Scientists have tracked a tagged polar bear swimming at least 74 km in just one day - and maybe up to 100 km - providing the first conclusive proof the bears can cover such giant distances in the water.
Bears often roam thousands of kilometres in a year in search of prey such as seals and there has often been anecdotal evidence of prodigious ursine swims, with bears turning up on remote islands or across wide bays.
However, previously there had been doubts about whether the bears had walked over ice part of the way or hitched a ride on an iceberg.