Pet rats, also commonly known as 'Fancy Rats, ' are a domesticated version of the common brown rat and are therefore part of the species known as 'Rattus Norvegicus.' However household rats have been selectively bred for looks, color, size and temperament over the course of the last 100 years. They have been selectively bred to the point where there is almost no immediately obvious similarities between the household rat and their wild ancestors. Household...