The origins of the Bullmastiff are unclear. In the 18th century, in some regions of England, the
Old English Mastiff and
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.[2] 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.[3] 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.[2] The
American Kennel Club recognised it in 1934.[4] It was definitively accepted by the
Fédération Cynologique Internationale in 1955.[5]
In 1928, the
De Beers diamond mining company imported Bullmastiffs to South Africa to guard the mines.[6]
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.[1]
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.[1]
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.[8]
Health concerns within the breed include hip and elbow dysplasia, progressive retinal atrophy, bloat, and cancer, with a relatively high incidence of lymphoma and mast cell tumours.[9][10][11] Bullmastiffs are prone to certain hereditary diseases, including:
Progressive retinal atrophy is a particular problem, since the trait is an
autosomal dominant one. (This has recently been called into question by another medical team and has been proven that some Bullmastiffs have autosomal recessive PRA genes. In America, this is being investigated by the American Bullmastiff Health and Research Committee, and the DNA Optigen test only works for dominant genes, so it is considered inadequate at this time.)[15]