The brown rat (Rattus norvegicus), also known as the common rat, street rat, sewer rat, wharf rat, Hanover rat, Norway rat and Norwegian rat, is a widespread, common species of rat. One of the largest muroids, it is a brown or grey rodent with a body length of up to 28 cm (11 in) long, and a tail slightly shorter than that. It weighs between 140 and 500 g (4.9 and 17.6 oz).