The Roof Rat
Rattus Rattus – the roof rat is one of two most prevalent rats found in the contiguous 48 states. The Norway rat is the other species and is well-known because of its widespread distribution. Rattus Rattus is commonly known as the roof rat, black rat or ship rat and is well known for carrying the plague.
One can distinguishing between the Norway rat and Roof rat by examining the tail. If you pull the tail back over the body the Roof rat’s tail will reach the nose. The tail of a Norway rat will not reach beyond the ears. This rat has a long record as a carrier of plague.
The regular occurrence of crossbreeding between subspecies has resulted in unreliability when identifying a rat by color.