The Australian Cattle Dog, also known as the Blue Heeler, the Queensland Blue Heeler, and the Queensland Red Heeler, is a breed from the 19th century. Because of Australia’s rugged and demanding terrain, stockmen found themselves in need of a herding dog strong and tenacious enough to withstand the continent’s conditions. Although the specific breeds used for the modern day Cattle Dogs is unknown and hotly debated among breeders, it is speculated that Dingoes, Dalmatians, Bull Terriers, Smooth Haired Scotch Merle Collies (themselves a cross-breed between the Rough Haired Scotch Collie and the Blue Italian Greyhound), and Australian Kelpies play a role.