I have 2 ferrets and 2 dogs. Most of my cats don't like the dogs(although my springer adores the cats, and wins most of them over!), and they get along wonderfully with the ferrets. I don't leave them unattended for the ferrets safety, but they've never tried to hurt them. I love watching Gracie with the ferrets-first she chases them, then they chase her, back and forth for hours until they collapse in a heap together and sleep.