Question: “What’s the difference between a mouse, a rat, and a squirrel?”
Answer: “Beats me, but one them just ran under that pile of boxes!”

All jokes aside, how confident are you in your ability to identify and classify? While mice, rats, and squirrels are all rodents and all considered pest animals, they’re definitely not “the same thing.” Let’s take a moment to learn the visual differences between the three:

All About Mice

General Size / Appearance

For all the trouble that they can cause, mice are quite small (nothing t be scared of here) —adults are usually less than 8 inches from their nose to the tip of their tail, and at least half of this length is just their tail. Overall, mice have round bodies, narrow snouts and ears that seem fairly large and floppy for the size of their heads. Their fur can be brown, dark gray or black. Their “hands” and “feet” are relatively hairless.

Tail Structure

Mice tails are about the same length as their bodies and very skinny. Hair can be seen on the tail relatively easily, but it can appear bald from a distance. A mouse’s tail is usually a similar color to the rest of its skin, so it may be pink, dark gray or even tan. Mice tails are not prehensile and stay low to the ground regardless of the mouse’s posture.
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Movement Style

Folks often talk about mice “scurrying about,” and that’s certainly a correct observation. Despite their round bodies and short legs, mice can run fast when they feel threatened. If you surprise a mouse, you may still only catch a glimpse of its tail as the animal disappears into a hole or crack in the wall.

 Photo courtesy of George Shuklin via Wikimedia Commons

All About Rats

General Size / Appearance

An adult rat can easily reach a nose to tip-of-tail length of almost 16 inches, making them substantially larger than mice. Their bodies also tend to be longer and more tube-shaped (especially when the rat is stretching or running) and their snouts are blunter. They have relatively small, hairless ears and their fur can be brown, gray, black or even white in color. Like mice, rats also possess hairless hands and feet.


Tail Structure

Rat tails are noticeably thicker than mouse tails, and their tails are typically shorter than the combined lengths of their heads and bodies. They often have a visibly “scaly” texture. Rat tails appear bald at normal magnification, but they do have some very fine hairs that are visible up close. So how close do you want to get?

Movement Style

Again, “scurrying” is the name of the game—and rats can move very quickly when they’ve been startled. It’s also worth mentioning that, due to their larger body size and shorter tails, rats often have trouble standing upright or balancing on their hind legs for more than a few seconds at a time. Thus, domesticated “fancy” rats have learned to lean on their owners, toys or furniture when they don’t have all four paws on the ground!

Photo courtesy of Peter O’Connor on Flickr

All About Squirrels

General Size / Appearance

Squirrels don’t look nearly as much like mice or rats, as rats and mice look like each other. A squirrel’s head is even blunter than a rat’s, and its eyes are proportionately larger. Squirrels have fur on their feet and tails, and their coat can be a mixture of gray and brown. Including their tails, adult squirrels are typically between 38 and 52 cm long (that is, 15 and 20 inches), larger than even adult rats.


Tail Structure

Unlike rats and mice, a healthy squirrel will have a decidedly bushy tail. Said tail will be covered in thick, bristly fur that is similar in color to the fur on the rest of the squirrel’s body. When squirrels stand, crouch, or sit, their tails also tend to go up. Instead of being completely vertical, though, their tails will “flop” or curl over maybe 2/3 of the way up.

Movement Style

Besides the appearance of their tails, this is probably the easiest way to pick out a squirrel amongst rats and mice. Squirrels typically travel by bounding; their bodies move in an arc-like shape. It may even look like the squirrel is hopping instead of walking!

Photo courtesy of Keith Sutton on Flickr


So, let’s say some kind of mystery rodent has made you their unwitting landlord. Chances are, you won’t be able to get a very good look at the creature the first time—or first few times—you cross paths with it. But if you’re determined to identify it, then here are some tips:

  • Look at its size. Yes, the pest probably won’t hold still long enough for you to get out a ruler or measuring tape, but your best estimate will be sufficient. If the mystery critter is 8 inches or less in length, it could be a mouse, a young rat or a young squirrel. If it’s larger than 8 inches, then it’s probably not a mouse.
  • Look at its ear shape. Ears that are proportionately small compared to the animal’s head and body usually belong to rats and squirrels. Meanwhile, ears that are large or somewhat floppy-looking usually belong to mice.
  • Look at its tail. If it’s bushy or fluffy, you’ve definitely got a squirrel on your hands. Thick tails that appear hairless suggest rats, and thin tails with visible fur may be mice.
  • Watch its movements. An up-and-down, wave-like motion indicates a squirrel. “Normal” running and scurrying is indicative of mice or rats.


Despite their differences in size and behavior, rats, mice and squirrels are all capable of causing serious damage and spreading diseases when they take up residence in human homes. Determining your furry squatter’s species isn’t nearly as important as having them professionally evicted as soon as possible! Still, knowing what you’re dealing with can be somewhat comforting. You won’t feel guilty about tossing a “poor, defenseless baby animal” out of your home when you know that the “baby” is actually a fully-grown, adult mouse. Conversely, you can calm yourself with the knowledge that the animal you saw in your attic or garage was a normal-sized squirrel—not an enormous rat!

If mice, rats or squirrels are driving you nuts in Dallas, Ft. Worth, Houston or Amarillo then don’t delay—contact Chimney and Wildlife Specialists today!