bingo.  They are pussy for a head shot.     
Those saying "just kick it" are fucking stupid.  You have a 80 lbs slab of muscle running at you full go-aimed square at your nuts-your not kicking a fucking thing.     
I only know you can-because I have been attacked-by a big german, and a cage fighting pit.     
Me 2, dogs 0, but that pit Fauked up my calf.   If a dog like that gets a HOLD of you, think lock jaw-think "yer fucked"