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By Anastasia Gubin
The study published on June 1 "White-beaked dolphins trapped in ice and eaten by polar bears", led by scientist Jon Aars of the Norwegian Polar Institute, describes a polar bear with 2 white-beaked dolphins - Lagenorhynchus albirostris - on April 23, 2014, and another bear eating a dolphin on July 2, of the same year, something never seen in the past.
The authors cite that the polar bear -Ursus maritimus- is one of the species that is anticipated to be greatly reduced, especially in the Barents Sea and Svalbard area, although dolphin carcasses trapped in the area could be a solution to the lack of their usual food.
These polar bears live in arctic areas, where before they normally fed on ringed -Pusa hispida- and bearded seals - Erignathus barbatus.
Depending on availability, they also feed on other species. Among them, seven species of whales are part of their menu, and now for the first time they are seen eating the white-beaked dolphin (Lagenorhynchus albirostris), a species of whale usually found in sub-arctic waters and less frequently in areas of sea ice, according to Reeves studies from 1999, cited by Jon Aars.
Svalbard, where the observations were made, consists of a group of islands in the Norwegian part of the Barents Sea area. A branch of the North Atlantic Ocean Current runs north along the west coast of Spitsbergen, the largest of the islands in the archipelago, and brings warmer water from the south.
As temperatures have been seen rising in the water in the northwestern area of Svalbard, a recent decrease in summer sea ice cover has also been seen on the other hand, reaching 14% in the area of the Barents Sea, quotes the author.
"On April 23, 2014, we found an adult male polar bear with the corpse of a white-beaked dolphin in Raudfjorden, at 79 ° 45'1" N and 11 ° 56'28 ", they reported in their investigation . The body of one of the dolphins (named A) was in the sea of ice about 5 meters from shore. Another (B) was dead about 50 meters further south and 5 meters from shore.
Dolphin A was in a hole about 60 by 75 cm in diameter, covered with water snow ice. The sea ice that surrounded it was about 8 inches thick. This was the only place in the fjord without solid ice, and it appeared to be a hole that served as a breathing hole for the dolphins. The researchers believe that the polar bear trapped both dolphins in the hole, or moved the second dolphin (B) and after eating the fat layer, covered it with ice.
After immobilizing the polar bear for study, due to tooth wear, Aars' team estimated that he was 16 to 20 years old and extremely skinny.
“With the ribs clearly visible, the bear was very skinny. The figure also shows that the bear had a very full belly, reflecting a recent large amount of food, probably much of the B dolphin and parts of the A dolphin. The male was in the process of covering a dolphin with snow. This could decrease the likelihood of other bears, foxes or seagulls cleaning up the remains, "he added.
The presence of the dolphins was probably due to the lack of ice. The fjords and around the north coast of Spitsbergen, are an area normally covered by annual ice, but in winter 2013/14, they were ice-free. It is postulated that some white-beaked dolphins, including the two found dead, were trapped by suffocation after strong winds moved the ice.
Dolphin sighting records in Svalbard indicate groups of up to 200 units, with an average of six, essentially in the summer months. In April 2014, seven dolphin carcasses were reported in the area near the images of the bear with the two dead dolphins.
On July 2, a photo was taken of “an adult polar bear feeding on the remains of a white-beaked dolphin in Raudfjorden. "The dolphin is presumed to be a member of the same group as the dolphins eaten by the bear in April."
“An increase in white-beaked dolphins in areas where sea ice moves north may, given the considerable size of these animals, offer a new prey or food source of carrion to bears, in an environment where access to ringed and bearded seals may decline in the future, "concluded the study author.
Regarding the other whales that the polar bear sometimes feeds on, there are the small white beluga whales (Delphinapterus leucas) and the narwhals (Monodon Monoceros). These are hunted by bears in some circumstances, while the rest are large enough to be prey, but they are also food for polar bears: Balaena mysticetus, from Greenland, which adapted to the Arctic and sea ice; fin whale (Balaenoptera physalus), gray whale (Eschrichtius robustus), minke whale (Balaenoptera acutorostrata) and sperm whale (Physeter macrocephalus). The latter are common in arctic areas, but they are not really species from this area.
The Epoch Times