My Kaiser just turned one recently and has never shown any signs of aggression at all. Not towards anyone he knows nor strangers. He is still very mouthy, but only when we're playing. He never intentionally tries to hurt anyone. Just puts everything in his mouth lol. Today, I took him to Petsmart. Normally he's pretty skittish and shy around new people and will sometimes bark but only out of fear, and has never tried to snap at anyone. The hair on his back will stand up when he meets someone new and he is just very standoff ish. While at Petsmart, I was speaking with some employees right next to the cashier and a little girl approached him, did not ask if it was okay, and I heard him growl for the first time. Then he lunged at her. I have never seen him act this way, nor did I know how to correct him. Everyone has been telling me it's normal, he was startled, it was instinct, lots of dogs don't like kids, etc. But if he would have bitten that little girl.... It doesn't matter if it was instinct, he would have to be put down, no questions asked. Does anyone know what I can do to prevent this from ever happening again? He's in intermediate training classes now and he's very well mannered, I guess she just spooked him. Thanks in advance!