15. American Bulldog
The American Bulldog was bred for guarding, farm work, and fighting. When raised in a loving home, they can be friendly, social, and very devoted. Without proper training and attention, though, they may develop temperamental traits. Training is key to a happy family life with this breed. American Bulldogs are strong and muscular and could unintentionally hurt children or small pets due to their size. They must learn to understand their own strength.