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Every year,
winter transforms our world,
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creating dazzling displays
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of frost, snow and ice.
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For us, it's a magical season,
but for other animals,
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it's the toughest time of the year.
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I've been lucky enough to spend time
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in the company of some of the
extraordinary animals
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that live through the wildest
winters on Earth.
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I'm fascinated by the strategies
they've developed
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to get them
through those challenging months.
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SQUAWKING
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So now I'm finding out more about
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how animals prepare for winter...
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..how they stay warm in some
of the coldest temperatures
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on the planet...
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..and manage to find food
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even in the deepest snow.
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I want to discover
how their priorities
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and survival tactics change
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as winter comes to an end.
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SQUEALING
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I'm uncovering the fascinating
stories behind
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how animals living in some of the
most demanding places on Earth
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have evolved ingenious ways
to survive,
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no matter what winter may bring.
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Winter,
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the season of sparkling, icy beauty.
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But this time of year poses
a real challenge
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for the animals living through it.
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As winter arrives,
temperatures start to drop.
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Here in the Alps they can plummet
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to a bone-chilling minus
33 degrees C.
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All around the world
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animals have to face these
conditions day in, day out.
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BIRD CHIRPS
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And it's harder to find food.
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The vegetation has,
for the most part, died out,
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and underneath all this
ice and snow,
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it makes it so much harder to hunt.
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00:03:01,800 --> 00:03:03,320
The days are also shorter.
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Here in the Alps, we're getting
about eight hours of sun,
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But as you move closer
to the North Pole,
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there's virtually no daylight,
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which ultimately means
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there's even less time to feed.
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Whether it's taking to the ice
in the far north...
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..or huddling up at the bottom
of the world...
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..every animal must find a way
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to get through the toughest season
of all.
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The key to surviving winter for many
animals is preparation,
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and the work must begin
months in advance.
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On the island of Hokkaido in Japan,
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forests are alight
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with the blazing colours of autumn.
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This change is a sign
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that winter is fast approaching.
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And for the Siberian chipmunk,
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it's a critical moment.
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This male must gather
as much food as possible
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to see him through what lies ahead.
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And it's a race against time.
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Chipmunks are one of
the smallest members
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of the squirrel family.
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But to survive the winter,
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they need to find and safeguard
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up to four kilos of food
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in their underground burrows.
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And they have an ingenious technique
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for gathering supplies,
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using their very own
built-in storage.
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These expandable cheek pouches
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can stretch to three times the size
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of the chipmunk's head...
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..allowing them to gather
up to 165 acorns
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every day.
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He needs as many
as he can get his paws on
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before he goes into hibernation.
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He's been working hard for weeks
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to build up his winter larder.
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But it can be a struggle
to get the goods
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before others do.
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SQUEAKING
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SQUEAKING
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The competition is fierce...
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..especially when an animal
three times your size
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appears in your territory.
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But this chipmunk won't let
the red squirrel
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get the better of him,
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defending his patch ferociously.
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After all, his life depends upon it.
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SQUEAKING
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When the food gathering is complete,
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he collects leaves and grasses
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to create a cosy den to sleep in.
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Once settled in,
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he'll be waking up every few days,
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feeding on his stockpile
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to keep him going.
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Chipmunks are not the only species
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hard at work storing food.
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As winter approaches,
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animals all around the world
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are frantically gathering nuts
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and for very good reason.
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Nuts are the perfect packaged foods
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to see animals through winter.
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Their hard shells preserve
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all the goodness inside.
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Acorns, for example,
are packed full of
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vitamins and calcium and fats.
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They're a high-energy food.
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In fact, this many acorns,
about 100g,
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is equivalent to 400 calories.
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Now, that's the same as about
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ten chocolate biscuits,
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or...
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..this many raspberries.
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Now, the fact that nuts
are so highly nutritious
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and key to the survival of so many
animals during winter
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has led to some pretty remarkable
adaptations.
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The fox squirrel can hide
anything between
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3 to 10,000 nuts
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in different places every season.
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To remember where it's hidden
those stashes,
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it builds up a mental map
of its surroundings.
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This requires so much brainpower,
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it's thought it actually causes
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the squirrel's brain to grow in size
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during prime, nut-hoarding season.
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The ability to store food
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has created a virtual lifeline
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for so many animals,
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but for others, that strategy
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simply isn't an option.
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They've got to approach it
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in an entirely different way,
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and that's resulted
in some of the greatest
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natural spectacles on Earth.
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BIRDS SQUAWK
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As winter closes in,
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millions of animals
are on the move...
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..in the air...
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..the sea...
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..and on land.
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They embark on these epic migrations
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in search of new food sources,
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or to escape the harsh weather.
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Caribou, known in Europe
as reindeer.
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In North America,
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these incredibly resilient animals
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travel to their wintering grounds
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in huge numbers.
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There can be close to 200,000
in one herd.
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Majestic narwhals spend
their summers
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in the coastal waters of the Arctic,
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but when winter approaches,
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the whales head far out to sea.
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Here, these almost-mythical
creatures find food
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deep beneath the surface,
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00:10:11,920 --> 00:10:14,120
coming up to breathe through holes
in the ice.
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And in Alaska,
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hundreds of thousands
of sandhill cranes head south
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to Mexico, over 3,000 miles away.
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Cranes are one of the oldest bird
families on Earth
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and it's thought that they've been
making journeys like this
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for millions of years.
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It's an arduous flight,
but they must persevere
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in order to survive.
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CRANE CALLS
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Not all animals flee
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the tightening grasp
of winter, however.
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In fact, one Arctic specialist
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is eagerly awaiting its arrival...
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..the polar bear...
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..basking in the last
rays of autumn sunshine.
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Here in the Canadian Arctic,
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the bears are gathering
at the coast,
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waiting for the sea to freeze
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so that they can hunt on the ice.
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Their main prey is ringed
and bearded seals,
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but they spend much of their time
out at sea
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and the bears need the ice
as a platform to reach them.
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The bears must bide their time
on the land.
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Over the summer,
they live off their fat reserves,
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but now these are dwindling.
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Many bears turn to eating plants,
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roots and berries,
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but it's not enough to sustain them.
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And as our climate changes,
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winter sea ice forms later
in the year
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and is reducing,
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leaving the bears
to survive on these meagre rations
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for even longer.
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Polar bears are usually
solitary animals,
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so seeing them together
like this is rare.
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For them, it's a chance to size
up future rivals,
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but it also uses
up valuable energy reserves.
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At last, the wait is over...
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..the ice is on its way.
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00:13:33,120 --> 00:13:35,400
With the arrival of deep winter,
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much of the planet undergoes
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a magical transformation.
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As temperatures plummet...
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..lakes and rivers freeze...
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..and snowflakes dance in the air.
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Landscapes become
winter wonderlands.
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00:14:20,520 --> 00:14:23,360
But now, life is much tougher.
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00:14:27,280 --> 00:14:31,320
And one of the biggest challenges
animals face is finding food.
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Snow acts as an obvious barrier
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to the food lying beneath it
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and it's often much deeper
than this, many metres in depth,
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so any animals looking
for vegetation
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or any small rodents beneath it all
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are going to have a very hard time
reaching it.
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00:14:56,280 --> 00:14:57,520
Not only that,
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00:14:57,520 --> 00:15:00,320
but snow is excellent
at absorbing sound waves...
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00:15:01,520 --> 00:15:04,440
..effectively acting as a layer
of sound proofing
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00:15:04,440 --> 00:15:07,280
and stopping any animals that rely
on their hearing
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00:15:07,280 --> 00:15:09,160
from detecting their prey.
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00:15:09,160 --> 00:15:11,360
Now, in the Rocky Mountains
of North America
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is an animal that is harnessing all
of its skills
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00:15:14,520 --> 00:15:16,040
to overcome these challenges.
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00:15:22,920 --> 00:15:25,320
In this imposing mountain range,
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00:15:25,320 --> 00:15:27,960
the snow can lie in huge drifts.
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00:15:33,680 --> 00:15:36,720
This is home to a particularly
elusive cat...
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..the bobcat, a species of lynx.
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To survive in these conditions,
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it's always on the lookout
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00:15:49,080 --> 00:15:50,360
for its next meal.
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00:15:55,960 --> 00:15:58,800
Bobcats have evolved
excellent hearing
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00:15:58,800 --> 00:16:01,280
with ears that can swivel
back and forth
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00:16:01,280 --> 00:16:03,200
independently of one another
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00:16:03,200 --> 00:16:06,280
in order to pinpoint any noise
coming from their prey.
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00:16:07,400 --> 00:16:09,960
And those characteristic ear tufts
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00:16:09,960 --> 00:16:11,720
are thought to amplify the sound.
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00:16:15,680 --> 00:16:17,720
But the deeper the snow,
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00:16:17,720 --> 00:16:19,480
the harder this task is.
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00:16:24,080 --> 00:16:27,160
Even the experts
don't always get it quite right.
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00:16:34,560 --> 00:16:37,120
Perhaps the river can provide
an opportunity.
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00:16:38,840 --> 00:16:41,080
It's fed by volcanic hot springs,
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00:16:41,080 --> 00:16:43,400
so it never freezes over.
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00:16:43,400 --> 00:16:47,600
It's a refuge of warmth, which draws
in animals from miles around.
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00:16:52,600 --> 00:16:56,360
The bobcat's preferred diet
is rabbit and hare,
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00:16:56,360 --> 00:16:58,000
but it's a resourceful cat
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00:16:58,000 --> 00:17:00,000
and will try its luck with
almost anything.
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00:17:06,720 --> 00:17:09,000
Although this one doesn't seem
to be very keen
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00:17:09,000 --> 00:17:10,320
on getting its paws wet.
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00:17:13,400 --> 00:17:16,040
It needs to find a suitable target.
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00:17:40,360 --> 00:17:42,440
DUCKS QUACK
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00:17:47,680 --> 00:17:48,960
No luck this time.
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00:17:50,680 --> 00:17:52,600
But these determined cats
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00:17:52,600 --> 00:17:54,640
are masters of perseverance.
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00:18:00,360 --> 00:18:02,800
With those finely-tuned ears,
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00:18:02,800 --> 00:18:06,240
perhaps this bobcat has caught
the faintest of sounds
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00:18:06,240 --> 00:18:07,440
beneath the snow.
256
00:18:14,320 --> 00:18:17,800
Its paws are soft and well-padded.
257
00:18:17,800 --> 00:18:20,200
Using the boulders
as stepping stones,
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00:18:20,200 --> 00:18:22,240
it can move without making a sound.
259
00:18:35,160 --> 00:18:37,680
In this particular game
of cat and mouse,
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00:18:37,680 --> 00:18:39,760
there's a clear winner.
261
00:18:45,640 --> 00:18:49,400
To overcome the problem of finding
food in deep snow,
262
00:18:49,400 --> 00:18:52,360
one group of animals is using
a different strategy -
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00:18:52,360 --> 00:18:54,480
changing its diet in winter.
264
00:18:56,760 --> 00:18:58,240
As herbivores,
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00:18:58,240 --> 00:19:00,680
deer feed on grasses
and other vegetation on the ground
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00:19:00,680 --> 00:19:04,520
and then browse the leaves of trees
and shrubs, so when winter arrives,
267
00:19:04,520 --> 00:19:08,240
their food is often hidden deep
beneath the snow or has died back.
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00:19:08,240 --> 00:19:09,920
Now, in this wildlife park,
269
00:19:09,920 --> 00:19:12,640
these deer are being given
supplementary food,
270
00:19:12,640 --> 00:19:15,680
but in the wild, deer have to become
much more resourceful.
271
00:19:24,200 --> 00:19:26,640
This is the Shiretoko Peninsula
272
00:19:26,640 --> 00:19:28,640
in the far north of Japan,
273
00:19:28,640 --> 00:19:31,920
where snow covers the mountain peaks
for eight months of the year.
274
00:19:38,800 --> 00:19:42,320
It's home to an incredibly
tenacious animal -
275
00:19:42,320 --> 00:19:43,480
the sika deer.
276
00:19:50,400 --> 00:19:51,880
At this time of year,
277
00:19:51,880 --> 00:19:54,280
there's little to eat
in these snowbound forests.
278
00:19:57,560 --> 00:19:59,600
Just getting around
in these conditions
279
00:19:59,600 --> 00:20:01,560
is difficult enough
280
00:20:01,560 --> 00:20:03,160
and to add to the challenge,
281
00:20:03,160 --> 00:20:05,640
many of the females are pregnant,
282
00:20:05,640 --> 00:20:07,400
due to give birth in the spring.
283
00:20:14,640 --> 00:20:16,000
To find food,
284
00:20:16,000 --> 00:20:17,840
the deer dig down through the snow
285
00:20:17,840 --> 00:20:22,120
using their hooves, looking for any
vegetation that might be available.
286
00:20:29,000 --> 00:20:30,760
But during harsh winters,
287
00:20:30,760 --> 00:20:33,560
sika deer are able to adapt
their diets
288
00:20:33,560 --> 00:20:35,400
to add another food source
289
00:20:35,400 --> 00:20:37,120
that can be found more easily...
290
00:20:38,080 --> 00:20:39,480
..tree bark.
291
00:20:50,760 --> 00:20:54,920
Perhaps surprisingly, tree bark does
have some nutritional value.
292
00:20:58,760 --> 00:21:01,520
But deer are only able to survive
on bark
293
00:21:01,520 --> 00:21:03,960
because of how their digestive
system has evolved.
294
00:21:16,320 --> 00:21:19,160
Deer stomachs are made up
of four compartments
295
00:21:19,160 --> 00:21:20,840
containing special enzymes
296
00:21:20,840 --> 00:21:24,200
that allow them to digest plants
and twigs and bark
297
00:21:24,200 --> 00:21:26,920
and to break down cellulose,
298
00:21:26,920 --> 00:21:28,720
a tough material that stands
in the way
299
00:21:28,720 --> 00:21:30,640
of all the nutritious stuff.
300
00:21:33,800 --> 00:21:36,800
But not only is bark especially
difficult to digest,
301
00:21:36,800 --> 00:21:38,520
it also contains tannins,
302
00:21:38,520 --> 00:21:40,160
which can be toxic.
303
00:21:40,160 --> 00:21:44,880
Deer have overcome this by producing
a special protein in their saliva
304
00:21:44,880 --> 00:21:46,600
that neutralises the tannins,
305
00:21:46,600 --> 00:21:48,480
rendering them harmless -
306
00:21:48,480 --> 00:21:50,680
a remarkable adaptation
that allows them
307
00:21:50,680 --> 00:21:52,680
to make the most of the scant
food available.
308
00:21:57,160 --> 00:21:59,200
WOLF HOWLS
309
00:22:04,080 --> 00:22:06,440
WOLVES HOWL
310
00:22:09,680 --> 00:22:11,320
All around the world,
311
00:22:11,320 --> 00:22:14,440
animals must be resourceful
and creative
312
00:22:14,440 --> 00:22:17,200
to secure the food they need
in winter.
313
00:22:22,440 --> 00:22:24,080
Wolves work together
314
00:22:24,080 --> 00:22:26,240
to hunt large prey like bison
315
00:22:26,240 --> 00:22:28,480
that could keep the whole pack going
for weeks.
316
00:22:36,360 --> 00:22:38,600
Voles burrow under the snow
317
00:22:38,600 --> 00:22:40,600
to reach the vegetation they need.
318
00:22:42,600 --> 00:22:46,920
And bald eagles will fiercely
fight off any competition.
319
00:22:46,920 --> 00:22:48,960
EAGLE SCREECHES
320
00:22:58,040 --> 00:23:00,520
It's not easy staying well-fed
in winter...
321
00:23:05,200 --> 00:23:08,240
..and animals that can adapt
to new circumstances
322
00:23:08,240 --> 00:23:10,680
will be the ones to come out on top.
323
00:23:22,920 --> 00:23:26,800
The Arctic fox can cope
with sub-zero winter temperatures
324
00:23:26,800 --> 00:23:28,600
in the extreme north
325
00:23:28,600 --> 00:23:30,920
thanks to its thick white fur coat.
326
00:23:35,680 --> 00:23:37,600
It's an accomplished hunter,
327
00:23:37,600 --> 00:23:39,680
feeding mostly on lemmings
and voles.
328
00:23:44,840 --> 00:23:47,000
But it's a constant struggle
to get enough food.
329
00:23:54,400 --> 00:23:58,640
Here in Alaska, new opportunities
are presenting themselves.
330
00:24:02,680 --> 00:24:04,720
TRUCK HORN BLASTS
331
00:24:05,720 --> 00:24:07,040
The town of Deadhorse
332
00:24:07,040 --> 00:24:09,920
is one of the most remote
settlements on Earth,
333
00:24:09,920 --> 00:24:11,880
more than 200 miles north
334
00:24:11,880 --> 00:24:13,360
of the Arctic Circle.
335
00:24:17,360 --> 00:24:20,120
The Arctic fox knows there's
food to be found here.
336
00:24:28,840 --> 00:24:30,320
But it will need to be careful.
337
00:24:33,000 --> 00:24:36,200
Not only does it have to avoid
humans and machinery...
338
00:24:39,600 --> 00:24:41,680
..but red foxes live here too.
339
00:24:44,040 --> 00:24:46,040
They've also been lured into town
340
00:24:46,040 --> 00:24:47,760
by the promise of sustenance.
341
00:24:53,880 --> 00:24:56,160
The Arctic fox's sense of smell
342
00:24:56,160 --> 00:24:58,440
is leading it towards
much-needed food.
343
00:25:00,960 --> 00:25:03,400
But the red fox is twice its size
344
00:25:03,400 --> 00:25:04,880
and could easily kill it.
345
00:25:21,440 --> 00:25:24,120
The Arctic fox has found
what it was looking for.
346
00:25:29,000 --> 00:25:30,800
This frozen meal of scraps
347
00:25:30,800 --> 00:25:32,280
is enough to keep him going.
348
00:25:39,680 --> 00:25:41,640
This intrepid little mammal
349
00:25:41,640 --> 00:25:44,920
is successfully exploiting
a new world to survive.
350
00:26:07,400 --> 00:26:10,240
And it also has the uncanny ability
351
00:26:10,240 --> 00:26:12,880
to vanish into the Arctic landscape
352
00:26:12,880 --> 00:26:14,240
thanks to its white coat.
353
00:26:17,960 --> 00:26:20,240
But he's not the only winter animal
354
00:26:20,240 --> 00:26:21,840
to use this disappearing act.
355
00:26:27,160 --> 00:26:30,720
The Yukon is the coldest place
in North America.
356
00:26:33,400 --> 00:26:37,240
Temperatures can fall to
minus 63 degrees Celsius
357
00:26:37,240 --> 00:26:38,960
and snow covers the ground
358
00:26:38,960 --> 00:26:40,480
for five months a year.
359
00:26:44,000 --> 00:26:47,640
This provides a distinct advantage
for one of its residents,
360
00:26:47,640 --> 00:26:49,240
if you can find it...
361
00:27:04,320 --> 00:27:05,920
..the snowshoe hare.
362
00:27:11,840 --> 00:27:14,960
It's fur perfectly matches
this white world.
363
00:27:22,360 --> 00:27:25,400
But the hare doesn't look
like this all year round.
364
00:27:27,360 --> 00:27:29,480
Throughout the spring
and summer months,
365
00:27:29,480 --> 00:27:31,440
its fur is reddish brown
366
00:27:31,440 --> 00:27:34,640
to match its habitat
at this time of year,
367
00:27:34,640 --> 00:27:38,600
but as winter approaches
and the snow starts to fall,
368
00:27:38,600 --> 00:27:41,040
it transforms from brown
369
00:27:41,040 --> 00:27:42,680
to purest white.
370
00:27:48,560 --> 00:27:51,640
Snowshoe hares have many predators,
371
00:27:51,640 --> 00:27:54,480
from coyotes to golden eagles...
372
00:27:56,680 --> 00:27:58,760
..and lynx.
373
00:27:58,760 --> 00:28:01,080
LYNX GROWLS
374
00:28:01,080 --> 00:28:03,520
So the hare's winter white coat
375
00:28:03,520 --> 00:28:05,280
makes for an excellent camouflage.
376
00:28:08,680 --> 00:28:10,520
With its perfect disguise,
377
00:28:10,520 --> 00:28:12,360
even out in the open,
378
00:28:12,360 --> 00:28:14,960
it can still remain hidden
from the sharpest eyes.
379
00:28:18,040 --> 00:28:20,760
And if it thinks it's been spotted,
380
00:28:20,760 --> 00:28:22,280
it has a getaway plan.
381
00:28:24,520 --> 00:28:26,960
The aptly-named snowshoe hare
382
00:28:26,960 --> 00:28:29,600
has especially large furry paws,
383
00:28:29,600 --> 00:28:31,760
which stop it from sinking
into the snow...
384
00:28:33,280 --> 00:28:36,320
..and help it to be fast and nimble
385
00:28:36,320 --> 00:28:39,160
and leap three metres
in a single bound.
386
00:28:45,280 --> 00:28:47,880
With all these
impressive adaptations
387
00:28:47,880 --> 00:28:49,640
and a little bit of luck,
388
00:28:49,640 --> 00:28:52,000
the snowshoe hare
will live to see another day.
389
00:29:02,280 --> 00:29:04,080
Only a few species,
390
00:29:04,080 --> 00:29:05,840
like this least weasel,
391
00:29:05,840 --> 00:29:08,200
have this special ability
to turn white in winter.
392
00:29:11,440 --> 00:29:13,080
But how does this
changing colour work?
393
00:29:16,040 --> 00:29:18,600
Colour in the fur and feathers
of animals
394
00:29:18,600 --> 00:29:20,960
is all down to a pigment
called melanin
395
00:29:20,960 --> 00:29:24,080
that's produced by specialised cells
in the skin
396
00:29:24,080 --> 00:29:26,400
and a combination of different types
of this pigment
397
00:29:26,400 --> 00:29:28,720
creates a whole range of colours.
398
00:29:28,720 --> 00:29:30,960
Now, white fur and feathers
399
00:29:30,960 --> 00:29:32,920
don't contain this melanin pigment.
400
00:29:35,240 --> 00:29:38,840
And the really clever bit is that
animals that can change colour
401
00:29:38,840 --> 00:29:40,720
switch off melanin production
402
00:29:40,720 --> 00:29:44,160
as they grow their glorious
white winter coats.
403
00:29:46,360 --> 00:29:49,800
This remarkable change is triggered
by day length.
404
00:29:49,800 --> 00:29:52,520
As the days
shorten before winter,
405
00:29:52,520 --> 00:29:54,920
these animals shed their
darker coats
406
00:29:54,920 --> 00:29:57,040
and gradually grow
their new winter ones.
407
00:29:58,520 --> 00:30:00,840
It's also thought that white fur
408
00:30:00,840 --> 00:30:03,000
might be more insulating
than dark fur.
409
00:30:04,440 --> 00:30:06,200
Because it doesn't have any melanin,
410
00:30:06,200 --> 00:30:09,360
it's hollow and contains more
trapped air in it.
411
00:30:09,360 --> 00:30:12,840
Trapped air equals greater
insulation and warmth...
412
00:30:16,400 --> 00:30:19,480
..making this transformation
a vital adaptation
413
00:30:19,480 --> 00:30:21,520
for surviving winter.
414
00:30:33,800 --> 00:30:35,760
Polar bears, on the other hand,
415
00:30:35,760 --> 00:30:38,880
keep their magnificent white coats
all year round.
416
00:30:45,280 --> 00:30:46,720
Out on the ice,
417
00:30:46,720 --> 00:30:49,080
conditions are some
of the harshest on Earth.
418
00:30:51,160 --> 00:30:53,240
The bears face high winds
419
00:30:53,240 --> 00:30:56,080
and temperatures of minus 50
degrees Celsius.
420
00:31:02,880 --> 00:31:04,760
Their insulating white fur
421
00:31:04,760 --> 00:31:06,400
provides their main protection.
422
00:31:13,000 --> 00:31:14,720
But in this frozen world,
423
00:31:14,720 --> 00:31:17,360
even these coats aren't enough
to keep them warm...
424
00:31:25,720 --> 00:31:28,440
..so polar bears have a dense layer
of blubber
425
00:31:28,440 --> 00:31:31,800
beneath their fur that can be up to
ten centimetres thick.
426
00:31:35,040 --> 00:31:37,920
This also protects them as they hunt
for seals...
427
00:31:39,160 --> 00:31:42,000
..often having to swim between
the ice floes...
428
00:31:43,200 --> 00:31:45,920
..their huge paws acting as paddles.
429
00:31:56,160 --> 00:31:59,640
The combination of this layer
of fat and thick white fur
430
00:31:59,640 --> 00:32:03,520
means that polar bears lose very
little heat to the environment.
431
00:32:03,520 --> 00:32:06,560
Now, we have a thermal imaging
camera trained on me at the moment
432
00:32:06,560 --> 00:32:08,120
to show you what I mean.
433
00:32:08,120 --> 00:32:10,200
Now, these cameras show up
hot objects
434
00:32:10,200 --> 00:32:12,080
as white or yellow or orange,
435
00:32:12,080 --> 00:32:13,880
and then cold objects
436
00:32:13,880 --> 00:32:16,320
as purples and dark blues
and even blacks.
437
00:32:16,320 --> 00:32:19,160
Now you can see, even though
I've got loads of layers on,
438
00:32:19,160 --> 00:32:20,680
I'm mostly orange
439
00:32:20,680 --> 00:32:23,440
and then my face is really yellow,
440
00:32:23,440 --> 00:32:26,920
as are my hands, because I've got
hand warmers in my gloves,
441
00:32:26,920 --> 00:32:31,440
but it goes to show how much heat
I am losing to the air around me.
442
00:32:31,440 --> 00:32:34,200
Now, if we look at a thermal
image of a polar bear,
443
00:32:34,200 --> 00:32:36,800
it's a very different
picture altogether.
444
00:32:36,800 --> 00:32:38,680
The polar bear is mostly dark blues
445
00:32:38,680 --> 00:32:40,920
with just a little bit of light
at its extremities
446
00:32:40,920 --> 00:32:44,360
like its nose, where it's losing a
tiny bit of heat,
447
00:32:44,360 --> 00:32:48,400
but that just goes to show polar
bears lose hardly any heat at all,
448
00:32:48,400 --> 00:32:51,560
making it one of the most
resilient animals on the planet.
449
00:32:58,200 --> 00:33:01,560
This is Valdez Harbour in Alaska,
450
00:33:01,560 --> 00:33:04,400
a winter refuge for a charismatic
little creature.
451
00:33:12,800 --> 00:33:16,840
Sea otters spend nearly
their whole lives on the water.
452
00:33:19,920 --> 00:33:23,320
But unlike polar bears and other
marine mammals,
453
00:33:23,320 --> 00:33:25,840
they don't have a layer of blubber
for insulation...
454
00:33:31,080 --> 00:33:35,120
..so they have evolved the thickest
fur coat of any animal.
455
00:33:39,840 --> 00:33:43,400
The outer layer is made up
of long waterproof hairs...
456
00:33:45,320 --> 00:33:48,640
..while underneath, there's a short,
dense underfur layer.
457
00:33:50,800 --> 00:33:53,640
This keeps cold water
completely away from the skin.
458
00:34:00,720 --> 00:34:03,760
This female has an extra
challenge on her hands.
459
00:34:03,760 --> 00:34:05,840
PUP MEWLS
460
00:34:07,040 --> 00:34:10,200
Sea otters can give birth
all year round
461
00:34:10,200 --> 00:34:12,280
and this is not ideal timing.
462
00:34:14,600 --> 00:34:16,160
To keep her pup warm,
463
00:34:16,160 --> 00:34:17,760
she has to groom it constantly.
464
00:34:20,400 --> 00:34:23,280
She also blows air into its fur -
465
00:34:23,280 --> 00:34:25,640
the fluffier it is,
the warmer it will be.
466
00:34:32,400 --> 00:34:34,000
When it's a little older,
467
00:34:34,000 --> 00:34:36,200
she takes it out to sea to hunt.
468
00:34:36,200 --> 00:34:39,680
To find food,
she has to leave it at the surface.
469
00:34:47,640 --> 00:34:50,480
PUP MEWLS
470
00:34:50,480 --> 00:34:52,480
But thanks to its fluffy coat
471
00:34:52,480 --> 00:34:54,960
and especially large lung capacity,
472
00:34:54,960 --> 00:34:57,040
it's so buoyant, it just won't sink.
473
00:34:59,880 --> 00:35:02,000
PUP MEWLS
474
00:35:02,000 --> 00:35:03,320
When she surfaces,
475
00:35:03,320 --> 00:35:06,400
its cries lead her back so she can
feed it too.
476
00:35:13,960 --> 00:35:15,880
The evolution of thick winter coats
477
00:35:15,880 --> 00:35:18,560
is yet another exquisite adaptation
478
00:35:18,560 --> 00:35:22,040
that allows animals to withstand
the coldest temperatures,
479
00:35:22,040 --> 00:35:25,000
but even then, that may not
be quite enough.
480
00:35:25,000 --> 00:35:27,480
But nature always finds a way,
481
00:35:27,480 --> 00:35:30,480
and some species have developed
a very different,
482
00:35:30,480 --> 00:35:33,000
but equally effective,
survival strategy.
483
00:35:40,680 --> 00:35:43,840
In the frozen mountain forests
of southern China,
484
00:35:43,840 --> 00:35:46,920
2,500 metres above sea level,
485
00:35:46,920 --> 00:35:48,960
lives an astonishing animal.
486
00:35:54,080 --> 00:35:55,480
Rarely seen,
487
00:35:55,480 --> 00:35:58,720
this is the highest-living
monkey in the world -
488
00:35:58,720 --> 00:36:00,720
the Yunnan snub-nosed monkey.
489
00:36:04,680 --> 00:36:08,800
These monkeys have developed some
remarkable adaptations to cope with
490
00:36:08,800 --> 00:36:11,720
the freezing temperatures of their
Himalayan home.
491
00:36:17,600 --> 00:36:20,480
Their noses are
almost completely flat
492
00:36:20,480 --> 00:36:22,320
to avoid getting frostbite...
493
00:36:24,920 --> 00:36:27,400
..and they're covered in dense fur
494
00:36:27,400 --> 00:36:29,600
that can be
up to 15 centimetres long.
495
00:36:34,880 --> 00:36:36,720
But in this heavy snowfall,
496
00:36:36,720 --> 00:36:38,600
even this isn't enough...
497
00:36:40,360 --> 00:36:42,800
..so they do something very clever.
498
00:36:46,080 --> 00:36:48,680
Snub-nosed monkeys
are social animals
499
00:36:48,680 --> 00:36:50,760
who live in large family groups.
500
00:36:52,600 --> 00:36:54,080
As night approaches,
501
00:36:54,080 --> 00:36:56,560
they gather together amongst
the branches of trees.
502
00:37:00,480 --> 00:37:03,960
Mothers and babies are usually
at the centre
503
00:37:03,960 --> 00:37:06,400
with all the other members
of the family surrounding them.
504
00:37:11,040 --> 00:37:13,480
They'll stay huddled
like this until morning.
505
00:37:15,720 --> 00:37:17,360
In this bitter cold,
506
00:37:17,360 --> 00:37:19,800
they simply wouldn't survive
the night on their own.
507
00:37:27,920 --> 00:37:30,320
So what's the science
behind huddling?
508
00:37:30,320 --> 00:37:32,000
Exactly how does it work?
509
00:37:32,000 --> 00:37:35,240
Well, we have a thermal imaging
camera trained on me
510
00:37:35,240 --> 00:37:37,840
to help explain exactly
what's going on.
511
00:37:37,840 --> 00:37:40,440
Now, heat is a thermal energy
512
00:37:40,440 --> 00:37:43,480
that's constantly flowing around us
513
00:37:43,480 --> 00:37:47,160
and as it flows, it naturally
moves from hotter objects
514
00:37:47,160 --> 00:37:48,440
to colder objects.
515
00:37:48,440 --> 00:37:49,880
To show you what I mean,
516
00:37:49,880 --> 00:37:52,560
I'm going to fill this solitary mug
517
00:37:52,560 --> 00:37:54,520
in the snow
518
00:37:54,520 --> 00:37:56,320
with some hot chocolate.
519
00:37:57,960 --> 00:38:00,040
Now, you can see it's hot -
520
00:38:00,040 --> 00:38:03,120
white or yellow in the centre -
but very quickly,
521
00:38:03,120 --> 00:38:04,680
it's losing that heat
522
00:38:04,680 --> 00:38:07,080
to the colder air around it,
523
00:38:07,080 --> 00:38:08,200
but if I fill...
524
00:38:09,640 --> 00:38:12,120
..all of these mugs of chocolate
525
00:38:12,120 --> 00:38:14,760
huddled together like our monkeys...
526
00:38:16,280 --> 00:38:18,480
..we should be able to see something
527
00:38:18,480 --> 00:38:20,520
very different is happening.
528
00:38:20,520 --> 00:38:23,760
All of the mugs are losing
their heat much less quickly,
529
00:38:23,760 --> 00:38:26,960
particularly the one in the centre
530
00:38:26,960 --> 00:38:30,520
and that's because it's protected
by the hot mugs around it,
531
00:38:30,520 --> 00:38:34,600
but also, it's gaining some heat
from the collective huddle
532
00:38:34,600 --> 00:38:36,760
that's hotter than it is.
533
00:38:36,760 --> 00:38:38,360
Therefore, the heat is transferring
534
00:38:38,360 --> 00:38:39,800
to that mug in the centre.
535
00:38:41,640 --> 00:38:42,880
In just a few minutes,
536
00:38:42,880 --> 00:38:44,960
you can clearly see the
difference, can't you?
537
00:38:44,960 --> 00:38:47,360
This cup is now completely cold,
538
00:38:47,360 --> 00:38:49,560
having lost all its
heat to the elements,
539
00:38:49,560 --> 00:38:52,760
while this one is
nice and cosy and warm
540
00:38:52,760 --> 00:38:54,000
in the centre.
541
00:38:56,440 --> 00:38:58,120
Now, in the Antarctic,
542
00:38:58,120 --> 00:39:01,320
one particular species is
using this huddling strategy
543
00:39:01,320 --> 00:39:03,480
in such a beautifully complex way
544
00:39:03,480 --> 00:39:07,120
that scientists are only just
beginning to fully understand it.
545
00:39:10,880 --> 00:39:14,240
Emperor penguins are one
of nature's great survivors.
546
00:39:19,440 --> 00:39:22,840
They can endure the extreme
cold of an Antarctic winter
547
00:39:22,840 --> 00:39:24,520
where temperatures can plummet
548
00:39:24,520 --> 00:39:26,480
to minus 40 degrees Celsius.
549
00:39:30,360 --> 00:39:32,080
And the key to their survival
550
00:39:32,080 --> 00:39:33,960
is how they huddle together.
551
00:39:38,720 --> 00:39:42,800
One by one, the male emperor
penguins lock themselves together
552
00:39:42,800 --> 00:39:44,440
in a tightly-packed group
553
00:39:44,440 --> 00:39:47,240
to keep warm and shelter
from the intense winds.
554
00:39:49,240 --> 00:39:50,760
These huddles can contain
555
00:39:50,760 --> 00:39:52,920
as many as 4,000 penguins.
556
00:39:56,800 --> 00:39:59,360
And they are constantly moving -
557
00:39:59,360 --> 00:40:01,560
those on the outside push forward
558
00:40:01,560 --> 00:40:04,520
to get closer to the warmth
in the centre of the group
559
00:40:04,520 --> 00:40:07,560
and away from the full force
of the Antarctic storms.
560
00:40:10,560 --> 00:40:12,800
But the penguins on
the inside of the huddle
561
00:40:12,800 --> 00:40:14,280
also move around
562
00:40:14,280 --> 00:40:17,320
to stop themselves
from getting too warm.
563
00:40:17,320 --> 00:40:20,520
Recent studies have shown
that temperatures at the centre
564
00:40:20,520 --> 00:40:23,400
can reach an incredible
37 degrees Celsius...
565
00:40:25,640 --> 00:40:28,680
..so the penguins move
away to avoid overheating,
566
00:40:28,680 --> 00:40:30,120
with others replacing them.
567
00:40:34,200 --> 00:40:36,400
It's one of the most
phenomenal examples
568
00:40:36,400 --> 00:40:38,440
of cooperation in nature
569
00:40:38,440 --> 00:40:41,280
and a vital strategy
for the emperor penguins' survival.
570
00:40:45,040 --> 00:40:48,720
Bracing yourself against everything
that winter throws at you
571
00:40:48,720 --> 00:40:50,600
in such a sophisticated way
572
00:40:50,600 --> 00:40:53,080
is testament to just how resilient
573
00:40:53,080 --> 00:40:55,520
and awe-inspiring nature is,
574
00:40:55,520 --> 00:40:58,640
but nature is
also incredibly versatile
575
00:40:58,640 --> 00:41:02,440
and other animals are avoiding
the onslaught of winter altogether.
576
00:41:06,840 --> 00:41:10,120
To save energy when food
is in short supply,
577
00:41:10,120 --> 00:41:12,560
some animals go into hibernation.
578
00:41:15,800 --> 00:41:18,120
After feeding up in the autumn,
579
00:41:18,120 --> 00:41:20,080
hedgehogs find a cosy den.
580
00:41:24,360 --> 00:41:27,160
Here, they fall into
a state of inactivity,
581
00:41:27,160 --> 00:41:28,760
which can last all winter.
582
00:41:31,600 --> 00:41:33,680
Their body temperature drops,
583
00:41:33,680 --> 00:41:35,480
their heart rate slows
584
00:41:35,480 --> 00:41:37,720
and they live off their fat reserves
585
00:41:37,720 --> 00:41:38,920
for about four months.
586
00:41:48,800 --> 00:41:51,200
When winter arrives
in North America,
587
00:41:51,200 --> 00:41:54,240
the Arctic ground squirrel retreats
beneath the frozen ground...
588
00:41:59,120 --> 00:42:02,120
..where it will sleep
for an astounding eight months.
589
00:42:04,360 --> 00:42:07,240
A thermal camera inside
a filming burrow
590
00:42:07,240 --> 00:42:10,240
shows how the squirrel's body
temperature cools.
591
00:42:10,240 --> 00:42:11,840
It can drop to a staggering
592
00:42:11,840 --> 00:42:14,040
three degrees below freezing.
593
00:42:18,280 --> 00:42:22,160
Its major organs shut
down almost entirely,
594
00:42:22,160 --> 00:42:23,720
but every few weeks,
595
00:42:23,720 --> 00:42:27,320
it shivers and its muscles
send a flow of warm blood
596
00:42:27,320 --> 00:42:30,160
around its body,
rebooting its brain.
597
00:42:34,440 --> 00:42:37,880
It will do this about a dozen times
during the winter
598
00:42:37,880 --> 00:42:40,800
until finally,
it's time to wake up again.
599
00:42:53,640 --> 00:42:56,960
Bats are another group of animals
that are known to hibernate
600
00:42:56,960 --> 00:43:00,040
and new research has revealed
that one particular species -
601
00:43:00,040 --> 00:43:03,200
the Ussurian tube-nosed
bat from Japan,
602
00:43:03,200 --> 00:43:05,640
no bigger than the size of my palm -
603
00:43:05,640 --> 00:43:07,520
may hibernate in the snow.
604
00:43:09,800 --> 00:43:12,440
For many years, their whereabouts
during the harsh winters
605
00:43:12,440 --> 00:43:15,840
remained a mystery, but now it's
thought that when temperatures drop
606
00:43:15,840 --> 00:43:17,400
and the first snows fall,
607
00:43:17,400 --> 00:43:19,520
they leave their roosts
in the cavities of trees
608
00:43:19,520 --> 00:43:21,320
and the crevices of rocks
609
00:43:21,320 --> 00:43:23,200
and settle onto that snow.
610
00:43:24,400 --> 00:43:25,680
As more snow falls,
611
00:43:25,680 --> 00:43:28,280
they become covered and surrounded,
612
00:43:28,280 --> 00:43:30,920
their tiny movements
creating a cavity
613
00:43:30,920 --> 00:43:34,320
with much more stable temperatures
than their tree roosts,
614
00:43:34,320 --> 00:43:36,000
exposed to the elements,
615
00:43:36,000 --> 00:43:39,920
and there they'll remain in what's
called a super-cooled torpor
616
00:43:39,920 --> 00:43:41,880
or deep sleep.
617
00:43:41,880 --> 00:43:45,760
It's believed they'll stay
there until the snow melts,
618
00:43:45,760 --> 00:43:48,240
potentially hibernating
in their cavities
619
00:43:48,240 --> 00:43:50,600
all the way through to the spring.
620
00:44:06,160 --> 00:44:09,400
The shortest day of the year
occurs at the end of December
621
00:44:09,400 --> 00:44:10,720
in the Northern Hemisphere.
622
00:44:10,720 --> 00:44:13,000
It's known as the winter solstice.
623
00:44:14,960 --> 00:44:17,520
Gradually, days begin to lengthen
624
00:44:17,520 --> 00:44:20,040
and some animals start planning
for the future.
625
00:44:28,480 --> 00:44:30,240
The Himalayas,
626
00:44:30,240 --> 00:44:32,920
home to one of the planet's
most majestic
627
00:44:32,920 --> 00:44:34,680
and elusive creatures...
628
00:44:43,400 --> 00:44:45,040
..the snow leopard.
629
00:44:50,600 --> 00:44:53,200
Living in
the world's highest mountains,
630
00:44:53,200 --> 00:44:55,800
this big cat's home range
can be as large
631
00:44:55,800 --> 00:44:57,600
as 400 square miles.
632
00:45:03,760 --> 00:45:06,160
These cats are endangered.
633
00:45:06,160 --> 00:45:08,120
Scientists estimate
there may be as few
634
00:45:08,120 --> 00:45:10,440
as 4,000 left in the wild.
635
00:45:13,080 --> 00:45:15,960
So the odds are well and
truly stacked against them
636
00:45:15,960 --> 00:45:18,320
when it comes to
finding a potential mate
637
00:45:18,320 --> 00:45:19,760
in this winter landscape.
638
00:45:23,040 --> 00:45:25,960
But this snow leopard
doesn't seem to be too fazed
639
00:45:25,960 --> 00:45:27,560
by the challenge.
640
00:45:27,560 --> 00:45:29,920
He has a tried-and-tested strategy.
641
00:45:36,720 --> 00:45:40,760
First, he patrols the well-worn
tracks of his territory
642
00:45:40,760 --> 00:45:42,720
over and over again.
643
00:45:45,680 --> 00:45:47,360
This is his patch,
644
00:45:47,360 --> 00:45:50,640
but it might overlap
with the territory of a female
645
00:45:50,640 --> 00:45:52,880
and, with any luck,
their paths will cross.
646
00:45:55,920 --> 00:45:58,160
Next, he uses scent marking
647
00:45:58,160 --> 00:45:59,760
to advertise his presence.
648
00:46:06,520 --> 00:46:10,360
Snow leopards scent mark
their territory by spraying urine
649
00:46:10,360 --> 00:46:13,800
and scent chemicals and rubbing
scent glands against rocks
650
00:46:13,800 --> 00:46:15,360
or patches of earth.
651
00:46:16,480 --> 00:46:19,400
He also checks for the scent
of any potential mates
652
00:46:19,400 --> 00:46:20,680
who may have passed by.
653
00:46:22,120 --> 00:46:23,560
He's very diligent,
654
00:46:23,560 --> 00:46:26,520
sometimes spraying as many
as 20 times an hour.
655
00:46:28,840 --> 00:46:30,640
He wouldn't want to miss his chance.
656
00:46:34,960 --> 00:46:38,400
Scent marking and detecting
is a crucial part
657
00:46:38,400 --> 00:46:40,360
of the lives of snow leopards.
658
00:46:40,360 --> 00:46:42,880
It's how they communicate
as solitary animals
659
00:46:42,880 --> 00:46:45,920
and it's incredibly important
when it's time to breed.
660
00:46:45,920 --> 00:46:49,560
Snow leopards may have tens
of millions of scent receptors.
661
00:46:49,560 --> 00:46:52,320
We humans only have a paltry
five million.
662
00:46:52,320 --> 00:46:55,320
Their ability to detect different
chemicals in a scent mark
663
00:46:55,320 --> 00:46:57,240
is nothing short of extraordinary.
664
00:47:01,800 --> 00:47:03,960
It can take a snow leopard
over a week
665
00:47:03,960 --> 00:47:06,640
to cover his entire territory,
666
00:47:06,640 --> 00:47:09,040
walking hundreds of miles in search
of a mate.
667
00:47:11,560 --> 00:47:13,840
Not even the deepest snow
will stop him.
668
00:47:24,280 --> 00:47:27,320
At last, his determination pays off,
669
00:47:27,320 --> 00:47:29,400
he picks up the scent of a female.
670
00:47:34,960 --> 00:47:37,440
Eagerly, he rubs his own scent
671
00:47:37,440 --> 00:47:41,560
over the scent she has left to
declare his presence and interest.
672
00:47:48,680 --> 00:47:51,840
He may be able to smell the marks
of the female,
673
00:47:51,840 --> 00:47:54,000
but now he needs to find her.
674
00:47:56,320 --> 00:47:58,760
Then, across the mountains,
675
00:47:58,760 --> 00:48:01,400
comes the cry
of a female snow leopard.
676
00:48:02,440 --> 00:48:04,480
SNOW LEOPARD CALLS IN DISTANCE
677
00:48:12,720 --> 00:48:14,280
He returns the call.
678
00:48:33,160 --> 00:48:35,200
If they do finally meet,
679
00:48:35,200 --> 00:48:37,320
these rare leopards will have
a chance
680
00:48:37,320 --> 00:48:39,040
to add to the next generation...
681
00:48:44,760 --> 00:48:47,400
..and with such
low population numbers,
682
00:48:47,400 --> 00:48:50,000
every new litter of cubs
is precious.
683
00:48:51,760 --> 00:48:53,720
SNOW LEOPARD CALLS
684
00:49:03,880 --> 00:49:05,440
As the snow begins to melt...
685
00:49:09,200 --> 00:49:11,720
..and the sun's rays
become stronger,
686
00:49:11,720 --> 00:49:13,560
spring will soon be on its way.
687
00:49:15,840 --> 00:49:19,440
But what causes these dramatic
changes between the seasons?
688
00:49:21,720 --> 00:49:25,520
It's all down to the fact
that planet Earth is tilted
689
00:49:25,520 --> 00:49:29,040
23.5 degrees off its axis.
690
00:49:29,040 --> 00:49:32,080
So when it's winter
in the northern hemisphere,
691
00:49:32,080 --> 00:49:35,520
where we are in the UK
and where I am here in Austria,
692
00:49:35,520 --> 00:49:37,640
the planet is in this position
693
00:49:37,640 --> 00:49:39,640
and it's tilted away from the sun,
694
00:49:39,640 --> 00:49:42,000
which means
in the northern hemisphere,
695
00:49:42,000 --> 00:49:45,240
days are shorter and it's colder,
696
00:49:45,240 --> 00:49:47,280
but as the Earth moves
around the sun...
697
00:49:49,000 --> 00:49:50,960
..over 365 days,
698
00:49:50,960 --> 00:49:54,000
spinning on its own axis
every 24 hours, obviously,
699
00:49:54,000 --> 00:49:56,000
as it hits spring around here
700
00:49:56,000 --> 00:49:57,880
and then summer here,
701
00:49:57,880 --> 00:50:02,120
you can see the northern hemisphere
is tilted towards the sun,
702
00:50:02,120 --> 00:50:05,480
which means days are longer
and warmer.
703
00:50:05,480 --> 00:50:08,000
Now, if our planet wasn't tilted
at all,
704
00:50:08,000 --> 00:50:10,680
we simply wouldn't have any seasons
705
00:50:10,680 --> 00:50:13,480
and the Earth would be
a very different place indeed.
706
00:50:24,640 --> 00:50:26,920
High in the northern hemisphere,
707
00:50:26,920 --> 00:50:28,920
with the arrival of spring,
708
00:50:28,920 --> 00:50:31,520
Arctic ground squirrels
are beginning to stir
709
00:50:31,520 --> 00:50:32,960
from their very deep sleep.
710
00:50:35,280 --> 00:50:38,040
It takes three hours for them
to heat up
711
00:50:38,040 --> 00:50:40,360
and a full day for their
entire bodies
712
00:50:40,360 --> 00:50:41,920
to be fully functional again.
713
00:50:47,760 --> 00:50:49,600
As soon as they're up and about,
714
00:50:49,600 --> 00:50:51,680
males spring straight into action.
715
00:50:55,120 --> 00:50:57,160
SQUIRREL CHIRPS
716
00:51:03,280 --> 00:51:06,280
First, this male needs to
reclaim his territory.
717
00:51:10,560 --> 00:51:12,600
SQUIRREL CHIRPS
718
00:51:16,640 --> 00:51:18,280
He sees off any rivals.
719
00:51:24,360 --> 00:51:27,080
He's ready for the most
important day of his year.
720
00:51:34,320 --> 00:51:36,560
Female Arctic ground squirrels
721
00:51:36,560 --> 00:51:38,800
emerge a few days after the males.
722
00:51:43,040 --> 00:51:44,480
He needs to look his best...
723
00:51:47,720 --> 00:51:49,560
..but he mustn't miss his chance.
724
00:51:52,880 --> 00:51:55,440
Females are only fertile
725
00:51:55,440 --> 00:51:57,720
for 12 hours each year.
726
00:51:57,720 --> 00:51:59,800
SQUIRREL CHIRPS
727
00:52:09,000 --> 00:52:11,280
He approaches her cautiously.
728
00:52:11,280 --> 00:52:13,320
He doesn't want to scare her off.
729
00:52:14,360 --> 00:52:16,160
But what will she make of him?
730
00:52:28,480 --> 00:52:30,200
He politely taps a greeting...
731
00:52:31,600 --> 00:52:34,040
..and she returns the gesture.
732
00:52:34,040 --> 00:52:36,200
THEY CHIRP
733
00:52:36,200 --> 00:52:38,360
He can't afford to be complacent.
734
00:52:38,360 --> 00:52:41,800
She could go in search of another
partner at any time,
735
00:52:41,800 --> 00:52:44,840
so he won't leave her side
for 24 hours.
736
00:52:49,320 --> 00:52:53,280
And with any luck, the circle of
life will start all over again.
737
00:52:58,800 --> 00:53:01,520
While some animals are beginning
to pair up,
738
00:53:01,520 --> 00:53:04,120
others are already a few
steps ahead.
739
00:53:05,360 --> 00:53:07,280
CALF BLEATS
740
00:53:13,720 --> 00:53:15,680
CUB GRUNTS
741
00:53:20,760 --> 00:53:22,800
CHICK CALLS
742
00:53:29,120 --> 00:53:31,600
Arctic fox cubs emerge
from their den
743
00:53:31,600 --> 00:53:33,440
at just over three weeks old.
744
00:53:34,600 --> 00:53:36,960
Their mother has her work cut out
with six...
745
00:53:38,280 --> 00:53:41,640
..but they can have up to 14 cubs
in a single litter,
746
00:53:41,640 --> 00:53:44,080
the most of any of the fox family.
747
00:53:46,480 --> 00:53:50,120
Weddell seal pups are born
straight onto the ice.
748
00:53:50,120 --> 00:53:52,680
They'll double in weight
in just the first week
749
00:53:52,680 --> 00:53:55,080
and soon after, they'll take
their first swim.
750
00:53:58,680 --> 00:54:01,920
Young wild goats make the journey
to their spring pastures
751
00:54:01,920 --> 00:54:03,400
when they're only a few weeks old...
752
00:54:05,720 --> 00:54:07,120
..following their mothers,
753
00:54:07,120 --> 00:54:09,360
who'll protect them for the first
year of their life.
754
00:54:15,400 --> 00:54:17,040
Young animals everywhere
755
00:54:17,040 --> 00:54:19,920
are out exploring their new world
756
00:54:19,920 --> 00:54:22,920
and the rising temperatures
are enough to put a spring
757
00:54:22,920 --> 00:54:23,960
in everyone's step.
758
00:54:37,760 --> 00:54:42,440
The last places to feel the full
effects of spring are the poles
759
00:54:42,440 --> 00:54:46,400
and beneath the snow in the Arctic,
new life is emerging.
760
00:54:47,720 --> 00:54:49,760
CUB GRIZZLES
761
00:54:51,560 --> 00:54:54,840
These polar bear cubs are
just two months old.
762
00:54:57,640 --> 00:54:59,520
They were born beneath the snow
763
00:54:59,520 --> 00:55:01,840
while their mother lay in her deep
winter sleep.
764
00:55:08,240 --> 00:55:11,040
They're seeing the world
for the first time.
765
00:55:11,040 --> 00:55:12,960
CUB GRUNTS
766
00:55:14,200 --> 00:55:15,600
They need to find their feet...
767
00:55:18,960 --> 00:55:20,880
..and mum is on hand to help.
768
00:55:25,080 --> 00:55:27,160
CUB GRIZZLES
769
00:55:29,360 --> 00:55:31,880
After five months in hibernation,
770
00:55:31,880 --> 00:55:34,040
this is a chance to stretch
her legs.
771
00:55:46,760 --> 00:55:48,880
Following the long winter,
772
00:55:48,880 --> 00:55:51,680
a mother bear's first task
is to find food.
773
00:55:53,200 --> 00:55:55,640
She's headed for the sea ice
to hunt,
774
00:55:55,640 --> 00:55:58,000
before it melts fully
in a few months' time.
775
00:56:06,360 --> 00:56:09,880
Polar bears are dedicated and
protective mothers.
776
00:56:14,800 --> 00:56:16,840
CUB CALLS
777
00:56:18,920 --> 00:56:20,760
They keep their cubs close
778
00:56:20,760 --> 00:56:23,640
and call to them when
they wander too far.
779
00:56:23,640 --> 00:56:25,600
POLAR BEAR ROARS
780
00:56:25,600 --> 00:56:27,720
CUBS CALL
781
00:56:31,960 --> 00:56:33,720
Over the next two years,
782
00:56:33,720 --> 00:56:36,800
she will teach her cubs to swim
and to hunt
783
00:56:36,800 --> 00:56:41,120
and how to survive the challenging
Arctic winters by themselves.
784
00:56:50,960 --> 00:56:54,320
Until then, as they step out
into a new year,
785
00:56:54,320 --> 00:56:57,120
she will always be at their side.
786
00:56:57,120 --> 00:56:59,160
POLAR BEAR GROWLS
787
00:57:06,160 --> 00:57:08,480
CUB GRIZZLES
788
00:57:08,480 --> 00:57:10,400
MOTHER BEAR GROWLS
789
00:57:12,360 --> 00:57:15,360
From the first frosts
to the first thaws,
790
00:57:15,360 --> 00:57:18,240
our animals have developed
remarkable adaptations...
791
00:57:24,680 --> 00:57:26,840
..from making sure
they have enough food...
792
00:57:31,320 --> 00:57:34,480
..to staying as warm as possible
in the coldest months.
793
00:57:41,640 --> 00:57:45,080
The strategies they've evolved
to survive and thrive
794
00:57:45,080 --> 00:57:48,440
in our winter wonderlands make for
some of the most inspirational
795
00:57:48,440 --> 00:57:50,160
stories from the natural world.
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