American Mastiff Dog Breed: Pictures, Colors, Bark, Characteristics, and Diet

We may earn a small commission when readers buy products through links on this page. It supports our team to keep posting great content. Learn more about this here.

The American Mastiffs are a new breed of a dog developed over 20 years ago.

They came from the line of Mastiffs, an ancient breed from England discovered more than 2000 years ago.

An American Mastiff standing outdoors
Meet Zeus, a beautiful American Mastiff – Image source

American Mastiffs are also called AM Mastiff, North American Mastiff, and AmMas. 

AM Mastiffs are large-sized colossal dogs with an average weight of 160 to 180 lbs (72.6 to 81.6 kg).

They do not differ much from their English Mastiff ancestors in terms of size.

The females weigh about 140 to 180 lbs (63.5 to 81.6 kg) compared to males weighing between 160 to 200 lbs (72.6 to 90.7 kg). 

When fully grown, male AM Mastiffs are a bit taller at 32 to 36 inches (81.3 to 91.4 cm) in height, whereas females are between 28 to 34 inches (71.1 to 86.4 cm)

Characterized as calm, loyal, quiet, and courageous dogs, American Mastiffs are protective and devoted to their loved ones.

As much as possible, they like to bond with their family. However, they may not be overly friendly with everyone.

They are not aggressive, but they have a bite force that is as strong as 550 PSI.

American Mastiffs have a comprehensive rectangular head with dropped ears that are v-shaped.

Their short, straight, and dense coats come in apricot, fawn, and brindle colors. They also have a medium-sized muzzle and a black nose. 

AM Mastiff’s eye color possibilities are hazel-brown, dark-brown, and amber.

Unlike their English Mastiffs ancestors, they have less drooling tendencies and generally drier mouths.

American Mastiffs have a lifespan of 10 to 12 years, which is relatively short compared to other dogs but is typical in large breeds.

For optimal health, 0.5 to 1 hour of exercise per day helps.

These giant dogs have a big appetite, as evident by their size. It will be good to give them 6 to 8 cups of food, which is specifically created for large breed dogs, per day.

American Mastiffs are highly recommended to eat high protein foods with the right carbs, fatty acids, vitamins, and minerals

American Mastiffs bark in an unknown amount because they are typically quiet unless their family is threatened. They also bite like other dogs, but they are not dangerous.

They are cautious if there are strangers, but they will become friendly and comfortable once they get familiar with them. 

There’s no record as to the speed of running of American Mastiffs. It can be attributed to the fact that their bodies do not need enormous physical work.

Activities such as running and cycling are not for their body type.

If you want to learn more about American Mastiffs, continue reading about these gentle giants.

What is an American Mastiff?

A close-up image of an American Mastiff
Meet Duke, a brindle American Mastiff – Image source

The American Mastiff is a large-sized dog that is relatively a new breed. Despite their vast size, they are known to be naturally calm and mellow.

They are not aggressive but very protective of their families, making them a good watchdog.

Initially, they came from the line of Mastiffs, an ancient old war dog used to attack enemy soldiers.

AM Mastiffs are similar to the Mastiffs breeds when it comes to physical characteristics and temperament.

This canine came into existence to have a healthier version of the American Mastiffs.

Why are They Called American Mastiff?

There is no explicit and available information about why they are named American Mastiffs. One thing can be that they came from the breed of ancient old Mastiffs.

Basically, they are products of English Mastiffs and Anatolian Shepherds

Where Did the American Mastiff Come From?

American Mastiff came from Piketon, Ohio.

Their ancestors are English Mastiffs, an old breed of dog used to protect the homestead and wealthy families, including their properties.

Colonists who owned Mastiffs brought these dogs to America. English Mastiffs have been crossbred with the Anatolian Shepherd, bringing American Mastiffs to life.

When Did the American Mastiff Originate?

An American Mastiff sitting indoors
Meet Tuukka, a loyal American Mastiff – Image source

English Mastiffs came to the United States during the colonial era. Unfortunately, breeders encountered breeding issues that caused the dogs’ health problems. 

Later on, an American named Fredericka Wagner, a breeder, and owner of Flying W Farms, started developing English Mastiffs with Anatolian Shepherds.

They were carefully regulated and bred, which later developed as a new breed of Mastiffs.

English Mastiffs, large and powerful dogs, combined with Anatolian Shepherds, a loyal and fierce livestock guardian, resulted in American Mastiffs, giant dogs with leaner physiques and tight line lips.

In 2000, the Continental Kennel Club recognized the new breed as purebred. 

How Many American Mastiffs are there in the World?

There is no actual record of how many American Mastiffs are there worldwide.

The absence of documents might be because it is a young breed discovered more than two decades ago. 

The American Kennel Club does not recognize American Mastiffs. Hence, they are not part of the organization’s official list of registered dog breeds.

What is certain is it’s not as many as their mastiff parent breeds.

Also, it’s important to note that the Continental Kennel Club accepts only the offspring of two purebreds and registered American Mastiffs as purebred AMs.

What are the Characteristics of an American Mastiff?

An American Mastiff wearing a scarf
Tuukka, the American Mastiff, happily wears his scarf – Image source

American Mastiffs are a strong, powerful, reliable, and robust breed. They are great acquaintances at home.

Here, we list some of the characteristics of an American Mastiff:

  • Calm: These dogs are gentle and, as mentioned earlier, loving. Because of their large size, American Mastiffs might establish an aggressive look to strangers. They might get confused for being hostile. Contrary to what they may look like, the truth is that American Mastiffs have a calm temperament. 
  • Quiet: American Mastiffs like to be in a peaceful environment. These dogs don’t bark a lot unless threatened. They are very kind and serve as a great companion.
  • Courageous: These giants are a constantly devoted breed of dogs. American Mastiffs are alert and dignified, especially in the presence of danger. They will protect their family and loved ones at all costs
  • Loyal: They are known to be faithful to their family. American Mastiffs are warm and affectionate. They are playful amongst children too. 
  • Protective: American Mastiffs are known as defensive. They are neither vicious nor uncontrolled. These dogs will not hesitate to fight for their family in the presence of harm. 

Take a look at how we rated the behavioral characteristics of the American Mastiff:

American Mastiff Characteristics Rating
Relation with Family 5
Good with Children 4
Friendly with Strangers 3
Friendly with Other Dogs 4
Easy to Train 2
Energy Level 3
Barking Level 2
Mental Stimulation Needs 3

What Does an American Mastiff Look Like?

An American Mastiff standing straight
Zeus, the American Mastiff, flaunts his strong physique – Image source

American Mastiffs have a short coat which is also dense: their coats are straight, smooth, and come in different colors. They have long, solid, and powerful legs.

American Mastiff’s body is leaner than their English ancestors, with a broad, massive, and heavy rectangular-shaped head that suits their body. 

They also have expressive eyes and dropped ears. The American Mastiff has a black nose, a medium-sized muzzle, and a strong jaw.

And, unlike their English Mastiff predecessor, this breed has a drier mouth that drools less. 

Check out this video to give you an idea of what American Mastiffs look like:

How big is the American Mastiff?

American Mastiffs’ height and weight may vary per sex.

Males, when fully grown, are between 32 to 36 inches (81.3 to 91.4 cm) in height which is a bit taller than females, who are between 28 to 34 inches (71.1 to 86.4 cm) tall. 

These dogs have an average weight of 160 to 180 lbs (72.6 to 81.690 kg).

The females weigh around  140 to 180 lbs (63.5 to 81.6 kg), while the males are 160 to 200 lbs (72.6 to 90.7 kg).

You can find more detailed physical structures of the American Mastiffs below:

American Mastiff
Physical Features
Male Female
Height  32 to 36 inches
(81.3 to 91.4 cm)
28 to 34 inches
(71.1 to 86.4 cm) 
Weight 160 to 200 lbs
(72.6 to 90.7 kg)
140 to 180 lbs
(63.5 to 81.6 kg)

How long does an American Mastiff grow?

It takes three years before an American Mastiff puppy will be grown up and reach maturity. This is due to the fact that they are a giant breed of dogs.

The length of time may alter on a case-to-case basis, but they will attain their 80% size in around 12 to 18 months

What is the average weight of American Mastiff dogs?

American Mastiffs’ average weight may vary depending on their age, lifestyle, and gender. On average, American Mastiffs weigh 160 to 180 lbs (72.6 to 81.690 kg).

Females weighed 140 to 180 lbs (63.5 to 81.6 kg) on average. In contrast, males have an average weight of 160 to 200 lbs (72.6 to 90.7 kg).

What is the Average Life Expectancy of American Mastiffs?

Generally, American Mastiffs live up to 10 to 12 years on average. Their life expectancy is relatively short, which is usually the case with large and giant breeds.

While the American Mastiffs are generally a healthy breed, they are prone to conditions such as eye and skin problems, joint dysplasia, foreleg lameness, and hyperthyroidism, among others. 

What Coat Type Do American Mastiffs Have?

An American Mastiff lying on the ground
Meet Henry, an American Mastiff with a gorgeous coat – Image source

American Mastiffs have a double-layered, straight, relatively dense coat.

It is short, which makes it easier to groom them. Once a week, brushing will eventually suffice unless they shred a lot.

What is the American Mastiffs dog’s coat like?

American Mastiff’s coat is smooth. The dense undercoat lies close to the skin, while the straight outer coat is coarse.

The good thing is that it is not spiky, unlike other breeds with short coats. They have the same coat as the one that you would expect in a Mastiff.

How long is the American Mastiff’s coat?

The American Mastiff’s coat is short in length. It’s the same length from their head down to their legs and muzzle.

It’s a good thing at some point since they aren’t high maintenance.

However, it has consequences, such that it will not protect them during cold weather, unlike breeds with double-layered, long, and highly dense coats.

What’s the coat density of the American Mastiff?

American Mastiff’s coats are slightly above normal but not highly dense.

The density of the coats merely compensates for their sizes. Their coat does not look fluffy but uniform across body parts. Instead, it makes them look sharp.

Do American Mastiffs shed much?

American Mastiffs shed to a moderate degree. But, because of their short and straight coat, it’s a lot easier to maintain their appearance.

Once a week, coat brushing with a firm bristle will do. However, it still depends on whether you see it as needed.

In the shedding season, which happens once or twice yearly, brushing twice weekly will be best.

Can American Mastiffs Live in Hot Weather?

While the American Mastiffs have short, double coats, they prefer moderate to warm temperatures.

Hence, you should keep them away from places with extreme weather. 

There is no record of the definite weather that an American Mastiff should live in.

Still, a moderate atmosphere of 45 to 65 degrees Fahrenheit (4 to 18 degrees Celsius) is advisable for large and giant dog breeds.

What Colors Are American Mastiffs?

An American Mastiff dog with a brindle coat
Meet Turbo, an American Mastiff with a brindle coat – Image source

American Mastiffs come in different colors. They can be apricot, fawn, and brindle with white markings.

The most popular color of American Mastiff is fawn which may range from soft yellowish-brown to tan color.

What Marking Do American Mastiffs Have?

American Mastiffs have black masks. Some also have patches on their chest, nose, chin, and feet. These are white markings.

The background color of brindled American Mastiffs can be fawn or apricot and will be covered by dark stripes markings.

Are American Mastiffs Good Family Dogs?

An American Mastiff looking at its owner
Otis, an American Mastiff, relaxes by the fire with his hooman – Image source

American Mastiffs are great family dogs. Calm, gentle, and loyal are their most common attributes.

They like to bond with their family and might even be considered clingy.

They are very patient with children and love to get along, making American Mastiffs great family companions and watchdogs

You can find below the temperament American Mastiffs have: 

American Mastiff’s Temperament Rating
Adaptability 3
Friendliness 4
Mouthiness 4
Playfulness 3
Family-Oriented 5
Stranger Tolerance 3

Are American Mastiffs good with other dogs?

As long as you teach and expose American Mastiffs to other dogs regularly, they can get along since they have a natural pack instinct.

The key here is to socialize even at a young age since this breed can be lazy and stubborn, especially with age. 

American Mastiffs also know how to treat other household pets so long as they properly get to know each other.

Despite this, they still prefer to hang out with their families.

Are American Mastiffs friendly with other people?

Generally, American Mastiffs are naturally cautious with other people. They examine other people’s actions towards them and their families.

As time goes by and when the American Mastiff becomes familiar with those people, they will be friendly, warm, and kind. 

Can American Mastiff dogs get along with strangers?

American Mastiffs can get along with strangers when they become used to their presence.

At first, they are suspicious and curious about whether the stranger may be trusted, which is only a natural reaction for dogs.

They possessed this protective demeanor. When trust is already established, American Mastiff will start to be cordial.

How do American Mastiffs get along with young children?

American Mastiffs love children in their families.

These giants are calm and easy to play with since they do not get wild or overstimulated. They get along with children and like to bond with them. 

However, adults must remain vigilant and not leave toddlers unsupervised as these American Mastiffs are large breeds of dogs and might unintentionally injure small kids.

Can American Mastiffs Adapt Easily?

An American Mastiff relaxing
Tuukka, the American Mastiff, loves the lifestyle he leads – Image source

American Mastiffs cope with their environment. As long as their loving families accompany them, they thrive in changes.

They can usually adapt to different lifestyles, given that they are assisted by experienced dog owners that can perfectly handle a massive dog.

Are American Mastiff Dogs Aggressive?

These dogs aren’t aggressive as opposed to their prominent imposing appearance.

They are gentle except if danger poses or they are, and their families are on the verge of threat.

They can easily sense whether a person imposes a threat and requires an immediate defense. It is only a rare instance when they can get aggressive.

Are American Mastiff Dogs Dangerous?

American Mastiffs are not dangerous. The only time you will see them bold is when in danger or when there is a provocation.

They possess an alert, dignified, and defensive trait, making them reliable guard dogs. 

However, like most large dogs such as Cane Corso and Rottweiler, American Mastiffs can be dangerous when not appropriately trained, given their enormous size and strong bite force.

Do American Mastiff Dogs Bite?

An American Mastiff sticking its tongue out
Bruce, an American Mastiff, wants to say he does not bite – Image source

Generally, AM Mastiff dogs have a moderate chance of biting. The primary considerations which force them to bite are pain, danger, provocation, and excitement. 

American Mastiffs, as large-sized dogs, have forceful a bite. They have a pretty strong bite which is 550 PSI.

Therefore, although they aren’t naturally aggressive, these giants should be taught well to get along with other people and pets.

Otherwise, their bite might be pretty dangerous.

Are American Mastiff Dogs Protective?

Indeed, American Mastiffs are a protective breed of dogs. They are consistently keen observers aimed at safeguarding their families and properties.

American Mastiffs won’t hesitate to take a stand against others in the existence of danger.

They are not just protective but also territorial, making them an excellent watchdog.

Are American Mastiff Dogs Affectionate?

This breed of Mastiffs is very affectionate. They would love to spend time and hang around with people.

Often characterized as loving, loyal, calm, dignified, and courageous, American Mastiffs are a perfect companion at home. 

American Mastiffs are recommendable for the elderly because of their affectionate character, but at the same time, they are inherently strong and protective.

They are also suitable for couples and even for families with children as long as they are perfectly capable of managing a giant breed. 

Are American Mastiff Dogs Easy to Train?

An American Mastiff puppy biting on a toy
Turbo, as an American Mastiff pup, was easy to train – Image source

Most American Mastiffs have average intelligence levels, making them trainable.

However, they have a stubborn and willful side, difficult to train, especially with repetitive training for long hours. Plus, they get bored quickly.

It is advisable to train American Mastiff in short periods. And since they quickly respond to positive reinforcement, it would be great to reward them with treats.

American Mastiffs should start to train early to ensure they will be well adjusted. 

Can American Mastiff dogs be used as working dogs?

Historically, the ancestors of American Mastiffs, English Mastiffs, were the working dogs who fought during war eras.

In comparison, American Mastiffs can be considered working dogs.

However, they aren’t trained as service, therapy, or even detection dogs but rather excellent watchdogs. They can also excel in cart pulling or drafting. 

Do American Mastiff Dogs Bark a Lot?

An American Mastiff puppy looking up
Turbo, as a 5-month-old American Mastiff pup, did not bark a lot – Image source

American Mastiffs do not bark a lot. They are suitable for you if you are looking for a quiet breed of dog that serves as a companion at home.

Their barking levels are low, and it is rare to hear them bark without something foreign to them. 

How does an American Mastiff bark?

American Mastiffs bark in a low to average tone. American Mastiffs don’t bark unless there is a reason to do so.

These dogs bark for reasons such as but not limited to the presence of threat, boredom, separation anxiety, or excitement.

Do American Mastiffs Have High Energy Levels?

Typically, American Mastiffs have only moderate energy levels, so they aren’t required to exercise frequently.

They aren’t used to running and cycling because their massive bodies are not designed for continuous fast-paced activities. 

Jumping heights, long walks, and running on stairs are not recommended for them.

Although they are muscular, American Mastiffs are low maintenance for physical activities.

The recommended duration of activity for American Mastiffs is 30 to 60 minutes per day.

Are American Mastiffs Active?

An American Mastiff puppy lying down on a wooden floor
Duke, as an American Mastiff pup, was easy to please – Image source

American Mastiffs are low to moderately active breed of dogs. On a scale of 1 to 5, they only have an exercise requirement of 2 out of 5.

They need one or two daily walks, which will be enough to keep them happy. 

Are American Mastiffs Playful?

American Mastiffs are fairly playful dogs. Just like other dogs, they even bark in excitement at playing. However, their attitude toward play is on the light and calm side.

It would be good to give these dogs interactive toys if they should be left alone because they enjoy playing with toys and respond to their mouthiness.

Does the American Mastiff Drool a Lot?

One of the distinctive factors of American Mastiffs compared to their English Mastiff ancestors is that they drool less than their parent dog.

American Mastiffs have a drier mouth. However, this does not mean that they don’t drool at all. 

What Does the Family Life of American Mastiff Dogs Like?

An American Mastiff lying down close to its owner
Bruce, the American Mastiff, gets clingy with his hooman – Image source

The top characteristics of American Mastiff are calmness, loyalty, and love. It means American Mastiffs are sensitive to their families and require time and attention.

They would happily bond with adults, kids, and older people.

What is the Average Cost of an American Mastiff Puppy?

American Mastiff puppies can cost between $1,000 to $1,500 on average. However, it may still be more expensive, depending on the breeder.

In contrast, rescuing an American Mastiff may cost around $300 for necessary fees

What Kind of Food Should American Mastiffs Eat?

An American Mastiff looking at food
Zeus, the American Mastiff, patiently waits for his food – Image source

High protein animal meat sources are excellent for giant dogs like American Mastiffs.

It would be great to give them high-quality food with moderate fat content and low-calorie levels. 

Yet, their diet should still be regulated since adult American Mastiffs can suffer from being overweight, which can cause illnesses and complications as they age.

Make sure to feed them 6 to 8 cups per day, depending on their lifestyle.

What are the Best Dog Foods for American Mastiffs?

Dry, raw, and wet dog food is suitable for American Mastiffs. Be mindful to choose one mainly for a large breed of dog.

More importantly, it should be good-quality, healthy, and affordable.

For American Mastiff puppies, we recommend the following:

Meanwhile, here are the best dog food products for full-grown American Mastiffs:

What Other Dog Breeds Look Like the American Mastiff?

A Boerboel standing outdoors
Meet Hulk, a Boerboel – Image source

English Mastiffs, their parent dog, look like the American Mastiffs.

They inherited their physical traits on Mastiff’s line as to size and appearance from their Anatolian Shepherd parent.

As to other dogs, here are some that resemble American Mastiffs:

Final Thoughts: Should you Buy or Rescue an American Mastiff?

We would love an attentive companion at home, especially those who are calm, loyal, quiet, and courageous. An American Mastiff possesses all those traits.

They are devoted and dignified to families. Their large size, territorial, and protective character make an American Mastiff an excellent watchdog.

Buying or adopting an American Mastiff also means you are willing to spend time and attention on them.

Although these breeds are typically quiet, they enjoy bonding with their families. 

American Mastiffs would be pleased to hang out and play, but they should not be exposed to too voluminous physical activity.

Their massive bodies are not suitable for continuous fast-paced running, cycling, and jumping, but they would love to walk with you once to twice daily. 

So long as you take care of them properly, these gentle giants will be there to protect you.

Do you have an American Mastiff dog? What do you love most about them? Let us know in the comments!

Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.