Up to 40 cm in length, with a tail shorter than the head and body.
Blunt nose, small ears and a thicker body when compared to the Black Rat (Rattus rattus).
Gestation period of about 3 weeks.
Usually ground living and burrowing, but sometimes climbs. The only species to occur in sewers in Ireland.
Preferred food is cereals.
Will eat around 30 g of food a day and drink 60 ml.