One expedition leader to Svalbard once witnessed a polar bear come very close to successfully capturing a Greenland shark. This is very odd behaviour, especially as the flesh of this shark is toxic, reeking of ammonia due to them urinating through their skin. It has been stipulated in recent times, that the Greenland shark will kill and eat polar bears and remains have been found in the sharks’ stomachs to suggest this. But scientists who study the bears or sharks remain sceptical that the bear would lose such a conflict if they were in good condition. Far more likely is that the shark’s victim had already passed or was in a weakened state.
Polar bears are generally thought of as solitary animals and usually this is the case. But social tendencies in the Arctic are always dictated by the amount of available food. As shown in the BBC’s ‘Frozen Planet’ a whale carcass washed up on a shore in Svalbard and for the next year, large groups of polar bears congregated to feast together.