Normally, the dolphins make their way up north during the warmer summer, but this year they got off to an early start and arrived in spring, The Independent reports.
Like seals, the white-beaked dolphins poke holes in the ice so that they can come up to breathe, and this is when an enterprising bear can nab them.
Researchers first observed this behavior last year. Since then, at least six bears have been seen eating dolphins, the scientists wrote in a recent report, “White-beaked dolphins trapped in the ice and eaten by polar bears.”
In one instance, when a bear had eaten its fill, it covered the dolphin carcass with ice so that it could be stored for later. This type of behavior is rare in polar bears (Ursus maritimus), and it may mean that the animals aren’t finding enough to eat.
The study authors noted that the bear had “clearly visible ribs” and was “very skinny.”
Typically, the bears hunt ringed and bearded seals, but they are known to be opportunistic predators and scavengers, IFLScience reports. The bears are known to eat at least seven species of whale when they get the chance.
While on an annual bear capture-release expedition in Raudfjorden in April 2014, Jon Aars, of the Norwegian Polar Institute, along with several colleagues encountered a male polar bear with the nearly intact carcass of a white-beaked dolphin (Lagenorhynchus albirostris) on the sea ice only a few meters from the shore. The carcass was only missing a bit of the fat layer on its dorsal side. Parts of another dolphin — the spine, ribcage, and skull — were found on land 50 meters south. Tracks in the snow meant it was likely the same bear fed on both.
A small hole covered with slushy ice near the mostly intact dolphin was likely a breathing hole kept open by dolphins who were trapped in the ice. This was the only spot on the entire fjord where the dolphins could breathe. Everywhere else, the surrounding sea ice was 20 centimeters thick, IFLScience reports.
White-beaked dolphins are frequently found in Norwegian High Arctic waters during the summer, but rarely do they go that far north in early spring. This area in the winter of 2014, however was ice-free, and the animals were swimming in open water. Suddenly strong northerly winds packed drifting ice into the fjords on April 17 and 18, effectively trapping the dolphins. As they rose to breathe, they were likely grabbed and killed by the big bear.
When the team chanced upon the polar bear, no meat had been stripped from the carcass, and he was in the middle of covering it with snow, probably as a way to discourage foxes, gulls and other would-be nibblers. In this case, this is fairly rare behavior as the bears usually consume whatever fat they can from carcasses and digest it within a day. They usually only need to keep scavengers away for a short while.
“We think he caught the second dolphin because he could, and then had extra food later,” Aars said, according to New Scientist.
The team subsequently came upon at least five other bears feeding on dolphins in the same area.
“We were surprised as dolphins have not been reported in that area before,” Aars said. There’s a possibility that the Svalbard waters were warmer than usual, and a dolphin pod may have become trapped when strong north winds pushed them out of the open water and in among the ice.
It’s not really that big of a surprise that the bears feasted on the dolphins when they had the chance, as opportunistic predators, they are going to eat whatever they can manage.
“They will eat any marine mammal given a chance,” says Ian Stirling of the University of Alberta, Canada. “The bigger surprise was that the dolphins were entrapped before they could migrate south for the winter.”
It’s a sign of the warming climate, and Stirling thinks the sight of polar bears consuming peculiar meals could very well become commonplace. The bears are “willing to take and use anything possible when available,” he notes.
The Svalbard fjords and the coastline are usually covered in ice, but the winter of 2013 and 2014 was unusual, and when the dolphins and bears were seen together, there was no ice, The Independent reports.
Note: For an up-close and personal view of a hungry polar bear, check this video out.
