In his classic work, Arctic Dreams, Barry Lopez occasionally refers to the remarkable navigational abilities displayed by animals of the far north. Polar bears for example:

“ Bears make use of mountain passes, ravines, and other features of the land in such a way as to suggest that these are traditional routes…

” Beyond using celestial clues and a knowledge of prevailing winds and currents, which reliably guide Eskimos across the angular topography of shifting sea ice, no one knows how bears find their way. But they consistently travel directly to aggregations of seals; they return to core denning and breeding areas every year; and they find their way unerringly to the coast from hundreds of miles offshore. This would be astonishing enough if they only did it on land, where there are perennial landmarks, but they also do it at sea, where a frozen landscape is created anew each year, which can change from one day to the next… In some areas of stable ice, bears may travel for weeks without seeing a break in the continuity of the sharp blue line of the horizon…” [from Chapter 3, Tôrnâssuk.]

Maybe, as Lopez suggests, the bears do indeed use celestial cues, like the azimuth of the sun. Maybe they also know about prevailing winds or currents. It’s equally possible that they use their acute sense of smell. Lopez also speculates that the bears make use of maps in their heads - or cognitive maps - but I’m not sure the evidence really supports such a claim. Perhaps they are just good at DR? In any case, the secrets of polar bear navigation are one more mystery to add to my growing personal list of puzzles!