2. German Shepherds: German shepherds are typically larger dogs with a strong protective nature, and certain breeding lines have been associated with aggressive behaviors without proper training and socialization.
3. Rottweilers: Rottweilers are historically renowned as guard dogs and herding dogs, due to their muscular build and intimidating presence. However, their power and size can be a risk factor if they are not appropriately trained.
4. American Bulldogs: American bulldogs are known for being sturdy, robust dogs with a strong jaw. While they can make loyal companions, they might exhibit aggressive behaviors if not properly trained and socialized.
5. Bull Mastiffs: Bull Mastiffs are imposingly sized dogs with a reputation for being protective. They were originally bred as guard dogs and require consistent training and socialization to ensure they remain gentle giants.