Planet Earth - Season 1 Episode 6

The polar caps have the most extreme seasonal contrasts, growing and melting vast ice masses, so wildlife adapts by annual migrations. The majority of Antartica is a vast barren permafrost. Only 3% of the coast and peninsular peaks are where life migrates to in the spring, for a short fertile summer, attracted by rich supplies of krill and fish. Only the Emperor penguin males breed 4 months in winter 100 miles inland. The Arctic has a more complete fauna which migrates back North from the continent. Here, the Polar bear is threatened because global warming defrosts its seal hunt platform ice too fast.