Breed At A Glance


Loyal, protective, and gentle towards family members

Life Expectancy
10-12 years

Average Height
Males 30+ inches; Females 27+ inches

Average Weight
Males 160-230 lbs; Females 140-190 lbs

Coat Color
Golden fawn, light fawn, brindle, silver, tiger, and apricot

Coat Length/Texture
Short and smooth, with no undercoat

Shedding Propensity
Consistent year round

Also known as English Mastiff, Old English Mastiff

General Temperament

The Mastiff is a patient and noble breed, a far cry from their ancestry as fighting dogs. They are calm, dignified and good-natured. They are surprisingly docile and gentle with family members and children (although they should be supervised with toddlers because of their size). They are also intensely loyal and protective, often courageously positioning themselves between their master and a perceived danger; if the offending stranger does not back down, they should be prepared for defensive action. Like many breeds, they crave the attention and affection of their families and can become destructive if left alone for long periods.

The massive Mastiff functions best in a country or suburban setting, where they have plenty of room to move, although they can function well in an apartment if they have enough time to exercise. They are laid back and easy-going, and can tend toward laziness as they age. For this reason, it’s important for owners to be sure to maintains the dog’s activity to help prevent obesity and other potential medical issues.

Training is very important with this breed due to their massive adult size. An owner will be wise to begin consistent obedience training from puppyhood, otherwise the dog can be uncontrollable as they get bigger, often outweighing their owners as adults. Mastiffs are intelligent and eager to please, and training should always be gentle and respectful, never harsh or heavy-handed. Socialization from puppyhood is also very important, otherwise they can be combative with other family pets.

Breed History

The Mastiff is descended from the ancient Molossers, a group comprised of several breeds of large, solidly-built dogs, probably all descended from the same root stock (the name is derived from Molossia in North-West Ancient Greece). The Old English Mastiff was probably brought to England by Phoenician traders as early as the 6th century BC. They are recognized as the oldest British breed, although it can be found throughout world history and has contributed to the development of a number of dog breeds. Mastiffs were used in the blood sports of bear-baiting, bull-baiting, dog fighting, lion-baiting, and even in the gladiator arena. On the lighter side, they were also used as sheep guardians, bodyguards and companions.

There is evidence that the Mastiff originally came over the to United States on the Mayflower. In England, they were almost extinct by the end of World War II as a result of the Cruelty to Animals Act of 1835, which banned the baiting of animals. But with imports from the United States and Canada, the breed was once again well established in England.

Body Structure and Composition

The Mastiff is one of the largest and heaviest breeds, with males weighing as much as 200+ pounds; females are usually slightly smaller but still quite massive. They have a rectangular and symmetrical body, with a square and massive head and short muzzle. The lips hang long and loose from the cheeks, and some Mastiffs have a slight underbite. The fur on the ears, muzzle and around the eyes is always black, despite the color of the rest of the body. Mastiff ears are pendulous and lay flat against the face. The tapered tail is set high and hangs down with a slight curve when the dog is in motion.

Medical Information

Like many large breeds, the Mastiff is prone to Hip or Elbow Dysplasia, a condition in which the head of the bone no longer fits firmly in the “cup” provided by the socket, causing lameness and arthritis-like symptoms. Another major problem for this breed is Gastric Dilation Volvulus (GDV), also know as bloat/torsion. Excess gas trapped in the dog’s stomach causes “bloat,” and twisting of the stomach (volvulus or “torsion”) causes or is caused by said excess gas. GDV is an emergency condition requiring immediate veterinary treatment. Feeding a Mastiff two or three meals daily, instead of one large meal, can help to prevent GDV. (Some suggest that feeding the dog from a raised platform may also help.)

A more minor concern for Mastiffs is Cystinuria, an inherited disorder that is characterized by the formation of cystine stones in the kidneys, ureter, and bladder. They can also experience various eye abnormalities, including Entropion (eyelids folded inward) Persistent Pupillary Membrane (PPM, when remnants of a fetal eye membrane persist as strands of tissue crossing the pupil, potentially causing cataracts), and Progressive Retinal Atrophy (PRA, a degeneration of cells of the retina later in the dog’s life, leading eventually to loss of sight).

Some Mastiffs develop Osteosarcoma, the most common form of malignant bone cancer, although this generally affects the dog later in life. Another bone-related disease seen in this breed is Osteochondritis Dissecans (OCD), a painful condition in which fragments of cartilage or bone have become loose within a joint, leading to pain and inflammation. Cardiomyopathy, or the deterioration of the function of the heart muscle, has also been seen this breed, although it is somewhat rare.

When purchasing a purebred Mastiff, experts often suggest that the dog undergo tests for hips, elbow, eyes, thyroid, and DNA for PRA.

Mastiff puppies grow very quickly, and their diet should be closely monitored. Also, they have a tendency to drool and snore – a nuisance for owners, but something you just have to get used to.

Anecdotal Information

In 1989, a male Mastiff named Zorba de la-Susa was recognized by Guinness World Records as the heaviest dog in the world at 343 pounds.

When Sir Peers Legh was wounded in the Battle of Agincourt in 1415, his Mastiff stood over and protected him for many hours through the battle. Legh later died, but his Mastiff returned to his family’s home and sired the Lyme Hall Mastiffs. This line featured prominently in the foundation of the modern English Mastiff breed.

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