Thanks for the responses. Here is more background. Brutus had been a problem at his prior residence as he had nipped at a couple of kids (always around the granddaughters) so I guess he was showing his protectiveness. We now have him at our house 95 percent of the time and we just moved to be close to the grandkids. The child he bit a few days ago was new to him. There was a puncture of the forearm, a gash in the calf and a bite in the back that showed all four canine teeth in action. Fortunately he released, probably when I intervened. He is now four and we got him when he was two. He had training at about one year old but I don't know what kind.