Are there arctic foxes in Antarctica

Eight large cages stand in the Norwegian tundra below bare hills, covered with green-brown moss, grass and lichen. Something is moving in one of them. A pair of arctic foxes walk together along the meter-high fences, past draped slate rocks and green painted barrels that serve as hiding places. They are still wearing their brown and white summer fur, which protrudes disheveled in some places. Its run is easy, the large, fluffy tail swings elegantly behind it.

The arctic fox is something of a national animal in Norway, but it is critically endangered here and in Sweden. While there are still quite a few animals in Siberia, Svalbard, Greenland, Canada and Alaska, their populations on the Scandinavian mainland have become so small that they are completely dependent on conservation measures like this one - and on people like Arild Landa. The 61-year-old with short gray hair and a tanned face heads the rearing project near the town of Oppdal, south of Trondheim. His dark blue overalls and gray hiking shoes are covered with a light, earthy layer. The Norwegian has specialized in high alpine ecology. He speaks slowly and chooses his words carefully. "A large, dark shadow hangs over the arctic foxes: climate change," says the biologist, pulling off his thick work gloves.

The largest arctic fox population in Norway lives in Dovrefjell National Park, which begins here, says Landa. This year, however, there are few offspring. Only 19 puppies in the station, in the previous year there were almost 50. Even in the wild there are very few, a litter with two puppies. "Maybe they take a year off," says Landa seriously. Then his phone rings. A mountain ranger calls who is in the national park.

A report by the International Union for Conservation of Nature (IUCN) warns that the arctic fox is one of the animals that will be hardest hit by climate change. Because with their white or bluish, thick winter fur, their compact body with fat reserves, their ability to lower the metabolic rate in order to survive longer periods of hunger, the animals are ideally adapted to the Arctic. Dense veins in the paws limit heat loss. In the 19th century, the arctic fox population in Scandinavia was still very large, there were more than 10,000 animals. But they were so hunted for their fur that they almost became extinct. Although they have been under protection for 90 years, the population has never recovered. Today almost 300 adult animals roam all of Scandinavia, Landa says.

The foxes only reproduced when the station was moved to its natural environment

Now the tundra and the permafrost are retreating as a result of advancing global warming. The related red fox conquers the arctic fox territories from the south. In competition with the arctic fox, which is only about half the size, it has an advantage, be it when hunting or fighting against each other. In addition, the white winter fur will probably no longer camouflage the arctic fox in the long term. Although its brown summer fur blends in perfectly with the tundra colors, if the snow disappears earlier or falls later, the bright white animals will stand out in winter.

The search for food is already difficult: According to Landa, the rising temperatures and the changed winter conditions are affecting the life cycles of the lemmings, the main food of the arctic fox. Since its reproduction is in turn closely linked to the lemmings, there is no offspring for longer periods. The arctic fox is content with carrion. But he often finds it exactly where the next danger lurks: on busy roads. Landa reports that many of the abandoned animals are run over by cars.

Raising arctic foxes is not easy. First attempts in isolated enclosures failed, only the relocation of the station to its natural environment achieved success. In Norwegian the arctic fox is called "fjellrev", which means "mountain fox", because its natural range in Norway and Sweden is the mountains. In Oppdal, pairs of foxes from different regions have been brought together every year since 2005, and foxes with blue and white winter fur have been mixed in order to increase genetic variation. The pups are released into the wild in late winter in the hope "that there will soon be so many arctic foxes in the wild that they can sustain themselves," says Landa.

In order to get the foxes used to the conditions in the wild, the animals are provided with food at feeding stations. The feed bins have an opening that is so narrow that the cat-sized arctic fox can pass through, the larger red fox cannot. The animals are shy in the enclosures, they stay hidden most of the time. When they show up, they stick their snouts out from under the stones, sneak out, and then jump back again. In the wild, on the other hand, the animals are amazingly active hikers. The sea ice serves as a hunting ground for them. Recently the intercontinental migration of a young arctic fox was recorded. The animal covered 3506 kilometers in 76 days on the way from Svalbard to Ellesmere Island in Canada, the fastest recorded migration of this species.

According to the researchers, the long-term melting of the sea ice in the Arctic will probably produce more isolated populations in the future, for example in Svalbard. Such small populations can be permanent: In Iceland, for example, there has been a stable population since the last Ice Age that has adapted to island life. The foxes there feed mainly on seabirds instead of lemmings, which do not exist in Iceland.

The foxes from Oppdal released after rearing are observed by cameras at the feeding stations, DNA samples and microchips in the ears. From this their survival rate can be derived, the migration can be tracked, explains Arild Landa. Most surprising was how many of the released foxes survived. With an average of 60 percent after the first year, the survival rate was higher than that of those born in the wild, of which only a good half survived the first year. Behind this, Landa suspects veterinary treatment and late winter abandonment when the toughest time of the year is over.

The animals have now been re-established in at least three mountain regions in Norway and Sweden where they were previously extinct. In one case, the foxes were able to help themselves, Landa proudly recounts: An abandoned pair of blue foxes had walked 200 kilometers to a place in Sweden where at that time there were only white foxes and thus the genetic variation was missing. "They finally saved the blue foxes genetically," says Landa. "Their name is now: Blues Brothers.