Yellowstone is home to North America's most iconic wildlife, and every year these animals must survive the Thaw-one of the harshest seasonal changes on Earth when temperatures can swing from minus 40ÀF in winter to almost 100ÀF in summer. Learn how animals cope with this range, and witness the impact on individual families of wolves, grizzly bears, beavers, and great gray owls.

"BBC Earth." Widescreen (16x9).

Episode one: Time of transition --Waking grizzlies -- A lonely otter -- The deep snow -- Hunting strategies -- Great gray owls -- Episode two: Signs of spring -- The beaver lodge -- Heralds of the season -- Gathering storms -- Going with the flow -- Leaving the nest -- Episode three: A harsh season -- Adapt or die -- The brown up -- Changing habitats -- Life from the ashes -- Beating the odds.