Polar bears are inbreeding due to melting sea ice

The loss of genetic diversity among the polar bears could be dangerous for the future survival of the species, researchers say

Alisha Rahaman Sarkar
Friday 10 September 2021 13:52 BST

Polar Bear helps scientists

Polar bears are turning to inbreeding to survive due to the loss of ice in the Arctic Sea as a the result of the climate crisis.

Inbreeding led to the loss of 10 per cent of genetic diversity in the polar bear population of Norway's Svalbard Archipelago between 1995 and 2015, according to a study published by The Royal Society journal on Wednesday.

Ecological and engineering data was studied by scientists from the Norwegian Polar Institute for two decades to investigate genetic trends in the polar bear population on the archipelago.

The loss of genetic diversity has been correlated to the “rapid sea ice loss in the Arctic Barents Sea,” the study pointed out.

The decrease in the gene flow is caused by habitat fragmentation owing to the loss of sea ice coverage, “resulting in increased inbreeding of local polar bears within the focal sampling areas,” it pointed out.

The Barents Sea is experiencing the fastest loss of ice in the Arctic region, driven by the climate crisis, according to the World Wildlife Fund.

“With genetic diversity, when the population becomes so small, you’ll find that there will be a higher chance of closely related individuals mating and producing offspring. But with that comes risk in the sense that some of the traits that are recessive, will now basically be unmasked in the population,” the study’s author Simo Maduna, of the Norwegian Institute of Bioeconomy Research, told ABC News.

The apex predators rely on ice for traveling, hunting, resting and reproduction. They mostly wander on sea ice and rarely move to shores.

Another study in April also suggested that the climate crisis is changing their diets.

Polar bears spend over half their time hunting for food, but with lesser opportunities to hunt seals, the hungry animals are forced to forage for seabirds and eggs.

With diminishing food sources, the bears have been observed as becoming increasingly cannibalistic. They are also becoming “increasingly separated” from their maternal dens, where they stay during pregnancy.

Last month, Russia’s chief environmental regulator Svetlana Radionova wrote on social media that “it is worrying that polar bears come to people more often”. In one instance, helicopters were said to have been deployed to scare a group of bears from entering reindeer settlements in the Yamal peninsula, northwest of Siberia.

Increased levels of isolation between the animals “may increase inbreeding in the future, most likely with negative effects such as inbreeding depression,” the study said. Other studies, however, have reported a low level of such inbreeding.

There are around 25,000 polar bears are left on the planet, distributed across the Arctic in Alaska, Canada, Greenland, Norway and Russia.

Already notified as an endangered species, the mammals could cease to exist by the end of this century, a study by the journal Nature Climate Change said.

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