Deep in south-east Greenland and almost completely isolated, a population of a few hundred polar bears has apparently been living for at least two hundred years, unknown to polar researchers and possibly providing important clues for the future of polar bears threatened by climate change.

Unlike all other nineteen polar bear populations around the North Pole, the animals are no longer dependent on pack ice when they hunt seals.

Instead, they content themselves with the sparse ice that has frozen over the late winter months and broken off at the glacier edges as a hunting ground.

Joachim Müller-Jung

Editor in the feuilleton, responsible for the "Nature and Science" department.

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Tissue and DNA material as well as knowledge about the polar bears obtained from satellite images and collected by Inuit from the region show: The South Greenland polar bears not only behave and breed differently than "ordinary" conspecifics, they are, as the publication in the current one issue of the journal "Science" shows that they can also be clearly distinguished genetically.

It is only very rarely that individuals from the north of Greenland have immigrated in the course of the last decades and centuries, or occasionally from the Russian population and from Svalbard or Alaska drifting into the southern fjords with pack ice.

What makes the South Greenland polar bears so special, however, is less the genetic distance to their relatives.

Above all, it is their way of getting along with the ice-free habitat south of the 64th parallel for many months and the largely absent pack ice.

Polar bears can smell seals, their preferred prey, under layers of ice up to a meter thick.

Usually they use the ice crevices that appear in the pack ice for their hunt.

The seals use the cracks in the ice as air holes.

Polar bears, drifting across the sea on the pack ice, will perch at the edge of these holes until the seal takes a breath, then yank their prey out of the water with their mighty paws and strong claws.

Many of the polar bears drift dozens of kilometers with the pack ice before returning to their home range overland.

In southeastern Greenland, this hunting method is severely restricted because, with the Arctic warming twice as fast, thick pack ice that drifts in the fjords for months only rarely forms.

While some of the Northeast relatives travel as much as 1,500 kilometers a year, averaging 40 kilometers per four-day hunt, the South Greenland polar bears average a mere 10 kilometers.

In fact, most of them stay in their home fjord all year round.

The main hunting season is between February and May, when it is still really cold in the southeast.

Then they use the comparatively thin ice that forms at the edge of the coast (“fast ice”), which breaks off and floats on the fjord water, to hunt for seals on the ice edges.

This border area with more fragile,

However, many of the animals have to fast for the rest of the year, much longer than the typical fasting period of three to six months for polar bears.

The fact that the animals survive this well is due to the enormous fat reserves, which are generally larger in polar bears than in all other bear species and which can also be attributed to the fact that polar bears neither really hibernate nor hibernate.

What is also striking about the South Greenland polar bears is that significantly fewer females with cubs than usual were observed in the spring – but this does not seem to affect the stability of the population.

Laidre and her team suspect that because their radius of action is also smaller than usual, the females may find fewer mating opportunities.

Elizabeth Peacock of Emory University in Atlanta suspects that the females give birth to fewer young because of the limited resources in the area.

Climate change could well be a factor in this.

Because it has also been observed in other arctic animals, such as seals, that a rapidly changing environment can significantly reduce birth rates.

However, Laidre and her colleagues do not see this as an existential threat.

Because the population in south-east Greenland has apparently been stable so far and the ice conditions are roughly similar to the conditions that are likely to prevail in the vast majority of polar bear distribution areas around the North Pole by the end of this century, the polar bear researchers even see this as a sign of hope.

In their Science publication, they suggest that other populations may also be able to "adapt and survive" in the pack-ice-free ice melange of Arctic coasts.

However, this resilience could also have limits and mean

that if warming continues to accelerate, the South Greenland polar bears could become the first population of their species to become extinct.

Because polar bears that survive in completely ice-free areas are not known.

The ice surfaces, which have been frozen for many months, are vital for the reproduction in ice caves and also for the hunting behavior of the animals.