The Norway rat is also called a "sewer rat". Norway rats tend to be larger and more aggressive to animals, humans and each other than Roof rats.
Norway rats eat a wide variety of foods but mostly prefer cereal grains, meats, fish, nuts, and some fruits.
When Norway rats invade buildings, they usually remain in the basement or ground floor. They also live in fields, farms, woodpiles and buildings. Their nests are usually lined with shredded paper or cloth.
These rats are known for the damage they cause by chewing on materials, urinating on food and eating stored foods. They have also been known to chew on wires, which can cause fires to start. They also carry disease and ectoparasites. Rats will also attack both animals and humans. Human babies and even adults have been killed in rat attacks.
Roof Rats are excellent climbers and get their name because they usually live high off the ground, like on the roof of a building. They have very poor vision and are color blind, but they have extremely strong senses of hearing, smell, touch and taste. Rats have four to six litters a year and each litter has 6 to 12 babies in it. These rats are only pregnant for about 21 to 23 days and they can start reproducing when they are three months old.
Roof Rats prefer eating fruits, berries, vegetables, cereal, pet food, nuts, grain, slugs, snails and rotten food.
Roof Rats are excellent climbers and they usually live in spaces on the tops of buildings, on roofs or in attics. They also live in sheds, garages, boxes, ceilings, under floors, in wood heaps and in thick grass.
Roof rats cause damage to structures by chewing, eating stored foods and carrying diseases, such as Hantavirus. They are most famous for spreading the highly contagious bubonic plague in the Middle Ages. Rats will also attack both animals and humans. Human babies and even adults have been killed in rat attacks.