According to the AKC breed standard, the Mastiff is a large, massive dog that gives off an impression of grandeur and dignity.
Both males and females of the breed are massive throughout with powerful proportions and strong muscles. Males stand at least 30 inches high while females stand at least 27.5 inches tall. Bodyweight ranges from 120 to 180 pounds for females and from 150 to 250 for males. The body is massive and heavy-boned, with a large, broad head and dark eyes. The Mastiff has a short, broad muzzle and a scissors bite.
The name "mastiff" can be confusing, because there are several dog breeds with that word in their names, e.g. the Neopolitan mastiff and the Tibetan mastiff. Officially, these breeds are known as "mastiff-type dogs." When kennel clubs use the name "mastiff" without qualification, it's usually safe to assume they're referring to the breed also called the English mastiff or the Old English mastiff.
When it comes to the body, the Mastiff is very muscular with a deep chest and well-rounded ribs. The tail is set moderately high and tapers to the end. The breed has a powerful gait that projects an image of balance at all speeds. The coat is short and close-lying with two layers. The outer coat is straight and coarse in texture while the undercoat is dense and close-lying.
The development of the mastiff as we know it started in 1835.Before 1835, mastiffs were bred largely (though not exclusively) to participate in these cruel and brutal "sports," and so they were intended to be tough and vicious. After 1835, viciousness was gradually bred out of mastiffs, transforming them into the gentle and peaceful giants we enjoy today.
The Mastiff is primarily known for his size and courage. These dogs are courageous and protective which is why they make such great livestock guardians. In the home, however, they are extremely gentle and kind. You may be surprised to learn that this breed gets along very well with cats and other household pets – they’ve even been known to try to take care of smaller animals. Mastiffs are also great with kids – they are gentle, patient, and loving, though they can sometimes be protective if they think a family member is in danger. This breed has a loud, formidable bark which can sometimes be scary for strangers. You should always introduce your Mastiff to new people you bring to the house to help counteract his protective tendencies.
These dog’s don’t typically work as attack dogs, but they will alert you when someone approaches the house and their size and bark is often enough to deter potential threats.
The Mastiff was developed partially as a livestock guarding breed, bred to work in the mountains of Asia. As such, these dogs have the ability to roam for hours on end but their needs for exercise are not particularly high. A 30-minute walk once a day is usually adequate for this breed and you should definitely not subject him to any rigorous exercise – especially before he is fully grown.
Kennel clubs accept three Mastiff coat colors. You get to choose between fawn (light yellowish tan), apricot (light reddish brown) or brindle (fawn or apricot mottled with black). If you see a dog of any other color advertised as a mastiff, it's not pure mastiff.