Is a Bullmastiff right for you?
Despite their large size and intimidating appearance, Bullmastiffs are typically docile and affectionate towards their owners. They are known to be protective of their loved ones, often displaying a natural instinct to guard and protect their home and family members.
Bullmastiff Origin
The Bullmastiff has ancient origins in England and Wales through crossbreeding practices between Bulldogs 40% and English Mastiffs 60%. This dog was originally created as a kind of gamekeeper; its primary roles were to catch poachers and keep them away from hunters’ game.
Bullmastiffs are Powerful
The Bullmastiff was selectively bred to be a silent, powerful deterrent rather than an aggressive attacker. Their natural wariness of strangers and intimidating presence made them perfect for patrolling estates without excessive noise. Unlike breeds that bark to alert, Bullmastiffs were bred to track quietly and confront intruders with sheer presence. They were trained to knock down and hold intruders (not maul them), making them effective yet controlled guardians. They are naturally wary of strangers but deeply devoted to their family.
Are Bullmastiff’s Aggressive?
Some assume their size and guarding instincts make them dangerous, but properly raised Bullmastiffs are discerning, not indiscriminately aggressive. Like other powerful breeds, their behavior reflects training, socialization, and environment. Neglect or poor handling can lead to issues. They’re “aggressive when necessary” (e.g., intruders, threats) but otherwise quiet and observant.
The Bullmastiff’s Closest DNA Relatives
In Landmark Research on Modern Dog Breed development, the Bullmastiff has been shown to share the most DNA with an ancestor of the following breeds:
Mastiff
Boerboel
Cane Corso
Bullmastiff Traits
✔ “Fearless & Confident” (Breed Standard) – Not easily rattled; they assess threats calmly before acting.
✔ Territorial & Hierarchical – They need clear leadership to understand their role (or they may assume the “alpha” position).
✔ Aloof but Not Hostile – Reserved with strangers, but not aggressive unless provoked (a trait often misunderstood).
✔ “Joy to Own” – When trained right, they’re gentle giants who bond deeply with their people.
Bullmastiff Size and Coat Colors
According to FCI Breed Standard the Bullmastiff breed can reach up to 27 inches in height and up to 130 pounds in weight. Accepted coat colors are:
“Any shade of brindle, fawn or red; colour to be pure and clear. A slight white marking on chest permissible. Other white markings undesirable. Black muzzle essential, toning off towards eyes, with dark markings around eyes contributing to expression.”
Grooming a Bullmastiff
Bullmastiff’s require little grooming and need only an occasional brushing or wipe down with a cloth to keep them looking good year round. They do, however, tend to drool and snore. Being a “flat-faced” breed, the Bullmastiff tends to swallow a lot of air causing flatulence. Being such a large breed, their gas can clear the room in no time!
| Trait | Bullmastiff | Neapolitan Mastiff | St. Bernard |
|---|---|---|---|
| Drooling | Moderate-heavy | Extreme (waterfall) | Heavy (slobber flaps) |
| Snoring | Loud | Earthquake-level | Thunderous |
| Gas | Room-clearing | Weaponized | Notable but less foul |
| Grooming | Minimal (wipe downs) | Wrinkle-deep cleaning | Heavy shedding |
Growing Up Bullmastiff
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How Fast Can a Bullmastiff Run?
The American Kennel Club (AKC) conducts dog racing trials each December in Orlando, FL. called the Fast CAT Invitational. This is a 100 yard race where dogs run individually chasing a lure. The average running speed by Bullmastiff’s is about 22 mph. The fastest recorded speed by a Bullmastiff was by a dog named Banshee’s Dream Lover at 27.57 mph!
Are Bullmastiff’s a brachycephalic breed?
There is an argument that the true Bullmastiff is NOT brachycephalic. According to the breed standard, the CORRECT proportion of the muzzle to the skull size does not meet the criteria for brachycephaly. Unfortunately, many breeders do not adhere to this standard, striving for a short muzzle which can cause additional health problems in the breed.
Bullmastiff Temperament
The CBARQ Dog Temperament Research study, conducted at the University of Pennsylvania, is a giant study of over 300 dog breeds and 60,000 individual dogs. In this study, the Bullmastiff ranks 20 out of 124 breeds for aggression towards other UNFAMILIAR dogs. If an unknown dog enters their personal space/territory they are likely to react by barking, growling, bearing of teeth or, in extreme cases, lunging or biting. In contrast, they rank very low for displaying these behaviors for other familiar dogs in the household.
Does the Bullmastiff Have a High Prey Drive?
In this Same Research the Bullmastiff ranks high (41 out of 124 breeds) in prey drive. If a cat, squirrel, rabbit or other small animal crosses their sight, they are very likely to give chase.
Bullmastiff Humor!
Bullmastiff Intelligence
In the Landmark Book entitled, “The Intelligence of Dogs”, professor Stanley Coren researched and documented the intelligence of over 130 different dog breeds. In his book, the Bullmastiff ranks 69th out of 138 breeds in working/obedience intelligence. Essentially this means they will learn new commands in 40 to 80 repetitions and obey first commands 30% of the time or better. This puts them in the “fair working and obedience intelligence” category. In contrast, the most intelligent breeds will learn the same command in 5 repetitions or less!
Bullmastiff Health and Lifespan
Bullmastiff’s Have an Average lifespan of 7-9 years. Some common health issues that affect this breed include:
Hip Dysplasia and Elbow Dysplasia
Hemangiosarcoma
Gastric Dilation and Volvulus or Bloat- as with many large dogs with a deep chest
Check Your Bullmastiff Facts and Take a Fun Bullmastiff Quiz!
Quick Facts About Bullmastiffs Infographic
Facts About Bullmastiffs-Final Thoughts
Bullmastiffs that offer a unique combination of loyalty, strength, and affection. Their solid build and imposing size make them ideal guardians, while their loyal and affectionate nature make them excellent family companions. Bullmastiffs have a tendency to gain weight easily, so portion control and small meals are a good idea to maintain a healthy weight. This is a very large and strong breed and, while they may not intentionally harm a child, a family with small children may want to look towards another breed. While Bullmastiff puppies may seem adorable, it is crucial to remember that they need early socialization and training as they will grow into powerful adult dogs. With their loving and gentle temperament, Bullmastiffs make excellent human companions and are known for being loyal till the end.
