[pyrnet] Strange reaction

My name is Brian Tuttle, and this is my first time posting. Please let me know if I am erroring in some way. I have a 12 month old neutered male Pyr named Bear. I just adopted a 2 year old spayed female Norwegian Elkhound from a shelter two days ago. Today, I was taking them both for their daily walk when we met a large male Chow. Bear, as usual, wagged his tail and wanted to meet the Chow. Ginger, the Elkhound, did the same. The Chow also looked happy and wanted to meet. The Chow's owner and I both verified that a meeting was ok with us, so we slowly approached. When the Chow was about ten feet away, Ginger started barking and lunging towards the Elkhound. Bear kept wagging his tail and trying to get to meet the Chow. The Chow's owner proceeded towards us, and when he was about five feet away(he was still wagging his tail happily), Ginger started growling and the Chow's owner stopped. The Chow suddenly tried to lunge and snap at Ginger. Bear dropped his tail, bared his fangs, stood all his hair on end, and went ballistic towards the chow as if to kill him (no playing here he went totally psycho). It was all I could do to hold him back. Bear has never exhibited any type of aggression in his life towards anyone or anything. I reined him in and told him no then vacated the vicinity ASAP. I think this is evidence of protectiveness towards the new dog, but it didn't even seem like my dog on the end of the leash. Is this normal behavior? Does anyone have any suggestions how to curb this? Is it normal for him to extend this type of protection to a new dog he just met? Bear has been the light of my wife's and my life, and I just want to make sure I don't do something to cause him problems so any help is greatly appreciated.