Distinguishing Norway Rats from Roof Rats People refer to rats by many names -- brown rat vs. black rat, for example -- without realizing that many describe the same two species. The most common home-invading rodents, Norway rats and roof rats, can be identified in several ways: Norway Rats About seven to ten inches long Tail shorter than the body Blunt snout Small ears and eyes Muscular, stocky build Roof Rats About six to eight inches in length Tail longer than the body Pointed nose Large eyes and ears Sleek, slender look While Norway rats are sometimes referred to as brown rats and roof rats may be called black rats, don't be fooled by their nicknames. Both species come in varying shades of brown and gray, so color isn't the most reliable way to identify them. Does Rat Species Affect Control? It may not seem important to know which specific type of rodent is squeaking in the walls or causing problems around the home, but determining whether there is a Norway rat vs. a roof rat infestation can be crucial.