 100 droppings at a time
LifespanUp to 2 yearsUp to one year
TailThick, hairless with a scaly textureThin and covered with hair
Litter Size5 to 10 babies, also called pups3 to 14 pups
DietPractically anything!Seeds, fruit, bread crumbs
Meat, bread, plants, seeds
Number of species60Hundreds
Kept as petsYesYes

The 5 Key Differences Between a Mouse and a Rat

Physical Size

The most noticeable difference between a mouse and a rat is a mouse is smaller. The body of a mouse can measure 3 to 4 inches in length. And, a mouse’s tail is equal in length to its body. Alternatively, an adult rat’s body is about 9 to 11 inches long with a tail measuring 7 to 9 inches. A mouse can weigh up to 3 ounces making it a lot lighter than a rat at 1.5 pounds.

Number of Species

Another notable difference between a mouse and a rat relates to the number of species. A comparison shows there are many more species of mouse. In fact, there are hundreds of species of mice and 60 species of rat.
Some species of mouse include:

  • House mouse
  • Deer mouse
  • White-footed mouse
  • Striped field mouse

Some species of rat include:

  • Brown rat
  • House rat
  • Australian swamp rat
  • Rice-Field rat

Rat Poop vs. Mouse Poop

Rat poop and mouse poop have different appearances. This is an easy way for someone to tell which type of rodent they have in their house without seeing the animal.

Rat poop is larger than mouse poop. Rat poop is black with an elongated oval shape measuring about ¾ of an inch. It can leave behind up to 50 droppings.

Alternatively, mouse poop looks like a black grain of rice about ¼ inch long. They can leave as many as 100 droppings at one time.

Tail Appearance

Mice and rats have different types of tails. A mouse tail is thin, long, and covered with hair. The hair on its tail is usually the same color as its body.

A rat’s tail is long, thick, and scaly. A rat’s tail is hairless.


The diet of each of these rodents is another difference that sets them apart. Rats are known to eat almost anything. They go through the trash and eat leftover sandwiches, fruit, eggs, meat, and more. Also, rats may eat plants and seeds. This makes it easy for a rat to find food.

A mouse eats seeds, fruit, and plants. They may nibble on bread crumbs, but they don’t have as much on the menu as rats!

FAQs (Frequently Asked Questions) 

What is the difference between a mouse and a rat?

Take one look at these two animals and you’ll see a mouse is smaller than a rat. A mouse is shorter in length and weighs less than a rat. Also, while a mouse has a thin tail covered with hair, a rat has a thick hairless tail with a scaly texture.

Study a mouse’s face and you’ll notice its ears are very large in proportion to its head. A rat’s ears are smaller and are more proportioned to its head.

Mouse and rat poop have different appearances. Mouse poop is smaller and rice-shaped whereas rat poop is large with an elongated oval shape.

A rat has a wide variety of things it can eat including vegetables, meat, bread, and other items in a garbage can. A mouse’s diet is more limited than a rat’s diet. It can eat seeds, plants, grain, and some small items from a tipped-over garbage can.

Are rats worse than mice?

Not necessarily. Both of these rodents can get into a home and chew electrical wires causing damage and maybe even a fire. Finding a nest full of wild baby mice or baby rats in a home is equally unsettling.

Due to their size, rats are usually considered a little more threatening than mice. But some owners of pet mice and rats may insist that both of these rodents have cute faces!

Does a mouse turn into a rat?

No, a baby mouse doesn’t grow into a rat. A mouse and a rat are two different types of rodents.