This video is about Arctic foxes.
From New Scientist:
Arctic foxes took ice bridge to reach Iceland
11:28 12 September 2012
by Jessica Hamzelou
FLUFFY, snow-white and dedicated trekkers. Arctic foxes (Vulpes lagopus) are known for their mammoth wanderings across the ice. Those journeys may have taken some to Iceland during the Little Ice Age.
Recent research into the foxes’ genetics has revealed that there are at least five distinct groups – or haplotypes – found in Iceland. But when Greger Larson at Durham University, UK, and his team looked at fox DNA in 1000-year-old bones from archaeological sites in Iceland, they found that all of the ancient Arctic foxes belonged to just one of the five haplotypes.
“It’s too short a time for the [other four] to have evolved,” says Larson.
Instead, his team think the Little Ice Age might provide an explanation. This period of cooling, about 800 years ago, froze huge areas of the Arctic seas. It provided nomadic Arctic foxes elsewhere in the frozen north with a bridge to Iceland.
“Some foxes are known to roam for hundreds of miles on sea ice,” says Larson. “All you need is a little ice, and bang – the foxes are there.”
Journal reference: Proceedings of the Royal Society B, doi.org/jb8
See also here.