One of our largest pure breeds, the Spanish Mastiff, a Livestock Guardian Dog, has been essential to Spain's sheep industry since the earliest times. He protected large flocks from wolves and bears as the flocks that were seasonally taken from the valleys to the mountains in search of grazing pastures. With the collapse of Spain's sheep industry, Spanish traditionalists resurrected this ancient breed so it can be preserved in form of the pure breed we know today.
History of the Spanish Mastiff
The first historical reference to the Livestock Guardian Dog of Spain dates back to before 100 AD and comes from a contemporary of Jesus. Basically it said the Spanish Mastiff had to be drop eared, had a body longer than height at withers, a wide chest, and big legs and feet covered with thick hair. He was athletic enough to chase wolves and bears when they flee, but heavy enough to fight them if necessary. He was alert enough to frighten either an animal or human thief, but discreet enough not to frighten the family of the Mesta or shepherd in charge of the flock. He was of one dark colour so that he was a formidable sight during the day, but did not stand out at night.
Spanish Mastiff with Flock
Over the next millennium, these dogs developed a little differently in different regions. By the eighteenth century, there were 5 million merino sheep circulating around Spain from the north to the south and from the east to the west in massive herds. These sheep moved along a number of trails up to 20 meters wide, twining up and down the mountains occupying 120,000 km or 1% of the country. The network was completed with many livestock landmark buildings, mills, troughs, resting places, pastures etc. The seasonal movement of flocks from one place to another, usually to better pastures is called transhumance.
The merino sheep and wool industries became vital to Spain's national economy. Because the wolf was such a threat to these massive herds, the traditional role these dogs played is as legendary as the Mesta or shepherds who were in charge of them. As these Mesta lived in remote places, they had to be clever in breeding the functional Spanish Mastiff. But as the sheep industry in Spain declined, so did Spanish Mastiff numbers.
The Spanish Mastiff becomes a Pure Breed
Spanish Mastiff on Duty
Many traditionalists became interested in preserving this wonderful breed whose reason for existence was so much a part of Spain's history. In 1946 the first Breed Standard was drawn up by the FCI. But many agreed it should have been based on the heavier type of dog located in Spain's North. So with sufficient breeding stock still available, in 1982 a new Standard was FCI approved, with the Stud Book overseen by the Spanish Association of the Dog (AEPME). But because these are the largest of the Mastiffs, it is important that the new breeders and judges alike understand the historic function of these wonderful dogs, and select those that are not only large, but also not too cumbersome to do the traditional job required by the nomadic Mesta of Spain who made them so famous.
The Spanish Mastiff Today
Spanish Mastiff Profile
Today the Spanish Mastiff is a giant breed with no size upper limit provided the the dog is of harmonious proportions and is over 31.5 inches (80 cm) for a male and 29.5 (75cm) for a bitch.
He has a balanced body with a body length that is longer than square. His massive head consists of a broad slightly rounded skull, at least as wide as it is long, with a slight stop. The skull is longer than the rectangular foreface or muzzle, with the bridge of the nose straight from the stop to the nose. The upper lip overhangs the lower lip with the skin folds extending to the corners of the eyes. The lips and membranes inside the mouth should be black and he has a normal scissors bite. The eyes are small in proportion to the head, and preferably dark hazel. The black eyelids are thick with the lower lid showing just a little haw. He has dropped ears, set just above the line of the eye, with the back one third coming forward when alert.
Spanish Mastiff leading Sheep
The neck should be of a length to give symmetry to the whole body. It should be broad and covered with a thick loose skin forming an amply developed double dewlap. The forelegs should have solid bone, be perfectly straight right down to the slightly sloping pastern and cat feet. Both the forequarters and hindquarters have moderate angulation capable carrying this large dog with an easy, strong, harmonious and powerful trot, without pacing. The hocks may have single or double dewclaws, but these may be removed. The tail is thick at the root and set as an extension of the topline. Sometimes there is a curve in a sabre fashion, especially when the dog moves or is animated, but it should never be carried over the back.
The skin over the body is thick and loose and covered with a dense, medium length smooth coat covering the entire dog. Sometimes the coat on the back itself differs from that on the flanks and ribcage. Although all colours are allowed, yellow, fawn, red, black wolf and deer colours are the most sought after as they blend best into the surroundings or the flock. To this end, brindle, parti-colours or dogs with a white collar are also acceptable.
References and Further Reading
 Ortros Group, http://mastinesibericos.es, Spain (paraphrased with permission).