Characteristics
Size : Larger rodents that may grow to a body length of 10 to 12 inches. Seldom will a rat weigh more than one pound.
Color : Can vary from gray to brown to black.
Norway rats, have a heavier body, smaller eyes and ears, and a shorter tail. Rats are more prevalent in urban and rural areas, and are found in homes less often than mice because of their larger size.
Behavior
Few people really like rats or mice, and no one wants them in their house. Rodents live everywhere outside and could enter at any time, but fortunately, this does not occur often. Usually, most home invasions occur in the fall, not because of cooler weather, but because the seeds and plants on which rodents feed outside are gone. Rats and mice must then seek new food sources. Unfortunately, one of these sources may be your home. Rats are excellent climbers and are capable of gaining entry through holes around soffit vents and around cables entering the building, through holes in gable vent screens, and through turbine and box vents on roofs. Many garage doors on homes allow enough space for rats to fit underneath, as well.
Habitat
Outside, rats live in fields, wooded areas, vacant lots, farms, and just about anywhere people have buildings. Rats are seldom a problem in homes except in urban and rural areas. This is due in large part to their size, since rats need a hole about the size of a quarter in order to gain entry into a building. Rats however, may find harborage in many areas around the home – especially in stacked firewood, stones and bricks, and piles of leaves or other debris.