Invasive Species — Norway Rat (Rattus norvegicus)
Norway rats are believed to be native to the plains of Asia, northern China and Mongolia. Beginning in the Middle Ages, they spread to Europe and are now in most major human settlements.
In environments lacking humans or human foods, brown rats prefer damp environments such as river banks, coastlines and wetlands. However, most are found associated with human-made environments, such as warehouses, ships, and sewage or storm water systems.