Weight: 200-480 g (7-17 oz.)
Overall Length: 30-45 cm (12″-18″)
Tail: 12.5-20.5 cm (5″-8″) in length. Stout, bald and shorter than body; dark above and pale beneath
Colour: Various, brownish-grey back, greyish-white belly.
Toes: Front paws four toes and rear paws five toes (length about 2.5 cm)
Ears: Thick and short with fine hairs nearly hairless.
Droppings: Capsule shaped, 25-30 mm (3/4′) long and often containing hairs; 40 to 145 are dropped each day.
Teeth: Grow up to 12.5 cm per year but gnawing keeps their length almost constant. Only the front surface of the incisors is covered with enamel, thus keeping them sharp and chisel-like.
Eyes/sight: Small, poor eyesight and colour blind. The young are born blind following a gestation period of between 20 to 25 days. Litters range from two to twenty-two young, with five to twelve being common. The eyes open on about the 14th day and the rat travels freely after one month the Norway Rat reaches sexual maturity at three months. Females usually produce four to seven litters per year. Rats have minimal control of their bladder and cannot vomit (any rodenticide they swallow cannot be voided from the stomach). Length of life in wild conditions is about one year. Normally, the Norway rat lives at or near ground level. It nests and burrows in the ground, under buildings, in rubbish and rubble, and under lumber and litter of various types. It is an excellent climber, swimmer, and jumper, and is found everywhere. Dumps and sewers are major habitats. It can consume 30-90 grams of food per day. A rat will often take food (or even rodenticide bait) and hoard it in a hiding place for consumption later, if the rat can find it again. They damage more food through contamination with their urine and droppings (16 cc of urine and 30-180 droppings per day are excreted) than by consumption. The Norway rat will live both inside and outside buildings but has a home range of 15-30 metres. The dominant male rat in the area is considered to be the alpha rat and will have several female rats in his territory. A rat is essentially a nocturnal animal, although sometimes it is active during the day. It prefers narrow, concealed, out-of-the-way routes when moving about. Since it is a creature of habit, it tends to follow the same pathways; however, it is highly adaptable.