The Collaborative International Dictionary of English v.0.48:
Shetland pony \Shet"land po"ny\ One of a small, hardy breed of horses, with long mane and tail, which originated in the Shetland Islands; a sheltie. [1913 Webster]WordNet (r) 3.0 (2006):
Shetland pony n 1: breed of very small pony with long shaggy mane and tail