Breed of sheepdog developed from a Scottish working dog to herd the small sheep of the Shetland Islands. The sheltie resembles the rough-coated collie but in miniature; it stands 13–16 in. (33–41 cm). Sturdy and agile, it is noted for its herding ability, intelligence, and affectionate nature. Its long, straight coat is generally black, brown, or blue-gray with black mottling.