Polar bears are running out. As the ice has continued to melt for years in the Arctic, these top predators must now use up to four times the energy to survive, reveals The Guardian. The more their habitat shrinks, the more polar bears struggle to find food and their nature is not adapted to this less and less icy Arctic.
According to a study published in the scientific journal The Journal of Experimental Biology, polar bears are physiologically designed to use as little energy as possible. To hunt, they sit and grab ringed and bearded seals, their main food source, through breathing holes in the ice. However, seals are increasingly difficult to find, and the surface of the ice on which bears hunt has declined by 13% every decade since 1979.
These arctic predators now have to swim for an average of three days to find seals or travel great distances on land in search of food, which has much lower energy and nutritional intake. “A polar bear should consume about 1.5 caribou, 37 arctic char, 74 snow geese, 216 snow goose eggs or 3 meters of crowberry. [une plante qui pousse au sol, ndlr] to equal the energy available in the fat of an adult ringed seal “, develop scientists.
Narwhals also threatened
This study corroborates existing research which predicts a decline of one to two thirds of the polar bear population by the end of the century, specifies The Guardian. Like bears, narwhals, unicorns of the seas, must also expend more energy on food. To hunt black halibut, their favorite prey, they can reach up to 1,500 meters deep. They still need to come to the surface to breathe.
With climate change, ice moves quickly, which means air holes too. “With a limited amount of oxygen in their muscles and blood, we find that narwhals adapt the speed, depth and duration of their dives. A miscalculation could lead to drowning ”, says Dr. Terrie Williams, co-author of the report.
The decline of polar bears and narwhals is likely to impact other ice-dependent species and their prey, resulting in “Rapid changes throughout the Arctic marine ecosystem”, according to scientists. Mammals like beluga whales, arctic foxes and musk oxen could end up in danger. “The arctic world is so much more unpredictable for these animals now”, alerte Terrie Williams.
Source: Slate.fr by www.slate.fr.
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