What’s the difference between a mouse and a rat?
Google didn’t help me here. So I am guessing the difference is domestication. A mouse is a domesticated rat.
They’re two completely different species, for one thing.
No, sorry. They’re two different species, by which biologists mean: They cannot interbreed. Their ovulating females are of no interest to the “other” males.
They occupy different ecological niches, and they eat different things.
They live in different kinds of habitats.
They have different social structures.
A mouse is different from a rat the way a lynx is different from a house cat. A house cat is not a “domesticated lynx”. A rat is not just “a mouse, but bigger”. A lynx is not just “a house cat, but bigger”. They’re two different species.
Actually, they are multiple species in each within multiple genera. For example, the house mouse, deer mouse, and dormouse are all different critters. There are over 60 species of deer mouse in the genus Peromyscus and 20 species of dormouse scattered across seven genera.
Basically, mice are smaller and more lightly built than rats. Within the order Rodentia mice and rats are accompanied by voles and lemmings. Each critter has a specific ecological niche and the physiognomy to take advantage of that niche.
My Windows computer will recognise a mouse just by plugging it in
but for a rat you have to install the drivers.
Just to add to tom and DDG’d answers, the genera Mus ( which includes the ubiquitous House Mouse ) and Rattus ( the ubiquitous Norway and Black Rats, among others ) diverged some 12-14 million years ago. They’ve been different critters for a long, long time.
- Tamerlane
Rats are nasty and mice are cute.
You know, Mammology wasn’t really as interesting as I thought it would be, but I can add a little bit to this.
The two species of rat that are found most often in people’s houses are the Norway Rat(basements and lower ground) and the Black Rat(attics and everywhere the Norway Rat doesn’t want). The Black Rat is smaller and thinner. In addition there are many species of woodland rats that are found more rarely
The House Mouse is the species of mouse found most often in the house. As others have said, mice are much smaller than rats, but otherwise they can be quite similar looking.
All of the Peromyscus species have hairy tails and white bellies. They’re really quite cute. Except for the one that bit me. He was not cute. Freaking deer mouse.
-Lil
And of course, we can’t forget to mention ROUS - Rodents Of Unusal Size.
OTOH, among domesticated (caged) critters, rats have a lot more personality and tend to be quite a bit cleaner.
Welcome, Michael411, to the SDMB.
Mice are good to eat. Rats aren’t. So said my cat.
Peace,
mangeorge
I just wanted to add that this line gave me the best laugh I’ve had in a while. Kudos.
We now return you to your regularly scheduled thread.
Rats are quite friendly and even cute if you get to know them.
Many people often think rats are mice. Rats are generally much smaller than people think. The majority of people who meet my rats think they are mice. Mice are also are generally much smaller than people think. Take Stuart Little for instance. No mouse is six inches tall (not counting tail). Stuart is clearly a rat.
Rats are known to hunt mice in the wild.
Speaking as someone who, due to sub-standard housing, has fought both rats and mice hand-to-hand, the difference is quite clear in my mind.
Essentially, a rat will have enough strength to break away when you have it by the tail with a pair of barbeque tongs; a mouse will not.
A rat, when beaten to death with a spatula, will roughly fill a metal tube in which bottles of vodka were sold; a mouse will not.
A mouse, chased by a flatmate with a hammer, will be able to take refuge in the toaster; a rat will not fit.
In the end, rats are bigger and easier to hit with the barbeque set. Mice are a much harder target, but can’t withstand so much of a beating.
Swings and roundabouts.
Armilla that response deserves a :D.
- Tamerlane
Tell that to my wife and several million other women in this country. 
<Manuel from Barcelona>
It’s not a rat, it’s a Siberian hamster!
</Manuel>
Tell that to my sister, who just borrowed my cat to deal with an infestation.
I breed rats, but I’ve done research into mice (but I’m not absolutely certain on any of it, and will gladly learn if someone corrects me).
Rats:
Rats are VERY good mothers. Most of them, anyway. I have a momma with 15 babies right now, and none of them have died (biggest litter I’ve ever had).
Rats are smart. I’ve read that some people consider rats to be “as smart as dogs,” and it wouldn’t be surprising. I haven’t tested it, tho. Heh. Can’t find any little pencils for their hands.
Rats don’t eat each other. When I rearrange who’s with whom, they’ll establish dominance or whatnot and live happily together.
Surprisingly not terribly stinky. I clean my cages whenever I can smell ickiness when I give them food and water, and even tho I have 3 females and 15 babies in one cage, 5 or 6 weanlings in another (for now), and two big males in the other, I only have to clean about ever 2 weeks.
Fairly nice. I don’t handle mine much (they’re not pets), and I’ve only been actually bitten once, and that was a first-generationevil rat from the petstore. Generations two and three might nibble on your finger until they know you’re not food, then wander off.
Ugly and big. I have some that I’m getting up to size, and I won’t keep more than those two males in a ten-gallon aquarium, because they get HUGE.
Mice (Or what I’ve read from mice breeders):
Rats can eat their babies if they don’t get enough protein.
Mice tend to eat each other if they get bored (or something - maybe they just don’t like each other). Adults, not just babies. This seems to be strees/enclosure size related, something I’ve never noticed in my rats. Apparently, they become stressed more easily. Also happens when introducing a new mouse into an established colony.
Male mice, so they tell me, STINK. Stink like a 10g with 5 rats.
Apparently they’re not so friendly. Nippy and such.
But they are all cute and small.
Now, this is pet rodents. Don’t know about wild ones, but you’re question was vague. What do you want to know?