A friend of mine said her brothers dog was in a fight and almost lost his testicles. Is this unusual behavior or have any of you ever hear of this happening when two males fight over a female???
Hmmm…I don't know...my hunch is that it was probably just a coincidence. Most of the damage I have seen in dog fights is neck, face, front legs...I haven't really ever seen much around the rear end....
I suppose it would depend on what was happening during the fight...if the one dog was trying to run away, and the other dog grabbed him then in the rear, that would make sense. But again, my hunch is that in dog fights they both want to control the head, where the dangerous tools are. If you are biting someone in the butt...they could also be biting you in the butt. So better to bite the head/neck, and push them down.
Of course this is all speculation 
I hope your friend's dog is okay.
Eddie will bite a dog in the butt to break up a fight, then Ed runs and hopes he can outrun the dog he bit!
When I watch the dogs play, I often see them flip around and throw their butt in the "attacker's" face. I assumed this was a protective measure, to keep the more vital areas like the neck away from being bitten, and also to allow the dog the freedom to be able to swing it's head around and bite it's attacker? Could this be part of what they are doing when they are actually fighting too? Making sure that the rear is the most likely target to protect the more important areas? Also I know the dogs attacking will want to go for the neck, but if they're chasing another dog, the rear end is the closest. lol That may end up getting the brunt of the bite just for proximity's sake? And of course the privates are very vulnerable unfortunately.
When I watch the dogs play, I often see them flip around and throw their butt in the "attacker's" face. I assumed this was a protective measure, to keep the more vital areas like the neck away from being bitten, and also to allow the dog the freedom to be able to swing it's head around and bite it's attacker? Could this be part of what they are doing when they are actually fighting too? Making sure that the rear is the most likely target to protect the more important areas? Also I know the dogs attacking will want to go for the neck, but if they're chasing another dog, the rear end is the closest. lol That may end up getting the brunt of the bite just for proximity's sake? And of course the privates are very vulnerable unfortunately.
We call that "butt check" at our house 
Yeah, definitely a big part of play…I wanna say that might be a way to say 'see we are still playing here'....I can't imagine a dog in a real fight taking the chance of turning his back on the attacker. Though, I am used to seeing girl, girl fights...where neither girl is willing to surrender...it could be that a dog who really doesn't want to fight will try to protect his head and neck by offering other 'parts'...it would definitely indicate that the other dog wasn't reading his signs correctly...either by the dog offering surrender, or running away...it isn't really appropriate for the attacking dog to continue attacking.
I am rambling
Eddie will bite a dog in the butt to break up a fight, then Ed runs and hopes he can outrun the dog he bit!
Querk will bite butts to get the girls ALL riled up so they chase him…the only one who REALLY takes offense to it is Ivy
…I can't imagine a dog in a real fight taking the chance of turning his back on the attacker. Though, I am used to seeing girl, girl fights...where neither girl is willing to surrender...it could be that a dog who really doesn't want to fight will try to protect his head and neck by offering other 'parts'...it would definitely indicate that the other dog wasn't reading his signs correctly...either by the dog offering surrender, or running away...it isn't really appropriate for the attacking dog to continue attacking...
This is probably what may have happened. I don't think anyone actually saw the fight… So it's hard to tell, but my friend now thinks it is a part of male dominance fighting! I told them I would ask on here and see if it is common or not...
