There is little evidence as to the origin of the present day North Ronaldsay sheep. Small and short-tailed, like other primitive sheep, this distinctive breed also shows a variety of colours and horn formations. However, their most unique feature is their diet, which consists mainly of seaweed. The sheep are confined to the foreshore by the Sheep Dyke, a dry stone wall that surrounds the island (see habitat map). There are also a few closely cropped grassy areas outside the dyke.
During the lambing period the ewes are brought inside the dyke to feed on grass for three to four months. Before being returned to the beach with their mothers, the lambs are earmarked so that their owners can identify them in the communal flock.
When the clipping season begins, the sheep are herded off the beach into the stone built 'Punds' by the collective efforts of the island's sheep farmers. The act of punding is perhaps one of the last remaining elements of communal farming in Orkney.