According to recent surveys, over half of Americans do not feel safe in their own homes due to factors like home invasions. While security systems help, they do not physically protect you against intruders, so many are choosing to invest in guard dogs. The ideal guard dog has a combination of intimidation, loyalty and alertness. Here are the top four guard dogs, according to canine experts. 4. Bullmastiff. Intimidation is the name of the game for the Bullmastiff. Their size and presence are enough to fend off most intruders. On top of that, these mastiffs are surprisingly good family pets, as they are gentle giants when they are not in protection mode. 3. Doberman Pinscher. The Doberman is a powerful, fearless and fast dog. Boasting an impressive amount of athleticism and alertness. While they make great companions, raising them from puppies is essential, as they are very cautious around people they are not familiar with. 2. Rottweiler. Rottweilers are the quintessential guard dog, being both intimidating and strong, with a bite force unmatched by any other dog. Where this breed loses out is its family integration. Due to their size and aggression, they are a risk around small children, even with training. 1. German Shepherd. When it comes to home protection, you cannot get better than the German Shepherd. These guys are bred to be fierce protectors. These courageous canines are also perfect family pets and easily trained.