Temporal range: Early Pleistocene – Recent |The common brown rat
(Rattus norvegicus)| Fischer de Waldheim, 1803 Stenomys Thomas,
1910 Rats are various medium-sized, long-tailed rodents of the
superfamily Muroidea. "True rats" are members of the genus
Rattus, the most important of which to humans are the black rat,
Rattus rattus, and the brown rat, Rattus norvegicus. Many
members of other rodent genera and families are also referred to
as rats, and share many characteristics with true rats. Rats are
typically distinguished from mice by their size; rats are
generally large muroid rodents, while mice are generally small
muroid rodents. The muroid family is very large and complex, and
the common terms rat and mouse are not taxonomically specific.
Generally, when someone discovers a large muroid, its common
name includes the term rat, while if it is small, the name
includes the term mouse. Scientifically, the terms are not
confined to members of the Rattus and Mus genera, for example,
the pack rat and cotton mouse