RESEARCHERS in Durham say a mini Ice Age allowed Arctic foxes to colonise Iceland.
They claim a bridge of sea ice appeared during a dip in temperatures between 200 and 500 years ago, known as the Little Ice Age.
This encouraged the Arctic foxes to migrate to Iceland from different Arctic regions including Russia, North America and Greenland.
The research, led by scientists at Durham University, said the findings highlight the importance of sea ice in creating and maintaining the population of the arctic fox across the polar regions.
The multi-disciplinary approach used for this project could also be used to track the migration of other animals found on remote islands.
The Little Ice Age saw temperatures plummet in the 16th to 19th centuries across large parts of Europe and North America in particular.
Rivers such as the Thames were frequently frozen enough to support ice skating and winter festivals.
The researchers analysed DNA samples from ancient remains of Icelandic Arctic foxes, dating from the 9th to 12th century and compared the findings to DNA data from their modern successors.
They found that the ancient foxes shared a single genetic signature, while the modern population possessed five unique signatures and concluded the most likely explanation was migration across sea ice that formed during the Little Ice Age.
Senior author of the research, Dr Greger Larson, in Durham University’s Department of Archaeology, said: “Even today Arctic foxes routinely travel hundreds of miles across sea ice and once the ice bridge was in place, they easily crossed the North Atlantic and were able to arrive on Iceland, increasing the genetic diversity of the population.
“To paraphrase Dr Ian Malcolm in Jurassic Park, ‘life will always find a way’, and in this case, once the Little Ice Age began, Arctic foxes didn’t need much of an opportunity to colonise Iceland.”
Dr Larson said that potential for animal migration had decreased significantly during the 20th century, a trend which global warming had accelerated.
He said: “Without the sea ice, there will be no new fox migrants and thus the Icelandic population will continue to diverge from their mainland relatives.”