When I hear "city folk" who don't know about Pet Rats talking about the kind of rats that inhabit their city sewers, they make these wild guys out to be REALLY big. "Cat-sized," they say.\n\nWell, Gus is a fairly large young adult (8 mo.) and he weighs 1 pound, 1 ounce. (17 ounces.) Even though he has some growing to do, I don't expect he will ever be much more than 2 pounds.\n\nI know that Pet Rats and their wild cousins are all Rattus Norwegicus (sp?) and come from the same family of rats. How large can this kind of rat get?\n\nAre wild rats generally larger than Pet Rats? Why?