English Mastiff

Stuart Fitzgerald
Dr Stuart Fitzgerald (MVB MANZCVS, University College Dublin)
Photo of adult English Mastiff

The Mastiff is the largest of our pedigree dog breeds, and well-built males can weigh in at over 110 kg. Despite their massive size and imposing appearance, they are renowned for their gentleness, and make ideal living bean-bags for young children, should space allow. Once known as the English Mastiff or Old English Mastiff, the breed was several times rescued from the brink of extinction in its native England.

Though the subject of much debate and many conflicting theories, it is clear the Mastiff has a long and noble lineage, and related dogs are believed to have featured in Roman amphitheatres, locked in mortal combat with each other, with unfortunate prisoners, and even with lions. In centuries past, the breed was used for a huge variety of purposes, but it is clear that many of these required the dogs to be highly aggressive. This characteristic has all but disappeared, for it is hard to imagine a more placid dog to bring into a family home. However, Mastiffs retain a protective instinct, and can unleash inner reserves of aggression if they feel their family is being threatened. This, coupled with their sheer size, makes them ideal guard dogs, although they are known to be reluctant to bark.

As with many other large breeds, they can produce a lot of drool, which can put some owners off, but they are otherwise clean dogs. They are prone to relatively few health conditions, but because of their size have a short life expectancy of 7–10 years.

About & History

The progenitors of the Mastiff were dogs of the molosser type – a large working dog originating in the mountains of Central Asia, which were used to protect and herd livestock in a harsh environment. The exact path which our modern breed travelled is hazy, because for over several millennia, these dogs travelled and were traded throughout Asia and North Africa, and different strains were developed for their various roles. Notable among these were the dogs used for gladiatorial combat, as well as the packs of fearsome war-dogs that travelled with the Mongol hordes and Roman armies into battle. Excavations of ancient Babylonian ruins have even revealed depictions of mastiff-type dogs fighting lions, which is testament to the ferocity and courage these dogs must have possessed.

Meanwhile, in a less exotic setting, the ancient Britons had themselves developed a molosser-derived dog, the Pugnaces Britanniae, which the Romans believed was superior to similar dogs they had encountered in Greece, being a more aggressive warrior while also more loyal and dependable toward its owner. This variation in the molossers is reflected in the range of modern breeds that can lay claim to similar heritage, including the Bullmastiff, Dogue de Bordeaux, Rottweiler, Boxer, and even the Pug, to name but a few.

Even with the passing of centuries, these dogs continued to be used as instruments of violence, being used in “sports”, such as bear-baiting and dog fighting. One of the founding sires of the Mastiff line was owned by Sir Peers Legh, whose loyal hound stood in protection of him for many hours after he had fallen at the Battle of Agincourt in 1415. This dog was held in high regard by the Legh family, and was used to found one of the lines instrumental in crafting the breed in the centuries ahead.

However, with the advent of more modern warfare, coupled with the banning of many blood sports in the nineteenth century, the demand for the Mastiff had dropped dramatically, and numbers plummeted accordingly, particularly in the United States. This had the effect of concentrating the breeding and refining of the breed to a few devoted patrons, who improved and standardised the Mastiff through the second half of the nineteenth century.

By the end of the First World War, the breed was believed to be almost extinct outside of Great Britain, and exports to the United States and Canada were necessary to re-establish a breeding population on the other side of the Atlantic. The breed’s great size almost led to its demise during the Second World War, as food rationing meant that few owners had the wherewithal to continue feeding such a massive pet. In the aftermath of the war, only a single adult female (Nydia) remained in England, and the Kennel Club were forced to register a Bullmastiff-type male dog as an English Mastiff to allow Nydia find a mate. Redemption for the breed came in the form of dogs re-imported from the US, which helped to re-establish a healthy breeding population. The breed has since gone from strength to strength, being now one of the most popular giant breeds registered by many kennel clubs.


English Mastiff Large Photo

To state the obvious, the Mastiff gives an impression of bulk and power in its appearance. The large, square head is very broad, with massive masseter muscle development in the forehead. The crown of the head is quite flat and square, although even the eyelids are heavily muscled, giving a slight arch above each eye. A ridge between the muscles on either side is appreciable, running from midway up the crown to the top of the muzzle. The muzzle itself is broad and square, short in relation to the overall proportions of the head, and the strong jaws have well-developed flews, allowing the large teeth to be visualised when the dog is at rest. The eyes are quite large and normally brown in colour.

One of the most striking features when presented with a Mastiff is the massive musculature of the neck that is so pronounced as to create an arch at the top. This muscling continues along the long, wide back. Mastiffs have a large chest, which is both wide and deep, and deep flanks, without a marked abdominal tuck. The limbs are held wide apart due to the breadth of the body, and are very well muscled and boned. In motion, the breed should be sound, with a level back, though many larger individuals appear cumbersome at a trot.

The Mastiff’s coat is short, close-lying, and quite coarse. Though Mastiffs may be seen in many different colours, those recognised by the Kennel Club are:

  • Apricot
  • Brindle
  • Fawn

Black and blue variations are not uncommon, but again, are not eligible for registration. All Mastiffs have a black mask covering the muzzle, eyes, and ears.

Males must be a minimum of 76 cm (30 in) tall at withers, with the minimum acceptable height for a female being 70 cm (27.5 in). Males can reach truly enormous weights, but most fall into the range of 80–100 kg (176–220 lb). Females are obviously more lightly built, and average 60–80 kg (136–176 lb).

Character & Temperament

The Mastiff is a calm and even-tempered dog, which is affectionate and protective toward its owners. They are quite comical as puppies, being more skittish and awkward, but generally mature quite quickly for such a large dog. They are usually indifferent toward strangers, and should be well socialised to ensure they are at ease in the company of others. Any tendency to be nervous must be addressed at an early stage, because the protective instincts of this giant can cause some awkward situations if he is overly distrustful of strangers, as his first reaction will be to step in in defence of his owner. Mastiffs are also very dependent on feedback from their owners, and can become withdrawn or nervous in response to criticism, so care must be taken not to mistake size for insensitivity.

The breed is often described as being lazy, and managing to rouse them from bed is sometimes no easy task. With adequate exercise, most Mastiffs will happily live in a large indoor setting. However, they will not manage to climb stairs in their elder years, and this needs to be borne in mind, as these large dogs age quickly.


Photo of English Mastiff puppy

The Mastiff is not a breed for anyone wishing to win awards for obedience trials. Though eager to please, the breed has mastered the art of appearing interested while steadfastly refusing to absorb anything from a training session. Thankfully, most are easy to control with gentle coaxing and understanding, and they are quite easy to housetrain as puppies, but unfortunately, their merits as students end there! This is not to say one shouldn’t try to train their Mastiff, as the process has other benefits, including reinforcing the hierarchy within the family.

As discussed above, socialisation of young Mastiffs is important, and should involve positive interactions with both people and other dogs to any issue with dog–dog or dog–human aggression later in life.


Given the quite short lifespan of the Mastiff, it is surprising how few health problems are a major concern in the breed.

Behavioural Abnormalities

Though normally very placid, it is possible for Mastiffs to develop problems with aggression, particularly in the hands of timid or inexperienced owners of male dogs, which can be inclined to assume a dominant role in interacting with strangers and other dogs.

Corneal Dystrophy

This is a common problem in many breeds, where the clear tissue which forms the cornea at the front of the eye becomes defective. Pits and depressions in the cornea are the result, and although these often do not cause a major problem, some cases can be troublesome and difficult to resolve.


Along with their cousin, the Dogue de Bordeaux, Mastiffs are amongst the dogs most commonly afflicted by recurrent bouts of infestation with Demodex mites.

These are commensal parasites, meaning they live on the skin of most animals without causing problems, but a genetic immune deficiency in the breed allows these mites to proliferate, causing severe skin irritation. Though this form of mange was traditionally very difficult to manage, some recently developed treatments have made this far more amenable to treatment.

Gastric Dilatation-Volvulus

Also known as bloat, this condition involves swelling and twisting of the stomach, creating a surgical emergency which carries a very high mortality rate, due to the severe shock which rapidly sets in.

Feeding one large meal per day, rather than dividing the food between two or three meals, is a predisposing factor, as is exercise immediately after feeding, as the heavy stomach tends to “swing” within the large abdomen.


Mastiffs are prone to thyroid dysfunction, as are many other breeds. With a usual age of onset of 3–5 years of age, hypothyroidism results from destruction of hormone-secreting cells within the thyroid gland. Symptoms include weight gain, lethargy, and skin and coat changes, such as hair loss or pigmentation.


This is a cancer of the lymphatic system, which runs throughout the body in a series of interconnected lymph nodes. These nodes become large and firm, causing a range of signs, depending on the location affected.

While some dogs may have palpable and obvious swellings around their neck and upper limbs, others will simply lose weight or drink excessively. Surgery is not curative, and medical treatment aims to reduce the size of these swellings in order to improve and extend the dog’s life.

Osteochondritis Dissecans

Particularly common in young Mastiffs that are fed poor-quality food and/or exercised excessively before two years of age. Lines of weakness develop in the rapidly growing joint cartilages, resulting in pain and lameness. The shoulder, stifle, and hock joints are commonly affected.

Vaginal Hyperplasia

May be seen in young Mastiff bitches while in the oestrus phase of their reproductive cycle. Excess swelling of the vaginal tissues causes protrusion of the vaginal mucosa. This soft, vascular structure can easily become damaged on exposure, and many dogs will also self-traumatise the area in response.

Treatment involves keeping the tissue clean and hydrated. The condition is self-limiting, and will resolve after around two weeks, but affected animals do need to be spayed.

Exercise and Activity Levels

The Mastiff has fairly modest exercise requirements with one or two walks of 20 to 30 minutes each being sufficient. Care must be taken during very warm weather, as Mastiffs are prone to overheating, and walks should be completed in the early morning or late evening.


The breed sheds a 'normal' amount; however, a Mastiff has a large surface area, and even quite light shedding can leave a lot of hair lying around the house. Brushing twice a week will help to control this, and occasional baths help keep the coarse coat in good condition.

Mastiffs have very strong nails, which are unlikely to wear adequately on walks. Cutting the nails every 3–4 weeks is a good habit to get into to ensure they do not get overly long, but a very strong professional-quality nail clipper will be needed.

Famous English Mastiffs

Mastiffs have been a common sight on the silver screen for many years.

  • Mason who appeared in the 2007 Transformers movie
  • Buster, a character in the 2010 movie, Marmaduke
  • Hercules and Goliath are the terrifying guard dogs in the Sandlot and the Sandlot 2
  • Lennie was a dog in the film, Hotel for Dogs, made in 2009


Mastiffs are popularly used in the creation of so-called designer dogs, including:

User comments

There are no user comments for this listing.