The secret lives of polar bears

A study tracking the behaviour of nine female bears from 2014 to 2016 found that some of the animals exerted so much energy during the hunting season that they lost up to 10% of their body mass in an 8-11 day period.

Polar bears live on a diet that is largely made up of ringed seals, which they hunt from the ice surface. However, sea ice cover in the Arctic is falling at a rate as fast as 14% per decade, which could be forcing bears to travel further in order to find their prey.

Warning: some of the footage contains scenes with blood and gore.