Polar bears are observed for the first time to be carrying cubs on their backs in Arctic waters, a change scientists believe is to spare the youngsters from exhaustion as the bears are forced to swim longer distances due to Arctic melt.

http://www.thesun.co.uk/sol/homepage/news/Green/3251865/Forced-to-travel-polar-bear-back.html
http://www.telegraph.co.uk/earth/environment/8168213/Polar-bears-spotted-swimming-with-cubs-on-back.html