The Pyrenean Mastiff (Spanish:Mastín del Pirineo, Aragonese:Mostín d’o Pireneu) is a large breed of dog originally from the Aragonese Pyrenees in Spain. It should not be confused with the Pyrenean Mountain Dog.
The Pyrenean Mastiff is a very large dog, males 77 centimetres (30 in) and females 71 centimetres (28 in) at the withers, although they can be up to 81 centimetres (32 in). They have a heavy white coat with large darker spots. The average weight is about 81 kilograms (179 lb), although males can often weigh over 100 kilograms (220 lb).
For a long time the Pyrenean Mastiff accompanied the herds of sheep in its migratory paths from the Aragonese and Navarrese Pyrenees until Maestrazgo. Its main function was to guard and protect the herds and its masters from the attacks of wolves, bears and thieves. During the 20th century, especially after the Spanish Civil War, due to economic difficulties, the mastiff went into decline as it was very expensive to keep a dog of its size. In the 1970s a group of fans started a job of recovery of the breed through the few specimens that were in the countryside and still had typical features of the ancient mastiff. It has been documented since 1977 as a modern purebred breed by the Club del Mastín del Pirineo de España in Spain.
The mountain dog breed is now being taken from its native region and promoted as a pet in other countries like USA by the Pyrenean Mastiff Club of America. It was recognised by the Fédération Cynologique Internationale in 1982.