(CNN)The isolated Faroe Islands were once home to an unknown population in 500 AD, about 350 years before Vikings ever arrived, according to new research. And the evidence comes from an unusual source: ancient sheep poop.
Ancient sheep poop reveals an unknown population on Faroe Islands before Vikings
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The striking Faroes are a small archipelago located in the North Atlantic halfway between Norway and Iceland. Vikings reached the islands once they developed ships for long-distance sailing, about 850 AD, before they moved on to Iceland in 874. For a long time, researchers believed they were the first human inhabitants of the rugged Faroes.
Until this century, the only evidence for the first people to set foot on the Faroes ahead of the Vikings came from mentions in medieval texts. There is no current evidence to suggest that Indigenous people ever lived there.
In 2013, researchers found ancient burnt barley grains beneath the floor of a Viking longhouse on the Faroese island of Sandoy.
The grains were dated between 300 and 500 years before the Norse occupation of the Faroes. Barley was not native to the islands ahead of humans living there.
In order to find more evidence of this group of humans, a research team formed to conduct an investigation of a lake on the Faroese island of Eysturoy. While no homes or archaeological evidence have been found from this early group of explorers, this team decided to take a different approach to determine when humans arrived on the Faroe Islands.
Specifically, the scientists wanted to collect lake sediment cores.
"Lakes are amazing archives of environmental information, because they accumulate material from the surrounding landscape in sequential layers in their sediments," said lead study author Lorelei Curtin, a postdoctoral research associate in the University of Wyoming's department of geology and geophysics.
"Each member of our team uses different tools to analyze the lake sediments, and by working together, we gain a holistic understanding of changes in the environment, including human impacts on the landscape," she said.
When they reached Eysturoy, the team members set out in a small boat on a lake near the village of Eiði, which once hosted a Viking settlement. They dropped weighted tubes into the lake bottom and collected cores that were 9 feet (2.7 meters) in length -- collecting 10,000 years of environmental history.
The analysis of the lake sediments revealed the sudden presence of domesticated sheep in large numbers, arriving between 492 and 512. Sheep leave distinctive biomarkers in their fecal matter that were traceable as DNA in the sediments. The researchers were able to use a layer of ash, from the known eruption of an Icelandic volcano in 877, to help them establish dates.
Before the arrival of these sheep, there is no evidence of mammals on the island, so the sheep must have been brought by people arriving on the Faroes. Today, sheep are a staple of the Faroese diet.
The appearance of the sheep also aligned with the disappearance of woody plants, like willow, juniper and birch.
"After humans arrived and brought sheep with them, the vegetation changed," Curtin said. "We see more grass-type vegetation, which is consistent with landscape modification from animal grazing. This what we see on the Faroes today."
The study published Thursday in the journal Communications Earth & Environment.
Archaeologist Kevin Edwards, an environment researcher and prof