7 Heaviest Dog Breeds On The Planet

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Looking at modern dogs, it’s incredible to think that not long ago, they were wolves. Over the millennia since their domestication, humans have bred dogs into a wide range of shapes and sizes, from tiny, energetic pups to large, majestic giants.

Dogs are the most variable mammalian species on Earth in terms of size. Some heavy dog breeds are truly big pups. Despite their size and often deep, loud barks, these giant breeds are some of the best cuddlers, most loyal companions, and friendliest family members.

According to the ASPCA, dogs are considered ‘giants’ when they reach around 90 pounds, though some classify them as giants once they hit 100 pounds. Unfortunately, larger dogs tend to have shorter lifespans, averaging closer to 10-12 years, with extra-large breeds often living just 8-10 years.

If you’re intrigued, let’s get to know these heaviest dog breeds that rule our hearts and homes.

Heaviest Dog Breeds

1. Leonberger

biggest dog breed by weight
Personality Friendly, playful, gentle
Energy Level Regular Exercise
Height 28-31.5 inches (male), 25.5-29.5 inches (female)
Weight 110-170 pounds (male), 90-140 pounds (female)
Life Expectancy 7 years

The Leonberger, originating in Leonberg, Germany, was bred by Herr Heinrich Essig to resemble a lion. This large breed features a tawny yellow coat with black markings on its muzzle and ears.

Leonbergers are calm and quiet, yet they are far from lazy. They thrive on companionship and do not fare well in kennels, preferring to stay close to their guardians. These dogs are very active outdoors and need more exercise than just a daily walk to stay happy and healthy.

Intelligent and trainable, Leonbergers can also be a bit stubborn at times. According to HillsPet, they are not typically aggressive towards people but may become reserved around strangers as they get older. Their grooming needs include brushing and combing twice a week, with no need for trimming.

Leonbergers enjoy various activities such as agility, carting, and sledding. This breed is perfect for guardians who want a large, active dog that enjoys outdoor adventures like hiking, backpacking, and swimming. However, Leonbergers do not do well when left alone for long periods and thrive best with plenty of companionship and activity.

2. Great Dane

biggest english mastiff in the world
Personality Friendly, patient, dependable
Energy Level Energetic
Height 30-32 inches (male), 28-30 inches (female)
Weight 140-175 pounds (male), 110-140 pounds (female)
Life Expectancy 7-10 years

The Great Dane, a breed of working dog developed in Germany over 400 years ago, was originally used for boar hunting. Known for its massive size and elegant appearance, the Great Dane is the tallest of the working breeds. This breed is swift, alert, courageous, friendly, and dependable, with a distinctive square-jawed head and sleek body lines.

Despite their large size, Great Danes are generally friendly and affectionate towards both family and strangers. The breed is easy to train, although they may not respond quickly to commands.

Great Danes require an enclosed yard with a fence, although they are not known for jumping over it. They are not excessively active but still need at least an hour of interactive play or walking each day. They enjoy games like tug-of-war, running, hiking, and trick training.

Britannica points out that Great Danes have a shorter lifespan compared to other breeds and are prone to gastric dilatation-volvulus (GDV). This potentially fatal bloating condition requires immediate and often costly veterinary care.

3. Irish Wolfhound

biggest dog breed by weight
Personality Courageous, dignified, calm
Energy Level Regular Exercise
Height 32 inches minimum (male), 30 inches minimum (female)
Weight 120 pounds (male), 105 pounds (female)
Life Expectancy 6-8 years

Irish wolfhounds are incredibly tall, a trait likely bred into them because they were used to hunting large animals like wolves, deer, and even bears. Despite their massive size, Irish Wolfhounds are gentle giants and make poor guard dogs due to their love for people. They can be very quick when motivated, a useful trait during their hunting days.

Originally bred to protect livestock from wolves in Ireland, Irish Wolfhounds are now primarily cherished as family pets due to their calm and relaxed nature. They do best with experienced owners who have the time to devote to their care. Given their large size, they are best suited to bigger homes with ample space. You might even need a larger car to take your Irish Wolfhound on outings or to the vet!

While they may appear laid-back, Irish Wolfhounds require plenty of exercise and space to stretch out. PDSA notes that these dogs thrive on companionship and, like most dogs, can become upset if left alone for long periods. When left alone, they might become destructive to relieve stress, leading to a big mess from a big dog!

4. Caucasian Shepherd

whats the biggest dog in the world
Personality Fearless, bold, kind
Energy Level Calm
Height 23-30 inches
Weight 99-170 pounds
Life Expectancy 10-12 years

The Caucasian Shepherd Dog is a fearless and intimidating breed known for its loyalty and love towards its family. As a natural guardian, this dog can be fierce and aggressive when it senses a threat. If you’re considering a Caucasian Shepherd puppy, be prepared for that cute fluff ball to grow into a massive dog.

These dogs are incredibly loyal to their owners but are also very independent. They are not ideal for first-time dog owners and need a home with plenty of space to roam within a secure fenced area. Due to their independent nature, many Caucasian Shepherds prefer to be the only pets in the household. They are also not the best fit for homes with young children, as they may not tolerate kids pulling on their tails or climbing on them.

PetMD states that if you travel frequently, a Caucasian Shepherd may not be the best choice, as they do not adapt well to being boarded or cared for by a pet sitter. This breed thrives in a quiet, calm environment with an owner who is home often.

5. Saint Bernard

biggest mastiff in the world
Personality Playful, charming, inquisitive
Energy Level Regular Exercise
Height 28-30 inches (males), 26-28 inches (female)
Weight 140-180 pounds (male), 120-140 pounds (female)
Life Expectancy 8-10 years

The Saint Bernard breed has been around for centuries, originally bred in Switzerland and Italy as alpine rescue dogs. These dogs were developed to withstand extreme weather conditions and rugged terrain, which required them to be larger than the standard working dog breeds of the time.

Saint Bernards make excellent family dogs due to their loving and affectionate nature. While their large size might initially intimidate strangers, their calm demeanor quickly puts people at ease. Despite their size, Saint Bernards are often very gentle and caring. They thrive on being around their family and participating in activities. If they feel left out, they might even sulk.

According to SpotPet, while Saint Bernards are sweet and gentle, they can become temperamental if they don’t get enough physical stimulation. Their size also means they can easily reach tables and countertops, potentially leading to some unintentional destruction.

Training Saint Bernards requires patience and positive reinforcement, as they do not respond well to punishment. Additionally, routine medical care for these large dogs can be more costly compared to smaller breeds.

6. Neapolitan Mastiff

what is the heaviest dog ever recorded
Personality Dignified, loyal, watchful
Energy Level Regular Exercise
Height 26-31 inches (male), 24-29 inches (female)
Weight 150 pounds (male), 110 pounds (female)
Life Expectancy 7-9 years

The Neapolitan Mastiff is a massive, powerful dog recognized by its loose, wrinkly skin and slow, bumbling gait. Historically used as a police and guard dog, this breed is now more commonly seen as a show dog and a companion. Neapolitan Mastiffs are loyal to their family and well-known friends and typically even-tempered, but they often remain reserved and aloof around strangers.

Like many large breeds, Neapolitan Mastiffs can be clumsy and unaware of their size and strength, so playtime should be approached with caution. Wrestling or biting games are not recommended due to their power. Purina warns that drooling is a significant trait of this breed, and it can get quite messy.

Adult Neos do not require extensive exercise; several shorter walks totaling about an hour each day are better for their joints than one long run. They are not particularly active or athletic and appreciate the freedom to move at their own pace.

Neapolitan Mastiffs need a lot of indoor space free of items that could be knocked over and, ideally, surfaces that are easy to clean. They do not turn easily in small spaces and do not fit well into small cars. Everything for a Neo, from bedding to crates, needs to be specialist or extra-large to accommodate their size.

7. English Mastiff

fattest dog breed
Personality Courageous, dignified, good-natured
Energy Level Regular Exercise
Height 30 inches & up (male), 27.5 inches & up (female)
Weight 160-230 pounds (male), 120-170 pounds (female)
Life Expectancy 6-10 years

The Mastiff is a calm, sensitive, and self-assured giant with a long history of being an excellent guard dog. Despite their enormous size and powerful build, Mastiffs make wonderful foot warmers and couch potato companions.

However, bringing a giant breed like the Mastiff into your home is a significant commitment. Early training and socialization are essential to ensure you have a well-mannered Mastiff. At home, Mastiffs are generally calm and patient but spring into action if they perceive a threat—even if it’s just the mail carrier.

Their gentle demeanor makes them suitable for families with older children who understand how to interact with dogs. However, they may not be the best choice for homes with younger children, who could be accidentally harmed by a bump from these enormous dogs.

PetMD notes that Mastiffs are intelligent and eager to please but can also be quite stubborn. It can be challenging to get them to cooperate if they are scared or confused or their sensitive feelings are hurt, even by harsh words. Keeping training sessions short, frequent, and fun can help ensure your Mastiff sees it as a game and responds well.


The heaviest dog breeds, such as the Great Dane, Saint Bernard, and Anatolian Shepherd Dog, are among the tallest and most imposing breeds in the world. These giant breeds are beloved by dog lovers for their loyalty, gentle nature, and impressive size. Owning one of these huge dogs comes with unique challenges, including the need for ample space, proper training, and regular exercise to ensure a happy and healthy life.

Dog lovers who appreciate the big dogs will find that these large dogs make incredible companions. From the tallest dog breeds like the Great Pyrenees to the sturdy and protective Anatolian Shepherd, each big dog breed offers distinct characteristics and a lot of love. While they require more care and attention, the rewards of having these magnificent animals as part of the family are immeasurable.

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