Brown Rat

brown rat, (Rattus norvegicus), also called Norway rat, common rat, street rat, or sewer rat, species of rat (family Muridae) found on every continent except Antarctica. The alternate name “Norway rat” came from a false hypothesis widely believed in 18th-century England that the rats were native to Norway. Research has confirmed, however, that the brown rat is native to Asia, specifically northern China or Mongolia. Outside its native region the brown rat is a largely disliked pest and an invasive species, though the animal is widely used in biomedical research and is sometimes kept as a pet.