I don't think there's any real rule about cats and ferrets.  My dentist
swears that his ferret killed his cat, and my secretary swears her cat
unexpectedly bit her ferret (deeply, on the side/belly), and although they
treated it, it died from infection.  The only rule I could give you is "it
depends on the cat and the ferret."
 
Personally, I would never trust a new/adult cat with my ferrets, declawed
or not, sweet or not.  Why?  Becuase Buttons is a little stinker who
doesn't like anyone bigger than she is.  Cats offend her dignity by
rolling her around on the floor, and she tends to bite them for no good
reason except that they were lying where she wanted to walk.  However,
even if she liked them, I think it's better safe than sorry.  A multi-pet
household is truly a lot of work.
 
Best of luck to all
Melissa
[Posted in FML issue 3685]