Originated from Asia and China.
First recorded in Europe at the beginning of the 18th Century.
They were referred to as Norway rats because they were thought to have travelled from the East on Norwegian timber ships.
R. norvegicus must drink water daily unless the food source is extremely moist.
Colour: This can vary but usually brown to grey-black with lighter underside.
Tail: Slightly shorter than head and body. The tail is dark above and lighter below.
Weight (adult): 400 – 550 g
Litters per year: 3 -6
Litter size: 8 – 10
Maturity: 2 – 3 months
Average life span: 12 months
They are considered omnivorous but if available, cereals seem preferred. They eat on an average one tenth of their body weight each day. R. norvegicus explores locations quite freely
However, it does have a fear of new objects. This is known as neophobia and this should be taken into account when baits are checked after an initial treatment.