 Domesticated rats are physiologically and psychologically different from their wild relatives , and — when acquired from reputable breeders and shops — pose no more of a health risk than other common pets . For example , domesticated brown rats are not considered a disease threat , while exposure to wild rat populations could introduce pathogens like Salmonella into the home . Fancy rats experience different health risks from their wild counterparts , and thus are less likely to succumb to many of the same illnesses as wild rats . 
