How are mice different from rats, other than size?

I thought the answer was rats are bigger...but then I was looking at a book of all the known mammals, and saw there are some species of mice that are actually heavier and bigger than some species of rats. So how do zoologists classify them?How are mice different from rats, other than size?
It's kind of like saying a goose is like a chicken, only bigger. They're two totally different animals; they just happen to both be birds. In the rat/mouse case, they just happen to both be classified as rodents.





The scientific classification of a mouse is:





Kingdom: Animalia


Phylum: Chordata


Class: Mammalia


Order: Rodentia


Superfamily: Muroidea


Family: Muridae


Subfamily: Murinae


Genus: Mus





Whereas a rat is classified as:





Kingdom: Animalia


Phylum: Chordata


Class: Mammalia


Order: Rodentia


Superfamily: Muroidea


Family: Muridae


Subfamily: Murinae


Genus: RattusHow are mice different from rats, other than size?
Rats and Mice are two separate species, but they belong to the same family, Murinae. There is a huge genetic difference between them though. The Norway rat for instance, have 22 chromosomes, while the house mice have 20. This means they are different species that can not interbreed. There are many way scientists classify animals though: biological, morphological, ecological, and such. So its kind of a combination of all of that. (Like, if it looks even slightly different, lives in different areas, and is genetically different, then it has to be a different species from each other).





Think of it like this:


A horse and a donkey look similar. But you wouldn't call a donkey a horse! Just like with the mice and rat, they are genetically different and have different characteristics from each other.
There's no clear cut line, so the common names are unreliable: scientific names are the only universally appropriate names. In the UK the only mice people tend to see are the ones that are smaller than rats, but a young rat can be easily mistaken for a mouse. As a rule, rats tend to have smaller ears and shorter tails in proportion to their body size, but this can be hard to determine in the field.
well i like both but mice are a little cuter, and a little more nice-tempered while rats sometimes have red eyes(creepy!) but they get a are a little more easily angered
rats are disgusting mice are tollerable
research has shown cancer in rats