A working breed native to England, the Bullmastiff was originally bred by game wardens to help them in their fight against poachers.  As its name suggests, the Bullmastiff was created by crossing English Bulldogs and English Mastiffs, and the modern Bullmastiff is highly representative of the 19th century versions of both breeds.  Originally a fierce protector, the modern Bullmastiff is known more for its loyalty and devotion, as well as for being surprisingly docile and gentle despite its great size.  Because of the breed’s surprisingly low exercise requirements, many Bullmastiffs make excellent apartment dogs.


Breed Information

Breed Basics

Country of Origin: 
XX-Large 90-120 lb+
8 to 10 Years
Moderate Effort Required
Energy Level: 
Medium Energy
Brushing Once a Week or Less
Protective Ability: 
Very Protective
Hypoallergenic Breed: 
Space Requirements: 
House with Yard
Compatibility With Other Pets: 
Known To Be Dog Aggressive
May Injure or Kill Other Animals
Not Recommended For Homes With Existing Dogs
Not Recommended For Homes With Small Animals
Litter Size: 
6-10 puppies
Keepers Night Dog, Poachers Beware; Common Misspelling: 'Bulmastif'


110-130 lbs, 25-27 inches
100-120lbs, 24 and 26 inches

Kennel Clubs and Recognition

American Kennel Club: 
ANKC (Australian National Kennel Council): 
CKC(Canadian Kennel Club): 
FCI (Federation Cynologique Internationale): 
KC (The Kennel Club): 
NZKC (New Zealand Kennel Club): 
UKC (United Kennel Club): 


The Bullmastiff is a relatively young breed, although its primary ancestors are quite old.  The Bullmastiff is the result of crosses between the English Mastiff and the Old English Bulldog.  These crosses began to be initiated in an organized way in the 1860’s, although it is possible that these two breeds had been mixed for centuries before that.  Along with both the Mastiff and the Bulldog, the Bullmastiff is a member of a group known as Molossers, or alternately the Alaunts, Mastiffs, or Dogues.  This group is quite ancient, and much of the information surrounding its origin is disputed.  The word Mastiff itself is even debated.  Some scholars believe it is the modern form of the ancient Anglo-Saxon word “masty,” which means powerful.  Others believe it is the Anglicized version of the old French word “mastin,” which loosely translates to tame.  Regardless of where the modern name came from, it is undeniable that Mastiff-type dogs have been present in the British Isles for many centuries.


There is also controversy surrounding the mystery as to how the first Mastiff arrived on British soil. There are at least four viable possibilities.  Based on surviving breeds across Europe and Asia, it is believed that the earliest farmers in the Middle East developed a large, livestock guardian breed similar to the modern day Great Pyrenees or Akbash Dog.  These dogs spread across Europe with agriculture.  Such dogs (now known as Lupomolossoids) may have arrived in Britain thousands of years ago to defend sheep and goats from predation from such creatures as wolves.  Although not true Mastiffs, the ancient Britons could have selectively bred these dogs until they became Mastiffs.  Depictions on ancient Mesopotamian and Egyptian artwork show dogs very similar to the modern Mastiff between 5,000 and 7,000 years ago.  These drawings typically show these dogs in a combat role, although some also depict them guarding livestock.  This region was also home to a people known as the Phoenicians, who were famous across the Mediterranean as traders.  Many stories claim that Phoenician traders brought the first Mastiff to England on a voyage of trade and discovery.  However, this story is impossible to verify and is unlikely for many reasons, not the least of which is that it would have been very hard to transport such a large dog such a long distance by sea in ancient vessels.  In truth, the validity of either of these theories is difficult to assess, as almost no records exist of pre-Roman Britain.  What is known for sure is that some type of massive guardian dog was present in Britain prior to Roman conquest.


When the Romans first invaded what is now England and Wales, they had to fight stiff resistance from the native Celtic tribes.  These tribes employed a giant war dog which the Roman army was much impressed by.  The Romans called this dog the ‘Pugnaces Britanniae’.  Most scholars believe that this dog was a Mastiff, but others believe it was more similar to the Irish Wolfhound.  Prior to the conquest of Britain, the Roman army used a war dog known as the Molossus, which had been developed by the tribes of Epirus (which consisted of parts of modern-day Albania, Greece, and Montenegro).  Some scholars insist that the Molossus was a Mastiff, while others claim that it was a smaller, more general purpose dog.  Either way, the Molossus was almost certainly crossed with the Pugnaces Britanniae in Britain and across the Roman Empire which likely resulted in a dog very similar to the modern Mastiff, although probably not as short-faced. 


With the eventual fall of Rome, a number of barbarian tribes would ravage the Western Empire.  One of these tribes was the Alans, a people native to the Caucasus Mountains.  The Alans were primarily known for their ferocious war dogs, which were known as Alaunts after their owners.  The Alaunt was almost certainly a breed of Owtcharka (giant livestock guardian breeds native to the Caucasus) and many scholars claim that all Mastiff-type dogs are primarily descended from the Alaunt, and that it was with this breed that the brachycephalic (pushed-in) face originated.  It is possible that Alaunt blood was added to existing British dog blood during the chaos following the fall of Rome or when the Normans conquered Britain, bringing their own Mastiff-type dogs.


However it was that the British Mastiff developed, it evolved to become primarily a protector of property.  It was customary for these massive dogs to be kept on a chain, and they became known as ‘Bandogges’ (a 13th or 14th century Middle English term referring to a mastiff type dog bound by a chain during the daytime and released at night to guard against intruders).  These original Mastiffs were not bred only for extreme size and power, but also for ferocity and protective instincts.  Eventually a sport developed known as bear-baiting, which involved a chained bear fighting several Mastiffs.  The end result was always the death of the bear, but a typical match usually resulted in the death of several dogs as well.  Neither bear baiting nor property protection required the Mastiff to be especially athletic, and the breed became quite slow.  In 1835, bear baiting was prohibited by Parliament, and the hyper aggressive Mastiff of the time unable to be used for this purpose soon found its employment opportunities dwindling.  Social mores were also changing, especially in the ever-growing cities, and Mastiff breeders no longer wanted a dog that would aggressively attack an intruder.  They instead geared their efforts toward creating dogs that would pin someone down and hold them until their owners could come and judge the situation for themselves.  The result was that by the 1860’s, the Mastiff had become much less ferocious than its ancestors.


Although not as viscous as its predecessors, the 19th century Mastiff would evolve through crosses with the Bulldog to find employment with British Game wardens defending the wildlife parks and private hunting reserves of the wealthy from poachers.  These poachers were different from modern day poachers who kill endangered animals for some valuable part of their hides.  Rather, 19th Century British poachers were mainly looking for food.  Their preferred quarry was rabbits and deer.  While many poachers were armed with guns, their primary hunting method was the use of either Longdogs (crosses between two breeds of sighthound) or Lurchers (crosses between a sighthound and another type of dog) to chase after and subdue prey.  Because the penalty for poaching was quite high, poachers were often unafraid to kill or seriously injure a warden to avoid capture.  Game wardens needed a dog that was capable of not only protecting them, but also of running down and subduing the poacher.  Although not as common, it was sometimes also necessary to subdue the poacher’s dog as well.  This was often times more dangerous than dealing with the poacher, as nearly any dog mixed with Irish Wolfhound or Scottish Deerhound is likely to be very large and intimidating.  The game wardens needed a dog that was not only large and powerful, but also athletic enough to run down a man.  Game wardens preferred a dog that would subdue without attacking in the same way as a Mastiff, but needed the dog to be able to attack both man and beast if necessary.  Game wardens initially attempted to use Mastiffs for their purposes and although these dogs proved quite capable of subduing a poacher when they caught one, they were usually not fast enough to do so.  In later decades, most Mastiffs would also lack the aggression to fight a determined or armed poacher.  A new breed would have to be found.


For many centuries, bull baiting was one of the most popular sports in England.  Bull baiting was very similar to bear baiting except the combat involved bulls instead of bears and Bulldogs instead of Mastiffs.  The ancestry of the Bulldog itself is a mystery, but they are likely descended from small Mastiffs crossed with other dogs or perhaps Alaunt-type dogs imported from Spain.  The Bulldog used for this purpose was very different than its modern descendant.  Such dogs were much lighter in build, especially around the head.  These dogs were very similar to certain lines of American Bulldog, extremely muscular without being overly thick, as well as being somewhat taller than modern English Bulldogs.  Bulldogs were famed across the world for their incredible fearlessness and tenacity, and would attack any opponent without stopping regardless of the odds against them or the severity of their injuries.


Like bear baiting, bull baiting was banned in England in 1835.  However, Bulldogs were much smaller and easier to keep than Mastiffs, and bulls were much easier to acquire than bears.  Bull baiting enthusiasts were thus able to continue their activity illegally for many decades, and bred Bulldogs that remained just as fierce as their ancestors.  This ferocity may have actually increased as dog fighting rose in popularity as an underground sport, likely to fill the absence left by the elimination of bear and bull baiting.  As the Mastiff became less and less well-suited for their needs, Game wardens attempted to use Bulldogs for their purposes but found them ill-suited to the task.  Bulldogs simply proved too aggressive.  They had a tendency to savagely attack the poacher rather than simply subdue him.  Bulldogs also were just as likely to ignore the game warden's commands and go after the poacher’s dog or another creature than to pursue the poacher himself.  Perhaps most damningly, Bulldogs would often attack the game the warden they were tasked with protecting.


It may seem strange that the game wardens did not simply use a breed such as a German Shepherd or Doberman Pinscher to aid them.  However, in the 1860’s these breeds had not yet been fully developed and in any case a foreign dog would likely have been too expensive for the game wardens to acquire.  Game wardens began breeding Mastiffs and Bulldogs together until they got the animal they most desired.  It is very likely that such crosses had been made for centuries.  However, during the mid-19th Century, a major craze for breed standardization and dog shows was occurring across the United Kingdom.  The game wardens likely got caught up in this craze and wanted to develop their own distinct breed.  The game wardens found that the ideal proportion for their purpose was 60% Mastiff and 40% Bulldog.  This mixture resulted in a dog with the great size and power of a Mastiff along with its more reserved attack, yet still retained the athleticism and ferocity of the Bulldog.  Breeders also deliberately selected for the ability to trail a poacher quietly for a lengthy period and then have a sudden burst of speed to subdue him.  Game wardens greatly favored brindle dogs, as it gave them extra camouflage at night.  The game wardens called their new breed the Bullmastiff in much the same way that Bulldog/terrier crosses became known as Bull Terriers. Although it would take several decades for the Bullmastiff to be standardized, this process was complete by the early 20th Century.


In spite of the fact that the Bullmastiff was originally developed as a utilitarian game warden’s dog, it would quickly find many other fanciers.  The breed was smaller and less expensive and onerous to keep than the Mastiff, and could thus be kept by a wider number of admirers; as well the dog was perfectly suited for the role of urbanite guardian.  The same traits that made the breed popular with game wardens (inclination to subdue rather than attack but a willingness to do so if necessary) also made it desirable for many property owners.  Many of the Bullmastiff’s new admirers were avid dog show enthusiasts who sought to get the breed formally recognized.  The fawn pattern of the Mastiff began to be favored over the game warden’s brindle.  In 1924, the Bullmastiff was formally recognized by the Kennel Club.


Since the early 1900’s, a number of Bullmastiffs had been imported to the United States, a number which increased after the dog was formally recognized by the Kennel Club.  In 1934, the American Kennel Club (AKC) granted full recognition to the breed as a member of the Working Group.  World War II saw meat rationing across the United Kingdom and breed numbers fell sharply.  However, because this breed had become more common than the English Mastiff prior to the War and it did not face the near-extinction suffered by that breed.  In fact, there are persistent rumors that the Bullmastiff was used by English Mastiff breeders to restore that breed postwar.  The Bullmastiff was also well-established enough in the United States and Canada at that time that imports were used to help replenish breeding stock.  In 1948, the United Kennel Club (UKC) also granted full recognition to the Bullmastiff.  In the latter half of the 20th Century, the Bullmastiff Association of America was founded to promote and protect the breed, and eventually became the official parent club of the Bullmastiff with the AKC.


As the 20th Century wore on, the breed’s initial purpose as a game warden’s dog was lost to time and other breeds.  However, the Bullmastiff would become a trusted guard dog and a devoted companion animal.  The vast majority of modern Bullmastiffs serve at least one of these functions, and many serve both.  In fact, the Diamond Society of South Africa still uses the breed to guard their diamonds.  The Bullmastiff can make an excellent pet and protector for the right family, but the size and nature of this breed mean that it is definitely not suitable to life in all homes.  Because of this, the Bullmastiff’s popularity will likely never be as high as some breeds.  This is actually preferred by many fanciers who fear that the breed’s quality could be lost in the hands of irresponsible breeders, and in any case the Bullmastiff has a very secure and sizable population in the United States.  In recent years, both giant breeds and protective breeds have become more popular and the Bullmastiff has seen some growth in popularity.  In 2010, the breed ranked 42nd out of 167 total breeds in terms of AKC registrations, a number which is quite high for a breed with the care requirements of this one.




The Bullmastiff is very similar in appearance to other members of the Mastiff family, especially the English Mastiff.  This is a large, powerful, brachycephalic breed.  Although not quite as large as its ancestor, the Bullmastiff is a very large dog.  A typical male Bullmastiff stands between 25 and 27 inches tall at the shoulder and weighs between 110 and 130 pounds.  The smaller females normally stand between 24 and 26 inches tall at the shoulder and weigh between 100 and 120 pounds.  While this breed is not exceptionally tall, it is exceptionally thick.  Bullmastiffs have a very wide and deep chest, as well as having an incredible musculature and very thick bones.  In particular, Bullmastiffs have very thick legs.  If the English Bulldog is not the tank of the canine world, the Bullmastiff certainly is.  While the Bullmastiff is thick, it should appear powerfully so, not obese.  The body of a Bullmastiff is roughly square in proportion, but the breed is slightly longer than it is tall.  This tail of this breed is quite long, and very thick at the base.  The tail should taper to a point and be carried either straight or slightly curved.


The head of a Bullmastiff sits at the end of an incredibly thick and powerful neck.  The head itself is very large and shaped like a cube, being almost as wide and deep as it is long.  The muzzle of a Bullmastiff is very short and pushed in, and often points slightly upwards.  The extent to which the Bullmastiff’s face is pushed in is intermediate between the longer face of a Mastiff and the shorter face of a Bulldog.  The wide muzzle of this dog gives it the widest possible area to bite down on.  Many Bullmastiffs have an undershot bite, but this is not always the case.  The face of this breed is very wrinkly, although most have large wrinkles rather than many smaller ones.  Both the muzzle and the face are covered in wrinkles, and the breed has seemingly extra skin over most of its body as well.  The wrinkles and extra skin make it harder for another animal or a man to get a firm hold of the dog in combat.  The eyes of this breed are medium in size and set far apart.  There is a furrow of wrinkles between the eyes which makes the breed look stern and wise.  The ears of this breed are small and triangular shaped.  These ears droop down close to the head, enhancing the square appearance of the skull.  The overall expression of a Bullmastiff is intimidating and imposing.


The coat of this breed is short, flat, and dense.  This gives the breed protection from the elements, especially the chill breezes and rainy days of England.  Bullmastiffs come in three acceptable color combinations, brindle, red, and fawn.  Any shade of these colors is acceptable, but they must cover the entire body.  Occasionally, a solid black Bullmastiff is born as well, but such animals are not acceptable in the show ring.  A small white patch on the chest is acceptable and quite common, but there should be no other white on the body.  The muzzle of a Bullmastiff should always be covered in a black mask, no matter what color the dog is.  Unless the dog is brindle, the only other acceptable location for black fur is on the ears, which are always darker than the rest of the dog.




The Bullmastiff has exactly the temperament one would expect of a guardian breed.  Bullmastiffs are incredibly loyal.  This is a breed that will stand beside its owner no matter what, and will defend its family no matter the cost to itself.  The average Bullmastiff craves to be in the company of its family, and many suffer from severe separation anxiety.  This breed does not like to be left alone in the yard and much prefers to be in the home.  Bullmastiffs like companionship to such an extent that they have been known to break down fences to find a playmate.  Bullmastiffs are somewhat variable in their level of independence.  Some of these dogs like to be in the same room as their family, but not necessarily on top of them.  Many others are devoted cuddlers who will always be on laps and under feet.


Proper training and socialization are very important for Bullmastiffs.  Well-trained Bullmastiffs are generally accepting of strangers that their family accepts, although are normally quite aloof and uninviting.  Bullmastiffs which have not been properly trained or socialized are often nervous around strangers, and not infrequently outright aggressive with them.  This breed also takes quite a bit of time to warm up to new people.  While most Bullmastiffs will eventually accept a new person such as a roommate or spouse, they will only do so on their own terms and time frame.  Bullmastiffs make some of the world’s finest guard dogs.  They are not only alert and naturally protective, but also incredibly intimidating and powerful.  Potential intruders will almost certainly not be met warmly by a Bullmastiff, and this breed will go to any length to defend its family from harm.


Bullmastiffs are one of the most fearless of all dogs and will stand their ground no matter who the opponent is.  That being said, a Bullmastiff is not quick to bite or attack and will almost always attempt to frighten off a threat with growls and teeth baring first.  Most Bullmastiffs are good with children.  This breed is not snappy and will tolerate a great deal of rough play.  Breed members often become very close to family children and become incredibly protective of them.  However, once again, socialization is very, very important to make sure a Bullmastiff does not become fearful of children.  Because the Bullmastiff’s urge to protect is so strong, it may see the rough play of children with each other as a threat and feel the need to intercede to protect its family.


Many Bullmastiffs suffer from severe dog aggression issues.  This breed is incredibly territorial, and will absolutely not tolerate a strange dog invading its premises.  Most Bullmastiffs are also very dominant and will take over any social situation by any means necessary.  Any dog that challenges a Bullmastiff is facing a losing situation because this breed will not back down from Some simply try to attack other dogs as a perceived threat.  This aggression is much higher between dogs of the same sex.  Some Bullmastiffs are unable or unwilling to tolerate the presence of a dog of the same sex.  On the other hand, most breed members are relatively willing to tolerate a dog of the opposite sex.  While male aggression is more severe in most breeds, both Bullmastiff sexes are equally dog-aggressive.  As is the case with all dogs, if a Bullmastiff is raised with another dog from a very young age, they will generally get along fine with them.  However, it is not uncommon for a fight to break out between a Bullmastiff and a dog it has lived with for years, necessitating permanent separation as Bullmastiffs hold grudges for years.  Dog aggression problems are especially severe with this breed; a Bullmastiff can kill almost any other dog with little effort, and severely injure all others.


Bullmastiffs are not generally good with non-canine pets.  These dogs have a very high prey drive and are also incredibly territorial.  Like all dogs, a Bullmastiff that has been raised with the family cats will probably give those individual cats few problems.    However, Bullmastiffs do not allow strange animals to come onto their property and will attack a neighbor’s cat that wanders up to their front door.  No cat is likely to survive a Bullmastiff attack.  Bullmastiffs are likely to pursue any animal that they see, whether it is a lizard or a bear, which can result in severe injuries or death for one or both animals.


Bullmastiffs are not the easiest dogs to train.  This breed is definitely not lacking in the intelligence department, but it is not very willing to please.  A Bullmastiff is not a dog that will obey blindly because its owner wants it too.  A Bullmastiff only obeys because it totally and completely respects its leader.  Bullmastiff owners must be firmly in a position of dominance at all times, otherwise their dog will likely get out of control.  The average Bullmastiff will regularly challenge an owner’s authority and if it finds that authority lacking will take charge itself.  Once in control, Bullmastiffs become almost intractable and extremely bossy.  Even the most in-control owner will find a Bullmastiff very stubborn.  This breed was bred to never back down, and they won’t.  With time and effort, Bullmastiffs can become well-trained and very polite, but are rarely obedience competitors and don’t do tricks.  If owners fail to train these dogs properly, they can and do become dangerously out-of-control.


Bullmastiffs have very low exercise requirements for a dog of this size.  As is the case with all breeds, Bullmastiffs need a long daily walk to avoid behavioral problems such as destructiveness from developing, but require little else.  This breed likes to take life at a slow pace, and does not make a particularly good jogging companion.  Owners must maintain control at all times on walks, otherwise anything from hard pulling to a dog fight may ensue.  Bullmastiffs sometimes have sudden burst of intense energy, but this is usually short-lived.  Although a Bullmastiff certainly enjoys having a yard to walk around in, these dogs do not like being left outside alone and make surprisingly good apartment dogs.  Bullmastiff puppies will occasionally play games like fetch, but most adults are not especially interested in playtime.  Too much exercise can actually be more of a problem for this dog than too little, and owners must carefully regulate a Bullmastiff’s exercise when a puppy, immediately after eating, and in the hot weather.


Potential Bullmastiff owners need to be aware that this breed is not for the excessively fastidious or the easily embarrassed.  Bullmastiffs drool, and they drool a great deal.  You and your possessions will regularly get covered in an immense amount of slobber.  Bullmastiffs snore very, very loudly, and do so almost constantly when they sleep.  This can be so loud that it keeps owners awake at night.  What most embarrasses owners is the breed’s flatulence.  As is the case with all brachycephalic breeds, Bullmastiffs pass gas frequently.  The releases of a dog this size can be absolutely overpowering and will almost certainly clear the room.


Grooming Requirements: 


The Bullmastiff has a very low-maintenance coat.  A regular brushing is all that this dog requires.  This breed also only needs infrequent baths.  The Bullmastiff is regarded as a light to average shedder, but because of its immense size will still shed more hair than most dogs.  Owners do have to carefully clean out the facial wrinkles of jowls of this breed, as well as its ears.  Such skin folds easily trap food, water, dirt, grime, and other particles.  If allowed to build up, these particles can cause irritations and infections.  It is absolutely imperative that owners begin facial cleaning, bathing, and other routine maintenance tasks from a very young age and that each is introduced as carefully as possible.  It is much easier to trim the toenails of a thirty pound and eager puppy than a 120 pound and resistant adult.


Health Issues: 


The Bullmastiff is known for suffering from a number of serious health defects and for having a short life span.  The life expectancy for a Bullmastiff is around 8 to 9 years, and few of these dogs live much beyond 10.  It is far from uncommon for a Bullmastiff to succumb to heart problems or cancer in middle or even early age.  Even though they often lead short lives, many Bullmastiffs suffer from a number of serious and uncomfortable health conditions for years before they pass.  However, the Bullmastiff’s short life and health problems are generally comparable to most similarly sized breeds, and this dog is probably healthier than most giant breeds.  Owners must be aware that any medical bills for a Bullmastiff will be much higher than the same procedure or medicine for a smaller dog.


Gastric torsion, more commonly known as bloat, is one of the chief health concerns faced by any Bullmastiff owner.  Bloat occurs when the dog’s stomach becomes twisted inside of its body, sometimes completely around.  This condition causes a number of internal problems and is almost always fatal without immediate medical intervention.  An expensive surgical procedure is necessary to correct bloat, and is often too late.  Bloat is very common in many breeds of deep-chested dogs as their organs are not as closely pressed and protected by their ribs.  There are many causes of bloat but one of the most common is exercising on a full stomach.  To prevent bloat, Bullmastiff owners are advised to feed their dog several small meals a day rather than one or two large ones and to limit their exercise immediately after a feeding.


Bullmastiffs are not very tolerant of high temperatures.  Their large bulk and protective coats mean that these dogs get hot quickly and require more air to cool off.  Unfortunately, the Bullmastiff’s pushed-in face has difficulty providing enough air to cool off the body.  As a result, not only do Bullmastiffs tire very quickly in the heat, but they also overheat more quickly and at lower temperatures than many other dogs.  Bullmastiff owners should carefully monitor their dogs when the temperature rises, and preferably keep them indoors until it drops.


Bullmastiffs are known to suffer from a number of health problems, but some of the most common or serious are:


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