With a lifespan of up to one year, the Norway Rat is the most common rat in the United States. It is not as long as the Roof Rat, at 6 to 8 inches in length, but appears larger because it tends to be heavy bodied. Its brown fur is shaggy and the Norway Rat has beady eyes and small ears with a blunt snout. The Norway Rat’s tail is shorter than its head and body and its droppings are capsule shaped. The Norway Rat is not very nimble on land, but is an outstanding swimmer.
Norway Rats are excellent tunnelers, typically entering buildings to search for meals through their underground burrows. Meals will usually center around meats, but Norway Rats are omnivorous, and they rely heavily on a source of water. Norway Rats will usually remain out of sight during the daylight hours.
Norway Rats are sexually mature at about 2 months, will breed throughout the year and have 4 to 7 litters with up to 12 young per litter. As with other rodents, Norway Rats often carry serious diseases, so it is best to have a pest control professional deal with them.
Originally called the “Hanover rat” by people wishing to link problems in 18th century England with the House of Hanover, it is not known for certain why the brown rat is named Rattus norvegicus (Norwegian rat) as it did not originate from Norway. (Factoid Source: wikipedia)