An Arctic fox travelled 3506 kilometres over sea ice and glaciers last year during a 76-day polar marathon. Biologists documented the journey, which began on the island of Spitsbergen in the Svalbard archipelago, and ended on Ellesmere Island in Canada’s remote Nunavut Territory.
“Crossing extensive stretches of sea ice and glaciers, the female moved at an average rate of 46.3 kilometres a day,” says the study’s co-author Eva Fuglei at the Norwegian Polar Institute. “The maximum movement rate was 155 kilometres a day and occurred on the ice sheet in northern Greenland.”
We’ve known for years that the Arctic fox is capable of wandering over large distances – but now researchers are wondering what climate change might mean for future marathons on the scale of last year’s.
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Satellite tracking
The researchers monitored the fox using satellite tracking, which transmitted the animal’s location every three hours. At one point the 1.9-kilogram juvenile female was located at 84.7 °N on the sea ice off Greenland.
The migration is the first evidence that Arctic foxes can undertake cross-continental migrations. “It opens our eyes to how connected these different populations are,” says Helle Goldman, also at the Norwegian Polar Institute, who was not involved in the study.
Fuglei and her co-author Arnaud Tarroux suggest Arctic foxes migrate to find food, with the sea ice serving as a platform to link distant populations. Under their hypothesis, both long-distance migration and gene flow would depend on the sea ice – raising questions about how the foxes will cope as Arctic continues to warm.
“What we documented here – an individual using the sea ice as a platform for crossing Arctic continents – may be more and more rare in the years to come due to climate warming and the reductions of the sea-ice,” says Fuglei.
Some populations will become isolated. To make matters worse, as the treeline moves further north so do red foxes, who often displace their Arctic cousins. A warming climate also impacts the lemmings and other species on which Arctic foxes prey. The changing conditions may even influence .
Polar Research
Article amended on 25 July 2019
We corrected the extent of the trek
