Norway rat – what is a Norwegian rat?

Definition of a Norway Rat (or Sewer Rat)

Better known as the “sewer rat,” the Norway rat is grey-brown in colour and measures between 30 and 45 centimetres, including its tail. This rodent is able to climb, swim, and jump to find its way inside buildings and homes. It may enter through construction defects, by widening existing gaps and holes, or through drainage pipes. In 95% of cases, the intrusion of Norway rats is due to a defect in the sewer system, while only 5% of rats enter through poorly closed doors or leaky windows, particularly in basements.

The Norway rat eats almost anything and, being occasionally cannibalistic, is in constant search of food. This rat prefers dark places to feed, hide, and build its nests. It is most active during the night when there is no human activity. The female typically gives birth to a litter of 6 to 14 young and can reproduce about nine times within her lifespan of approximately 18 months.