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Gran Mastin de Borinquen Breed Description

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Breed Organization

United Kennel Club (UKC)

Native Country
Puerto Rico

Other Names
Becerillo de Borinquen, Mastin Borincano, Puerto Rican Mastiff, Perro Barsino de Hacienda

Life Expectancy
Approximately 9-12 Years

Litter Size
No litter information available.

Breed Group

General Description

Large size dog with stately manor and robust build. The dog has hanging ears, short to medium hair, square muscle, dewlap and hanging tail, thick root. The temperament is noteworthy for patience, composure, boldness and courageousness.

Breed Standard

Head: The skull, broad; stop rather abrupt; the muzzle, moderately long. The nasal bridge, straight; the nose large and black. The upper and lower jaws, strong; and teeth strong with strong canines and scissors bite.
Eyes: Relatively small and dark brown in color with expression of dignity.
Ears: Relatively small. Rather thin, and set on high of skull sides, hanging close to cheeks.
Neck: Muscular.
Body: The withers are high, back is level and straight. The loins are broad and muscular. Croup is slightly arched at top. The chest is broad and deep, ribs are moderately sprung. The belly is drawn up.
Tail: High, thick at root and tapering to the end which reaches close to the hocks.
Forequarters & Hindquarters: The shoulders are moderately sloping. The forearms are straight, moderately long and strong. The pasterns are slightly inclining and robust. Muscles of the hind legs are well developed. The joints of the stifle and hock are moderately angled and vigorous.
Feet: Closed, the pads thick and elastic. The nails hard and dark is desirable.
Gait: Robust and powerful.
Coat: Short to medium, hard and dense.
Color: Black, fawn, brindle or bone white; with any or all of these colors with brindeling. Splashes of white permitted, large or small, on head, chest, legs, or tail.
Height: Males: 61 to 71 cm (24 to 28 inches); females: 56 to 66 cm (22 to 26 inches).
Weight: Males: 45-68 kg. (100-150 lbs), females: 41-57 kg. (90-125 lbs).


Rarely available today, El Gran Mastin was established as an internationally recognized rare breed by la Sociedad Cynologica Caribena( S.C.C.) in 1979. A tremendous amount of interest has been generated by the work being done to carefully restore the dog to its place among the Caribbean dog fancy. It was only during the last part of the 19th century that local recognition began with the overseer's of the Sugar Cane, Tobacco and Coffee plantations. El Gran Mastin de Borinquen are by origin and type the "Old Country" dogs tuned to cold rain forest region mountains, hot "campo" hills and the tropical valley lands of Puerto Rico. Country folk would come from near and far to acquire a pup- in exchange for produce, game chickens, goats, hogs or just plain friendship and a handshake.

This magnificent breeds ancestry is deeply rooted in the history of the Spanish Conquest in the Caribbean and Latin America. For centuries Spanish Landlords and Noblemen kept these Molossi (referred to as bloodthirsty) for protection and bloodsport. They are adept at bringing down feral steer, boar and dogs; fighting to the finish if allowed to, just as they did during the colonization servicing the Conquistadors as gladiators and war dogs. During those days their quarry was most of the time human, particularly during the "Spanish Encomendado"- early 16th century. Helping enforce the Spanish reign in Latin America, the El Gran Mastin de Borinquen did this out of loyalty and desire to please his master. The Mastin is noble, courageous and loyal- many died protecting their masters during the Spanish-Indian Wars. A perfect example is the case of Don Sancho de Arango in 1513, mentioned in the "Discovery, Conquest and Colonization of Puerto Rico" and in "Apuntes para la Historia de Humacao" both by Dr. Ricardo E. Alegria. These make reference to the Carib attack (cannibals) made against the plantations on the Cayarabon River now called Loiza. The attack was so violent that despite a heroic defense many were killed by Carib arrows. The Indians captured Don Sancho de Arango, but the fierce attacks of his dog Becerillo (legendary terror of Borinquen), forced them to release the master, who fled. The brave animal, who some say was really owned by Ponce de Leon, fought to the end, as did his son - Leoncillo. Both died in the aftermath of the terrible battle felled by poisoned arrows.


The dog would do anything to please its master. It forms a strong relationship with humans but the dog is not recommended for families with very small children. The sheer size not to mention the rather unstable temperament of the dog is potentially dangerous to the children. Because of the huge bulk, the dog is not recommended for a person with limited physical strength. This breed definitely needs socialization and obedience training because the dog is noted to be aggressive towards other dogs. The dog is intelligent but it has a stubborn streak. Throughout the history of the Gran Mastin de Borinquen, it has been used as a guard dog. The Mastin is already a phenomenally strong dog with well developed protective instinct. Further training to be a guard dog will not be necessary lest the dog become too aggressive.

The dog may prefer to lie around rather than to walk or run but an owner of this dog must ensure that the pet would have at least one hour of exercise everyday. This breed is not for apartment living not only because of the massive size but because the dog loves to be outdoors.


Guard dog, Pet.


The Gran Mastin de Borinquen is generally a very healthy breed, but is susceptible to issues that effect dogs of this size.

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