Breed Group: Working

Temperament and Behavior

The giant of the breeds frequently referred to as the gentle giants, Mastiffs are known best for their size and their calm, gentle, easy-going personality. They crave human companionship seeking out praise and affection. When well socialized and trained, they are loyal, devoted, and friendly, making them excellent companion dogs. They are generally good with children and other animals, however, given the breed’s size caution should be used with toddlers. They are respectful of strangers, which, when combined with their massive size, make them an above average guard dog and an exceptional watchdog even without barking, which they rarely do. Sedentary dogs with a relatively low energy level, they require a minimum of exercise and play time, although interaction with humans is crucial. They are not easily excited and make calm house pets, but require not only more interior space than many households have available, but a large car to transport them, large budget to feed them, and providing for all of their other giant-size needs. Not for people who need order and neatness, Mastiffs drool and sober copious amounts, especially after eating or drinking. When they shake their huge heads, everything nearby will be spattered with slime. Another trait, endearing to some, annoying to others, is their tendency to snort, grunt, and snore quite loudly. Many Mastiffs also howl at the sound of a close by siren.

Physical Characteristics

Massive, powerful dogs, their height averages from 28 to 34 inches tall and they weigh between 175 and 200 pounds with females being toward the lower end of these ranges. Although many pets are about 40 pounds lighter, Mastiffs can grow much larger and heavier. They have a short to medium coat, ranging in color from fawn to apricot, or brindle. No matter their coat color, all Mastiffs have a black mask surrounding their eyes and nose. Coat care is about average, brush them once or twice a week. They are average shedders. This breed does not tolerate heat and great care should be taken when exercising or traveling to protect them from it. Although capable of living outdoors in cool temperatures it is suggested Mastiffs live inside with their families- the companionship is important to them.

Trainer's Notes

With some lines being shy and some others tending toward aggression, Mastiffs need a reasonable amount of early, continuous socialization. If a shy dog is not socialized adequately, their shyness can turn into fear aggression which can result in defensive biting. To keep them under control, at the very least, owners should commit to basic obedience training well before they reach their adult size. With some having a propensity for stubbornness and a tendency to bore easily, they present a challenge to a novice trainer. Gentle training in short sessions several times a day is advised. Mastiffs have the potential to be wonderful companions, in fact, many are therapy dogs. But if not handled properly, they also have the potential to be a danger to society and a significant liability for their owner. As a result, this is not a breed for an unsophisticated dog owner.

Photo © by Radovan Rohovsky available under the GNUFDL



Health problems include 1 in 5 dogs affected by Hip Dysplasia with another 15% affected by Elbow Dysplasia. As with any deep-chested dog, owners should be familiar with Bloat. Several issues are seen that affect their eyes including Ectropion, PPM, and PRA, which causes blindness. Cystinuria, a specific type of urinary tract stone which requires special treatment, occurs in about 10% of males but very few females. Seizures affect another 10% of the breed with Epilepsy considered the leading culprit. Bone Cancer is also disproportionately seen. Mastiffs grow at such a fast rate, it’s important not to over-exercise dogs under 2 years of age as this can lead to joint problems. Like most giant breeds, Mastiffs have a relatively short life span, typically 6-8 years.


The AKC ranks Mastiffs 33rd in popularity with almost 7,000 dogs registered yearly.

Breed History

An ancient breed, their origins are lost in time; but many theories exist. Drawings similar to Mastiffs appear on Egyptian monuments, dating to 3000 BC. There is evidence of giant, mastiff-like dogs in Asia as far back as 2500 BC. Carvings from the Babylonian palace of Ashurbanipal depict mastiff-like dogs hunting lions. Phonecian traders may have brought them to England as early as the 6th century BC. The earliest reference to the Mastiff in literature appears in 1121 BC. In 219 BC, Hannibal had mastiff-type dogs in addition to elephants when he crossed the Alps to attack the Romans. The Romans used a mastiff-type dog called the Molossus as a war dog and as gladiators. English writer Geoffrey Chaucer described Mastiffs as “large as steer” in his writings in the late 1300s. In England, Mastiffs became popular as guard dogs and, as in Rome, they were used for entertainment in dog fights. There is evidence the first Mastiff came to America onboard the Mayflower with the breed becoming well established by the late 1800s. Nearly destroyed in Europe by both World Wars, it was reintroduced using stock from America.

Additional Information

Around the world Mastiff describes a number of breeds; but, in the U.S., Mastiff refers to the Old English Mastiff. The National Breed Club is the Mastiff Club of America.

Is A Mastiff THE BEST Dog For YOU?

Recommended Articles

Three Mistakes Most People Make Looking For A Dog

Six Questions You Must Be Able To Answer Before You Can Find Your Best Dog


The Complete Dog Selection System