Which Giant Dog Resembles a St. Bernard? Exploring 20 Colossal Canine Companions and Their Unique Traits

When you think of the biggest dogs on the planet, images of gentle giants towering over their human families often come to mind. These massive breeds aren’t just impressive because of their sheer size—they’re equally remarkable for their loyal hearts and fascinating histories. But before bringing one into your home, there’s plenty you should know about what life really looks like with a dog that weighs as much as a grown man.

Understanding Large Breed Dogs: More Than Just Size

The American Kennel Club notes that most enormous dog breeds fall into the working group—dogs originally developed to assist humans with demanding tasks. Whether it was hauling heavy loads, standing guard over property, or protecting livestock from threats, these canines were built for purpose. Their imposing stature, raw strength, and sharp intelligence set them apart from smaller companions.

“Owning a large breed dog can be rewarding as long as you’re genuinely prepared,” explains Charlotte Reed, a pet lifestyle authority and host of The Pet Buzz radio show. “These dogs maintain the drive they were originally bred for. That’s why they aren’t suitable for every dog lover out there.”

What You Really Need to Know Before Adopting a Giant Breed

Growth and Development Timeline

Unlike toy breeds that reach full maturity in months, big dogs take their sweet time developing. Most gigantic breeds won’t stop growing until 18 to 24 months of age, with some—like Great Danes, mastiffs, and Newfoundlands—potentially growing until they hit 2 years or beyond. This extended development period means extra caution around their joints and bones, as they’re vulnerable to injury during growth spurts.

Space, Food, and Living Requirements

Giant dogs demand giant accommodations. Think oversized beds, massive food bowls, industrial-sized toy collections, and spacious living areas where they can stretch out comfortably. The reality? Your home layout, yard size, and climate all become crucial factors in your decision.

The Financial Reality

Here’s the truth: bigger dogs equal bigger bills. Premium dog food costs more. Veterinary expenses skyrocket. Pet insurance premiums are steeper. Even toys and grooming supplies carry a heftier price tag. Make sure your budget can handle it.

Training Is Non-Negotiable

A 50-pound dog jumping on guests might be cute. A 150-pound mastiff doing the same? Dangerous. Pulling on the leash, jumping behavior, and dominant tendencies that get ignored in small breeds become serious issues with massive dogs. Professional training from puppyhood is essential.

The Top 20 Giant Dog Breeds Worth Knowing

Mastiff: The Ultimate Gentle Giant

Weighing up to 230 pounds and standing 30 inches tall, mastiffs reign supreme in the size department. Their wrinkled faces and massive frames command attention, yet their temperament is surprisingly gentle. Bred to protect families and property for millennia, they remain fiercely loyal and protective despite their calm demeanor.

Boerboel: South Africa’s Guardian Warrior

The name literally means “farmer’s dog” in Dutch, reflecting their roots with colonial settlers in South Africa. These athletic protectors were bred through careful crossbreeding of large guard dog lines and originally hunted big game. Today, they maintain the same watchful dedication to their families.

Saint Bernard: The Alpine Rescuer

From the treacherous Swiss Alps comes a breed famous for mountain rescue operations. Standing impressively tall with a massive head and soulful eyes, Saint Bernards combine incredible strength with genuine gentleness. Their legendary endurance and directional sense made them mountain heroes.

Great Dane: The Regal “Apollo of Dogs”

Often called the Apollo of the canine world, Great Danes reach heights of 32 inches and weights near 200 pounds—yet they’re affectionate lap dogs at heart. Originating in Germany, these elegant giants thrive on companionship and genuinely believe they’re house pets despite their palace-sized bodies.

Tosa Inu: Japan’s Revered Warrior

This Japanese mastiff carries a fascinating history as a fighting dog from Shikoku island, developed through crosses with mastiffs, bulldogs, Great Danes, and German pointers. In Japan, Tosa Inus receive the same cultural respect as sumo wrestlers. Though stoic and reserved with strangers, they display deep affection for their families.

Leonberger: The German Powerhouse

Weighing up to 170 pounds, Leonbergers sport thick double coats and powerful builds that somehow move with elegance. German in origin, these intelligent sweethearts excel at obedience training, therapy work, and water rescue. Their calm, patient nature makes them surprisingly gentle family members.

Neapolitan Mastiff: Italy’s Wrinkled Wonder

With distinctive wrinkled skin and massive frames, Neapolitan mastiffs are unmistakable. These calm, protective Italians bond deeply with their families and prefer lounging indoors to high-energy activities. Their low-key lifestyle suits families wanting a protective but relaxed companion.

Newfoundland: The Water-Loving Canadian

Originally from Canada, Newfoundlands are legendary swimmers with webbed feet and water-resistant coats. Their patient, gentle nature makes them excellent with children, and they’re strong enough to rescue drowning victims. Fair warning: they drool generously.

Anatolian Shepherd: Turkey’s Livestock Guardian

This Turkish breed has guarded livestock for centuries with unwavering bravery and loyalty. Their sturdy build and thick coat handle extreme weather, while their independence and intelligence make them excellent guardians. Though serious by nature, they show genuine affection to family members.

Tibetan Mastiff: The Mountain Guardian

From Tibet’s mountains comes a striking dog with a thick, fluffy coat designed for freezing temperatures. Known for their bone-deep loyalty, protective instincts, and distinctive deep bark, Tibetan mastiffs make formidable guardians. They’re gentle and loving with family but characteristically aloof with strangers.

Rottweiler: The Misunderstood Protector

Despite their tough appearance—sleek black coat with tan markings—Rottweilers are genuinely gentle with families they trust. Originally from Germany, these intelligent, easily-trained dogs thrive on companionship and benefit enormously from regular exercise and socialization. Their protective nature is real, but their capacity for love is equally strong.

Bullmastiff: England’s Estate Guardian

Bred to guard English estates, Bullmastiffs combine power with intelligence and calm temperament. Their muscular build and protective instincts made them perfect estate dogs, and they maintain those guardian qualities today. With proper training and socialization, they become devoted, affectionate companions.

Akita: Japan’s Loyal Companion

This Japanese breed is fiercely independent, intelligent, and sometimes stubborn—but undeniably loyal. Their strong, powerful build and thick double coat protect them in cold climates. While reserved around strangers, they demonstrate rock-solid devotion to their families and make excellent guard dogs.

Black Russian Terrier: Russia’s Confident Guardian

Developed in Russia, this confident breed sports a thick, usually black coat and protective instincts that make them excellent guard dogs. Though they appear intimidating, they’re intelligent, trainable, and genuinely gentle with their families. Consistent guidance and socialization keep them well-balanced.

Cane Corso: Italy’s Athletic Protector

This Italian breed combines muscular athleticism with unwavering loyalty and confidence. They’re intelligent, eager to please, and surprisingly gentle with families despite their protective nature. Early socialization with people and other dogs proves essential for this capable guardian.

Irish Wolfhound: The Gentle Irish Giant

One of the tallest dog breeds, Irish wolfhounds sport thin, athletic builds and characteristic shaggy coats. Their friendly, kind nature and calm temperament make them excellent family dogs. They’re known for loyalty and good-natured dispositions despite their imposing height.

Great Pyrenees: The Mountain Sentinel

From France’s mountains comes a dog with a distinctively thick white coat and gentle protective nature. Great Pyrenees are loyal, watchful guardians who remain calm, patient, and gentle with children and other pets. They need regular grooming and exercise to thrive.

Scottish Deerhound: The Graceful Hunter

This elegant Scottish breed has a slender, athletic build and shaggy coat in various colors. Known for friendly, mild-mannered behavior, Scottish deerhounds were historically used to hunt deer and still require regular exercise and plenty of running space. They’re gentle with children and good with other animals.

Bernese Mountain Dog: The Alpine Companion

From the Swiss Alps comes a sturdy, powerful dog with a distinctive tricolored coat. Bernese mountain dogs have gentle, patient natures perfect for families. They love outdoor activities, do well in cooler climates, and require regular exercise and mental stimulation.

Dogue de Bordeaux: The French Gentle Giant

Also called the French Mastiff, this powerful, loyal breed features a muscular build with loose, wrinkled skin and impressive head. Despite their intimidating appearance, Dogue de Bordeauxs are calm, gentle, and surprisingly good-natured with children. They’re devoted to their loved ones through and through.

The Real Talk About Size: Genetics and Growth Predictors

Want to know if that adorable puppy will actually become a 200-pound dog? Genetics are the primary factor determining adult size. When breeders are unknown—as with shelter and rescue dogs—paw size offers a rough estimate, though this method isn’t foolproof. The paw-to-size connection is helpful but imperfect for predicting final dimensions.

On average, most large breeds reach adult height between 12 to 18 months. Giant breeds (mastiffs, Great Danes, Newfoundlands) may continue growing until 24 months or beyond. Even after stopping vertical growth, these dogs continue filling out and developing muscle mass, making patience essential during their development years.

Shedding, Energy Levels, and Lifestyle Fit

Not all giant breeds are created equal when it comes to shedding and activity levels. Cane Corsos and Dobermans are considered moderate shedders—a relief for those with allergies—while many others shed considerably year-round.

As for laziness, opinions vary among veterinary professionals. Great Danes are notoriously loungers who’d rather nap than run marathons. Bullmastiffs rank among the laziest large breeds due to naturally low energy levels and love of relaxation. This makes them surprisingly good for people without acres of land, though they still need regular movement to stay healthy.

Making the Right Choice

Bringing a 200-pound companion into your life isn’t a casual decision. These magnificent breeds deserve families committed to meeting their unique physical and emotional needs. Whether you’re drawn to a dog that looks like a St. Bernard or prefer the independent spirit of an Akita, understanding what each breed truly requires—from joint care during growth to consistent training and socialization—separates successful partnerships from regrettable ones.

The payoff? Loyalty that’s unshakeable, protection that’s genuine, and the extraordinary experience of sharing your life with a creature whose heart is just as large as their impressive frame.