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Climate Change: Polar Bears Eating Dolphins?!

Jun 16, 2015 02:12 PM EDT
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Pictured: A male polar bear on the carcass of a white-beaked dolphin, 23 April 2014. Just to the left of the dolphin is a hole in the ice, assumed to be a breathing hole that dolphins trapped in the ice have kept open.

(Photo : Polar Research Journal)

For the first time ever, scientists have witnessed polar bears eating white-beaked dolphins in the Arctic, and they claim it's the bizarre result of climate change.

In a new study published in the Polar Research Journal, a team from the Norwegian Polar Institute say that the rapidly retreating Arctic ice shelves allowed the dolphins to migrate farther north than they would normally be this early in the summer.

"This is the first record of this species as polar bear prey," the authors, led by the Norwegian Polar Institute's Jon Aars, said in the paper. "The warming of the Arctic is significantly changing the ecosystem and relations between species."

As more Arctic ice melts, polar bears have had to get creative with their diet in order to feed themselves, increasingly turning to a mix of plants and animals on land. While they normally prey on ice-associated seals, warming temperatures have caused them to develop an appetite for dolphins.

Specifically, in April 2014 scientists observed an adult male polar bear preying on two white-beaked dolphins (Lagenorhynchus albirostris) that were trapped in the ice on a small fjord in Svalbard, a group of islands in the Norwegian part of the Barents Sea area.

The sighting is important because shrinking polar bear habitat is expected to change where the animals can live, particularly in the area of Svalbard and the surrounding Barents Sea.

He had eaten most of one dolphin, and was in the process of covering the second, which was more intact, with snow. The researchers noted that such "caching behavior" is extremely rare for polar bears (Ursus maritimus), since they tend to feed on the fat from their kills within a day.

"White-beaked dolphins are frequent visitors to Svalbard waters in summer, but have not previously been reported this far north in early spring," the researchers wrote. "We suggest they were trapped in the ice after strong northerly winds the days before, and possibly killed when forced to surface for air at a small opening in the ice."

During the following summer and fall, which were both ice-free for Svalbard, scientists saw seven white-beaked dolphin carcasses around the same area. And at least six different polar bears were seen scavenging on the carcasses.

In the past, polar bears have been known to consume seven different whale species, including white whales and narwhals, which are smaller in size. But this is the first record of polar bears ever feasting on the white-beaked dolphin, a species usually encountered in more sub-Arctic waters and less frequently in the sea-ice covered areas.

This may be bad news for the dolphins, but it's a hopeful solution for polar bears, as seal populations in the Arctic continue to dwindle.

For more great nature science stories and general news, please visit our sister site, Headlines and Global News (HNGN).

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