A small, compactly built pony of a breed originating in the Shetland Islands, having a long thick mane and tail. a small strong horse with long rough hair (Shetland islands north of Scotland). Breed of pony that originated in Scotland's Shetland Islands. Well adapted to the islands' harsh climate and scant food supply, Shetlands were used as pack horses. Around 1850 they were taken to England to work in coal mines and to the U.S., where a more refined pony suitable for children was developed. Except for certain dwarf ponies, the Shetland is the smallest breed of horse. Its average height is about 40 in. (102 cm; Shetlands are not measured in hands). Shetlands are long-lived and need little care; they are gentle and even-tempered if properly trained