For centuries, dogs have served as guardians of their owners' property, whether it be family members, homes, livestock or land. While most dogs do this naturally, some dog breeds are especially inclined towards this task. Guarding duty varies in the level of protection provided by dogs, such as being watchdogs or alarm dogs, guard dogs, and attack dogs.

Watchdogs or alarm dogs simply warn their owners by barking vigorously when anything out of the ordinary occurs, such as strangers who are passing by too close to the vicinity of the owners' homes. Guard dogs go one step further by having the ability to restrain intruders and attacking upon the instructions of their owners. Attack dogs are more vicious, and are trained to attack intruders on sight.

While watchdogs may provide sufficient warning to their owners, they usually do not have the ability to guard or act against an intruder. Meanwhile, attack dogs can become unsafe if not properly trained or handled. Guard dogs offer a comfortable medium between the two types, and are suitable for those who wish to protect their homes without the risk of injuring or killing anyone, even intruders.

There are many dog breeds that can be trained as guard dogs, but these are the most common ones used for their natural guarding ability:

1. Rottweiler

Rottweilers make great guard dogs and family companions. Their protective instincts ensure their immediate action once a family or 'pack' member is threatened by an intruder or a dangerous action. Massive in size, these dogs grow to a height of 24 to 27 inches (61 to 69 cm) and weigh between 93 to 110 pounds (42 to 50 kg).

Rottweilers are good guard dogs because of their alertness and wait-and-see attitude. They do not usually bark unnecessarily until and unless they see any harm is about to come upon their owners or the territory that they are guarding. They are quick learners but nevertheless, need firm handling and discipline due to their strong-willed nature.

2. Doberman

Standing tall at a height between 24 to 28 inches (61 to 71 cm) and weighing anywhere from 71 to 100 pounds (32 to 45 kg), Dobermans are well-known for their fierce temperament, making them excellent guard dogs. These dogs are increasingly being used in both the military and police force because of their obedience, intelligence, highly trainable attitude and ability to handle human assailants. Despite their ferocious reputation, Dobermans are actually loving and affectionate pets, willing to do anything for their owners.

3. German Shepherd

German Shepherds have been termed by some as one of the best guard dogs and family companion. Their gentle nature, especially with children, should not be misconstrued as a lack of capability to be fierce when necessary. Highly intelligent, these dogs are obedient and are able to attack and release on command. German Shepherds are known for their courage and protectiveness when it comes to their owners. However, because of their affection and dependence on their owners, German Shepherds are prone to separation anxiety, even if left alone for a few hours.

4. Bull Mastiff

Bull Mastiffs are crossbreeds composed of 60% Mastiff and 40% Bulldog. Their appearance alone is intimidating. These dogs are tall, standing at a height between 25 and 27 inches (63 and 69 cm), and heavy, weighing from 110 to 130 pounds (50 to 60 kg). Wonderful guard dogs, Bull Mastiffs usually knock intruders down and stand above them, baring their teeth and growling threateningly.

Because of their sheer size, Bull Mastiffs also serve as guard dogs by preventing aggressors from moving past them. These dogs are fiercely loyal to their people and regard strangers warily. Hence, early socialization is crucial to ensure that Bull Mastiffs do not become aggressive against people they do not know.

Guard dogs are trained to protect their owners against intruders and aggression. Yet, they may have a tendency to become overprotective, even with strangers who cause no harm or threat. Owners should therefore ensure sufficient training and socialization of their guard dogs in order to prevent occurrences such as unwarranted domineering behavior, bites and attacks.