Rat

Rat, name for numerous species of rodents belonging to many different families, largely Muridae and Cricetidae. The brown (Rattus norvegicus) and black (R. rattus) rats are familiar farmyard and warehouse pests. A strong exploratory urge and an ability to feed on almost anything make them persistent pests; in addition, they transmit a number of serious diseases, such as typhus and plague. Rats native to the New World include wood rats or pack rats, cotton rats, and the rice rats.