As for the future of the sheep, the team believes that they are still shrinking. Scientists first began studying Soay sheep, on the island of Hirta in the St Kilda archipelago, in 1985.Since then, the sheep have decreased in size by 5% – their legs getting steadily shorter and their body weight decreasing. The wild Soay sheep that live on the island of Hirta in the North Atlantic have been under careful scientific observation since 1985, partly because the island ecosystem is a simple one consisting of the sheep and the vegetation they eat.Further research will look at how much of the shrinkage is caused by a shift in sheep genetics and how much is the “young mum” effect where the lambs of young mothers are smaller because the mothers themselves are not yet fully grown.