Rats vs Mice

What is the difference betweens rats and mice? In this Rats vs Mice article we’ll put the two in the spotlight, helping you to distinguish the sounds, the appearance, the droppings and other aspects of a rat versus a mouse, covering babies and adults. Whether you suspect that you have one of these living in your home uninvited, or you simply want to know what species of rodent you own as a pet, this guide should help you to figure it out.

Rats vs Mice: The Basics

These two terms are not scientific terms and they can’t be used to describe all rodents we typically think of as one of these two animals. That’s because there are actually many different variations of both. Just like there are many versions of humans and a greater variety of primates, so there are a number of rats and mice and a huge number of rodents.

The term rat is used to describe rodents that are of medium size, while mouse is used to describe those of a very small size. Mice can range in size and appearance, with house mice, field mice, door mice, etc., while rats can include everything from naked mole rats to pack rats and more.

Because of all of this, it’s not easy to determine what a creature is based on a few descriptions. We can’t tell you, for instance, that a rodent of a specific size is a rat or a mouse, because there are too many different versions of each and once you factor in that a baby rat could the same size as an adult mouse, then it complicates things further.

However, if the rodent has invaded your home, then it gets a little easier as it’s likely to be a case of domestic rat vs domestic mouse, the former are better known as the Norway Rat and the latter are better known as the House Mouse.

Differences Between Mouse and Rat

If we focus on these two domestic rodents then the differences are quite easy to spot. What’s more these two species can not interbreed, so there are no issues with cross-breeding, which would definitely complicate the identification process.

Here are a few differences between these mice and rats:

  • Rats weigh around 300 to 700 grams; mice weigh around 30 to 100 grams, as much as 10x less.
  • Rats are 18 inches long on average; mice are 7 inches long
  • The head of a rat is blockier and chunkier; the head of a mouse tends to be more pointed
  • A rat’s ears are larger, but when compared to their bodies they are smaller than a mouse’s ears.
  • Rats have 12 nipples, mice have 10

Rat vs Mice Noise

If you can hear an animal scuttling around in your attic or in the walls, then there is a good chance it’s a rat. That’s because mice can be difficult to detect. It’s rare that you will hear their little feet running around, unless you have very thin walls. Of course, if they spend their time chewing through your possessions then you will hear them, but even if this is the case you will still hear more from a rat.

A rat tends to be shameless when it comes to invading a human’s space. They are still shy and will try to stay out of sight. But their larger, bulkier frame, as well as their bigger and stronger teeth, means they can often be heard and they tend not to shy away from a challenge if it will bring them food.

Rat vs Mouse Droppings

Rat vs Mouse

Another good way to determine whether you have a mouse or a rat is via the droppings. In both cases the droppings are small and black. There is a clear difference though. A rat’s droppings are much larger than a mouse’s droppings. Both will leave many little feces around, maybe even on counter tops and in cupboards.

As as size goes, a rat’s poop comes in the form of black pellets that are about 3 quarters of an inch long and about 1/3rd as thick as they are long. They may have a slight bulge in the center, tapering off at both ends. Bear in mind that the darker they are, the fresher they are. This is the opposite of what many people seem to believe, so it’s worth keeping in mind.

Mice droppings are about a quarter of an inch in length and they have a similar shape, although it’s hard to detect because they are so small.

To save you getting out the tape measure, consider this: the average grain of uncooked rice will be roughly the same length, if not slightly shorter, than the average rat dropping. It will also be about half the thickness. However, it will be bigger, sometimes twice as much, than the average mouse dropping.

Mice will also excrete many more per day, averaging about 100 to a rat’s 50.

Baby Rat vs Mouse

There are some key characteristics that differentiate mice and rats and these should be able to help you discern whether you have a baby rat or a full grown mouse. If you’re asking this question then there is a good chance you have them in your sight, in which case the facial features should give it away.

A baby rat will have noticeably odd proportions, with heads and feet that look too big for their body, as opposed to an adult mouse, who should be perfectly proportioned. They will also have stubby faces and wide noses, whereas, as discussed above, mice have more pointed and defined faces.

You can also look for a thicker tail and smaller ears (in proportion to the rest of its body) in baby rats.

Deer Mice vs House Mice

If you have determined that you have a mouse and not a rat and are not sure whether it’s a deer mouse or a house mouse, then there are a few key things to look for. The deer mouse has bigger ears and eyes, but it also has fur that contains two shades of color.

The deer mouse also has a white body and white hairs on its feet. They both have similar habits and they can both enter the home, but the deer mouse is often found in outhouses, tree stumps and anywhere that is away from humans but under shelter.

Field Mice v House Mice

The field mouse can be a little harder to differentiate from the house mouse. Some of the things that will help you to tell the difference are that the field mouse often have a yellow streak of fur on its sides and white underneath. It also has an orange color on its head.

Not much to go on, we know, but these color differences can be fairly easy to spot if you know what you are looking for and they should be able to tell you whether you have field mice or house mice.

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