Ever since being a kitten, my cat has hissed and growled at dogs. I don't think she has gotten in a cat/dog fight, but a couple of the dogs that I take her to now completely ignore her (and less hissing).

It would have made a great America's Funniest Videos, but one of the neighbors had a problem that they had 2 dogs that never got along well. One day they had a big dog fight, and were stressing how to safely break it up when Billy the Cat pounced into the middle of the dog fight, and apparently broke it up immediately.