Semi-wild and isolated to a 270-acre stretch of shoreline, the North Ronaldsay sheep are one of only two land animals that live exclusively on seaweed.
I didn’t think there could be anything cooler than the sea wolves who swim for miles and live off the ocean, found in a remote stretch of rainforest on Canada's Pacific coast. But then I heard about the sea sheep of Scotland’s North Ronaldsay island. The sea wolves have some competition.
Karen Gardiner at Atlas Obscura explains that they are a primitive breed, coming from the North European short-tailed sheep group. A relatively petite kind of sheep – measuring only 18 inches to their shoulder and rarely weighing more than 42 pounds – they’ve been on the island, evolving in isolation, maybe as far back as the Iron Age. And, as Gardiner writes:
Aside from the Galapagos marine iguana, they are thought to be the only land animals able to survive solely on seaweed. This is not just a quirk, but the result of necessary evolution.
The curious case of the sea sheep all began in 1832 when the island’s landowner made way for cattle and crops by exiling the sheep to the shore. Corralled in a 271-acre section of shoreline, the sheep are kept from wandering by a 13-mile-long stone wall called the sheepdyke. Being the master foragers that they are, they eked out a diet from among the black rocks of the shore, and have survived on the gifts of the sea ever since.
"They're very self-sufficient. They don't generally need human intervention in terms of lambing, or having problems with their feet, or anything like that," says Ruth Dalton of the Rare Breeds Survival Trust. "They're quite close to how sheep were in the wild, compared to what humans have done to them to put meat on in the right place and to have more wool and the rest of it."
Billy Muir, who has shared the rocky shore with the sheep for half a century as lighthouse keeper, knows the creatures well. He tells the BBC that they live by the tides, which determine when they eat and sleep. "They sleep when it's high tide and eat when it's low," says Muir. "They're governed by the moon and the stars, there's no doubt about that."
So there you have it. The sea wolves are incredible, but wee rugged sheep that live on seaweed, cavort with seals, and are ruled by the heavens? They might just give the wolves a run for the money.