Although there are many different looking pet rats with various coat types and colors, they all belong to the same species — Rattus norvegicus. This species still exists in the wild, but they are quite different from the pet rats that have been bred selectively by people for more than a century. The different types of pet rats are called varieties instead of breeds. Smooth coats, curly coats, and hairless are just a few coat types. The number of colors is more numerous. Mix them all together, and you get quite a lot of beautiful and handsome pet rats to choose from!