The Cimarron Uruguayo descends from Spanish and Portuguese dogs taken to South America by early explorers. A lot of these dogs were released/abandoned in the wild and over time, their numbers began to increase as they began to breed among themselves. These large packs of wild dogs became a nuisance as they would regularly attack and kill livestock. The Uruguayan government began to pay bounties to anyone that killed these dogs, as they tried to reduce their numbers and the impact they were having on livestock. Some farmers began to catch these dogs and instead of killing them, they began to domesticate them and work them around the farm. This was the beginning of the Cimarron Uruguayo breed as breeders began selectively breeding them for farm work.