Life Cycle: The young are born blind following a gestation period of between 20 to 25 days. Litters range from 2 to 22, with 5 to 12 being common. The Norway rat reaches sexual maturity at 3 months. Females usually produce 4 to 7 litters per year. Length of life in wild conditions is about 1 year.
Behaviour: The Norway rat lives at or under ground level. They will live both inside and outside buildings and have a home range of 15-30 metres. It is an excellent climber, swimmer and jumper, and is found everywhere. It prefers narrow, concealed, out-of-the-way routes when moving about.
Signs of Infestation: Droppings are 25-30mm long and often contain hairs. Look for live rats, droppings, gnawing, burrows and smear marks on the wall.