New studies suggest that the secret to winter survival for some
Arctic foxes is their incredible ability to keep on the go for months on
end.
IN SPRING 2008, Canadian biologists began monitoring
a female Arctic fox living on Bylot Island, a landmass of mostly
mountains and glaciers that rises from the Arctic Ocean just north of
Baffin Island, some 250 miles west of Greenland. At first, there was
nothing unusual about the animal’s behavior. She found a den and a mate,
and together the pair carried out the exhausting task of rearing 11
hungry pups. But as fall set in, a switch seemed to flip inside her
brain—a switch that caused her to do something that for most other
animals her size would be a death sentence: She began to wander.
Initially, the fox moved northward off the island and onto the
permanent Arctic ice cap. She remained there for nearly four months,
zigzagging hundreds of miles over crumbled ice under conditions that
included minus 40-degree F temperatures and close to 90 days without
direct sunlight. Come April, she headed southwest, eventually reaching
Baffin Island, where she spent three weeks tracing a 620-mile loop
before returning for yet more time on the sea ice. She wasn’t finished.
In mid-May, she turned west and trekked another 750 miles before
eventually spending the summer of 2009 on Somerset Island, a low-lying
mass of mostly barren rock the size of Vermont. By the time a year had
passed, the intrepid canine had logged more than 3,100 miles.
Unlike many denizens of the Far North, Arctic foxes don’t hibernate,
hunker down in a den beneath the snow or migrate south during the cold
months. Instead, they remain active, taking the full cruelty of the
Arctic winter head on. How they pull off such a feat has long been a
mystery, but recent advances in satellite-tracking technology have
finally enabled scientists to monitor the animals’ movements during the
nine months of the year when the little predators are otherwise
inaccessible.
The first completed studies suggest that, at least for some of the
creatures, one secret to survival is their incredible ability to wander.
Arctic foxes that decide not to stay in one area during the long winter
appear to be true nomads, roaming distances that are continental in
scale. “What we’re finding is that for most of the year, the foxes that
leave don’t seem to have a home range,” says Dominique Berteaux, a
biologist at the University of Quebec at Rimouski who heads the ongoing
research on Bylot Island. “There’s no home. It’s all range.”
Records of the species’ unusual behavior date back more than a
century. During his failed attempt to reach the North Pole on foot in
the spring of 1895, Norwegian explorer Fridtjof Nansen encountered
several sets of fox footprints as he crossed the ice cap above the 85th
parallel. “What in the world was that fox doing up here?” he wrote in
his journal. Nansen, who was heading home at that point, took this sign
of life to mean land was near. In fact, he had another three weeks of
solid slogging before he reached the remote islands now known as Franz
Josef Land.
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