The Polynesian rat is smaller than either the Norway rat (Rattus norvegicus) or the roof rat (Rattus rattus). Polynesian rats have slender bodies, pointed snouts, large ears and relatively small, delicate feet. A ruddy brown back contrasts with a whitish belly. Mature individuals are 4.5 to 6 inches long (11.5 to 15.0 cm) from the tip of the nose to the base of the tail and weigh 1.5 to 3 ounces (40 to 80 g). The tail has prominent fine scaly rings and is about the same length as the head and body. Female Polynesian rats have 8 nipples, compared to 10 and 12 nipples normally found on roof rats and Norway rats, respectively.