Frozen Planet BBC - S01 E04 - HD 720P - By Nature_DMT (Persia)

After non-stop summer months, the polar regions have expanded maximally, abundant food turns even the bears sociable. However the shortening of days soon starts reversing the process as frost expands the ice again. So many seasonal migrations turn too, mainly leaving for warmer regions. A stunning exception are the 'giant' emperor penguins, who arrive to mate, lay and raise their eggs in heroic defiance of the planet's harshest conditions.