What's the difference between rat and mouse?

We get this one a lot, and it isn't the easiest thing to figure out, especially when everyone is jumping on top of the table in fear of the little thing running across the floor. 

Good news is that it is way more afraid of you than you are of it. You usually have nothing to fear, but it could be a sign of bad issues hiding in plain sight.

Here is a quick run down on the difference between a mouse and a rat.

Image result for 6 week baby rat

Baby Rats

The baby rat that you think might be a mouse is usually around 6 weeks old and just finished weaning from the mother.

Since they are finished weaning and just beginning to explore on their own, it doesn't always mean you have a big issue. It could be just the one. A simple trap will usually do the trick in this situation.


When trying to notice rat-like features:

  • Their heads are short and broad. They are large compared to the body with large features. This is because they are babies when being confused with mice. Usually around 6 weeks old.
  • The muzzle is large and wide.
  • Ears are small relative to the head.
  • The tail is thick.
  • The tail is shorter than the body in the tail-to-body ratio.
  • Feet are large relative to the body, like a baby or adolescent's would usually be. Hind legs are especially large.
  • Weight is usually somewhere around 100 grams - 200 grams from 6- 8 weeks, respectively.
Image result for adult mouse


A mouse in this situation would be a fully-grown, adult mouse. They are around the same size as baby rats, but have different features that make them stand out.

Some features you should look for to identify mice:

  • Their head is small and triangular-shaped. The head is small relative to the body, since they are fully grown.
  • The muzzle is narrow compared to the rat with a sharp tip and small nose.
  • Ears are large relative to the head (think of Mickey Mouse).
  • The tail is thin.
  • The tail is around the same length or longer than the body in the tail-to-body ratio
  • The feet are small relative to the body. Again, this is because they are fully developed and no longer growing.
  • Weight is around 30-50 grams. Smaller than the baby rat, but you would never notice at a quick glance.

That's all there is to it! Most of the time, it won't really matter which you have. You'll probably give us a call either way. 

There can be some difference also in the level of infestation. Rats tend to be solo predators and scavengers, while mice tend to live in larger groups and breed more quickly. 

Issues with mice can get out of hand more quickly and have a better chance of signaling a larger problem behind the walls or just outside the home or business.

Either way, we can handle it. Get in touch with us today if you are in the NYC or NJ areas. We will be happy to get rid of them for you!

Until next time.

Annihilator Extermination Staten Island

NYSDEC Business Lic. No. 13915
NJ DEP 99201A

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