Polar bears breed because climate change is rapidly melting their habitat

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Climate change is reducing polar bear habitats in the Arctic, forcing majestic creatures to breed in order to survive.

A team of Norwegian scientists found that polar bear populations in the Norwegian archipelago of Svalbard suffered a 10% loss of their genetic diversity between 1995 and 2016 due to melting sea ice isolating them from each other. .

The increased isolation, according to the researchers, will only increase inbreeding in the future and cause what is known as “inbreeding depression,” which is the reduction in survival and fertility of the offspring. related individuals.

“The extent and rate of loss of genetic diversity and gene flow that we have observed is alarming given that polar bears have historically shown relatively little genetic differentiation, even on a global scale, but are now faced with increasingly strong climate selective pressure “, shared the researchers in the study published in the journal Proceedings of the Royal Society B.

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Climate change is reducing polar bear habitats in the Arctic, forcing majestic creatures to breed in order to survive. The increased isolation, according to the researchers, will only increase inbreeding in the future and cause what is known as “inbreeding depression,” which is the reduction in survival and fertility of the offspring. related individuals.

The team found that the west coast of Spitsbergen experienced the greatest loss of sea ice in the Barents Sea region and also shows the highest rate of change in genetic diversity.

Simulations of sea ice loss show that the region will only experience more melting in the future, isolating more polar bears.

Lead author Simo Maduna from the Norwegian Institute for Bioeconomics Research in Svanvik and his colleagues analyzed DNA samples from 622 polar bears living in the four geographic regions of the archipelago: northwest, northeast, southwest and southeast.

Not only did the samples show a loss of genetic diversity, but the results showed that polar bears begin to form genetic subpopulations, with significant genetic differentiation from region to region.

A team of Norwegian scientists found that polar bear populations in the Norwegian archipelago of Svalbard suffered a 10% loss of their genetic diversity from 1995 to 2016 due to melting sea ice isolating them from each other. .

A team of Norwegian scientists found that polar bear populations in the Norwegian archipelago of Svalbard suffered a 10% loss of their genetic diversity from 1995 to 2016 due to melting sea ice isolating them from each other. .

Scientists analyzed DNA samples from 622 polar bears living in the archipelago's four geographic regions: northwest, northeast, southwest and southeast.  Not only did the samples show a loss of genetic diversity, but the results showed that polar bears begin to form genetic subpopulations, with significant genetic differentiation from region to region.

Scientists analyzed DNA samples from 622 polar bears living in the archipelago’s four geographic regions: northwest, northeast, southwest and southeast. Not only did the samples show a loss of genetic diversity, but the results showed that polar bears begin to form genetic subpopulations, with significant genetic differentiation from region to region.

And the greatest impact was seen in the Northwestern group.

However, some polar bears turn to a different animal to breed: grizzly bears.

Paleontologist Larisa DeSantis told DailyMail.com that polar bears retreat inland to find food as the sea ice melts, and mate with grizzly bears that travel to Alaska.

And the offspring is a completely new species dubbed a “pizzly bear”.

“This new type of bear is more resistant to climate change and better suited to warmer temperatures,” said DeSantis, associate professor at Vanderbilt University.

Besides inbreeding, climate change is also pushing polar bears to cannibalism.

However, some polar bears turn to a different animal to breed: grizzly bears.  The offspring is a completely new species nicknamed a

However, some polar bears turn to a different animal to breed: grizzly bears. The offspring is a brand new species nicknamed a “pizzly bear” (photo)

Besides inbreeding, climate change is also pushing polar bears to cannibalism

Besides inbreeding, climate change is also pushing polar bears to cannibalism

In February 2020, Ilya Mordvintsev, senior researcher at the Severtsov Institute for Ecological and Evolutionary Problems in Moscow, revealed that animals were feeding on each other in the Arctic as the ice melted and the fossil fuel extraction were destroying their habit.

Ice levels are dropping due to rising temperatures and industrial businesses are moving to the area, forcing polar bears to leave their traditional hunting grounds or head to shores where food is scary.

The increase in incidents of cannibalism, according to the researcher, could also be partly due to an increase in human activity in the Arctic which is there to witness the horrific events.

“Cases of cannibalism among polar bears are a long established fact, but we are concerned that such cases have only been found rarely when they are now recorded quite often,” Mordvintsev told the news agency. Interfax press, AFP reported.

“We declare that cannibalism in polar bears is on the increase.”

Some polar bears adapt to their changing world and do so without killing each other.

WHY DO POLAR BEARS NEED ICE TO SURVIVE?

Ice loss due to climate change has a direct impact on the ability of polar bears to feed and survive.

Bears need ice shelves to reach their prey, ringed and bearded seals. Some sea ice covers more productive hunting areas than others.

Like other predators at the top of the food chain, polar bears have a low reproductive rate. One or two cubs are born in the middle of winter and stay with their mother for two years.

Therefore, females only breed every three years. Bears don’t breed until they are five or six years old.

From late fall through spring, mothers with new cubs live in snowdrifts on land or on ice floes. They come out of their dens, with the new cubs, in the spring to hunt seals on the floating ice.

Simply put, if there is not enough sea ice, seals cannot crawl across the ice and polar bears cannot continue to hunt.


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