The Shetland Sheepdog, often known as the Sheltie, is a breed of herding dog that originated in the Shetland Islands of Scotland. Rather, the Sheltie is a descendant of small specimens of the Scottish Collie and the King Charles Spaniel. They were originally a small mixed-breed dog, often only about 8 to 12 inches in height at the shoulder, and it is thought that the original Shetland herding dogs were of the Spitz type, and were crossed with Collies from mainland Britain. In the early 20th century, Shetland Sheepdogs have four times the risk of other dogs of developing transitional cell carcinoma, a cancer of the bladder. In the early 20th century, Shetland Sheepdogs have four times the risk of other dogs of developing transitional cell carcinoma, a cancer of the bladder.