- The norway rat is up to 40 cm in length, with a tail shorter than the head and body.
- It grows up to between 350–500g in weight.
- It has a blunt nose, small ears and a thicker body when compared to the Black Rat (Rattus rattus).
- Rats have 7–8 young per litter, and between 3–6 litters a year.
- The gestation period is about 3 weeks.
- It only takes 10–12 weeks from birth to reach sexual maturity.
- Preferred food is cereals, although they are omnivorous.
- They will eat around 30g of food a day and drink 60ml.