Do Mice Grow into Rats? (Nope!)

Do Mice Grow into Rats

If you saw a rodent scurrying across the floor you may not have had time to get a good enough look to know if it’s a mouse or a rat.

Even if you did, you might not be able to tell the difference – after all, mice and rats are both rodents and do look similar.

Mice are different from rats in many ways, however. A lot of people ask, do mice grow into rats or vice versa?

It’s not such a silly question as it sounds to those who know the difference, honest!

What Does the Terms Mouse and Rat Mean?

This can get a little confusing, so stay with me.

Basically, the terms mouse and rat are not specific scientific classifications.

They are two words to describe two types of rodents. Of which they share some characteristics, but also have a lot of different characteristics to help tell them apart.

There are actually a lot of different species of rodents that are called rats and mice.

Common pet rats, for example, are Black rats and Norway rats, and pet mice are usually “fancy mice”, which are common house mice (Mus musculus) available in various colors.

Generally speaking, you can use the term rat for any medium to large-sized rodents with long, thin tails.

You can also use the term mouse for any small rodents with long, thin tails. Obviously, within these classifications, there are various known species.

How Can You Tell Mice and Rats Apart?

How Can You Tell Mice and Rats Apart
Awe… cute, but rats, not mice. Look similar, don’t they?

If you can get a good look at a rodent or observe their behavior, there are quite a few differences that separate mice from rats.

Some of the more obvious differences are:

Size – Rats are noticeably bigger than mice. Obviously, you need to go with more than size, otherwise, you could mistake a baby rat for an adult mouse.

To give you an idea, however, an adult mouse is usually between 2-4 inches long. While an adult rat is around 7-9 inches in length. Quite the difference!

Tails – Rats have hairless and scaly tails, while mice have hairy tails.

Ears – Mice have larger ears. Combined with a smaller body, they look a lot different than a rat’s ears in ratio to their size.

Droppings – Mice produce a lot more droppings than rats. Despite being a lot smaller, they poop a lot more often. Their droppings are a lot smaller too.

Related How to identify mice droppings – and how to safely clean up mice droppings.

That covers the physical features. Some of the behavioral differences between the two are:

Braveness – Call it brave, bold, or crazy, but mice are a lot more willing to come out into the open to find food.

Hiding – Being smaller comes with some advantages. If you have rodents nesting it tight, small spaces, there’s a good chance it’s mice.

Damage – Being larger also comes with some advantages (for the rats, not you). Rats are able to chew through tougher materials and do more damage than mice.

Is It Worse to Have Mice or Rats in Your Home?

If you’re stressing over having rodents in your home and wondering if you’d rather find mice or rats, I’d probably go with rats as being a bigger problem.

I say this because;

Rats are capable of causing much more damage, they can chew through some pretty solid materials.

They are harder to catch in my experience. Rats seem to be a little less daring and willing to come out in the open and are a bit smarter when it comes to traps.

They are more of a nuisance to other pets and us. Hearing about a rat biting a human is rare, but it’s a lot scarier than being bitten by a mouse, isn’t it?

Either way, if you have a rodent issue in your home you need to do something about it.

If you want this information because you want to keep a rodent as a pet, both have their advantages and disadvantages.

In Summary

Hopefully, I’ve helped explain the differences between mice and rats. And, more importantly, destroyed the myth that mice grow up to be rats.

Both are rodents, but as I explained in this article, both mice and rats are very different in appearance and behavior. This applies to wild mice and rats, and pets too.


Image credits – Header image by Alexfrlepr and in-body image by sipa on

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