The summer melt of Arctic ice provides opportunities for millions of animals.
A look at the annual return of millions of salmon to the streams where they were born.
The story of a lion family's struggle to survive until the return of the great migration.
A look at the sardine run, which happens each winter along the South African coast.
The great flood in the Okavango turns 4,000 square miles of arid plains into a wetland.
Whales and sea lions alike journey to the seas off Alaska to feed on the plankton bloom.