Polar Bears Are on The Brink of Extinction, But Their DNA May Be Fighting Back

Climate Change is forcing polar bears to rewire parts of their DNA in surprising ways.

As the Arctic warms and sea ice disappears, polar bears are being pushed into conditions they have never faced before. Their hunting grounds are shrinking, food is becoming harder to find, and their numbers are falling rapidly across the Arctic.

If current trends continue, scientists estimate that more than two-thirds of remaining polar bears may be gone by 2050, with complete extinction possible before 2100. Today, just 26,000 polar bears are estimated to live in the wild. Polar bears are classified as a vulnerable species by the IUCN due to threats from climate change and sea ice loss, with most living in Canada

Surprisingly, a new study shows that some polar bears in southern Greenland are responding to this stress by changing how parts of their DNA behave. These genetic changes may help these animals cope with warmer temperatures and limited food, while revealing how species might react biologically to rapid climate change.

Although these changes do not stop climate change or guarantee survival, they suggest that some bears may be biologically adjusting, at least in the short term, to warmer and less predictable conditions.

“I believe our work really does offer a glimmer of hope — a window of opportunity for us to reduce our carbon emissions to slow down the rate of climate change and to give these bears more time to adapt to these stark changes in their habitats,” Alice Godden, first author of the study and a senior research associate at the University of East Anglia, told NBC News.

The curious case of ‘jumping genes’

Evolution is usually slow. Advantageous genetic mutations that help species survive in their environment often take thousands of years to spread through a population. Climate change, by contrast, is unfolding over decades. This mismatch has led many researchers to conclude that polar bears simply do not have enough time to adapt.

However, is it possible that bears’ own biology responds quickly enough to environmental stress to offer any chance of survival? To explore this question, the study authors analyzed genetic data from polar bears living in two very different parts of Greenland. 

They focused on bears from the colder, more stable north-east and compared them with bears from the warmer, more variable south-east. The latter population is unusual as earlier work showed that these bears became isolated from northern populations around 200 years ago and have since followed a different genetic path. This made them a natural test case for studying how climate conditions might shape biology.

However, instead of examining DNA alone, the researchers studied RNA extracted from polar bear blood samples. RNA acts as a messenger, revealing which genes are active and how strongly they are being used. The team then matched this genetic activity with long-term temperature records from Greenland to see whether changes in climate aligned with changes inside the bears’ cells. 

The analysis pointed to a surge in activity from transposable elements, often called jumping genes—mobile pieces of DNA that can move within the genome and influence how nearby genes function. In polar bears, these elements make up about 38.1 percent of the entire genome.

Under normal conditions, cells suppress this activity using small regulatory molecules. However,  the study found that in the warmer south-east, this control appears to weaken. More than 1,500 transposable elements showed increased activity in these bears, and many appeared to be relatively young, suggesting recent genetic changes.

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Some of this activity occurred near genes linked to heat stress, aging, metabolism, and fat processing. These are all critical processes for animals coping with warmer temperatures and reduced access to food.

“Essentially, this means that different groups of bears are having different sections of their DNA changed at different rates, and this activity seems linked to their specific environment and climate,” Godden said.

Signs of adjustment, not of sure survival

The genetic patterns suggest that south-eastern Greenland polar bears may be responding to food shortages and warmer conditions by adjusting how their bodies manage energy. With fewer opportunities to hunt seals, these bears may increasingly rely on lower-fat or alternative food sources, setting new demands on their metabolism.

However, the study does not claim that polar bears can simply adapt their way out of crisis. The challenge is severe because polar bears rely so heavily on sea ice, but their home, the Arctic Ocean, is now warmer than it has been at any point in the past 125,000 years. As ice retreats, bears are forced to travel farther, eat less, and endure longer periods of hunger.

Our research does not imply “that polar bears are at any less risk of extinction. We all must do more to mitigate our carbon emissions to help provide and extend this window of opportunity to help save this wonderful, vital species,” Godden said.

Future research will examine whether similar patterns appear in other polar bear populations facing extreme conditions. This is important because understanding which groups show genetic flexibility, and which do not, could help conservationists identify populations most at risk.

The study is published in the journal Mobile DNA.