Dog breed

Bullmastiff

The Bullmastiff is an English mastiff breed created by crossing the Mastiff with the Bulldog, bred to stop poachers on country estates. Males stand 64–69 cm at the shoulder and weigh 50–59 kg. At home, it's calm, quiet and deeply attached to its family, while with strangers it is watchful and self-assured. It needs consistent training from puppyhood, because an adult is hard to hold back by force.

FCI Group II · Molossers, pinschers and schnauzers · standard no. 157

Weight: 41–59 kg
Height: 61–69 cm
Lifespan: 8–10 years
Origin: United Kingdom

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Photo: Corpusdigitalis (FHvB), CC BY-SA 2.0 de, Wikimedia Commons

Temperament

The FCI standard describes the Bullmastiff as powerful, enduring, active and reliable, high-spirited, alert and faithful. The AKC gives it the top rating for watchdog instinct and the lowest for barking. That sums up its guarding style well: instead of making noise, a Bullmastiff steps between its family and an intruder and watches. At home, it can be a couch potato, likes being close to people and may sleep through much of the day. It is usually patient with the children in its own home, but given its size and strength, it shouldn't be left with them unsupervised. Conflicts with other dogs can happen, especially with dogs of the same sex, so early socialization is essential. It learns well when training is calm, short and rewarding, because heavy-handed methods easily reinforce an adult dog's stubbornness.

Energy: calmvery energetic
Affection: independentvelcro pet
With children: not idealgreat
With other pets: difficultgreat
Trainability: stubborneager to learn
For first-time owners: for experienced ownersyes
With strangers: waryoutgoing
Playfulness: dignifiedeternal puppy
Shedding: minimalheavy
Grooming: easydemanding
Being left alone: strugglescopes well
Apartment living: needs a house and yardgreat in a flat
Barking: quietvocal
With other dogs: difficultgreat
Protectiveness: lowhigh
Drooling: hardly anya lot
Cold tolerance: feels the coldexcellent
Heat tolerance: strugglescopes well

Scores of 1–5 compare the breed with other breeds of the same species, based on the sources at the bottom of the page. Every animal is different. How we score traits

Who is the Bullmastiff for?

The Bullmastiff suits a calm, decisive person or a family with older children who have experience with large dogs and a house with a fenced yard. It fits someone who wants an alert guardian rather than a sporty dog. We don't recommend it for people looking for a running partner, those living in a cramped walk-up apartment, or anyone who can't keep it cool in summer.

Pros

alert, quiet guardian
calm at home
low grooming needs
devoted to its family

Challenges

short lifespan
doesn't handle heat well
needs consistent training
high costs of keeping a large dog

Size and looks

Size and looks: Bullmastiff
Height at the withers	males 64–69 cm, females 61–66 cm
Weight	males 50–59 kg, females 41–50 kg
Lifespan	8–10 years
Coat	short
Colors	brindle, fawn, red
Country of origin	United Kingdom
Classification	Group II: Pinscher and Schnauzer, Molossoid and Swiss Mountain and Cattledogs
Also known as	Bull Mastiff, Gamekeeper's Night Dog

Care and exercise

45–90minof exercise a day

1/5grooming needs

3/5shedding

The Bullmastiff isn't a running dog. The AKC recommends moderate daily exercise, brisk walks and play in a well-fenced yard, and warns against overtiring puppies during their rapid growth. In practice, two walks a day totaling about an hour plus some play are enough for most dogs. The fence must be solid, because the dog guards its territory and shouldn't have contact with passersby. The short coat needs a weekly going-over with a grooming mitt, but Bullmastiffs shed seasonally, and the facial wrinkles need wiping and drying. It drools moderately, mostly after drinking. Its shorter muzzle makes it handle heat poorly: in summer, walk early in the morning and late in the evening. Feed twice a day and wait before exercising after a meal to lower the risk of bloat.

How much should the Bullmastiff eat?The calculator starts from this breed’s typical weight: calories and grams a day.

Health and breed-related conditions

The Bullmastiff is a short-lived breed. The AKC gives 7–9 years, the Kennel Club under 10, and in the British McMillan et al. (2024) study the median was 10.2 years. The AKC notes that breeders should avoid overly massive dogs, since agility matters for guarding work, and should screen for heart disease, hip and elbow dysplasia, hypothyroidism and eye diseases. The breed can also develop cancer and bloat. Before buying, ask for X-ray, heart and eye exam results for both parents.

heart diseaseThe AKC lists it among the conditions breeding dogs are screened for.
hip and elbow dysplasiaTypical of heavy, big-boned dogs.
hypothyroidismDetected with a blood test; signs include weight gain and skin problems.
cancerThe AKC notes that Bullmastiffs can develop cancer.
bloat (GDV)A life-threatening emergency typical of large, deep-chested dogs.
eye and eyelid diseasesBreeders have their dogs examined by a veterinary ophthalmologist.

Health tests to ask the breeder about

hip and elbow X-rays (HD/ED)
heart exam (echocardiogram)
eye exam (ECVO)
thyroid testing

This is general breed information, not a diagnosis. If something worries you, talk to your veterinarian.

Breed history

The AKC says the Bullmastiff's documented history begins around 1860 in England. Poaching was rampant on large country estates at the time, and a captured poacher faced harsh punishment, so he often fought back. Gamekeepers needed a big, fast, brave dog that could run down and pin a man at night without mauling him. According to the AKC, the best results came from crossing the Mastiff with the Bulldog in a ratio of about 60 to 40. That's how the “gamekeeper's night dog” came about. Over time, the Bullmastiff became a family dog and home guardian. The AKC registered the breed in the 1930s, and the FCI recognized it in 1955.

Fun facts

The nickname “gamekeeper's night dog” comes from the breed's work guarding estates against poachers.
According to the AKC, an adult male Bullmastiff averages about 66 cm at the shoulder and 54 kg.
The FCI standard allows brindle, fawn and red, always with a black mask.
The breed was created by crossing the Mastiff and the Bulldog, in a 60 to 40 ratio according to the AKC.

Frequently asked questions

How long do Bullmastiffs live?

Shorter than most dogs. The AKC gives 7–9 years, and a large 2024 British study calculated a median of 10.2 years. Lifespan is influenced by the parents' health testing, a moderate weight and careful exercise during growth.

Is a Bullmastiff a good first dog?

Not really. It's calm and devoted to its family, but it is a very strong dog with a pronounced guarding instinct. A first-time owner should at the very least work with an experienced trainer from the first few weeks.

Do Bullmastiffs drool?

Moderately. The AKC rates the breed's drooling 3 on a 1–5 scale, less than a Newfoundland or Mastiff. Most drool comes after drinking, eating and in hot weather.

Is the Bullmastiff a restricted breed in Poland?

No. Poland's 2003 Interior Ministry regulation doesn't list the Bullmastiff, so no permit from the local municipality is needed. Even so, the owner of such a strong dog is responsible for training it and handling it safely on walks.

How much does a Bullmastiff weigh?

Adult dogs of this breed usually weigh: males 50–59 kg, females 41–50 kg. Height at the withers: 61–69 cm. That range is for healthy adults in good condition.