Rats are various medium-sized, long-tailed rodents. Species of rats are found throughout the order Rodentia, but stereotypical rats are found in the genus Rattus.
Rats are typically distinguished from mice by their size. Usually, the common name of a large muroid rodent will include the word “rat”, while a smaller muroid’s name will include “mouse”. The common terms rat and mouse are not taxonomically specific. There are 56 known species of rats in the world.
