American Mastiff

The American Mastiff is a recently developed breed, and was only first recognized as purebred in 2000.  Developed by Fredericka Wagner of Flying W Farms, the American Mastiff is the result of crossing English Mastiffs with Anatolian Shepherd Dogs.  The goal of Wagner’s breeding was to develop a dog that was virtually identical to the English Mastiff but that drooled less and had fewer health problems.  The development of the American Mastiff has proven to be extremely controversial with English Mastiff breeders, who are generally strongly opposed to it.  The American Mastiff has been developed exclusively as a companion animal with good temperament always remaining central to breeding efforts.  The American Mastiff is not to be confused with the Panja American Mastiff, which is an entirely separate breed with a completely different history.

Breed Information

Breed Basics

Country of Origin: 
XX-Large 90-120 lb+
8 to 10 Years
Moderate Effort Required
Energy Level: 
Low Energy
Brushing Once a Week or Less
Protective Ability: 
Very Protective
Hypoallergenic Breed: 
Space Requirements: 
House with Yard
Compatibility With Other Pets: 
Generally Good With Other Dogs
Generally Good With Other Pets If Raised Together
May Have Issues With Other Dogs
Not Recommended For Homes With Small Animals
Litter Size: 
4-10 puppies


160-200 lbs, 32-36 inches
140-180 lbs, 28- 34 inches

The American Mastiff as a unique breed was first developed between 20 and 25 years ago in Piketon, Ohio.  However, it can trace its lineage back many centuries through both of the breeds used in its development.  The American Mastiff is primarily descended from the English Mastiff, often known simply as the Mastiff.  The origin of the Mastiff is perhaps the most disputed and contentious of all dog breeds, with theories as to when and where it was developed ranging from 10,000 to 1,000 years ago and from Ireland to Tibet.  What is known for sure about the breed is that it is one of the oldest English breeds, if not the oldest, and that it has been well-known in its homeland since the Dark Ages.  The origin of the word Mastiff is unclear.  Some claim that it comes from the French word Matin, meaning, “tame.”  Others claim that it comes from the ancient Anglo-Saxon word Masty, which means, “powerful.”

The English Mastiff was originally a ferocious beast of war, set loose to attack enemy soldiers.  In times of peace, these dogs were tasked with guarding the massive estates of the nobility.  These aggressive animals were kept chained to a stake during the day so that passerby could come at go at will and then released at night to prowl the ground.  Such chained Mastiffs were known as Bandogs or Bandogges.  Mastiffs were also pitted in fights to the death against chained bears, a brutal blood sport known as bear-baiting.  Improving military technology had made the Mastiff useless as military combatant by the end of the Renaissance, although it continued to be a very common guard dog.  Social mores meant that it was no longer desirable for Mastiffs to attack intruders; instead the dogs were bred and trained to physically hold wrong doers down until they could be released.  In 1835, bear-baiting was formally banned by parliament, and the last strongly aggressive tendencies were eliminated from the breed shortly thereafter.  The English Mastiff became a gentle, protective giant and began to be kept primarily as a companion animal, especially by butchers who had enough meet to feed them.  However, the great cost of feeding these dogs as well as the introduction of new giant breeds such as the Saint Bernard and the Newfoundland meant that Mastiff numbers began to plummet.  By the end of World War II, there was only one half-blooded Mastiff capable of reproducing left in England.  This dog was subsequently bred to the fewer than 20 Mastiffs remaining in the United States along with a female Dogue de Bordeaux to restore the breed’s population.  This is only the history of the Mastiff as it most relates to that of the American Mastiff, for more information on that breed please check on the article on the Mastiff.

Mastiffs have a longer history in what is now the United States than almost any other breed.  A Mastiff was brought to America by the Pilgrims on the Mayflower, and many other early colonists imported these dogs for protection as well.  After World War II, the Mastiff rapidly regained popularity in the United States, eventually becoming one of the 30 most popular breeds according to American Kennel Club (AKC) registration statistics.  Many breeders worked diligently to restore the breed to its former glory, while maintaining an excellent temperament.  Among these breeders was Fredericka Wagner, who operated Flying W Farms out of Piketon, Ohio.  Unfortunately, the Mastiff began to suffer from a number of problems.  As is the case with all large breeds, the Mastiff suffered from a number of health problems such as bloat, skeletal growth abnormalities, and a relatively short lifespan.  The dog also suffered from problems common to many brachycephalic (pushed-in face) dogs such as shortness of breath and heat intolerance.  Because the breed had become heavily inbred, other genetic issues were also quite common.  Additionally, the Mastiff is known to drool very heavily, often dangling saliva from the corners of its mouth.  Many fanciers became worried about the breed’s future, especially as inexperienced or dishonest breeders Mastiffs looking for a profit.

At some point in the late 1980’s or early 1990’s, Fredericka Wagner decided to attempt to develop a considerably healthier dog by crossing the English Mastiff with a breed she refers to as the Anatolian Mastiff, but which is much better known as the Anatolian Shepherd Dog.  Thought to be among the oldest breeds in the world, the Anatolian Shepherd Dog and its ancestors may have been present in what is now Eastern Turkey for more than 6,000 years.  Until the 1970’s when it was first introduced to the West, the Anatolian Shepherd Dog was bred essentially exclusively as a livestock guardian.  The dog spent its lives with flocks of sheep and goats, defending them from wolves, human thieves, and other predators.  Some claim that this breed is a member of the Mastiff family, but many others classify the breed differently.  What is clear is that this is one of the largest breeds of dogs in the world, with many breed members being comparable in height to the tallest Great Danes and Irish Wolfhounds.  Anatolian Shepherd Dogs have a reputation for being considerably more hard-tempered than English Mastiffs, as well as having a much stronger protective instinct.  However, they also have a reputation for being considerably healthier.  The few health studies that have been conducted indicate that the Anatolian Shepherd Dog lives an average of 2 to 5 years longer than most other giant breeds, as well as suffering from significantly lower rates of many health conditions.  This breed also has relatively tight lips and is not nearly as heavy a drooler as the English Mastiff.

Wagner’s goal was to keep the appearance and temperament of the English Mastiff but introduce the light drooling and good health of the Anatolian Shepherd Dog.  She worked on her breed throughout the 1990’s.  Anatolian Shepherd Dogs were only used in the earliest stages of the breeding program, with English Mastiffs and Mastiff/Anatolian Shepherd Dog crosses being used thereafter.  Calling her dogs American Mastiffs, Wagner eventually settled on a ratio that was approximately 1/8 Anatolian Shepherd Dog and 7/8 English Mastiff.  Wagner carefully regulated whom she allowed to breed the offspring of her dogs, only allowing a few approved breeders to continue her work.  By the end of the 1990’s, Wagner was sufficiently satisfied with the Flying W Farms dogs that she stopped any additional outcrosses and began breeding exclusively from her existing lines.

In 2000, the Continental Kennel Club (CKC) granted formal recognition to the American Mastiff, becoming the first canine organization to do so.  In 2002, the American Mastiff Breeder’s Council (AMBC) was formed by Fredericka Wagner and the small number of breeders she had allowed to breed the dogs.  The AMBC has remained very exclusive, with only 11 official breeders as of 2012.  The AMBC has worked to maintain the health, temperament, and conformation of the breed.  The group has as of yet decided against applying for recognition with larger kennel clubs such as the AKC and United Kennel Club (UKC).  Part of this is their personal preference to make the American Mastiff exclusively a companion breed, rather than a show dog.  It is felt that this will help maintain the breed’s good health.

There is another dog breed which is known as the American Mastiff, specifically the American Mastiff Panja or the Panja American Mastiff.  This breed was developed by crossing Mastiffs, Pit Bulls, Rottweilers, American Bulldogs, and numerous other supposedly “aggressive breeds” by drug dealers in Detroit and other cities to guard their homes and territories.  The American Mastiff Panja has no relationship to the American Mastiff other than partial Mastiff ancestry.  However, the similarities between the two names have caused confusion.  This is considered extremely undesirable by the AMBC as the American Mastiff Panja has earned a reputation for aggressiveness and dog bites.


The development of the American Mastiff has not been without extreme controversy, primarily from breeders of English Mastiffs.  English Mastiff fanciers are generally extremely critical of American Mastiffs, especially the breed’s name.  They feel that the introduction of Anatolian Shepherd Dog blood has seriously compromised the temperament and appearance of their breed.  They strongly object to the American Mastiff being called a Mastiff at all, and have repeatedly considered legal action to force a name change, seeming to prefer the terms American Anatolian Molosser or American Anatolian Mastiff/Molosser.  What seems to anger English Mastiff fanciers the most is that American Mastiffs are usually described as being virtually identical to the English Mastiff in appearance and temperament, but with less drool and greater health.  These claims are all strongly disputed by the Mastiff Club of American (MCOA), and many fanciers.  Disputes between the two groups often result in highly personal attacks.  Interestingly, these same fanciers have no problem with other use of the word Mastiff for other Mastiff breeds, such as the Bullmastiff, Spanish Mastiff, Neapolitan Mastiff, or Tibetan Mastiff claiming historical preference and that breeders of those dogs do not compare their breeds directly to the American Mastiff.  Some fanciers have gone so far as to claim that they have no issue with the American Mastiff Panja, only the American Mastiff.


Because the American Mastiff has been so recently developed it is still too early to tell exactly how effective Fredericka Wagner and other AMBC breeders have been in meeting their goals.  They claim that their dogs drool significantly less than English Mastiffs, have significantly fewer health problems, and have a longer average life expectancy.  Preliminary evidence may support these claims, but it is still too early to tell.  English Mastiff breeders strongly and loudly dispute them, either claiming that they are outright fraudulent or that any health improvements are the result of careful breeding practices and that English Mastiff breeders who take the same care and precautions get identical results.  However, these detractors don’t seem to point to any evidence to support their claims.


American Mastiff breeders also claim that their dogs are virtually identical in appearance and temperament to English Mastiffs, claims that are even more strongly disputed by English Mastiff fanciers.  English Mastiff fanciers believe that American Mastiffs exhibit poor physical features and conformation and are prone to more aggressive, shy, and unstable temperaments.  It will probably take several decades of records and studies before anything definitive can be said about the temperament of the American Mastiff, although it is almost impossible to get unbiased information as all parties in the debate have a definite side.  As for the appearance aspect, both sides probably have solid ground to stand on.  The American Mastiff does look similar enough to the English Mastiff that most casual fanciers would not notice a difference.  However, most casual fanciers can’t tell the difference between most dogs, and would probably mistake a Shih Tzu for a Lhasa Apso or a Belgian Mallinois for a German Shepherd.  In the opinion of this writer (who admittedly has a significant amount of experience with dogs), an American Mastiff would probably never be mistaken for a pure bred English Mastiff by a serious dog fancier, especially one with Mastiff experience.  American Mastiffs are generally leaner and less bulky than English Mastiffs, but the primary difference is in the face.  American Mastiffs tend to have significantly longer muzzles and fewer wrinkles than other English Mastiffs, along with a less intimidating appearance and lack of the traditional Mastiff expression.  These differences are not necessarily a bad thing, and are likely primarily responsible for any drool reduction and health improvements found in the American Mastiff compared to its English ancestor.


Despite the criticisms, the AMBC continues to operate just as it has in the past and does not appear to have any plans to change the breed’s name.  Because the club is so tightly regulated, breed numbers are growing slowly.  This is by design as the club wishes to prevent problems that have been caused by too rapid expansion of the populations of other breeds.  American Mastiffs are definitely growing in popularity and continue to find new fanciers.  Bred from creation as a companion dog, the future of the American Mastiff almost certainly will be as a pet.  Because of low numbers and a recent creation, the long term future of this breed remains uncertain, and it remains to be seen whether the American Mastiff will become established as a unique breed.




The American Mastiff is generally similar in appearance to the English Mastiff, but exhibits several notable differences primarily in the face.  Both the English Mastiff and the Anatolian Shepherd Dog from which it descends are among the world’s largest breeds, and the American Mastiff is no exception.  Breed standards call for males to stand between 32 to 36 inches tall at the shoulder and weigh between 160 and 200 pounds and for females to stand between 28 and 34 inches and weigh between 140 and 180 pounds.  However, individual dogs may be significantly smaller or larger than these standards.  The American Mastiff is a generally well-proportioned dog, but is slightly longer than it is tall.  American Mastiffs are powerfully constructed dogs with thick legs and deep chests.  However, this breed is generally slightly leaner than the English Mastiff, with a somewhat more athletic appearance.  Most breed members tend towards being more muscular and fit than bulky.  The tail of the American Mastiff is quite long and tapers strongly from base to tip.  When the dog is at rest, this tail is carried low with a curve.


The biggest difference between the American and English Mastiff’s in regards to their faces.  The American Mastiff would probably still be considered a brachycephalic (short-faced) breed, but not nearly to the extent of the English Mastiff.  The head of the American Mastiff is usually somewhat large in proportion to the size of the body, but only moderately so at best.  The muzzle of this breed is relatively short, but the length varies from dog to dog.  Some breed members have a muzzle that is noticeably shorter than the skull while others have a muzzle that is about equal to the length of the skull.  This breed has a wide and powerful muzzle, but one which is more similar to the width of a Great Dane’s than most English Mastiffs.  Scissors bits are preferred, but slight under bites are acceptable as long as no teeth show when the dog’s mouth is closed.  The lips of American Mastiffs are considerably tighter fitting than those of most English Mastiffs, but some individuals still have pronounced jowls.  The American Mastiff usually possesses a wrinkly face, but not an excessively wrinkled one with some individuals having almost no wrinkles at all.  The American Mastiff should have darkly-colored, widely-set eyes and proportionately-sized ears that drop down.


American Mastiffs almost always possess a short and dense coat, although rarely a longer-coated puppy will be born.  Known as Fluffies, these longer-coated dogs are not considered a fault in this breed.  There are only three accepted coat colors in American Mastiffs: fawn, apricot, and brindle.  All puppies are born dark and attain their adult coloration with time, although all colors may retain dark hairs without being faulted.  All American Mastiffs regardless of color must possess a black mask that covers most of their muzzles and extends to surround the eyes.  Additionally, most breed members have darker ears which are often black as well.  White markings may be found on the chest, feet, nose, and chin without penalty.  Occasionally an American Mastiff will be born with alternate coloration.  Such dogs do not meet breed standards and should not be bred but are otherwise no different from other American Mastiffs.




There is substantial disagreement as to the temperament of the American Mastiff, mainly between fanciers of that breed and English Mastiffs.  American Mastiff fanciers claim that their dogs are essentially identical in temperament to English Mastiffs, while English Mastiff fanciers usually claim that these dogs are more aggressive, suspicious, and unstable.  Unfortunately, neither side seems to be able to provide any unbiased evidence to support their claims.


Bred primarily as a companion dog, American Mastiffs are known to form very intense and close bonds with their families.  There is nothing that one of these dogs would rather do than be in the company of those it’s knows best, to whom it is unfailingly loyal.  Some American Mastiffs may become somewhat clingy, and many come to think that they are lapdogs, both of which can be problematic for a dog of this immense size.  In general, American Mastiffs that have been properly socialized are very tolerant and gentle with children, and many become extremely fond of them.  Owners need to be cautious when children are playing roughly that their dog’s protective instinct is not triggered.  Additionally, an American Mastiff puppy may not be the best housemate for very young children because they may bowl them over accidentally in an attempt to play.


American Mastiffs retain the strong protective instinct of both the English Mastiff and the Anatolian Shepherd Dog.  In general, this breed is wary of strangers although there is substantial disagreement as to how wary.  An American Mastiff is rarely timid or shy, but rather bold and protective.  With socialization, this breed is usually polite and cautiously friendly, although it is almost never eager or excited to meet new people.  Although they can be slow to warm up, most breed members will eventually accept new people such as a roommate or spouse, and treat them like any other family member.  It is absolutely imperative than owners of American Mastiffs properly socialize their dogs.  Even though this breed is definitely not inherently aggressive, if it is not taught how to properly distinguish between friend and foe it may think that everyone is a threat.  Even the minutest human aggression from a dog this large and powerful could be disastrous.  Not only is the American Mastiff very protective, but it is also territorial and alert making it an excellent watchdog.  An American Mastiff would make a highly effective guard dog.  Although this breed prefers to intimidate rather than take action, the mere presence of this mighty animal should be enough to deter almost any wrongdoer.  This breed would also be highly suited to personal protection as this is a dog that would go to any length to prevent physical harm from coming to a loved one.


There does not seem to be a consensus on the American Mastiff’s temperament with non-human animals.  As most breeders keep several of these dogs together, it apparently can live with other dogs in peace and harmony.  However, dog aggression, especially between males, is far from unheard of in both Anatolian Shepherd Dogs and English Mastiff, and should be carefully watched for.  Any inter-canine conflict involving an American Mastiff is extremely serious as this dog could seriously injure or kill essentially any other dog with virtually no effort.  Even greater caution should be taken with non-canine animals although this breed can be socialized to accept their presence and even protect them.


American Mastiffs are an intelligent breed that is capable of learning a great deal.  However, these dogs may present training difficulties for many owners.  Breed members have a tendency to be stubborn and rarely perform tasks they don’t want to do eagerly.  While this is not an overly obstinate breed, it is definitely one that would prefer to do its own thing than obey someone else’s wishes.  In particular, many of these dogs don’t like repeating simple tasks over and over.  Although this is not necessarily a breed that will constantly challenge its owner’s authority, it is definitely one that will recognize that no one is in control and take charge itself.  Owners of these dogs must be able to maintain a constant position of dominance.  In general, owners who want a dog that will learn manners, basic obedience, and perhaps a few simple tricks will probably be satisfied with an American Mastiff.  Those looking for an agility dog or obedience competitor would probably be better suited with a different breed.


Much like the English Mastiff, the American Mastiff tends to accept whatever activity level is provided by its family.  This dog could probably go for long hikes in the woods if provided the opportunity, so long as everything goes at a walking pace.  However, this breed will also be fine getting a long daily walk and adapts much better to apartment life than many smaller breeds.  As is the case with every breed, American Mastiffs that do not receive sufficient exercise and stimulation will probably develop behavioral problems such as destructiveness, excessive barking, and nervousness.  However, this is not a dog that will run an owner ragged meeting its needs, and properly exercised American Mastiffs are often very lazy and laid back in the home.  In fact, many fanciers describe their dogs as committed, “couch potatoes.”


The American Mastiff generally suffers from fewer issues than other Mastiffs, but this is still not a breed for the excessively clean or the easily embarrassed.  Although to a lesser extent than their English ancestors, American Mastiffs do drool, snore, make unusual noises, eat and drink very messily, and pass gas with great frequency and unbelievable potency.  Although this breed can make a calm and dignified pet, it certainly does not make a refined or dainty one.


Grooming Requirements: 


American Mastiffs do not need professional grooming; only a regular brushing is necessary, although the size of the dog can make this relatively time consuming.  This breed does shed, and many shed very heavily.  One of these dogs can easily cover an entire home and anything in it with hair.  This breed would be a very poor choice for those with dog hair issues of any kind, whether of a cleanliness or allergic nature.  Owners do have to clean the wrinkles on their dogs’ face at least every day, and preferably after every meal.  Otherwise, food, water, and other particles will become lodged in between the folds of skin causing irritations and infections.


Health Issues: 


The English Mastiff has long suffered from many health issues and a shortened life expectancy. The reduction of these problems was the primary reason behind the development of the American Mastiff.  There is substantial disagreement as to whether or not there has been a reduction in health problems, and if so to what extent.  There does not seem to have been any health studies conducted on American Mastiffs and in any case the breed is probably too young to make any definitive statements about anyways.  Virtually all sources claim that the American Mastiff is in substantially better health than most large breeds in general and English Mastiffs in particular, although it is unclear what evidence these claims are based on.   It is also claimed that these dogs usually have longer lives than most giant breeds, at around 8 to 11 years, but it is also unclear what these claims are based on.


Like all giant breeds, American Mastiffs suffer from skeletal growth abnormalities.  The bones of these dogs grow much faster than those of smaller breeds, often at an unnatural rate.  As a result, if an American Mastiff puppy is provided with an improper diet or exercise while it grows, its bones may develop improperly.  Improperly grown bones and joints can lead to pain, arthritis, nervous system problems, difficulty breathing, lameness, and in severe cases death.  Owners must carefully select their dog’s diet, as one that is either too rich or too poor in nutrition can be equally damaging.  It is best to select high quality large breed puppy formulas.  The exercise American Mastiff puppies get must also be carefully monitored as too much exercise or improper exercise can both cause problems.  For example, this breed should never be required to jump greater than a certain height.


Because skeletal and visual problems have been known to occur in this breed, it is highly advisable for owners to have their pets tested by both the Orthopedic Foundation for Animals (OFA) and the Canine Eye Registration Foundation (CERF).  The OFA and CERF perform genetic and other tests to identify potential health defects before they show up.  This is especially valuable in the detection of conditions that do not show up until the dog has reached an advanced age, making it especially important for anyone considering breeding their dog to have them tested to prevent the spread of potential genetic conditions to its offspring.  It is highly advisable to request that breeders show any OFA and CERF documentation that they have on a puppy or its parents, which essentially all reputable breeders will have.


Although there have not been any health surveys conducted on the American Mastiff, it is widely believed that this dog suffers from the same problems as the English Mastiff, although possibly at lower rates.  Some of the problems that may be of greatest concern to the American Mastiff include:



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