.....yesterday, she growled & snapped at him and he went after her again..I was able to pull him off before a fight broke out. He has a tendancy to bite down on my arm and when reprimanded he will growl and show his teeth (they told me that this is his way of playing). I understand he will try to demonstrate his dominance but shouldn't he be the submissive one and respect HER environment after these few altercations?)quote

Dogs will work out their own dominance issues. They have to work out their own place in the pack. You could have a chiqua. in a new home where there's a St. Bernard, and the Chi will establish dominace.

Also I'm not sure about the dane "biting down on your arm" a behaviorist would really need to see the body lanquage, but with the growl and teeth baring I'm not sure it's not part of "fear bite" which is directed at your dog in response to her aggresion, and you just "got in the way. A friends lab bites down on my arm to say hello, but it's sooooo gentle, and no growling or teeth. Perhaps your dog does not want a buddy, how does she do around other animals. The rescue should also test the dane with other dogs to see just how he is with other dogs. Did they do this, did a behaviorist do this????