Not being the Dog Whisperer but it is a defense mechanism. A startled dog will either choose fight or flight. Most dogs choose flight. Of the ones who choose fight, the majority of that is nothing more than a display. Funny how it works but as owners it is a must to differentiate between the real and the display, and best case scenario is to never leave it to chance.

We were at a show once and I was getting my dog out of the truck, about to walk him out before we weighed and this guy out of nowhere stepped from around the truck. (maybe taking a leak or something, who knows) but my male went ape shit. He had never once acted like that in any situation before. Luckily it was a short lead, any more room and he would have snatched hold.

Funny part when the guy identified himself and most think of him as not an exactly upstanding guy, there was this old dude who said, "If he tried to bite him your dog must be a real shit eater".

When we own dogs with the propensity to bite we can never leave it up to them to make the decision. And as I say that I use to own Fila Brasileiros and kept two in the house. If someone broke in, odds are that is where we would have found them. But in that case it is better to be judged by 12 than carried by six. EWO