Clash of the fiercest predators as shark eats polar bear

Global warming may not be the only threat to the polar bear. Scientists are puzzling over the discovery of the jawbone of a young polar bear in the stomach of a Greenland shark, a species that thrives in the cold waters of the far north.

The find suggests that the polar bear may have a serious challenger to its place at the top of the Arctic food chain. Until now, only killer whales were thought to offer a threat to Ursus maritimus as the Arctic's top predator.

Kit Kovacs, a seal expert at the Norwegian Polar Institute in Tromso, stumbled across the polar bear remains while attempting to find out who or what was killing large numbers of harbour seals in the Arctic archipelago of Svalbard.

The Greenland shark, one of two species of sleeper sharks, was the obvious suspect, she said, so they performed autopsies to see what they had been eating. That's when they found the polar bear bone. Read More