brown rat 
noun
A rat found throughout the world, typically living in association with man and regarded as a pest. It is commonly kept as a laboratory animal and as a pet, and is also bred in the albino form. Also called common rat, Norway rat.
- Rattus norvegicus, family Muridae.
- Many people mistake the endangered water vole for the brown rat and accidentally poison them or disturb their burrows.
- Originating in Asia and arriving in North America about 1775, the brown rat is humanity's worst animal pest.
- beat
- beatable
- beat about the bush
- beat a (hasty) retreat
- be at a loose end (or at loose ends)
- beat a path to someone's door
- beat a retreat
- be at a stand
- beatbox
- beatboxer
- beatboxing
- be at daggers drawn
- beat down
- be at each other's throats
- beaten
- beater
- beater bar
- beat frequency
- beat-frequency oscillator
- beat generation
- beatific
- beatifically
- beatification
- beatify
- beating