Polar Bear and Cub, Svalbard

Photograph by Philip Dien

As we watched from our Zodiac, this polar bear gave her cub a lift as she swam across the fjord, shaking herself dry after emerging from the water with her cub hanging on. Polar bear cubs have been known to occasionally ride on the backs of their mothers as they swim together in Arctic waters, possibly to reduce exposure to cold.

(This photo and caption were submitted to the 2010 National Geographic Expeditions Photo Contest.)