Brown rat (Rattus norvegicus) adult. This small mammal is a rodent found worldwide, especially in Europe and North America. It is found nearly everywhere that humans live, especially in urban areas. The brown rat reaches a body length of 25 centimetres. It is an omnivore, but in much of its range it feeds on grass and cereal seeds, though it will also forage for scraps of food in urban areas. Photographed in July, in Dorset, UK.