Polar bears no longer have ice - they are starving and will soon disappear

Polar bears and narwhals use up to four times more energy to survive due to the great ice loss in the Arctic

Climate change and melting ice are putting the survival of the animals that populate those areas at risk. But a new study reveals that polar bears, as well as narwhals, use four times as much energy to survive. That's why the predators of the Arctic, to which one is dedicated World Day on February 27 each year, they are exhausted.

Polar bears and narwhals use up to four times more energy to survive due to the large ice loss in the Arctic, according to the new study published in the Journal of Experimental Biology.

Once fully evolved and adept at withstanding the harsh conditions of polar life, these animals are now struggling to survive as their habitats shrink. But it's not just this. They are becoming less and less "fit" to survive in an increasingly less frozen Arctic.

Mammals are physiologically designed to use as little energy as possible. Polar bears are mainly sedentary hunters, they have adapted to catching seals almost stationary while narwhals have evolved to dive very deep without making quick movements. Adaptive energy saving mechanisms, essential for surviving in a difficult and cold environment.

Polar bears are getting hungrier and hungrier

But today such animals have to work much harder to survive. Polar bears feed mainly on seal fat but this food source is more difficult to find. The sea ice they hunt on has shrunk by 13% every decade since 1979. Which is why they now need to swim at least three days to find seals or search for less energy-rich terrestrial food sources. In fact, they have to travel longer distances with a high expenditure of energy.

Read also: The horrifying image of the undernourished polar bear

Mammals in the polar regions face an uncertain future as unprecedented warming leads to catastrophic loss of sea ice, pushing polar bears to land after losing access to ice and the high-calorie seals they feed on. According to the study, a polar bear would need to consume about 1,5 caribou, 37 arctic char, 74 snow geese, 216 snow goose eggs (i.e. 54 nests with 4 eggs per brood) or 3 million cranberries to equal the energy available in the fat of an adult adult seal.

"There are few resources on earth within the polar bear range that could offset the decline in feeding opportunities for seals," the scientists explain.

Pagano and Williams measured the energy cost of moving narwhals and polar bears and found that the increased ice loss translates into 3 to 4 times more displacement than expected when sea ice cover is normal. This increase in energy consumption, coupled with the loss of access to the polar bear's main food source, makes them particularly vulnerable to starvation.

According to the scientists, the decline of these predators at the top of the food chain “will lead to rapid changes in the Arctic marine ecosystem ”.

The loss of ice

If global warming continues with the current trend, the Arctic sea could be ice-free in the summer months by 2035. For the polar bear, whose survival depends on the presence of sea ice, it would be a no-appeal. Arctic ice is in fact an integral part of the life of this incredible and majestic animal.

Today in the world, the WWF recalls, it is estimated the presence of a number of polar bears ranging from 16.000 to 31.000 individuals, divided into 19 populations in the arctic regions of Europe, Asia and America. The shrinking of their habitat is making the species increasingly endangered around the world. Polar bears spend most of their life on the frozen sea (as their scientific name, Ursus maritimus indicates), cross it to travel long distances to new areas, and hunt for seals waiting for prey to emerge from the water. Sometimes, females dig into sea ice to create shelters for giving birth. In Greenland and Norway, polar bears are classified as a vulnerable species, therefore at risk of extinction.

Climate change has reduced the expanse of sea ice that once stretched from the North Pole to southern Hudson Bay. And just in the southern Hudson Bay area, between 2011 and 2016, a decline in the polar bear population of 17% has been estimated, with the decrease in the number of individuals from 943 to 780.

In 2020, the polar ice reached a new negative record: in the last 50 years, only in 2012 at the end of the summer was an extension of the ice pack smaller than this recorded. A clear sign that global warming is unfortunately getting stronger, and that the polar bear habitat is inexorably disappearing. The researchers found that in November 2020, the month in which the ice is expected to expand and harden to allow polar bears to hunt, the opposite phenomenon occurred: the ice in the bay that had just formed fragmented due to too much temperatures. high. Sea ice concentrations have decreased by 13% every decade since 1979 due to rising global temperatures. Arctic regions have warmed up twice as fast as the rest of the world, so seasonal sea ice forms later in the fall and breaks up earlier in the spring.

In short, polar bears are in danger of disappearing from the Arctic within the century.

Sources of reference: Eurekalert, Journal of Experimental Biology