We had a doberman, he was the greatest watchdog ever. Very loving and friendly, but ONLY if you came in through the front door, greeted by the family. When they were dating, my brother-in-law to be thought it would be very funny to climb over our back fence and try to scare my sister by banging on our bedroom window. BIG MISTAKE. We found him against the fence, our Dobie standing with one forepaw at each of his shoulders, and growling right in his face. Rajah didn't bite him or anything, just held him there. As soon as we told Rajah it was OK, he jumped down and was all wags and doggie grins. We raised him as a puppy and he never had any kind of special training, but he was a great watch dog.