John Walton
Written by John Walton

If you’ve never met a bullmastiff before, then you’ll come to learn quite quickly that they are a firm and fearless breed. They can be somewhat standoffish towards people they don’t know, but he has an incredibly large soft spot for his family. What he makes up for in a short coat that’s easy to take care of, he lacks in manners with his copious amounts of drooling.

Breed Characteristics

TrainabilityAbove Average
Health and GroomingHigh
All Around FriendlinessAbove Average
Exercise NeedsAbove Average

Dog Breed Group:Working dogs
Height:Twenty-four to twenty-seven inches at the shoulder
Weight:100 to 130 pounds
Life Span:8 to 10 years

The original bullmastiff was originally developed by gamekeepers on England’s large estates in order to serve as guardians. They were bred to be confident, courageous, very strong, and extremely fast. They’re built with power in mind, with most of their weight being muscle, and they can have quite a formidable appearance that will deter any attackers or intruders from the home. He takes his role of protecting the home quite seriously, but can be quite a loving companion when he isn’t on duty. He can do quite well in homes where everyone leaves to go to work, fulfilling his guardian role. However, he should be provided with plenty of human interaction when his family is home in order to compensate. Thankfully, he’s not a barker; he prefers to watch intruders silently and will stop intruders with his sheer size alone. Biting is only a last resort for the bullmastiff.

He’s quite easy to groom with his short coat, and he doesn’t shed excessively when the seasons change. However, he can be quite a drooler, which not a lot of people are prepared for. It’s important that you keep something to wipe his saliva off of you (and other people) at all times. When it comes to energy, however, he’s extremely low key. He only needs a few short walks a day in order to keep him happy. This mellow attitude makes him perfect for living in an apartment or a condo, as long as he’s kept busy.

Don’t misunderstand this low-key energy as being lazy. The bullmastiff will excel at several dog sports, including agility, conformation, tracking, and obedience. They also serve quite well as therapy dogs, as they’re not very excitable and won’t jump around knocking people over. This is what also makes him very suitable for children. He exercises and extraordinary amount of patience. Their size can be a bit intimidating to young children, and he is not intended to be a babysitter.

Main Highlights
  • If a bullmastiff is not properly socialized, he can become quite aggressive towards other animals.
  • Despite their large size, they don’t do well living outside all the time. They should be kept within the home, and only allowed to run outside in a fenced-in area.
  • They are quite prone to heat exhaustion and heatstroke in hot weather.
  • Along with their drooling, they’re also prone to gassiness.
  • Bullmastiffs will enjoy spending time with you on the couch, even if they do end up taking over most of it with their large sizes. They definitely have a lot of love to give.
  • The breed was developed with a high threshold for pain, so it can be difficult to tell when your dog is hurt.
Breed History

The bullmastiff is a relatively modern breed with not a lot of history behind it. It was developed in the mid-19th Century by British gamekeepers. They needed a large, quiet, and fearless dog that was capable of tracking down poachers and being able to hold them. The breed was developed from the mastiff/bulldog cross: the mastiff itself was large, but not aggressive, while the bulldog had tenacity and bravery, but lacked the side to knock down and hold a person. While all of the effort was put into the breed’s function and temperament, none of it was put into his looks. Some effort was given to provide him with a dark brindle coat, which made it more difficult to spot him at night.

With poaching at an end, the bullmastiff served as a guard dog instead. It wasn’t until the early 20th Century that they were being bred as their own separate breed, rather than the use of the two originals to create a cross breed. This made it easier to create a standard, allowing the AKC to officially recognize the breed in 1933.


The bullmastiff male can be 25 to 27 inches at the shoulder, and around 110 to 130 pounds. The female can be 24 to 26 inches at the shoulder, and weigh about 100 to 120 pounds.

Personality and Character

The best bullmastiff should be fearless and confident, but also obedient to do what his owner’s wish. He can be smart and extremely reliable in any given situation. He can be an independent thinker at times, but this doesn’t allow him to stray to far from pleasing his people. He’s a natural guardian of the home, and will respond instantly when they’re being threatened. Taking him to training classes and early socialization will help him get used to having visitors in the house, and will teach him the difference between intruders and people that you invite into your home.

Health and Potential Problems

Bullmastiffs can be prone to certain conditions, though they are not guaranteed to get any or all of them. It’s important that you be aware of them, however, before you decide to make one a part of your family. Some of these conditions may not present themselves until your dog has reached full maturity

  • Hip Dysplasia: this is a heritable condition in which the thighbone doesn’t fit snugly into the hip joint. Some dogs show pain and lameness on one or both rear legs, but you may not notice any signs of discomfort in a dog with hip dysplasia. As the dog ages, arthritis can develop. X-ray screening for hip dysplasia is done by the Orthopedic Foundation for Animals or the University of Pennsylvania Hip Improvement Program (PennHIP). Dogs with hip dysplasia should not be bred. Hip dysplasia is hereditary, but it can be worsened by environmental factors, such as rapid growth from a high-calorie diet or injuries incurred from jumping or falling on slick floors.
  • Elbow Dysplasia: this is a heritable condition common to large-breed dogs. It’s thought to be caused by different growth rates of the three bones that make up the dog’s elbow, causing joint laxity. This can lead to painful lameness. Your vet may recommend surgery to correct the problem or medication to control the pain.
  • Hypothyroidism: caused by a deficiency of thyroid hormone, this disease may produce signs that include infertility, obesity, mental dullness, and lack of energy. The dog’s fur may become coarse and brittle and begin to fall out, while the skin becomes tough and dark. Hypothyroidism can be managed very well with a thyroid replacement pill daily. Medication must continue throughout the dog’s life.
  • Entropion: this defect, which is usually obvious by six months of age, causes the eyelid to roll inward, irritating or injuring the eyeball. One or both eyes can be affected. If your Bullmastiff has entropion, you may notice him rubbing at his eyes. The condition can be corrected surgically, which is best done after the dog reaches maturity at one or two years of age.
  • Subaortic Stenosis: this common heart defect occurs when the aorta narrows below the aortic valve, forcing the heart to work harder to supply blood to the body. This condition can cause fainting and even sudden death. It’s an inherited condition, but its mode of transmission isn’t known at this time. Typically, a veterinary cardiologist diagnoses this condition after a heart murmur has been detected. Dogs with this condition should not be bred.
  • Cystinuria: this genetic disorder is caused by an inability to reabsorb cystine, an amino acid, back into the kidney tubules. This results in the formation of kidney or bladder stones, which can cause life-threatening blockages of the urinary tract, especially in males. It’s identified through an inexpensive urine nitroprusside test for cystine available through the University of Pennsylvania. Medication, diet, and surgery are all options that may help. Dogs with this inherited defect should not be bred.
  • Gastric Dilatation Volvulus, Gastric Torsion, Bloat: this life-threatening condition can affect large, deep-chested dogs such as Bullmastiffs, especially if they are fed only one large meal a day, eat rapidly, drink large volumes of water after eating, or are allowed to exercise vigorously after eating. Raised feeding dishes and the type of food given may also be factors. It is more common among older dogs. GDV occurs when the stomach is distended with gas or air and then twists. The dog is unable to belch or vomit to rid itself of the excess air in its stomach, and the normal return of blood to the heart is impeded. Blood pressure drops and the dog goes into shock. Without immediate medical attention, the dog can die. Suspect bloat if your dog has a distended abdomen, is salivating excessively and retching without throwing up. He also may be restless, depressed, lethargic, and weak with a rapid heart rate. It’s important to get your dog to the vet as soon as possible. There is some indication that a tendency toward GDV is inherited, so it’s recommended that dogs who develop this condition be neutered or spayed.
  • Ruptured Anterior Cruciate Ligament: this common knee injury tends to occur in large young dogs during play and older overweight dogs. A twisting of the dog’s hind leg, which causes the anterior cruciate ligament to tear or rupture resulting in a sudden lameness in a hind leg. When the ligament is torn or ruptured, the tibia and femur can move against each other. This can lead to arthritis fairly quickly. Surgery is one form of treatment if the ligament is completely torn. If the ligament is only partially torn and other circumstances rule out surgery as an option, the rupture can be treated medically with special instruction on low-impact exercise and, if the dog is overweight, diet.
  • Cancer: dogs, like humans, can develop cancer. There are many different types of cancer, and the success of treatment differs for each individual case. For some forms of cancer, the tumors are surgically removed, others are treated with chemotherapy, and some are treated both surgically and medically. Cancers found commonly in Bullmastiffs include lymphosarcoma, osteosarcoma, hemangiosarcoma, and mast cell tumors.
  • Panosteitis:this is an elusive ailment sometimes seen in young dogs. Its primary sign is sudden lameness, and puppies usually outgrow it by the age of two years with no long-term problems. The lameness can be slight or severe and can be managed with canine pain relievers. Panosteitis is often misdiagnosed as elbow dysplasia, hip dysplasia, patellar luxation, or even more serious disorders. If misdiagnosed, the vet may want to do surgery on your dog that isn’t needed. If signs occur, ask for a second opinion from an orthopedic specialist before allowing surgery to be performed.
  • Skin Problems: bullmastiffs have sensitive skin that can be prone to rashes, sores, and irritations. They may also be prone to contact or inhalant allergies, caused by a reaction to substances such as detergents or other chemicals or airborne allergens such as pollen, dust, and mildew. Check your Bullmastiff’s skin regularly and treat any rashes quickly. Provide soft, clean bedding in crates and other sleeping areas to prevent sores. Sometimes a change to a diet with few or no chemical additives can help. Other Bullmastiffs need long-term treatment with antibiotics or steroids to keep skin problems under control.
Care Features

The bullmastiff can adapt well to many home environments, given his low energy. A fenced yard works best in order to keep him save from traffic, as well as prevents from expanding his territory beyond the boundaries of your yard. It’s best to keep his guarding skills to the area of your home rather than giving him more property to worry about, especially property that isn’t his.

His short muzzle makes him very prone to heat exhaustion and heatstroke. Exercise should be avoided during the hottest times of the day, and he should be kept indoors when it is extremely humid out. Always provide water to keep him cool and ensure that he has access to coming back inside or a shady tree.

Although he aims to please, the breed tends to think for themselves, and requires a constant trainer in order to keep them in line. Using positive reinforcement with consistency and a firm hand will definitely help the bullmastiff to shine. You should avoid repetitive training, however, or he will become bored quite quickly and start doing his own thing. This makes it easy for him to housetrain, since he’s always eager to please. He should be provided with a regular schedule and plenty of opportunities to go outside.

Feeding Schedule

Bullmastiffs care quite large dogs, and require a lot of food, even though they don’t have high energy. The recommended daily amount of food is 3 1/8 to 4 1/8 cups of food a day.

Coat, Color and Grooming

The coat of the bullmastiff is quite short and dense, and offers very good protection from rain, snow and the cold. It comes in three colors: red, fawn and brindle. He typically has a dark muzzle and ears, and may have a white mark on his chest. They don’t shed heavily, so they are quite easy to keep clean in maintaining their appearance. A quick brushing using a rubber curry will do the trick. Bathing is at a minimal and should only be done when necessary.

His ears should be checked on a regular basis in order to clean out dirt and ensure that there are no signs of infection. In the off-chance that you do find waxy material that resembles coffee grounds, then it’s more than likely that you have an ear infection or a mite infestation. In either case, your dog should be taken to the vet immediately.

Children And Other Pets Compatibility

Bullmastiffs are quite patient with children, but they are prone to knocking them over quite easily. Take their age and size into consideration when deciding to get a bullmastiff. Children should be taught how to approach your dog, especially when they’re sleeping or eating. This will prevent your dog from accidentally biting children. The bullmastiff can be aggressive towards dogs and other animals that he doesn’t know. They do better with dogs of the opposite sex, especially if they have been raised together. He may not resist the urge to chase cats within the home, even if he has been raised with them. You’ll do better if you have a cat that can stand up for itself.

This gentle giant looks more intimidating than he really is. The bullmastiff is a big softy who knows how to care for the home in your absence, and gladly accepts the job. A large dog with a large heart, his looks alone should dissuade any would-be intruder from trying to break in. He’s low energy, low maintenance, and is quite adaptable to any home environment. However, if you’re not able to be responsible for such a large dog, then the breed may not be for you.

About the author
John Walton
John Walton

John Walton lives in Somerville, MA, with his two dogs, two sons, and very understanding mate. He is a Certified Pet Dog Trainer, a member of the International Association of Animal Behavior Consultants, a mentor trainer for the Animal Behavior College, an AKC Certified CGC Evaluator, and the Training Director for the New England Dog Training Club.