Breed library

Bull Mastiff

Also known as English Bullmastiff.

Bull Mastiff photograph.
Bullmastiff edited.JPG - Fausto Moreno. CC BY-SA 3.0. Source: https://commons.wikimedia.org/wiki/File:Bullmastiff_edited.JPG. License: http://creativecommons.org/licenses/by-sa/3.0/. License: CC BY-SA 3.0.

Breed overview

The Bullmastiff is an English breed of dog of mastiff type and large size, with a solid build and a short muzzle. It was developed as a guard dog in the nineteenth century by cross-breeding the English Mastiff with the now-extinct Old English Bulldog. It was recognised as a breed by The Kennel Club in 1924.

  • Breed type: dog breedBreed reference breed kind.
  • Country of origin: United KingdomBreed reference country of origin.

Breed facts

  • In the 18th century, in some regions of England, the English Mastiff and Old English Bulldog were commonly inter-bred to produce dogs suitable for guarding people and their property.
  • By the beginning of the 20th century, this cross-breed was in widespread use as an aid to gamekeepers in the control of poaching.
  • As a result, the Bullmastiff is known as the Gamekeeper's Night Dog.
  • The Bullmastiff was recognised as a breed by The Kennel Club in 1924.
  • The American Kennel Club recognised it in 1934.It was definitively accepted by the Fédération Cynologique Internationale in 1955.

Size and appearance

The Bullmastiff is a large dog. Bitches stand some 61 - 66 cm at the withers, and usually weigh 41 - 50 kg; on average, dogs stand about 3 cm taller and weigh 9 kg more. The coat may be fawn, red, or brindle, in any shade; some limited white marking on the chest is allowed. The muzzle is black, becoming paler towards the eyes.

  • Body mass reference: 41 - 50 kgAdult breed reference quantity from the article infobox. Original value 41 - 50 kg. Unit conversion where applicable: 1 inch = 2.54 cm; 1 pound = 0.45359237 kg. Original field and references are retained in the revision-pinned article evidence.
  • Body mass reference: Up to 50 kgBreed reference body mass. female, maximum.
  • Body mass reference: 41 kg or moreBreed reference body mass. female, minimum.
  • Body mass reference: 50 - 59 kgAdult breed reference quantity from the article infobox. Original value 50 - 59 kg. Unit conversion where applicable: 1 inch = 2.54 cm; 1 pound = 0.45359237 kg. Original field and references are retained in the revision-pinned article evidence.
  • Body mass reference: 50 kg or moreBreed reference body mass. male, minimum.
  • Body mass reference: Up to 59 kgBreed reference body mass. male, maximum.
  • Height reference: 61 - 66 cmAdult breed reference quantity from the article infobox. Original value 61 - 66 cm. Unit conversion where applicable: 1 inch = 2.54 cm; 1 pound = 0.45359237 kg. Original field and references are retained in the revision-pinned article evidence.
  • Height reference: 61 cm or moreBreed reference height. female, minimum.
  • Height reference: Up to 66 cmBreed reference height. female, maximum.
  • Height reference: 64 - 69 cmAdult breed reference quantity from the article infobox. Original value 64 - 69 cm. Unit conversion where applicable: 1 inch = 2.54 cm; 1 pound = 0.45359237 kg. Original field and references are retained in the revision-pinned article evidence.
  • Height reference: 64 cm or moreBreed reference height. male, minimum.
  • Height reference: Up to 69 cmBreed reference height. male, maximum.
  • Coat length: short
  • Height category: tall
  • Weight category: giant
  • Weight category: large

Personality and behavior

Care planning: record what your dog enjoys, how they greet visitors, and how they respond to new places. Add notes after walks and training so you can see their habits over time. Where this profile includes behavior research, use the same named measures when comparing your shortlist.

  • Attachment and attention seeking (C-BARQ mean): 1.98 / 4Owner-reported attachment and attention seeking factor mean for US reference population Bullmastiff.
  • Chasing (C-BARQ mean): 1.75 / 4Owner-reported chasing factor mean for US reference population Bullmastiff.
  • Dog-directed aggression (C-BARQ mean): 1.17 / 4Owner-reported dog-directed aggression factor mean for US reference population Bullmastiff.
  • Dog-directed fear (C-BARQ mean): 0.58 / 4Owner-reported dog-directed fear factor mean for US reference population Bullmastiff.
  • Energy (C-BARQ mean): 1.70 / 4Owner-reported energy factor mean for US reference population Bullmastiff.
  • Excitability (C-BARQ mean): 1.79 / 4Owner-reported excitability factor mean for US reference population Bullmastiff.
  • Familiar-dog aggression (C-BARQ mean): 0.43 / 4Owner-reported familiar-dog aggression factor mean for US reference population Bullmastiff.
  • Non-social fear (C-BARQ mean): 0.70 / 4Owner-reported non-social fear factor mean for US reference population Bullmastiff.
  • Owner-directed aggression (C-BARQ mean): 0.04 / 4Owner-reported owner-directed aggression factor mean for US reference population Bullmastiff.
  • Separation-related problems (C-BARQ mean): 0.40 / 4Owner-reported separation-related problems factor mean for US reference population Bullmastiff.
  • Stranger-directed aggression (C-BARQ mean): 0.64 / 4Owner-reported stranger-directed aggression factor mean for US reference population Bullmastiff.
  • Stranger-directed fear (C-BARQ mean): 0.41 / 4Owner-reported stranger-directed fear factor mean for US reference population Bullmastiff.
  • Touch sensitivity (C-BARQ mean): 0.37 / 4Owner-reported touch sensitivity factor mean for US reference population Bullmastiff.
  • Trainability (C-BARQ mean): 2.64 / 4Owner-reported trainability factor mean for US reference population Bullmastiff.

Exercise and activities

Care planning: build a weekly routine with walks, play and time to explore. Enter the minutes and sessions that work for your dog, then compare the weekly total with your available time. Keep notes about the activities your dog enjoys and adjust the routine together.

Training and enrichment

Care planning: choose one everyday skill to practice and keep a record of each session. Note the cue, the reward your dog enjoys and what went well. Rotate familiar games and new activities, and use your notes to choose the next small step.

Coat and grooming

Care planning: use the coat details above to discuss a grooming routine with your groomer. Record brushing sessions, baths and appointments in the app. Add the tools you use and your preferred schedule so the whole household can follow the same routine.

  • Coat length: short

Health and lifespan

A 2024 UK study found a life expectancy of 10.2 years for the breed compared to an average of 12.7 for purebreeds and 12 for crossbreeds.

Living with this breed

Care planning: compare this profile's adult dimensions, coat care and available activity information with your household's routine. Make a shortlist, plan who will handle daily care and save the questions you want to ask a breed club, rescue or breeder.

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Compare supported adult height and weight ranges, matching research measures and sourced coat and care categories.

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Breed history

The origins of the Bullmastiff are unclear. In the 18th century, in some regions of England, the English Mastiff and Old English Bulldog were commonly inter-bred to produce dogs suitable for guarding people and their property. By the beginning of the 20th century, this cross-breed was in widespread use as an aid to gamekeepers in the control of poaching. They were bred for strength, size and speed using a cross of the tough, heavy and aggressive 19th century bulldog with the large, strong, less aggressive mastiff. As a result, the Bullmastiff is known as the Gamekeeper's Night Dog. The Bullmastiff was recognised as a breed by The Kennel Club in 1924. Dogs had to have a minimum of four generations of descent from Bullmastiff stock without input from either Bulldog or Mastiff; cross-bred animals could not be registered. The American Kennel Club recognised it in 1934.It was definitively accepted by the Fédération Cynologique Internationale in 1955.

Clubs and further reading

Sources

  1. Bullmastiff - WikipediaWikipedia contributors Retrieved 2026-10-14.License: CC BY-SA 4.0. Adapted excerpts from Wikipedia contributors, Bullmastiff, revision 1368874266. CC BY-SA 4.0. Formatting, citations and selection changed. Source history: https://en.wikipedia.org/w/index.php?title=Bullmastiff&action=history
  2. Wikidata structured breed dataWikimedia contributors Retrieved 2026-10-14.License: CC0 1.0. Wikidata contributors (CC0).
  3. National C-BARQ breed and all-breed means from USA.PLOS ONE / Figshare Retrieved 2026-10-14.License: CC BY 4.0. Bohland, Kyle R.; Lilly, Meghan Leanne; Herron, Meghan E.; Arruda, Andréia G.; O’Quin, Jeanette M. (2023). National C-BARQ breed and all-breed means from USA.. PLOS ONE. Dataset. https://doi.org/10.1371/journal.pone.0289356.s003 CC BY 4.0. Selected rows and field names adapted; values unchanged.
  4. File:Bullmastiff edited.JPGWikimedia Commons Retrieved 2026-10-14.License: CC BY-SA 3.0. Bullmastiff edited.JPG - Fausto Moreno. CC BY-SA 3.0. Source: https://commons.wikimedia.org/wiki/File:Bullmastiff_edited.JPG. License: http://creativecommons.org/licenses/by-sa/3.0/.
  5. Palipaws everyday care planningPalipaws Retrieved 2026-10-14.License: Palipaws original factual summaries. Palipaws. Original care-planning text, separate from breed measurements and licensed article summaries.
  6. AKC national parent club directoryAmerican Kennel Club Retrieved 2026-10-14.License: Factual reference only. Names and verified external links only. No source descriptions, logos or endorsement reused.