our 2 doggies, Chaser (pit bull) and Holly (GSD) got into a sudden fight last night. They are best buds normally, they love each other. This is the 3rd time this has happened. Now I am afraid to leave them alone together. I don't understand why they do this other than them both thinking they are alpha dog. Chaser will be 11 in June, Holly is 2. Chaser has seniority and assumes the position of alpha dog, but Holly refuses to submit. Chaser starts it and Holly always wins. Chaser ends up hurt and Holly is fine. Yes, the pit bull is the loser. If I hadn't got them apart when I did, Chaser might have been killed. Help, I need Cesar Milan!! Any professional advice from dog trainers on here?