All depends on the breed. the only real life experience i have is when a german shep mix was attacking our beagle, around the neck blood and broken skin, I ran up gave the shep one kick in the ribs and then had one of each of my hands on his upper and lower jaws pulling as hard as i could didnt work I began punching it in the pivot of its jaw, and it let loose, I tumbled with the dog for a bit before it left. this was one of the few times I wasnt wearing my knife, If I'm in a situation where I feel threatened seriously by a dog he better watch his throat. I love dogs we've sheltered/housebroken over 40 dogs working with a shelter, but it doesnt mean I dont know how dangerous they can be.