The difference between roof rats and Norway rats is all about where they like to live, in addition to differences in physical appearance. Scratching, whining, shrieking and bickering, roof rats brashly publicize their existence in the rafters, attics and kitchens they live in. Norway rats circulate in basements and lower levels of buildings, culverts and tunnels. Omnivorous (eats everything), roof rats and Norway rats eat a wide variety of foods. Roof rats prefer seeds, vegetables and fruit, wheat and corn. Norway rats prefer a diet of carbohydrates and proteins: livestock feed, fruits and vegetables, meat, sugar, flower bulbs, corn flour, wheat, beans, bread, even injured rats may be eaten. Norway rats have heavy, thick bodies, blunt muzzles and small, close-set ears. Roof rats have really long tails, large floppy ears and pointed muzzles. Roof rats are expert climbers and gain access to buildings by climbing onto roofs from trees or overhead utility lines. Norway rats are excellent swimmers and enter buildings at the foundation or below the ground level.
https://www.linkedin.com/pulse/roof-norway-rat-randy-bilesky?published=t
http://www.delta-optimist.com/opinion/blogs/blog-the-roof-and-norway-rat-1.2305064