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Form and Function

This nearly square breed is powerful and active, a combination of strength, endurance, and alertness. The Bullmastiff appears to be 60 percent Mastiff and 40 percent Bulldog. This dog’s gait is smooth and powerful, but the angulation is moderate. The coat is short and dense, and the expression keen and alert.


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Breed Traits

Energy Level

1 out of 5

Exercise Requirements

2 out of 5


1 out of 5

Affection Level

3 out of 5

Friendliness To Dogs

2 out of 5

Friendliness To Other Pets

4 out of 5

Friendliness To Strangers

1 out of 5


5 out of 5

Ease of Training

1 out of 5

Grooming Requirements

1 out of 5

Heat Sensitivity

5 out of 5


5 out of 5

Breed Attributes




110-130 lb




Mastiff, Bull

Area of Origin


Date of Origin



Although the Mastiff is one of Britain’s oldest breeds, its immediate descendant, the Bullmastiff, is probably a fairly recent development. It is true that occasional references to the Bullmastiff, or mixes of the Mastiff and Bulldog, can be found as early as 1791; however, no evidence exists that these strains continued.

The documented history of the Bullmastiff begins near the end of the nineteenth century, when poaching game from the large estates had become such a problem that the gamekeepers’ lives were endangered. They needed a tough courageous dog that could wait silently, but the Mastiff was not fast enough, and the Bulldog was not large enough. The breeds were mixed in an attempt to create their perfect dog; the aptly named “Gamekeeper’s Night Dog.” The preferred color was dark brindle, as it faded into the night. As the breed’s reputation grew, however, many estate owners chose the dogs as estate sentries and preferred the lighter fawns, especially those with black masks, a coloration reminiscent of their Mastiff ancestry.

The ideal Bullmastiff ultimately appeared to be 60 percent Mastiff and 40 percent Bulldog. By 1924, the breed was deemed to be pure and was recognized by the English Kennel Club. AKC recognition followed in 1933.


The Bullmastiff is gentle and quiet, a devoted companion and guardian. This dog is not easily roused, but once threatened it is fearless. Bullmastiffs are stubborn and cannot easily be goaded into action against their will. Some can be assertive towards new dogs, and should be introduced carefully. Males especially tend to not tolerate other males. They are good with children, but should be raised with them. The Bullmastiff needs a firm but loving home. This breed is not for fragile or timid owners.


The Bullmastiff is a big dog and needs daily exercise to stay in shape. Their needs are moderate, however, and can be met with walks on leash and short romps. They do not do well in hot, humid weather, and need a soft bed and plenty of room to stretch out. They drool; some snore. Coat care is minimal.


  • Major concerns: gastric torsion, CHD, elbow dysplasia
  • Minor concerns: entropion
  • Occasionally seen: hemangiosarcoma, osteosarcoma, lymphosarcoma, mast cell tumors, cardiomyopathy, SAS, hypothyroidism
  • Suggested tests: hip, elbow, eye, cardiac, thyroid
  • Life span: 8–10 years


Note: While the characteristics mentioned here may frequently represent this breed, dogs are individuals whose personalities and appearances will vary. Please consult the adoption organization for details on a specific pet.

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