Norwegian lemmings may have survived the last Ice Age sequestered from other mammals by a large ice sheet in the northern Nordic extremes, according to a new report.
Ancient DNA analysis of the Norwegian lemmings - which are endemic to the Fennoscandian mountain tundra - has revealed that the creatures are too far genetically removed from other lemming species that originated farther south. The revelation suggests that the tiny creatures managed to survive an entire Ice Age by holding out along the coastal areas or mountain plateaus in the north of Fennoscandia, which encompasses the Scandanavian Peninsula, Finland, Karelia and the Kola Peninsula.
Twenty-thousand years ago, Fennoscandia was covered in a thich sheet of ice. At that time, the land was presumably inhospitable for most animal and plant life, and creatures living in a less icy Fennoscandia today are thought to have come from populations originating farther south or east.
Writing in the journal Molecular Ecology, a team of researchers from the Swedish Museum of Natural History reports on their investigation into the origin of the Norwegian lemming.
"We found that even though the populations surrounding the ice sheet were closely related to modern day lemmings, none of them were similar enough to be the direct ancestor of the Norwegian lemming," said Love Dalén, an associate professor at the Swedish Museum of Natural History.
Dalén and the other researchers concluded that the because the modern populations of lemmings in the regions are not genetically similar enough to be direct ancestors of the Norwegian lemming, the best explanation for the unique genetic composition of the creature is that it came from a linage that lived in isolation on the north side of the ice sheet, cut off from other lemming populations.
"The Norwegian lemming is the only endemic mammal in Fennoscandia, and its unusual origin is probably the reason why," said lead study author Vendela Lagerholm.