what's the difference between "a rat" and "a mouse"?

hello everyone,
please tell me the difference between “rat” and “mouse”, and when will we use “rat”, when will we use “mouse”?

A rat and a mouse are different animals. Both are rodents. Rats are larger than mice.

rat - Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Rodentia
Superfamily: Muroidea
Family: Muridae
Subfamily: Murinae
Genus: Rattus

rats - images.google.com/images?hl=en&q=rat&gbv=2

mouse - Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Rodentia
Superfamily: Muroidea
Family: Muridae
Subfamily: Murinae
Genus: Mus

mice - images.google.com/images?gbv=2&h … rch+Images

Hi Anhgiap…

[color=blue]Below are the Apparent Differences Between a Mouse and a Rat

The size difference is a major factor. A full grown mouse may weigh a few ounces where a full grown rat may weigh as much as a pound.
A young rat, while still hairless, is already the size of a full grown mouse, where a baby or young mouse is very tiny.
A rat will dig a deep or long burrow to nest, 3 feet or longer, whereas a mouse will generally not go any deeper than 6 inches to a foot if they dig at all, they would prefer to live between a wall, behind or under an appliance.
A rat is much more aggressive than a mouse. If you corner a rat, it may jump up and attack to get away. A mouse will generally freeze and back off in absolute fear.
The size of their droppings is another difference. Mouse dropping will range from 1/8 to 1/4 inch at best in length, whereas rats droppings will be double that size, in the area of 1/2 inch.
Common breeds of rats in the US would be The Norway and Roof Rat. Common breeds of mice in the US would be the Field and House mouse.
There are slight differences regarding shapes, tail length, snouts and ears, but again, are all related.
A rat will venture much further away from their nest to find a food or water source, whereas a mouse will usually not venture more than 15 feet from home.
A rat is generally smarter than a mouse. For instance, if there is a new food source in their area of transit, they may force an older weaker rat to eat it and then watch to see if he dies or not in case the food is no good or contains poison. If that rat dies, they will urinate on it and avoid it. You have probably heard that you may only catch rats once on a snap trap and then you have to try something else. With mice this is not the case, they will come back to the same trap over and again.
Both rats and mice will generally use the same route of travel on a regular basis, both being creatures of habit. Rats will leave more evident proof of their route leaving oily stains rubbing off from the sides of their bodies that will appear over a period of time, along a wall, entry to an opening or corner they travel, often called run marks.
As far as similarities, they both must gnaw on a regular basis. If not their teeth will grow too long and into their heads and could kill them. They are both responsible for the contamination of major quantities of food in the world by chewing through packaging or urinating on raw materials or the finished product which is then destroyed. Also, rats especially, are the cause of many electrical fires due to their gnawing into live wiring. Not to mention the diseases they may carry and transfer. Consider the bubonic plague for instance.
They both live in nests with others and have similar breeding habits, however a rat is much more cruel, I hope is the best word here. For instance, if a rat colony is already over crowded and food source is low, they will actually kill and eat new borns immediately so they won’t effect their food source. I have never heard of this to be true within a mouse nest.

A rat is much more bigger then a mouse. Cats like to hunt mice and after some time it will eat the mouse. A rat has a long tail and somebody told me the is poisson for cats.therefore cats don’t eat tails of rats !