Uruguayan dog breeds are mostly known for their loyalty, intelligence and athleticism. The most popular Uruguayan breeds are the Rastreador Uruguaya, the Dogo Uruguayo and the Ao Terceira. These breeds were developed from crosses between native South American dogs and imported European breeds such as the Boxer, Doberman and German Shepherd. All Uruguayan dog breeds are strong and hardworking, making them loyal and affectionate companions. They are excellent guard and working dogs, but are also very loving and gentle with their families.