Bullmastiff Overview

Dog Breed:
Breed Group:
Working Group
Fearless, affectionate, loyal, docile and reliable
24-27 inches
100-130 pounds
Life Span:
7-9 years
Coat Colors:
Red, fawn or brindle
Area of Origin:
Best For:
Experienced owners/Knowledge of the needs of large guarding breeds/Committed to the training and socialization of their dog.
Adult Food:
Best Dog Food for Bullmastiffs
Puppy Food:
Best Puppy Food for Bullmastiffs

Bullmastiff Characteristics

Good for First-Time Owners
Good with Children
Easy to Train
Exercise Requirements
Ease of Grooming
Amount of Shedding
Amount of Drooling
Tendency to Bark

About The Bullmastiff

  • Loving and loyal

  • Guarding tendencies

  • Docile once exercised

When you have a bullmastiff in your home, you’ll be rewarded with a loving and loyal companion. However, their generally easy-going nature, they do tend to retain their guarding nature. True to their nickname, ‘The Gamekeeper’s Night Dog,’ this is not a breed that is likely to welcome a stranger into your home in exchange for a fuss or a throw of a ball. 

At up to 130lbs, this is also a lot of dog to have in your home, and when combined with their tendency to drool and snore, they are probably most suitable for real fans of the breed. 

Bullmastiffs are not overly demanding with their exercise needs, a brisk walk each day and a chance to stretch their legs off-leash are probably enough for most dogs. Then you’ll find that they’re a pretty docile breed to live with. 

Bullmastiff Breed History

  • Bred to track and hold poachers

  • Developed from the Mastiff and Bull Terrier

  • Recognized in the US in 1933


It’s back in1860 when the documented history of the Bullmastiff has been known to commence. This was when it was stated that the Bullmastiff was bred to help the gamekeepers on large English country estates. At that time, poaching was a big problem, and it was down to the gamekeepers to reduce the growing losses. 

They needed a dog who could track, quickly cover short distances, and then hold poachers without causing them serious harm. They trialed several different breeds without too much success. They first tried the mastiff, but they were found to be too slow. Then they turned to the bulldog, but at that time, he was a ferocious dog and so not suitable for this task.

But there were traits from both breeds which the gamekeepers did want. So, they began to develop crosses and eventually found that a ratio of 60% Mastiff and 40% Bulldog provided the temperament and physique of the dog they needed to complete the task. The Bullmastiff breed was born.

Rivalries quickly developed between the gamekeepers over who had Bullmastiffs of the best quality. Competitions were held, and the Bullmastiff became recognized by the English Kennel Club in 1924. Nine years later, they also gained full recognition from the American Kennel Club.

Bullmastiff Size & Weight

  • Large, imposing breed

  • Males weigh up to 130 pounds and stand at up to 27 inches

  • Females weigh up to 120 pounds and stand at up to 26 inches


Although smaller than the mastiff, this is still an imposing dog.

They measure 25-27 inches for the males and 24-26 inches for the females. As to their weight, males are 110-130 pounds, and females are 100-120 pounds.

Although known as being a gentle breed, precautions still need to be taken due to their size and ability to knock accidentally knock a person over.


Bullmastiff Personality & Temperament

  • Territorial nature

  • Dependable family companion

  • Intelligence and willingness to learn


The Bullmastiff was bred to undertaken guarding work, and they still retain the temperament suited for that job. That means that they can be territorial and loyal dogs who will prevent intruders from coming into the home. However, this is also a very biddable breed, and with training can also be relied upon to be a dependable family companion.

So, it does need to be recognized that this is not the breed for everyone. The Bullmastiff’s intelligence is a considerable asset, and combined with their willingness to follow instructions, they can be a fantastic family pet. However, to achieve that, the owners need to be prepared to commit to training and socialization to ensure they have a well-mannered dog.

Bullmastiffs can be very patient children, but their size can be overpowering for toddlers who may be easily knocked over. As with any breed, dogs and young children should not be left alone unsupervised. 

The breed can be aggressive toward dogs they don’t know and may be best living with dogs of the opposite sex. You can reduce the likelihood of problems by teaming up with an experienced rewards-based trainer who can provide guidance as your Bullmastiff grows up. They can get along with cats if they’re raised with them, though you may find that they chase any other cat who dares to enter the garden.

In terms of the size of home that’s needed, well, they are generally a pretty docile breed. So that means that as long as they have room to stretch out and get good walks each day, they can adjust to smaller home environments. Coming from the UK, the Bullmastiff can tolerate colder weather though they will do better when not living in extremes. 

Bullmastiff Health & Grooming

  • Short life span

  • Testing needed before dogs are bred from

  • Minimal grooming needs but a drooler


The Bullmastiff does have a relatively short life span, and so testing for inherited conditions becomes even more important to reduce the risk of further problems.

The American Bullmastiff Association strongly recommend that dogs are tested for the following conditions before any breeding takes place:

  • Hip and elbow evaluations to asses for any join abnormalities
  • Thyroid checks for hypothyroidism, a condition where the body fails to produce enough of the thyroid hormone.
  • Eyes examined as Bullmastiffs can inherit or develop a number of different eye conditions, including glaucoma and cataracts.
  • Heart ECG to check for the life-threatening heart condition dilated cardiomyopathy (DCM) . This condition causes the heart to become so large, thin, and weak that it can no longer effectively pump blood around the body

The Bullmastiff doesn’t need their owners to spend much time on grooming. A weekly brush to remove any dirt and loose hair is all that’s needed most of the year. They do tend to shed once a year, and then they may need a brush every few days. 

This is a breed that can be a drooler, so you’ll find that most owners always have a towel to hand to mop up!

Bullmastiff Training

  • Early training and socialization essential

  • Independent-minded breed

  • Not known for being vocal


The Bullmastiff must receive appropriate early training and socialization. We recommend getting in touch with a reward-based trainer even before you get your pup so that you can have a plan in place for when they join your family.

This can be an independent-minded breed, just as their history required them to be. Consistency and structure combined with training will get you the best results. Bullmastiffs can excel in many competitive dog sports, including agility and obedience. They love using their noses, so scent work and tracking can be great options to keep their brains busy.

Although not excessive in their prey drive, this does vary between individuals, and all breeds of dog can be tempted into a chase when the motivation is there! Bred as a silent watchdog, they tend not to be a very vocal breed, so if they are barking, it usually means that you need to go and investigate what’s happening.

Bullmastiff Exercise Requirements

  • Early training and socialization essential

  • Independent-minded breed

  • Not known for being vocal


Your Bullmastiff will enjoy daily exercise, though you’ll generally find that it doesn’t need to be of an intensity demanded by some of the more active working breeds. 

Brisk walks and the opportunity for off-leash outdoor play are needed though you will need a securely fenced area so that strangers and unfamiliar dogs don’t infringe on their fun. 

The Bullmastiff loves to play, but this is more likely to be for short periods rather than the play all day approach of say a Border Collie

Bullmastiff Diet & Feeding

  • Good quality food needed to support growth

  • A tendency to develop bloat

  • Feed smaller meals across the day


For personalized feeding advice for your dog, do speak to your veterinarian or pet nutritionist. 

More generally, most dogs will start on specially designed puppy food, which ensures that they receive all the nutrients they need while going through their growth phase. As they reach around 6 months, then they will generally move across on to an adult formulation.

Bullmastiffs can develop bloat, which is a sudden and life-threatening swelling of the stomach. While it hasn’t been possible to identify all the causes, it is thought that feeding one large meal a day and vigorous exercise before and after eating may be contributing factors.

You may also be interested in:

Bullmastiff Rescue Groups


There will be times when a Bullmastiff will find themselves in need of a new home. In the US, the breed association provides the main point of contact for help and advice on rescue dogs.

American Bullmastiff Association Rescue Service – https://bullmastiff.us/rescue/

As well as providing rescue information, there’s a whole range of additional detail on this magnificent breed on the breed association’s website – https://bullmastiff.us