As a dog owner, your best friend is also one of your best lines of defense against danger. Regardless of size, your dog's responses to threats are largely determined by their breed. Some dog breeds have an ingrained instinct to protect, while others develop profound loyalty to good owners. Whether you're concerned about home invasion or safely walking the streets at night, these seven breeds make the best guard dogs.

1. Akita

Strength: Protective instincts

Despite their medium size, Akitas are muscular and sturdy with standing heights between 24 and 28 inches. As an independent breed, they're generally quiet and curious about their environments. If there's a disturbance in the home, Akitas will investigate and only bark if there's trouble. Originally bred in Japan, they're prized for their protective instincts and their thick fur. As a symbol of health and loyalty, gifts of Akita figurines are often given to families when a child is born.

2. Great Dane

Strength: Intimidating Size

Despite their large size, Great Danes are friendly and easy-going. Male Danes grow to be between 30 and 34 inches tall, with females standing only a few inches shorter. Usually, the sight of this breed is enough to deter an intruder. However, despite their sonorous bark, Great Danes are not aggressive dogs, and they're unlikely to attack if they're confronted with a criminal. They'd rather lounge around the house, snacking and playing the family.

3. Collie

Strength(s): Loyalty and loud bark

Thanks to the enduring legacy of Lassie, Collies are one of the most beloved dog breeds in the U.S. They're extremely affectionate and protective of their owners, but they're also noted to be very vocal with an intimidating bark. Unless they're surrounded by individuals they know and trust, they're unsettled by strangers. As sensitive and intelligent animals, they often serve as service dogs, police dogs, and search and rescue dogs.

4. German Shepherd

Strength(s): Strong and obedient

Known for being hard workers, these dogs are heavy and muscular. They're eager to learn commands, and their natural agility makes them swift runners who respond quickly to orders. Often seen as police dogs and special needs animals, they're incredibly obedient and loyal, but they need to maintain a highly active lifestyle to avoid becoming restless.

5. Bullmastiff

Strength(s): Intimidating appearance and fast speed

These large dogs are natural hunters who use their hefty weight and agility to pin down their prey–or an intruder. However, Bullmastiffs were specifically bred not to bite. Despite their intimidating appearance, they're not an aggressive breed. They're eager to please their owners, require little grooming, and are notably quiet. While their gentleness and loyalty make them an excellent family pet, their instinct to pounce on a threat or enemy make them common guard dogs.

6. Boxer

Strength: Powerful

As highly energetic dogs, Boxers are a preferred breed for families with children or owners with active lifestyles. At an average height of 24 inches tall, Boxers are powerful despite their smaller size. While they're prone to jumping on loved ones, they're very intelligent and easily trainable.

7. Saint Bernard

Strength(s): Large and protective

As large, powerful, and loving dogs, Saint Bernards are the most popular breed of family guard dogs. With fierce protective instincts, these dogs have been traditionally used to rescue travelers buried under avalanches in the Swiss Alps. When they're not saving the day, however, they need firm training from their owners and plenty of space to roam.