While Cimarrón Uruguayo is the official registered name this breed may go by many different names including Cimarron, Cimarron Creole, Cimarron Dog, Maroon Dog, Cerro Largo Dog, Uruguayan Gaucho Dog and Perro Cimarron.
It is believed that the Cimarrón Uruguayo is the product of various molosser breeds brought by Spanish and European settlers to Uruguay. Many such dogs were released or abandoned causing a stock of wild dogs to flourish. At one point in the 18th century the wild Cimarrón population grew very large and was the cause of many attacks on livestock and humans. As a result, bounties were taken out on them in order to reduce their population. Many escaped the hunter however and many were taken in by ranchers and tamed so as to later become guard dogs.
Due to its history or fierceness and survival the Cimarrón later became a national symbol and the mascot for the national army of Uruaguay.
While many molosser breeds exhibit cropped ears history tells a unique story of why this has become known for this particular breed today. At a time when the breed was hunted for bounty the ears were often turned in to collect on the bounty award. By cropping the ears yet keeping a good guard dog this undoubtedly seemed the best of both worlds for some. Unique to their cropping is that the crop is rounded much the same way of the Cão de Fila.
Because the breed shares much of the same history as other molosser breeds it is not a surprise that it bears a strong resemblance to the American Pit Bull Terrier. As such this breed can be considered a good candidate in the now developing American Bully breed.