The Norway Rat

The Norway Rat or Rattus norvegicus, is 6 to 8 inches in length, brown and heavy-bodied. Has small ears and eyes; tail is shorter than body length. This species burrows under ground and enters buildings in search for food; generally nocturnal. Breeds about four to seven litters per year, 8 to 12 per litter. The Norway rat is the most common rodent in the U.S. This species also is the carrier of many serious diseases.