Here's a short article with a bit of information about common small rodents found in pet stores...http://exoticpets.about.com/cs/resourcesgeneral/a/choosearodent.htm :mouse:
Fancy mice live one to three years on average and are quite easy to care for. They are the smallest of the mentioned rodents here with bodies that are only about three inches long and a long hairless tail (like a rat).
They are social and females do well in pairs or small groups (males tend to fight if kept with other males). They require only a relatively small cage (a minimum of 12 x 18 inches and 12 inches tall), although a larger cage is recommended if you have more than one pair.
Mice can become quite tame if handled regularly but are small, fast, and can be skittish. They are low maintenance, active, playful and entertaining to watch.