I have the same problem! We adopted a three-year old female, who lived in a country house. She was known to hunt mice in the walls. Things are less exciting for her at our place. She loves the dog (a huge Golden Retriever) and the cat, but she cannot abide other carpet sharks. What she has against her own species, I don't know! I have tried to leave them together for short periods, but I think one will be killed if they are together too long. I have tried smacking her nose, spritzing them with water, holding them close but not in biting range, switching cages between the different ferrets, etc. Short of Valium, I am stumped. Incidentally, the other ferrets no longer trust her, so the problem is two ways now. I am hoping that our young male, who is easy-going and utterly fearless/senseless, will be able to hold his own when he reaches full size. For now, she is the only thing he avoids. [Posted in FML issue 2088]