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Alaska.
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America's last frontier...
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..and greatest wilderness.
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Immense.
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Unspoiled.
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00:00:21,280 --> 00:00:23,880
Awe-inspiring.
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Home to half the world's glaciers...
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..America's highest mountains...
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..and ice sheets that stretch
to the North Pole.
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00:00:40,520 --> 00:00:44,800
Inhabited by the world's largest
land predators...
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..herds of ancient beasts...
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..and leviathans from the deep.
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00:00:55,520 --> 00:00:58,240
The land is hostile
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00:00:58,240 --> 00:01:02,600
but its richness and diversity
is unparalleled
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in the northern hemisphere
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All must be resilient and adaptable
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if they're to survive a year
in the wild of Alaska.
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Alaska is the largest
of America's 50 states.
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It is seven times the size of the UK
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but home to fewer than
a million people.
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There are three million lakes...
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..12,000 wild rivers
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and 44,000 miles of coastline.
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That's more than the rest
of the US combined.
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It is the gateway to the Arctic.
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Half a million square miles
of wilderness
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that stretches from Canada
in the east
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to Russia in the west.
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Winter here is one of the harshest
anywhere.
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00:02:55,720 --> 00:02:59,520
Temperatures can plummet
to -60 degrees Celsius.
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Snowfall measured in feet,
not inches.
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And in the far north
the sun sets for two months,
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casting a huge swathe
of the state into darkness.
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The only light coming from
the Aurora Borealis.
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Winter lasts seven months.
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That's longer than spring,
summer and autumn combined.
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Creatures must battle to avoid
starvation and predators.
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To survive here is tough.
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But Alaska has one of
the world's toughest.
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Musk ox roam the Arctic tundra.
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Vast treeless plains
where winters are long and brutal.
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Out here they're exposed to the
worst that nature can throw at them.
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But these conditions are nothing new
for musk ox...
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..as they're relics
of the last great ice age.
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They migrated here from Siberia
with giant bears and woolly mammoths
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over 150,000 years ago.
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The other giants went extinct.
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Only musk ox survived.
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Standing five feet at the shoulder
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and weighing almost half a tonne,
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they need a steady supply of food.
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But there's a problem.
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The Arctic blast has frozen
the snow solid,
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trapping the vegetation below,
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starving these giants
of vital nutrition.
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MUSK OX GRUNTS
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It's like digging through concrete.
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Even their toughened hooves
are useless.
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As hunger kicks in
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they become irritable.
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00:06:02,920 --> 00:06:04,920
MUSK OX GRUNTS
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Musk ox are naturally
jumpy and defensive.
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MUSK OX GRUNTS
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One is startled...
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..and they bolt.
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When musk ox sense danger,
they retreat to the high ground...
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..where they close ranks.
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..horns facing outwards,
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prepared to fight off aggressors
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such as Alaska's 11,000 wolves.
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It's a defence strategy
that's helped them survive
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two million years.
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But this time it's a false alarm.
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A waste of valuable energy
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when food is in such short supply.
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Many of the females are in
the early stages of pregnancy.
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They must protect
their fat reserves...
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00:07:27,880 --> 00:07:30,600
..as it's only going to get colder
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and birthing season is still
a massive six months away.
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Musk ox are not the only ones
struggling to find food.
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Harsh storms batter
the west coast...
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..turning it into
a frozen wasteland.
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00:08:12,080 --> 00:08:15,760
Arctic foxes have evolved
to live out here.
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They're one of Alaska's
most resilient creatures.
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But even they're finding it hard
this year.
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And they must compete
with the world's largest
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and most formidable land predator.
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Alaska in winter.
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Temperatures drop low enough
to freeze the ocean...
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..trapping many of the state's
2,500 islands in thick sea ice.
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00:09:15,770 --> 00:09:20,010
One of the most remote Alaskan
islands is St Lawrence,
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which lies just 40 miles
off the Russian coast.
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WIND HOWLS
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Much of it is deserted.
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Only scavengers are active.
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BIRDS SQUAWK
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Arctic foxes are well adapted
to live out here.
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Each winter their coats
turn from brown to white
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to help with camouflage
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and double in length for warmth.
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Their small squat bodies
and a thick layer of insulating fat
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conserve heat.
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00:10:23,290 --> 00:10:27,450
Furry feet enable them walk on ice
and snow without sticking.
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00:10:33,770 --> 00:10:38,290
These adaptations help them
go longer between meals...
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00:10:43,770 --> 00:10:48,450
..which is vital if you live in
a place with so little to eat.
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Throughout the winter
they're solitary
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and travel great distances
to find food.
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But in the right circumstances
they will gather.
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The remains of a bowhead whale
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that was killed by hunters
in the autumn
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attracts foxes
from all over the island.
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00:11:31,370 --> 00:11:35,810
A feast like this will keep them fed
for months.
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That's assuming they can get their
teeth into the frozen flesh.
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And that it's not discovered by
the world's largest land carnivore.
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Polar bears are most at home
on the Arctic sea ice.
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They use it to travel huge distances
between islands and the mainland...
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..and from where to hunt
their main prey...
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..seals.
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00:12:33,970 --> 00:12:36,210
But they're also scavengers...
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..and can smell food 20 miles away.
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If one of Alaska's many polar bears
were to discover this carcass,
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they would soon take possession.
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00:13:01,530 --> 00:13:05,930
Feeding quickly, the foxes
must remain constantly alert.
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00:13:11,010 --> 00:13:13,530
They'll need all the help
they can get
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if they're to make it
through to spring.
126
00:13:34,250 --> 00:13:36,930
Winter still has four months to run.
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00:13:41,290 --> 00:13:44,050
While freezing temperatures
grip the north...
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..storms batter the south.
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1,000 miles from St Lawrence Island,
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in Alaska's south-east,
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lies Glacier Bay.
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This coastline is dominated
by an oceanic climate.
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Winters here are warmer but no less
severe than in the north.
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00:14:23,250 --> 00:14:26,530
Wet, warm air blows in off the sea.
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00:14:33,530 --> 00:14:35,410
Rises...
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..cools
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00:14:38,250 --> 00:14:40,490
and falls as snow.
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00:14:43,490 --> 00:14:46,210
More than seven feet every year.
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00:14:51,850 --> 00:14:53,850
BIRD SINGS
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00:14:59,850 --> 00:15:02,290
Over thousands of years,
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much of this snow has thickened
to form glaciers.
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00:15:13,090 --> 00:15:16,210
Slow moving rivers of ice,
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hundreds of feet thick...
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00:15:31,370 --> 00:15:35,690
..that carve steep sided valleys
out of solid rock...
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00:15:44,890 --> 00:15:47,930
..as they grind their way
down to sea level.
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00:15:56,970 --> 00:15:58,570
On the coastline,
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higher temperatures stop
the streams freezing over...
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..throwing a lifeline to one
of Alaska's most resilient
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little birds.
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The American dipper.
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00:16:14,970 --> 00:16:16,930
BIRD SINGS
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00:16:24,770 --> 00:16:29,370
Each winter, dippers leave
their frozen mountain streams
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to feed on the coast.
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00:16:38,490 --> 00:16:41,450
Pushing her wings upwards
and outwards,
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she quickly drops below the surface.
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00:16:47,530 --> 00:16:50,450
Dippers feed by diving down
to the riverbed...
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..where they pick
amongst the debris...
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..to disturb insects and fish.
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00:17:05,490 --> 00:17:08,770
She emerges with an insect larva,
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00:17:08,770 --> 00:17:12,450
splitting it open
by hitting it on the surface.
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00:17:16,770 --> 00:17:19,290
But it'll take more than scraps
like this
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to keep her alive
through the winter.
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00:17:24,810 --> 00:17:27,930
She heads out to hunt
in open water.
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And is rewarded with a fish.
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Which she kills
by beating it against a rock.
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She spends up to half the day
feeding
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in water just a few degrees
above freezing.
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00:18:21,530 --> 00:18:27,010
So to keep well insulated
she preens her 4,000 feathers
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00:18:27,010 --> 00:18:30,410
and the thick layer of down
underneath...
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00:18:37,970 --> 00:18:41,970
..then fluffs up and squats down
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to help keep her feet warm.
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Before heading back to the sea
to do it all over again.
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The mountains and valleys inland
from the dipper's stream
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are cloaked in coniferous woodland.
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00:19:19,770 --> 00:19:23,370
Up here, heavy snow
continues to fall...
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..carpeting the forest floor.
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It makes it difficult
for Alaska's smaller animals
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to forage on the ground.
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00:19:57,530 --> 00:20:01,690
To survive here you must be prepared
for the worst.
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00:20:08,530 --> 00:20:12,530
American red squirrels
are active all winter
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and rely on food they cached
in the autumn.
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00:20:23,130 --> 00:20:26,450
Sitting on his favourite perch,
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a male hungrily rips open
a spruce cone
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00:20:29,730 --> 00:20:32,930
to eat the energy-rich seeds inside.
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00:20:36,650 --> 00:20:39,690
He can get through 40 cones a day.
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00:20:42,010 --> 00:20:47,690
If he is to survive the winter, he
must have a cache of 10,000 cones.
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00:20:50,370 --> 00:20:54,690
Storing them is one thing,
keeping hold of them is another.
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An intruder trespasses
on his territory.
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He's got an eye on the cache.
190
00:21:12,570 --> 00:21:14,690
He edges closer...
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..but is spotted.
192
00:21:31,730 --> 00:21:34,530
The territory owner warns him
by drumming.
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00:21:34,530 --> 00:21:36,650
DRUMMING NOISE
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00:21:40,610 --> 00:21:43,570
When that doesn't work,
he chases him off.
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00:22:00,290 --> 00:22:04,210
His hoard safe,
He quenches his thirst.
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00:22:06,010 --> 00:22:10,450
He has to be on constant alert if
he's to make it through to spring.
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00:22:11,970 --> 00:22:13,970
BIRDS SQUAWK
198
00:22:26,250 --> 00:22:28,530
In a remote valley on the tundra,
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00:22:28,530 --> 00:22:31,690
1,000 miles north
of the squirrels...
200
00:22:32,770 --> 00:22:36,930
..a group of Arctic specialists
has plenty to eat...
201
00:22:37,970 --> 00:22:40,850
..regardless of the freezing
conditions.
202
00:22:49,290 --> 00:22:53,570
Snowshoe hares rarely travel far
from their birthplace.
203
00:23:00,530 --> 00:23:05,690
They feed on twigs, bark
and buds of stunted willow trees.
204
00:23:11,490 --> 00:23:13,770
But despite their camouflage,
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00:23:13,770 --> 00:23:16,930
they're still vulnerable
to predators.
206
00:23:20,530 --> 00:23:26,250
Lynx are Alaska's most skilful
and secretive hunters
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00:23:26,250 --> 00:23:31,450
and snowshoe hares
are their number one prey.
208
00:23:47,490 --> 00:23:52,410
Late February and four months
into a brutal Alaskan winter.
209
00:23:55,210 --> 00:23:58,650
But even out here
it's possible to thrive
210
00:23:58,650 --> 00:24:01,370
if you've adapted to the conditions.
211
00:24:07,210 --> 00:24:11,810
Snowshoe hares are perfectly
designed for life in the Arctic.
212
00:24:14,450 --> 00:24:17,610
Their white coats
help them blend in.
213
00:24:19,210 --> 00:24:22,690
Their huge back feet,
which give them their name,
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00:24:22,690 --> 00:24:26,610
let them move around easily
on top of the soft snow.
215
00:24:32,210 --> 00:24:35,650
Essential, as hares are
the favourite prey
216
00:24:35,650 --> 00:24:38,850
for one of Alaska's top predators.
217
00:24:41,650 --> 00:24:43,130
Lynx.
218
00:24:46,930 --> 00:24:51,410
They're stealth hunters
with incredible hearing,
219
00:24:51,410 --> 00:24:53,810
excellent eyesight
220
00:24:53,810 --> 00:24:56,210
and, like hares,
221
00:24:56,210 --> 00:25:00,850
they have big furry paws
that act like snowshoes.
222
00:25:07,210 --> 00:25:10,930
But hares have eyes
high on top of their heads,
223
00:25:10,930 --> 00:25:14,530
giving them almost 360 degrees
of vision.
224
00:25:17,570 --> 00:25:20,130
They also have acute hearing.
225
00:25:26,530 --> 00:25:29,650
When one senses danger...
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00:25:29,650 --> 00:25:31,770
they bolt.
227
00:25:40,210 --> 00:25:44,130
Four out of five lynx hunts
end in failure.
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00:26:01,690 --> 00:26:07,010
Hares are not the only Alaskan
animal to gain safety in numbers.
229
00:26:10,930 --> 00:26:16,530
Back on St Lawrence Island,
100 miles off the Alaskan coast,
230
00:26:16,530 --> 00:26:21,850
winter storms have buried the whale
carcass under six feet of snow...
231
00:26:25,210 --> 00:26:28,130
..forcing the Arctic foxes
to dig deep.
232
00:26:35,410 --> 00:26:37,850
But they can't stay down for long.
233
00:26:45,210 --> 00:26:49,530
They take it in turns to keep
a look out for polar bears.
234
00:27:09,930 --> 00:27:14,170
This group of ten foxes
may have travelled many miles
235
00:27:14,170 --> 00:27:16,130
to join the feast.
236
00:27:21,650 --> 00:27:23,650
FOX SNARLS
237
00:27:27,250 --> 00:27:30,890
With the coast clear,
it's time for a clean up.
238
00:27:34,490 --> 00:27:38,170
Scrubbing removes dried blood
and oil from their fur.
239
00:27:48,570 --> 00:27:53,650
Fluffing-up traps air
and helps them keep warm.
240
00:27:58,610 --> 00:28:02,130
Essential grooming
that could mean the difference
241
00:28:02,130 --> 00:28:04,250
between life and death.
242
00:28:20,970 --> 00:28:26,410
The sea ice surrounding St Lawrence
Island is now nearly six feet thick.
243
00:28:29,690 --> 00:28:32,690
It stretches over 1,000 miles,
244
00:28:32,690 --> 00:28:35,410
all the way to the North Pole.
245
00:28:41,450 --> 00:28:44,690
This may look like a frozen desert
246
00:28:44,690 --> 00:28:47,010
but there is life.
247
00:28:49,730 --> 00:28:53,730
Ringed seals haul out on it
to warm up.
248
00:28:57,770 --> 00:29:02,130
And polar bears roam across it
to hunt.
249
00:29:07,490 --> 00:29:11,690
Each winter, polar bears fatten-up
by feeding on seals
250
00:29:11,690 --> 00:29:14,170
ahead of the lean summer months.
251
00:29:15,250 --> 00:29:18,210
The sea ice lets them
travel further,
252
00:29:18,210 --> 00:29:20,890
giving them access to more prey.
253
00:29:22,490 --> 00:29:26,410
Without the ice, polar bears
simply could not exist.
254
00:29:31,490 --> 00:29:34,970
Thankfully for them
this winter is a cold one
255
00:29:34,970 --> 00:29:38,410
and the sea ice will be here
for a few months yet.
256
00:29:54,250 --> 00:29:58,170
Inland, the long winter
means ever-deepening snow.
257
00:30:01,250 --> 00:30:03,970
Those animals not able to
dig through it
258
00:30:03,970 --> 00:30:07,570
are forced to search further
and for longer.
259
00:30:07,570 --> 00:30:09,570
WIND HOWLS
260
00:30:10,610 --> 00:30:12,610
OX GRUNT
261
00:30:15,970 --> 00:30:19,570
The musk ox herd has moved
to higher ground
262
00:30:19,570 --> 00:30:22,850
where the wind-blown snow
lies thinner,
263
00:30:22,850 --> 00:30:25,530
making access to food easier.
264
00:30:35,970 --> 00:30:39,450
Up here, the wind chill
reduces the temperature
265
00:30:39,450 --> 00:30:41,890
by a further ten degrees.
266
00:30:45,250 --> 00:30:48,570
Musk ox have adapted to survive
such a battering.
267
00:30:52,250 --> 00:30:55,410
Their massive bulk
helps them conserve heat.
268
00:30:59,450 --> 00:31:02,210
Their fur is made up of two layers.
269
00:31:03,290 --> 00:31:06,690
A long thick weather resistant
outer one
270
00:31:06,690 --> 00:31:08,930
and a deep inner fleece.
271
00:31:11,010 --> 00:31:15,610
Called qiviut, it's eight times
warmer than sheep's wool.
272
00:31:16,650 --> 00:31:18,730
So little heat escapes
273
00:31:18,730 --> 00:31:22,650
that their bodies can remain cloaked
in ice right through the winter.
274
00:31:24,690 --> 00:31:26,690
OX GRUNTS
275
00:31:34,450 --> 00:31:37,170
Access to food is essential...
276
00:31:38,210 --> 00:31:41,170
..particularly for pregnant females.
277
00:31:43,410 --> 00:31:47,450
The next three months will be
crucial both for them
278
00:31:47,450 --> 00:31:49,650
and their unborn calves.
279
00:31:53,250 --> 00:31:56,490
Especially as winter
tightens its grip.
280
00:32:13,250 --> 00:32:16,770
Temperatures drop to
-30 degrees Celsius.
281
00:32:23,930 --> 00:32:26,410
Ice crystals fill the air.
282
00:32:37,050 --> 00:32:39,730
The longer winter drags on,
283
00:32:39,730 --> 00:32:44,410
the more difficult it is for those
roaming the land in search of food.
284
00:32:55,250 --> 00:32:59,130
Alaskan moose
are the world's largest.
285
00:33:00,210 --> 00:33:05,250
At seven feet tall, they can
stretch up to ten feet high,
286
00:33:05,250 --> 00:33:09,410
giving them access to nutritious
buds and young shoots.
287
00:33:11,210 --> 00:33:13,090
MOOSE GRUNTS
288
00:33:15,130 --> 00:33:17,730
During a long, harsh winter,
289
00:33:17,730 --> 00:33:20,970
moose can't eat enough calories
to stay alive
290
00:33:20,970 --> 00:33:25,170
so must rely on fat they put on
during summer and autumn.
291
00:33:31,690 --> 00:33:34,250
If they use up these fat reserves,
292
00:33:34,250 --> 00:33:37,210
they start consuming
their own muscle
293
00:33:37,210 --> 00:33:40,010
and will quickly starve to death.
294
00:33:47,730 --> 00:33:50,650
Young moose are particularly
vulnerable.
295
00:33:52,490 --> 00:33:56,050
They allocate most of their food
to growth,
296
00:33:56,050 --> 00:33:59,490
and come into winter
much leaner than the adults.
297
00:34:03,690 --> 00:34:05,650
Many don't make it.
298
00:34:18,490 --> 00:34:23,170
A scavenging magpie grabs
what it can of the frozen flesh.
299
00:34:26,210 --> 00:34:30,170
The death of one animal
bringing life to another.
300
00:34:40,250 --> 00:34:43,450
While it's still freezing
in the north,
301
00:34:43,450 --> 00:34:48,410
in Alaska's south-east
temperatures are starting to rise.
302
00:34:53,250 --> 00:34:57,890
Sediment-laden meltwater
pours from the land into the sea.
303
00:35:02,850 --> 00:35:07,730
Strong winds and high tides
stir up the nutrients,
304
00:35:07,730 --> 00:35:12,930
turning the Gulf of Alaska into one
of the most fertile bodies of water
305
00:35:12,930 --> 00:35:14,650
on Earth.
306
00:35:18,210 --> 00:35:20,890
It's incredibly rich in life.
307
00:35:23,410 --> 00:35:25,250
Both above...
308
00:35:26,930 --> 00:35:29,050
..and below the surface.
309
00:35:36,970 --> 00:35:39,970
The shallow waters
along the edge of the bay
310
00:35:39,970 --> 00:35:44,170
make this the perfect nursery
for young Pacific herring.
311
00:35:46,210 --> 00:35:47,930
Called fingerlings,
312
00:35:47,930 --> 00:35:50,250
they're only five inches long
313
00:35:50,250 --> 00:35:54,650
and feed on microscopic plankton
that floats in the water.
314
00:35:59,810 --> 00:36:04,890
For protection they form huge
schools of over a million fish.
315
00:36:07,210 --> 00:36:09,170
And for good reason.
316
00:36:11,250 --> 00:36:16,170
As the Gulf is home to Alaska's
biggest, most effective predator.
317
00:36:17,210 --> 00:36:19,210
BIRDS SQUAWK
318
00:36:32,410 --> 00:36:35,410
Late winter in the Gulf of Alaska.
319
00:36:35,410 --> 00:36:37,410
BIRDS SQUAWK
320
00:36:41,690 --> 00:36:44,610
Young Pacific herring
are under attack...
321
00:36:52,170 --> 00:36:54,130
..from harbour seals...
322
00:36:57,650 --> 00:36:59,450
..and steller sea lions.
323
00:37:03,210 --> 00:37:06,170
In an attempt to avoid
the onslaught,
324
00:37:06,170 --> 00:37:08,130
they head deep.
325
00:37:15,650 --> 00:37:17,610
But are chased down.
326
00:37:24,210 --> 00:37:27,130
In the confusion,
the herring are split up.
327
00:37:31,650 --> 00:37:34,610
Some rushing back to the surface.
328
00:37:36,170 --> 00:37:38,970
But even here, there's no respite.
329
00:37:38,970 --> 00:37:40,970
BIRDS SQUAWK
330
00:37:43,770 --> 00:37:48,890
As they're ambushed from above
by a raucous flock of sea birds.
331
00:38:10,690 --> 00:38:15,050
But for the young herring,
the worst is yet to come
332
00:38:15,050 --> 00:38:20,090
as they're now under attack from one
of the world's largest predators.
333
00:38:39,170 --> 00:38:41,130
Humpback whales.
334
00:38:56,210 --> 00:38:59,170
Every year, a small number
of humpbacks
335
00:38:59,170 --> 00:39:01,370
overwinter in these waters.
336
00:39:09,210 --> 00:39:12,130
They gorge on the shoals
of young herring.
337
00:39:17,170 --> 00:39:20,130
Humpbacks hunt by diving deep,
338
00:39:20,130 --> 00:39:22,370
then explode to the surface...
339
00:39:24,170 --> 00:39:26,610
..their huge mouths gaping.
340
00:39:30,210 --> 00:39:33,250
They devour thousands of herring
at a time.
341
00:39:38,130 --> 00:39:40,130
WHALE SONG
342
00:39:44,610 --> 00:39:48,130
Over the next few months,
their numbers will grow...
343
00:39:52,490 --> 00:39:55,690
..as humpbacks from across
the Pacific Ocean
344
00:39:55,690 --> 00:39:58,890
return to feed
in this quite unique bay.
345
00:40:15,650 --> 00:40:17,650
EAGLE SCREECHES
346
00:40:20,210 --> 00:40:24,370
An American bald eagle
is attracted by the commotion.
347
00:40:32,690 --> 00:40:35,930
Bald eagles normally hunt
larger prey
348
00:40:35,930 --> 00:40:39,650
but perhaps hungry
after the long, hard winter,
349
00:40:39,650 --> 00:40:42,370
this one seizes the moment.
350
00:40:56,210 --> 00:41:00,930
South-east Alaska
has around 20,000 bald eagles.
351
00:41:00,930 --> 00:41:04,850
Roughly one-fifth
of the world population.
352
00:41:07,210 --> 00:41:11,210
As winter draws to a close,
they return to their nest.
353
00:41:13,770 --> 00:41:15,770
EAGLE SQUAWKS
354
00:41:21,210 --> 00:41:24,650
Reunited with their
lifelong partners,
355
00:41:24,650 --> 00:41:27,850
they quickly start re-building work.
356
00:41:32,450 --> 00:41:36,450
This is the most challenging time
of the year for them.
357
00:41:36,450 --> 00:41:40,330
Lower temperatures and bad weather
increase energy demands.
358
00:41:41,370 --> 00:41:44,130
Shorter days reduce hunting time.
359
00:41:45,690 --> 00:41:49,210
And with such a limited
breeding season,
360
00:41:49,210 --> 00:41:52,610
it's going to be a battle
to raise a family.
361
00:42:01,610 --> 00:42:06,210
Alaska in winter is one of the most
hostile places on Earth.
362
00:42:10,530 --> 00:42:12,850
Food is scarce.
363
00:42:15,010 --> 00:42:16,970
Conditions are brutal.
364
00:42:20,330 --> 00:42:25,090
Only the fittest and best adapted
made it through.
365
00:42:28,250 --> 00:42:32,850
With the northern hemisphere
swinging back round towards the sun,
366
00:42:32,850 --> 00:42:36,810
life can once again flourish
in Alaska.
367
00:42:40,050 --> 00:42:42,610
Next time, spring.
368
00:42:42,610 --> 00:42:44,890
Migrants start to return.
369
00:42:45,970 --> 00:42:49,610
Those animals that spent
the winter in hibernation
370
00:42:49,610 --> 00:42:52,090
emerge hungry
371
00:42:52,090 --> 00:42:54,890
having not eaten for eight months.
372
00:42:55,930 --> 00:42:58,650
But spring in Alaska is short
373
00:42:58,650 --> 00:43:01,570
and predators are many.
374
00:43:02,650 --> 00:43:06,050
It's going to be tough
for both parents
375
00:43:06,050 --> 00:43:08,170
and newborn.
376
00:43:33,130 --> 00:43:35,770
Subtitles by Ericsson
377
00:43:39,560 --> 00:43:41,080
Alaska.
378
00:43:42,560 --> 00:43:45,480
America's last frontier...
379
00:43:45,480 --> 00:43:48,080
MUSK OX GRUNTS
380
00:43:48,080 --> 00:43:50,360
..and greatest wilderness.
381
00:43:50,360 --> 00:43:52,640
BIRDS SQUAWK
382
00:43:52,640 --> 00:43:54,000
Immense.
383
00:43:55,040 --> 00:43:57,040
Unspoiled.
384
00:43:57,040 --> 00:43:59,000
Awe-inspiring.
385
00:44:00,880 --> 00:44:03,600
Home to half the world's glaciers...
386
00:44:04,640 --> 00:44:06,800
..America's highest mountains...
387
00:44:07,880 --> 00:44:12,440
..and ice sheets that stretch
to the North Pole.
388
00:44:12,440 --> 00:44:14,120
ARCTIC FOX SQUEALS
389
00:44:16,200 --> 00:44:19,560
Inhabited by the world's largest
land predators...
390
00:44:21,320 --> 00:44:23,800
..herds of ancient beasts...
391
00:44:25,320 --> 00:44:27,640
..and leviathans from the deep.
392
00:44:31,680 --> 00:44:33,760
The land is hostile
393
00:44:33,760 --> 00:44:38,360
but its richness and diversity
is unparalleled
394
00:44:38,360 --> 00:44:40,640
in the northern hemisphere.
395
00:44:42,360 --> 00:44:46,360
All must be resilient and adaptable
396
00:44:46,360 --> 00:44:51,520
if they're to survive a year
in the wild of Alaska.
397
00:45:00,800 --> 00:45:04,520
Alaska's been in winter's grip
for seven months.
398
00:45:07,120 --> 00:45:09,400
Animals have scraped by...
399
00:45:11,040 --> 00:45:13,760
..barely able to eke out a living.
400
00:45:18,320 --> 00:45:20,760
Finally, there's a glimmer of hope.
401
00:45:23,120 --> 00:45:25,000
Days are growing longer...
402
00:45:26,080 --> 00:45:30,040
..and rising temperatures have
triggered one of the most dramatic
403
00:45:30,040 --> 00:45:32,280
transformations on the continent.
404
00:45:35,000 --> 00:45:37,120
The sea ice is melting.
405
00:45:38,160 --> 00:45:41,280
The big break-up has begun.
406
00:45:57,560 --> 00:46:00,360
By April, waves are back,
407
00:46:00,360 --> 00:46:04,520
pounding the shore of Alaska's
largest northerly island.
408
00:46:08,600 --> 00:46:13,080
St Lawrence lies 100 miles
from the Alaskan mainland
409
00:46:13,080 --> 00:46:16,040
but shares a climate
with nearby Siberia.
410
00:46:19,040 --> 00:46:20,760
It's bleak here...
411
00:46:21,800 --> 00:46:23,760
..but not lifeless.
412
00:46:28,320 --> 00:46:30,320
ARCTIC FOX SQUEALS
413
00:46:35,080 --> 00:46:39,760
Five months ago, this female
Arctic fox was part of a group...
414
00:46:42,280 --> 00:46:46,000
..kept alive by the frozen remains
of a whale carcass.
415
00:46:51,600 --> 00:46:55,600
But now they've exhausted
every food cache
416
00:46:55,600 --> 00:47:00,040
and this female needs a fresh
supply of meat more than ever.
417
00:47:00,040 --> 00:47:01,840
ARCTIC FOX SQUEALS
418
00:47:06,280 --> 00:47:09,080
Murres abandoned St Lawrence
in the autumn
419
00:47:09,080 --> 00:47:11,520
when their feeding grounds
froze over.
420
00:47:14,320 --> 00:47:16,760
Now they're returning in droves.
421
00:47:22,600 --> 00:47:26,280
Around three million sea birds
nest here in the spring.
422
00:47:31,320 --> 00:47:34,080
But this year there's a problem.
423
00:47:35,600 --> 00:47:39,000
Access to the cliffs
is hindered by ice.
424
00:47:43,360 --> 00:47:47,280
The murres will have to put
any plans for breeding on hold.
425
00:48:01,080 --> 00:48:04,520
This delay is bad news
for the hungry fox.
426
00:48:08,320 --> 00:48:10,840
It's mating season.
427
00:48:10,840 --> 00:48:15,280
She's paired-up with a male and
due to give birth in seven weeks.
428
00:48:19,560 --> 00:48:21,360
If she doesn't eat soon,
429
00:48:21,360 --> 00:48:24,760
her body will reabsorb
her developing embryos.
430
00:48:27,080 --> 00:48:30,760
A desperate act to preserve
every scrap of nutrition.
431
00:48:39,840 --> 00:48:43,280
Salvation may be buried
under the snow.
432
00:48:50,320 --> 00:48:53,600
Arctic foxes have such keen hearing,
433
00:48:53,600 --> 00:48:57,000
they can find voles
even when they can't see them.
434
00:49:02,800 --> 00:49:04,520
But voles are canny.
435
00:49:05,600 --> 00:49:09,760
If they don't move,
the fox can't get a fix.
436
00:49:17,680 --> 00:49:22,280
By paddling her hind feet,
she may panic them into moving.
437
00:49:35,840 --> 00:49:39,520
But there's still a thick layer
of frozen snow to get through.
438
00:49:45,920 --> 00:49:50,520
She needs a regular supply of voles
each day whilst she's pregnant.
439
00:49:51,800 --> 00:49:54,520
It's a deadly game of hide-and-seek.
440
00:49:56,040 --> 00:49:57,760
And right now...
441
00:49:59,040 --> 00:50:01,000
..the voles are winning.
442
00:50:09,360 --> 00:50:12,960
Whilst spring drags its heels
on St Lawrence...
443
00:50:14,040 --> 00:50:16,520
..it's making headway
on the mainland.
444
00:50:17,600 --> 00:50:20,280
It still drops below freezing
at night.
445
00:50:21,360 --> 00:50:24,360
But there are only eight hours
of darkness.
446
00:50:25,440 --> 00:50:28,760
Barely enough time
for the Aurora to shine.
447
00:50:46,080 --> 00:50:49,760
Daybreak wipes the dazzling display
from the sky...
448
00:50:52,080 --> 00:50:55,280
..and replaces it
with one on the ground.
449
00:50:59,280 --> 00:51:01,520
GROUSE RATTLES ITS TAIL
450
00:51:11,080 --> 00:51:14,320
Male sharp-tailed grouse
gather here each morning
451
00:51:14,320 --> 00:51:16,600
for a ritual called a lek
452
00:51:16,600 --> 00:51:20,000
so that females can choose
who to mate with.
453
00:51:22,760 --> 00:51:24,480
And they're very fussy.
454
00:51:26,560 --> 00:51:29,800
Only the fittest,
most attractive males will do.
455
00:51:29,800 --> 00:51:31,800
GROUSE SQUAWKS
456
00:51:33,360 --> 00:51:37,120
If he's to coax one down
from the aspen,
457
00:51:37,120 --> 00:51:39,760
he needs to catch her eye.
458
00:51:43,080 --> 00:51:46,280
Tricky when a younger male
wants to hog the limelight.
459
00:51:51,840 --> 00:51:56,320
If he loses this spot, the hens
won't give him a second look.
460
00:51:59,320 --> 00:52:01,160
He stands his ground
461
00:52:01,160 --> 00:52:03,280
and it works.
462
00:52:07,480 --> 00:52:09,760
Now he's got her attention.
463
00:52:10,800 --> 00:52:13,680
Time to pull out all the stops.
464
00:52:17,040 --> 00:52:19,560
He rattles his tail quills,
465
00:52:19,560 --> 00:52:21,840
flashes his throat pouch
466
00:52:21,840 --> 00:52:25,000
and throws in
some of his finest moves.
467
00:52:28,440 --> 00:52:33,280
Proof that he's fit, healthy
and unencumbered by parasites.
468
00:52:35,320 --> 00:52:37,280
But she's not convinced.
469
00:52:42,600 --> 00:52:47,240
She always compares multiple males
before selecting a mate.
470
00:52:48,320 --> 00:52:50,840
If he's to sire any chicks
this year,
471
00:52:50,840 --> 00:52:54,760
he'll need to up his game
and try again tomorrow
472
00:53:00,360 --> 00:53:04,360
Whilst grouse fight for the right
to produce this year's offspring,
473
00:53:04,360 --> 00:53:08,360
500 miles away
in Katmai Wilderness Area,
474
00:53:08,360 --> 00:53:11,760
some animals are already
raising theirs.
475
00:53:16,080 --> 00:53:20,280
Female bears look after their young
for nearly three years.
476
00:53:23,360 --> 00:53:26,520
This family is fresh
out of hibernation...
477
00:53:28,960 --> 00:53:30,760
..and they're hungry.
478
00:53:33,080 --> 00:53:36,360
When these twins were born
15 months ago,
479
00:53:36,360 --> 00:53:41,200
they were blind, helpless and
weighed a little under a pound.
480
00:53:43,400 --> 00:53:46,280
They're already eighty-times
their birth weight.
481
00:53:48,320 --> 00:53:50,280
Big enough for a tussle.
482
00:53:51,960 --> 00:53:55,000
But small enough to be vulnerable.
483
00:53:57,360 --> 00:54:00,760
The beach is a good place
to find breakfast.
484
00:54:01,800 --> 00:54:03,760
But it's also dangerous.
485
00:54:04,960 --> 00:54:07,720
There are other hungry bears
out here.
486
00:54:08,800 --> 00:54:13,280
And adult males will kill youngsters
they don't know.
487
00:54:14,800 --> 00:54:17,080
They need to stick close to mum.
488
00:54:17,080 --> 00:54:19,760
She's the only thing
keeping them alive.
489
00:54:26,420 --> 00:54:28,540
It's May in Alaska.
490
00:54:29,620 --> 00:54:32,180
The time when bears leave
their winter dens
491
00:54:32,180 --> 00:54:34,140
in the Aleutian Mountains
492
00:54:34,140 --> 00:54:37,140
and head to the coast to find food.
493
00:54:40,620 --> 00:54:44,820
In spring, warm, wet air
blows over the sea,
494
00:54:44,820 --> 00:54:47,020
cools
495
00:54:47,020 --> 00:54:50,620
and casts a veil of fog
over Hallo Bay.
496
00:54:54,220 --> 00:54:57,660
But it won't deter this brown bear
from teaching her twin
497
00:54:57,660 --> 00:54:59,620
the art of clamming.
498
00:55:03,220 --> 00:55:06,860
There's a lot to learn about
surviving in this wilderness.
499
00:55:09,460 --> 00:55:13,180
Young bears must learn
where to find food
500
00:55:13,180 --> 00:55:15,420
and how to harvest it.
501
00:55:24,180 --> 00:55:26,380
Clams thrive here...
502
00:55:28,620 --> 00:55:30,860
..but they're buried in the sand.
503
00:55:33,220 --> 00:55:36,380
Bears have more scent receptors
than a bloodhound...
504
00:55:38,220 --> 00:55:41,140
..so it's just a case
of sniffing them out.
505
00:55:45,460 --> 00:55:48,860
Four-inch claws make light work
of digging...
506
00:55:52,700 --> 00:55:56,140
..letting her guzzle hundreds
of clams at low tide.
507
00:56:00,580 --> 00:56:05,140
Valuable extra protein for a bear
that hasn't eaten for months.
508
00:56:12,700 --> 00:56:15,700
The cubs should be paying
attention
509
00:56:15,700 --> 00:56:19,620
but seem more interested
in where the world's gone.
510
00:56:25,900 --> 00:56:28,660
And with a milk bar so close,
511
00:56:28,660 --> 00:56:31,620
it's hard to resist the easy option.
512
00:56:38,180 --> 00:56:40,300
She's having none of it.
513
00:56:41,300 --> 00:56:44,140
Maybe hunger will make them focus.
514
00:56:59,100 --> 00:57:04,860
Almost 50% of bear cubs don't even
make it past their first birthday.
515
00:57:08,660 --> 00:57:11,860
One of the reasons is wanderlust.
516
00:57:20,460 --> 00:57:24,860
Cubs are keen to explore
every new sound and smell.
517
00:57:35,460 --> 00:57:38,140
But it's easy to get lost
in the fog.
518
00:57:44,940 --> 00:57:49,580
And bumping into the wrong bear
could be fatal.
519
00:57:56,220 --> 00:58:00,380
Luckily, it's mum that looms
from the gloom first.
520
00:58:09,180 --> 00:58:11,380
The twins must learn fast.
521
00:58:14,340 --> 00:58:18,140
Or one day naivety will
get them killed.
522
00:58:36,700 --> 00:58:40,940
Warm air from the Pacific
is opening up feeding-grounds
523
00:58:40,940 --> 00:58:43,620
all along Alaska's
southern coastline.
524
00:58:47,660 --> 00:58:51,180
350 miles east of Hallo Bay
525
00:58:51,180 --> 00:58:53,860
lies the Copper River Delta.
526
00:58:55,220 --> 00:59:01,140
The drainage basin for 24,000
square miles of Alaskan wilderness.
527
00:59:04,700 --> 00:59:08,140
Meltwater bathes the mudflats
in minerals...
528
00:59:10,940 --> 00:59:14,860
..feeding a habitat teeming
with marine invertebrates.
529
00:59:19,180 --> 00:59:21,860
Food for hungry sandpipers.
530
00:59:36,940 --> 00:59:42,620
The delta is a vital pit-stop for
almost five million shore birds...
531
00:59:43,940 --> 00:59:47,900
..all racing to reach
their breeding grounds in the north.
532
00:59:47,900 --> 00:59:49,900
BIRDS SQUAWK
533
01:00:01,700 --> 01:00:05,140
Dunlins mingle with flocks
of western sandpipers.
534
01:00:06,220 --> 01:00:09,860
Some have travelled from
as far away as Peru.
535
01:00:30,220 --> 01:00:33,660
All have just two months
to find a mate,
536
01:00:33,660 --> 01:00:36,380
lay eggs and raise a family.
537
01:00:45,220 --> 01:00:48,140
They must refuel
as fast as possible.
538
01:00:50,940 --> 01:00:54,140
There's still an 800-mile journey
ahead.
539
01:00:58,180 --> 01:01:01,220
Slender bills with sensitive tips
540
01:01:01,220 --> 01:01:04,340
help them find tiny worms
and molluscs.
541
01:01:12,420 --> 01:01:14,900
Most feed for three days straight,
542
01:01:14,900 --> 01:01:17,140
only stopping at high tide.
543
01:01:20,340 --> 01:01:22,900
Only then will they have
enough energy
544
01:01:22,900 --> 01:01:25,140
for the final leg of their trip.
545
01:01:35,220 --> 01:01:39,100
It's not just migrant birds that
are in a rush to raise a family.
546
01:01:40,660 --> 01:01:43,620
160 miles north of the delta...
547
01:01:44,700 --> 01:01:48,340
..in a valley sheltered
by the Talkeetna Mountains...
548
01:01:50,220 --> 01:01:54,140
..one of Alaska's permanent
residents must also act fast.
549
01:01:56,700 --> 01:02:00,220
Arctic ground squirrels
sleep through the winter
550
01:02:00,220 --> 01:02:04,100
in cosy burrows
lined with fur and lichen.
551
01:02:05,460 --> 01:02:08,420
But now, according to
their body clocks,
552
01:02:08,420 --> 01:02:10,540
it's time to rise and shine.
553
01:02:14,220 --> 01:02:18,180
It's this male's first glimpse
of daylight for eight months
554
01:02:18,180 --> 01:02:20,380
but he can't hang about.
555
01:02:23,340 --> 01:02:25,860
SQUIRRELS SQUEALS
556
01:02:27,460 --> 01:02:30,740
Noisy neighbours are popping up
everywhere.
557
01:02:36,740 --> 01:02:41,740
Male squirrels emerge before females
to establish territories.
558
01:02:49,420 --> 01:02:52,540
Firstly, rivals must be driven out.
559
01:03:10,580 --> 01:03:12,620
Sometimes shouting's enough.
560
01:03:12,620 --> 01:03:14,620
SQUIRREL SQUEALS
561
01:03:15,700 --> 01:03:18,660
But when verbal warnings
aren't heeded,
562
01:03:18,660 --> 01:03:20,620
things get physical.
563
01:03:36,020 --> 01:03:38,220
By keeping rivals at bay,
564
01:03:38,220 --> 01:03:41,580
he increases his chances
of meeting females.
565
01:03:42,660 --> 01:03:45,860
And he'd rather be a lover
than a fighter.
566
01:03:48,420 --> 01:03:51,140
At last, a female.
567
01:03:54,900 --> 01:03:59,860
She'll only be receptive to mating
for four hours in any given year.
568
01:04:03,420 --> 01:04:05,660
Get his timing wrong,
569
01:04:05,660 --> 01:04:08,380
and he'll be painfully rejected.
570
01:04:15,620 --> 01:04:17,180
Success.
571
01:04:17,180 --> 01:04:19,380
He's at first base.
572
01:04:21,420 --> 01:04:25,620
Now all he has to do
is keep an eye on her
573
01:04:25,620 --> 01:04:27,460
and be patient.
574
01:04:30,500 --> 01:04:33,140
He won't help raise his offspring.
575
01:04:34,460 --> 01:04:37,220
But waiting for the right moment
to conceive them
576
01:04:37,220 --> 01:04:39,620
is a chance to get to know
each other.
577
01:04:49,220 --> 01:04:53,140
Every day, the sun has a little
longer to warm the ground.
578
01:04:56,180 --> 01:04:59,620
Snow melts and rivers begin to flow.
579
01:05:08,100 --> 01:05:12,260
Ice jostles and jerks its way
downstream.
580
01:05:27,580 --> 01:05:31,140
Even in Alaska,
ice doesn't sit still forever.
581
01:05:44,180 --> 01:05:47,180
As mountain streams thaw out,
582
01:05:47,180 --> 01:05:49,620
American dippers move in.
583
01:05:51,220 --> 01:05:54,860
There's plenty of food here
to feed their growing family.
584
01:05:56,260 --> 01:06:00,500
But the creek's become flooded
with meltwater.
585
01:06:00,500 --> 01:06:04,700
A gentle cascade
is now a raging torrent.
586
01:06:06,740 --> 01:06:09,180
Their nest and the chicks inside
587
01:06:09,180 --> 01:06:11,620
are in serious danger.
588
01:06:22,020 --> 01:06:25,220
This American dipper spent winter
on the coast...
589
01:06:26,300 --> 01:06:30,540
..where open water allowed her
to ride out the cold snap
590
01:06:30,540 --> 01:06:32,660
on a diet of fish.
591
01:06:39,780 --> 01:06:44,020
But every spring she returns
upstream to her favourite creek...
592
01:06:46,060 --> 01:06:47,940
..to raise a family.
593
01:06:49,740 --> 01:06:51,940
They've hatched four chicks.
594
01:06:52,980 --> 01:06:55,940
But this year there's a problem.
595
01:06:57,020 --> 01:07:00,700
The sudden thaw has flooded
the creek with meltwater.
596
01:07:03,340 --> 01:07:07,660
She had nested on the edge of a
waterfall to keep predators at bay.
597
01:07:10,780 --> 01:07:14,940
But now a tonne of water
crashes down every second.
598
01:07:19,300 --> 01:07:23,700
A thick outer shell of moss
protects her chicks from the spray.
599
01:07:26,020 --> 01:07:29,460
But access into the nest
is treacherous.
600
01:07:32,260 --> 01:07:35,260
Only strong toes and a powerful grip
601
01:07:35,260 --> 01:07:37,700
stop her sliding to oblivion.
602
01:07:40,380 --> 01:07:43,260
Chicks need feeding
every four minutes,
603
01:07:43,260 --> 01:07:46,140
keeping both parents very busy.
604
01:07:47,220 --> 01:07:50,340
They scan the shallows
from their favourite boulder.
605
01:07:53,540 --> 01:07:58,100
Highly oxygenated water
supports an abundance of bugs...
606
01:07:59,740 --> 01:08:01,780
..which the dippers hunt,
607
01:08:01,780 --> 01:08:04,380
either by snorkelling
in the gravel bed...
608
01:08:06,700 --> 01:08:10,220
..or by diving for richer pickings
further down.
609
01:08:19,260 --> 01:08:21,780
They hunt for an hour at a time,
610
01:08:21,780 --> 01:08:25,220
making up to 35 feeding trips
between them.
611
01:08:36,300 --> 01:08:40,260
To help them stay waterproof, they
spread oil from their preen gland
612
01:08:40,260 --> 01:08:42,220
through their feathers...
613
01:08:45,740 --> 01:08:47,940
..before taking the plunge again.
614
01:08:52,740 --> 01:08:54,780
Dipper chicks stay in the nest
615
01:08:54,780 --> 01:08:57,460
for longer than most other birds
their size.
616
01:08:59,180 --> 01:09:02,740
They won't fledge until they're
almost fully developed.
617
01:09:02,740 --> 01:09:05,100
That's over two weeks away.
618
01:09:07,500 --> 01:09:10,140
And with the thaw still in progress,
619
01:09:10,140 --> 01:09:13,940
the river will keep creeping
towards their nest.
620
01:09:23,020 --> 01:09:26,260
1,000 miles north-west
of the dippers,
621
01:09:26,260 --> 01:09:28,780
just outside the Arctic Circle,
622
01:09:28,780 --> 01:09:32,940
rising temperatures
are both a blessing and a curse.
623
01:09:39,340 --> 01:09:42,980
Musk ox still haven't shed
their thick winter coats
624
01:09:42,980 --> 01:09:44,980
and they're feeling the heat.
625
01:09:47,020 --> 01:09:49,020
MUSK OX GRUNTS
626
01:09:50,100 --> 01:09:52,940
Resting on a windy ridge
helps a little.
627
01:09:57,980 --> 01:10:00,260
Back in the depths of winter,
628
01:10:00,260 --> 01:10:02,060
females were pregnant...
629
01:10:03,100 --> 01:10:05,020
..food was scarce
630
01:10:05,020 --> 01:10:08,940
and woolly coats were the only thing
that kept them alive.
631
01:10:15,540 --> 01:10:18,940
Surviving until spring
has its own rewards.
632
01:10:21,260 --> 01:10:24,260
After an eight-month pregnancy,
633
01:10:24,260 --> 01:10:27,220
musk ox cows have given birth.
634
01:10:33,300 --> 01:10:36,940
Calves are up on their feet
within hours of being born.
635
01:10:38,980 --> 01:10:40,700
And for good reason.
636
01:10:44,020 --> 01:10:47,580
They need to suckle
at least 20 times a day.
637
01:10:50,780 --> 01:10:54,020
Mums use all their energy
for making milk
638
01:10:54,020 --> 01:10:57,260
so there's none left
for growing a summer coat.
639
01:10:58,340 --> 01:11:02,700
And until there is,
they can't shed their winter ones.
640
01:11:21,300 --> 01:11:24,700
Any physical effort
gets them hot and bothered.
641
01:11:32,300 --> 01:11:36,460
And calves caught dawdling
are given short shrift.
642
01:11:43,420 --> 01:11:45,780
It may not feel like it now,
643
01:11:45,780 --> 01:11:48,860
but this calf will find safety
in the herd.
644
01:11:52,020 --> 01:11:54,980
Come winter,
they'll rely on the adults
645
01:11:54,980 --> 01:11:57,780
not just for food and warmth
646
01:11:57,780 --> 01:12:01,220
but for protection from
ravenous wolves as well.
647
01:12:04,020 --> 01:12:07,940
If they're to survive,
best stick close to mum.
648
01:12:17,300 --> 01:12:21,020
Whilst musk Ox calves
fatten-up in the north,
649
01:12:21,020 --> 01:12:24,780
600 miles south,
on the Seward Peninsula,
650
01:12:24,780 --> 01:12:28,100
there are new arrivals
of different kind.
651
01:12:29,140 --> 01:12:30,980
Sandhill cranes,
652
01:12:30,980 --> 01:12:33,220
fresh in from California.
653
01:12:35,020 --> 01:12:38,540
Cruising at an average altitude
of 5,000 feet,
654
01:12:38,540 --> 01:12:42,940
they've been riding the thermals
for over 2,000 miles.
655
01:12:51,300 --> 01:12:54,260
Now, with their breeding ground
in sight,
656
01:12:54,260 --> 01:12:56,940
they spiral back down to earth.
657
01:13:09,340 --> 01:13:14,220
The breeding season starts as soon
as their feet touch the ground.
658
01:13:18,300 --> 01:13:21,300
Cranes form lifelong partnerships
659
01:13:21,300 --> 01:13:25,940
and nothing puts them in the mood
for mating more than a dance.
660
01:13:28,780 --> 01:13:31,700
Youngsters head off
to do their own thing.
661
01:13:33,420 --> 01:13:36,700
No-one wants to see dad dancing.
662
01:13:38,260 --> 01:13:40,700
It starts with a wing stretch.
663
01:13:41,980 --> 01:13:44,380
And once he's got her attention...
664
01:13:45,420 --> 01:13:47,540
..it's time to dance.
665
01:13:53,780 --> 01:13:56,220
It's not about how elegant you are.
666
01:13:57,300 --> 01:14:01,940
It's about relaxing
and letting go of inhibitions.
667
01:14:07,180 --> 01:14:08,980
CRANE SQUAWKS
668
01:14:08,980 --> 01:14:11,460
Dancing strengthens the pair-bond.
669
01:14:12,740 --> 01:14:15,780
If you can bust a good move,
670
01:14:15,780 --> 01:14:18,780
you're also likely to have
the skills required
671
01:14:18,780 --> 01:14:21,740
to drive predators away
from your nest.
672
01:14:23,780 --> 01:14:25,780
MUSIC
673
01:14:28,500 --> 01:14:30,500
CRANE SQUAWKS
674
01:14:33,260 --> 01:14:35,260
MUSIC
675
01:14:59,300 --> 01:15:03,060
They renew their commitment
to each other by singing.
676
01:15:04,500 --> 01:15:06,980
Which may also stimulate ovulation.
677
01:15:06,980 --> 01:15:08,980
CRANE SINGS
678
01:15:22,260 --> 01:15:25,220
And after all that song and dance...
679
01:15:28,780 --> 01:15:32,220
..mating is over
in under four seconds.
680
01:15:37,540 --> 01:15:40,780
Sandhill cranes build their nest
on the ground,
681
01:15:40,780 --> 01:15:43,460
which makes them vulnerable
to predators.
682
01:15:44,500 --> 01:15:46,780
If they're to hatch any chicks,
683
01:15:46,780 --> 01:15:49,980
these big birds will need to keep
a low profile
684
01:15:49,980 --> 01:15:51,940
for the next 30 days.
685
01:16:12,780 --> 01:16:16,700
Alaska is home to 30,000
brown bears.
686
01:16:21,140 --> 01:16:24,220
2,000 of them live
in Katmai Wilderness Area.
687
01:16:30,500 --> 01:16:32,700
Adults are normally solitary.
688
01:16:40,260 --> 01:16:42,020
But in spring,
689
01:16:42,020 --> 01:16:45,220
meadows brimming with sedge grass
draw them together.
690
01:16:53,300 --> 01:16:57,260
Sedge contains a lot less protein
than meat or fish
691
01:16:57,260 --> 01:17:01,540
so bears need to eat a lot of it
just to maintain their weight.
692
01:17:21,500 --> 01:17:24,780
Regular naps aid digestion.
693
01:17:35,300 --> 01:17:38,700
With the gathering comes an
opportunity to woo a mate.
694
01:17:45,180 --> 01:17:49,340
Competing males try to give
each other space.
695
01:17:50,300 --> 01:17:54,220
Submissive body language keeps
low-ranking bears out of trouble.
696
01:17:55,260 --> 01:17:57,740
Any that don't read the signs
697
01:17:57,740 --> 01:17:59,740
end up in a brawl.
698
01:17:59,740 --> 01:18:01,740
BEARS GROWL
699
01:18:17,300 --> 01:18:21,220
Young bears avoid trouble
by staying on the side lines.
700
01:18:22,780 --> 01:18:25,940
These two are almost
three years old.
701
01:18:28,540 --> 01:18:31,700
They've been nurtured by their
mother since they were born.
702
01:18:34,300 --> 01:18:37,460
She's gone grazing with the other
bears on the meadow.
703
01:18:39,260 --> 01:18:41,500
They don't know it yet
704
01:18:41,500 --> 01:18:43,700
but she won't be coming back.
705
01:18:55,330 --> 01:18:58,730
Two young bears have been abandoned
by their mother...
706
01:18:59,810 --> 01:19:02,490
..and are now facing
life on their own.
707
01:19:06,130 --> 01:19:09,770
She's been their teacher
and their comfort blanket
708
01:19:09,770 --> 01:19:11,730
for the past three years.
709
01:19:14,890 --> 01:19:18,730
But the time has come
to break up the family.
710
01:19:25,050 --> 01:19:27,250
She has a new admirer.
711
01:19:32,610 --> 01:19:36,250
He'll trail after her
until she's ready to mate...
712
01:19:38,690 --> 01:19:41,730
..fighting any other bears
that get in the way.
713
01:19:51,090 --> 01:19:55,770
There's no way her cubs will
get past 900 pounds of muscle
714
01:19:55,770 --> 01:19:58,090
and escape with their lives.
715
01:20:10,570 --> 01:20:13,050
They may have parted ways with mum,
716
01:20:13,050 --> 01:20:15,650
but they've still got each other.
717
01:20:18,050 --> 01:20:20,090
Which will help smooth the way
718
01:20:20,090 --> 01:20:23,250
as they set-off on the road
to independence.
719
01:20:36,330 --> 01:20:40,330
Their mother will be fertile
for up to 30 days.
720
01:20:42,530 --> 01:20:45,090
Footloose and cub-free,
721
01:20:45,090 --> 01:20:48,010
she may mate with several males
in that time.
722
01:20:55,450 --> 01:20:57,330
If she has twins again,
723
01:20:57,330 --> 01:21:01,010
it could be that each cub
has a different father.
724
01:21:08,450 --> 01:21:10,730
But she won't know till spring...
725
01:21:11,810 --> 01:21:14,770
..as her fertilised eggs
don't start to develop
726
01:21:14,770 --> 01:21:17,010
until she's back in hibernation.
727
01:21:21,090 --> 01:21:26,650
In that way, she can save raising
new cubs until next spring,
728
01:21:26,650 --> 01:21:29,010
when there'll be plenty
of food about.
729
01:21:41,090 --> 01:21:45,250
Other animals already have
hungry youngsters to feed.
730
01:21:46,570 --> 01:21:50,810
And Eagle Beach,
700 miles east of the bears,
731
01:21:50,810 --> 01:21:53,890
is the perfect place
to find baby food.
732
01:21:55,970 --> 01:22:00,170
This male bald eagle
returns here every spring.
733
01:22:00,170 --> 01:22:02,010
And not just for the hunting.
734
01:22:03,090 --> 01:22:06,570
But because this is where
he's always raised his family.
735
01:22:10,570 --> 01:22:15,010
He returned here three months ago
with his partner of 13 years.
736
01:22:16,090 --> 01:22:19,530
Their nest survived
the winter gales
737
01:22:19,530 --> 01:22:22,130
but was in need of some repair.
738
01:22:23,170 --> 01:22:25,770
They quickly get it up to scratch
739
01:22:25,770 --> 01:22:28,490
and today is a big day.
740
01:22:30,330 --> 01:22:33,250
The female hatched her solitary egg
this morning...
741
01:22:34,330 --> 01:22:37,770
..and by the sound of it
the chick's doing well.
742
01:22:37,770 --> 01:22:39,730
EAGLE CHICK CHIRPS
743
01:22:43,090 --> 01:22:47,010
For the next two weeks, the male
will do most of the hunting.
744
01:22:49,290 --> 01:22:52,490
There are fish here,
if you know how to get them.
745
01:22:56,570 --> 01:23:01,010
Sand lances hide in the sand
to escape predators at low tide.
746
01:23:03,250 --> 01:23:08,010
Finding them is simple if you're as
clever and well-equipped as a raven.
747
01:23:11,570 --> 01:23:15,250
Each fish is a high-fat,
high-energy snack.
748
01:23:18,050 --> 01:23:21,010
Perfect food for eagle chicks too.
749
01:23:23,090 --> 01:23:26,250
But this dad hasn't got the hang
of digging them up.
750
01:23:30,050 --> 01:23:32,010
There is another way.
751
01:23:34,770 --> 01:23:37,450
He looks to cash in
on the raven's success...
752
01:23:40,290 --> 01:23:42,770
..and launches a raid.
753
01:23:44,410 --> 01:23:46,250
In a split second...
754
01:23:47,290 --> 01:23:50,010
..the raven loses half his catch.
755
01:23:56,170 --> 01:23:58,090
One for him.
756
01:23:58,090 --> 01:24:00,730
The rest he'll take back
to the nest.
757
01:24:10,890 --> 01:24:15,330
The female spends most of the day
brooding her new hatchling,
758
01:24:15,330 --> 01:24:20,010
but the return of her mate gives her
an opportunity to stretch her wings.
759
01:24:24,570 --> 01:24:28,730
And a chance for him to feed
his progeny for the first time.
760
01:24:31,090 --> 01:24:35,010
Last year's chick was weak
and died after only two days.
761
01:24:36,050 --> 01:24:38,490
This one seems stronger.
762
01:24:39,570 --> 01:24:43,250
But it will need feeding
at least eight times a day.
763
01:24:44,810 --> 01:24:48,050
If this family are to avoid
another tragedy,
764
01:24:48,050 --> 01:24:50,730
the next few weeks are critical.
765
01:24:58,330 --> 01:25:01,450
Spring in Alaska arrived
with the melt...
766
01:25:02,530 --> 01:25:05,530
..and triggered a season
of rapid transformation.
767
01:25:05,530 --> 01:25:07,250
THUNDER
768
01:25:09,290 --> 01:25:11,690
The race was on to start a family.
769
01:25:12,770 --> 01:25:17,010
Sandhill cranes saw eggs
become chicks.
770
01:25:17,010 --> 01:25:20,610
Dippers saw chicks
become fledglings.
771
01:25:22,330 --> 01:25:26,250
Musk Ox calves survived
the school of hard knocks.
772
01:25:28,610 --> 01:25:32,770
And two young bears
learned to cope without mum.
773
01:25:34,810 --> 01:25:37,570
Spring saw many flourish
774
01:25:37,570 --> 01:25:41,290
but did it all come too late
for the Arctic foxes
775
01:25:41,290 --> 01:25:43,850
to raise a family of their own?
776
01:25:47,770 --> 01:25:50,370
Next time, summer is coming...
777
01:25:52,690 --> 01:25:54,810
..and new challenges begin.
778
01:25:56,530 --> 01:25:58,970
Youngsters must grow up,
779
01:25:58,970 --> 01:26:00,330
fatten up...
780
01:26:01,370 --> 01:26:03,490
..and stay out of danger.
781
01:26:05,330 --> 01:26:08,530
Summer is when the clock
starts ticking
782
01:26:08,530 --> 01:26:11,650
and the countdown to winter begins.
783
01:26:11,650 --> 01:26:15,690
Animals must make the most
of the good times
784
01:26:15,690 --> 01:26:18,850
or it'll all be for nothing.
785
01:26:18,850 --> 01:26:20,850
BIRDS CHIRP
786
01:26:49,770 --> 01:26:52,010
Subtitles by Ericsson
787
01:26:56,760 --> 01:27:02,160
Alaska. America's last frontier...
788
01:27:05,160 --> 01:27:06,760
..and greatest wilderness.
789
01:27:09,640 --> 01:27:11,240
Immense.
790
01:27:12,280 --> 01:27:14,480
Unspoiled.
791
01:27:14,480 --> 01:27:17,160
Awe-inspiring.
792
01:27:17,160 --> 01:27:19,720
Home to half the world's glaciers...
793
01:27:21,200 --> 01:27:23,880
..America's highest mountains...
794
01:27:25,360 --> 01:27:28,560
..and ice sheets that stretch to
the North Pole.
795
01:27:33,000 --> 01:27:36,560
Inhabited by the world's largest
land predators...
796
01:27:38,320 --> 01:27:42,000
..herds of ancient
beasts..
797
01:27:42,000 --> 01:27:44,200
and leviathans from the deep.
798
01:27:48,680 --> 01:27:53,600
The land is hostile, but its
richness and diversity
799
01:27:53,600 --> 01:27:56,800
is unparalleled in the northern
hemisphere.
800
01:27:59,120 --> 01:28:04,600
All must be resilient
and adaptable if they're to survive
801
01:28:04,600 --> 01:28:07,840
a year in the wild of Alaska.
802
01:28:19,480 --> 01:28:20,960
Summer has arrived.
803
01:28:24,160 --> 01:28:27,000
With the northern hemisphere tilted
towards the sun...
804
01:28:29,200 --> 01:28:34,520
..days are long, the air is
warm...
805
01:28:36,520 --> 01:28:40,080
..and snow has been banished
from all but the highest peaks.
806
01:28:45,320 --> 01:28:50,000
The far north is bathed in gold,
even at midnight.
807
01:28:51,440 --> 01:28:52,680
BIRD SQUAWKS
808
01:28:54,000 --> 01:28:56,200
But things are about to
change.
809
01:28:58,280 --> 01:29:01,200
Animals are in a race
against time.
810
01:29:01,200 --> 01:29:02,920
What they do now,
811
01:29:02,920 --> 01:29:06,320
could mean the difference between
life and death
812
01:29:06,320 --> 01:29:08,120
when snow and ice return.
813
01:29:28,680 --> 01:29:32,080
The ebb and flow of the
seasons is mirrored on the coast of
814
01:29:32,080 --> 01:29:33,720
Katmai every day.
815
01:29:38,560 --> 01:29:42,200
Where three million acres of
wilderness meets
816
01:29:42,200 --> 01:29:47,440
the Pacific Ocean in a deep
crescent known as Hallo Bay.
817
01:29:54,240 --> 01:29:59,680
Here, tides rise and fall for
seven sandy miles.
818
01:30:02,400 --> 01:30:05,360
Leaving opportunity for
brown bears in their wake.
819
01:30:13,720 --> 01:30:17,360
It's rare for a mother bear, to
bring cubs so small to the bay.
820
01:30:21,040 --> 01:30:25,040
But she's hungry... and combs the
beach for food.
821
01:30:33,160 --> 01:30:38,840
Her cubs are just six months old
and more used to the safety of their
822
01:30:38,840 --> 01:30:41,200
den than wide open spaces.
823
01:30:43,880 --> 01:30:46,280
Everything out here is new...
824
01:30:46,280 --> 01:30:47,440
EAGLE SQUAWKS
825
01:30:51,680 --> 01:30:53,400
..and very scary.
826
01:31:03,080 --> 01:31:08,560
Bald eagles aren't a threat but
there are good reasons to be jumpy.
827
01:31:11,080 --> 01:31:14,040
Many brown bear cubs die in
their first year.
828
01:31:15,240 --> 01:31:17,360
And many are
killed by other bears.
829
01:31:19,400 --> 01:31:21,920
Right now the coast is clear.
830
01:31:23,840 --> 01:31:25,840
It's a chance for
831
01:31:25,840 --> 01:31:30,320
this female to tackle the other big
cub killer... malnutrition.
832
01:31:37,440 --> 01:31:41,800
So far mum's milk has provided her
cubs with all of their nutrients.
833
01:31:43,200 --> 01:31:47,200
But a recent growth spurt has
fuelled an urge to try solid food.
834
01:31:49,720 --> 01:31:53,400
Crabs, clams, almost anything will
do.
835
01:32:05,960 --> 01:32:08,480
But the search is futile.
836
01:32:15,280 --> 01:32:17,120
The cubs do their best to help.
837
01:32:22,240 --> 01:32:26,160
They're learning fast,
but they're hungry.
838
01:32:29,400 --> 01:32:32,640
What this family
need is a feast of epic
839
01:32:32,640 --> 01:32:34,000
proportions.
840
01:32:40,120 --> 01:32:42,600
And there's one heading
their way.
841
01:32:49,600 --> 01:32:52,600
Over 300 million salmon
are coming home...
842
01:32:53,840 --> 01:32:57,240
..to spawn in the same rivers that
they were hatched in.
843
01:33:01,480 --> 01:33:04,480
Once they hit
shore and head upstream many will
844
01:33:04,480 --> 01:33:07,400
become food for bears.
845
01:33:13,680 --> 01:33:15,840
But there's
no telling when they'll arrive.
846
01:33:17,400 --> 01:33:23,920
Until then food is scarce. And this
family will grow weaker by the day.
847
01:33:29,360 --> 01:33:34,160
700 miles north-west of
here and just 40 miles off the
848
01:33:34,160 --> 01:33:38,880
Russian coast summer visitors to
St Lawrence Island have
849
01:33:38,880 --> 01:33:40,480
already arrived.
850
01:33:49,640 --> 01:33:53,600
Every year, over three million
auklets nest in colonies
851
01:33:53,600 --> 01:33:55,040
along the coast.
852
01:33:58,360 --> 01:34:01,720
They look for a
suitable spot to lay a single egg.
853
01:34:07,680 --> 01:34:10,760
Unaware that there are predators
waiting.
854
01:34:24,410 --> 01:34:26,330
It's midsummer in Alaska.
855
01:34:30,490 --> 01:34:34,490
And on St Lawrence Island, an
arctic fox is on the prowl.
856
01:34:36,690 --> 01:34:40,330
The coast is alive with
the clack and clamour of over
857
01:34:40,330 --> 01:34:41,730
three million auklets.
858
01:34:51,450 --> 01:34:54,650
It's just what he's
been waiting for.
859
01:35:03,490 --> 01:35:07,650
St Lawrence is smothered in snow for
almost eight months a year.
860
01:35:11,210 --> 01:35:14,890
With auklets absent, food is hard to
come by.
861
01:35:18,050 --> 01:35:20,090
If there's nothing to scavenge
862
01:35:20,090 --> 01:35:23,490
foxes are forced to hunt for voles
under the snow.
863
01:35:28,370 --> 01:35:32,090
It's a great deal of
effort, for very little reward.
864
01:35:34,850 --> 01:35:39,090
But now auk is back on the menu.
865
01:35:39,090 --> 01:35:42,250
And he has a new camouflaged coat to
hunt them in.
866
01:35:52,130 --> 01:35:56,290
Eggs are good. But an adult
bird is even better.
867
01:36:05,770 --> 01:36:09,010
His mate is
pregnant and she needs a regular
868
01:36:09,010 --> 01:36:10,210
supply of protein.
869
01:36:15,650 --> 01:36:17,930
They can't rely
on speed in this terrain.
870
01:36:25,450 --> 01:36:28,130
Only stealth will net them a meal.
871
01:36:37,250 --> 01:36:39,090
But there are eyes everywhere.
872
01:36:44,090 --> 01:36:50,730
And when a few birds panic, it
sets-off a chain reaction.
873
01:36:57,010 --> 01:37:00,810
Once their chicks hatch, the auklets
won't be going anywhere.
874
01:37:00,810 --> 01:37:02,170
FOX CALLS
875
01:37:06,610 --> 01:37:09,370
The foxes need to bide
their time...
876
01:37:11,530 --> 01:37:13,410
..keep their distance...
877
01:37:14,650 --> 01:37:17,210
..and wait for the auklets to
settle in.
878
01:37:25,250 --> 01:37:29,410
Alaska has over half a million
square miles of wilderness.
879
01:37:31,370 --> 01:37:34,730
It's big enough to fit two
Great Britain's in, end to end.
880
01:37:39,570 --> 01:37:43,090
One thousand miles south-east of St
Lawrence Island
881
01:37:43,090 --> 01:37:46,050
on the pacific coast of
south-east Alaska...
882
01:37:47,570 --> 01:37:49,930
..summer is in full swing.
883
01:37:58,610 --> 01:38:02,290
Warm air frees billions
of gallons of water from glaciers.
884
01:38:07,410 --> 01:38:10,170
Feeding a multitude of rivers and
lakes.
885
01:38:18,010 --> 01:38:21,690
There's more wood here than
in any other forest on Earth.
886
01:38:27,090 --> 01:38:29,290
Good news for a family of beavers.
887
01:38:36,050 --> 01:38:38,650
Yearlings help their parents with
chores.
888
01:38:42,090 --> 01:38:45,290
This family has enjoyed a
surplus of food all summer.
889
01:38:49,850 --> 01:38:53,690
But now, they must prepare for lean
times ahead.
890
01:39:01,370 --> 01:39:04,690
They harvest as many green
sprigs as they can...
891
01:39:13,650 --> 01:39:15,130
..ferry them across the pond...
892
01:39:20,810 --> 01:39:25,130
..dive, and store
them underwater.
893
01:39:27,130 --> 01:39:32,250
Down here, they'll
stay fresh. Providing food, even
894
01:39:32,250 --> 01:39:34,370
when the pond is frozen over.
895
01:39:44,450 --> 01:39:47,290
Bigger branches are used to
reinforce the lodge.
896
01:39:53,170 --> 01:39:58,330
This is their fortress. And
it needs to be strong enough to keep
897
01:39:58,330 --> 01:39:59,810
predators out.
898
01:40:06,330 --> 01:40:08,810
Beavers rely on deep
water for safety.
899
01:40:10,490 --> 01:40:14,090
So, to ensure there's always plenty
of it they build dams.
900
01:40:19,890 --> 01:40:23,090
The rush of water is
like an alarm bell to a beaver.
901
01:40:24,650 --> 01:40:26,770
Holes must be plugged up.
902
01:40:32,930 --> 01:40:35,450
Timber is gathered from the
surrounding forest.
903
01:40:44,850 --> 01:40:48,570
And by clearing forest, they
create new habitat.
904
01:40:57,090 --> 01:41:00,370
Grass grows in patches of light
where trees once stood.
905
01:41:04,250 --> 01:41:07,930
Providing Sitka deer with
tender stems to nibble on.
906
01:41:14,330 --> 01:41:18,290
Pollarded willow put out new shoots
within easy reach of a porcupine.
907
01:41:21,770 --> 01:41:24,890
She can devour up to a pound of
leaves every day.
908
01:41:30,650 --> 01:41:32,250
But not all beneficiaries of
909
01:41:32,250 --> 01:41:34,970
the beavers' building work are so
benign.
910
01:41:38,650 --> 01:41:40,930
Black bears also forage here.
911
01:41:44,050 --> 01:41:48,530
Plants make up the bulk of
their diet. But the scent of beaver
912
01:41:48,530 --> 01:41:50,730
could prove too good to ignore.
913
01:41:56,370 --> 01:41:59,130
Forays onto land are unavoidable.
914
01:41:59,130 --> 01:42:02,410
The further they go, the bigger the
risk.
915
01:42:24,490 --> 01:42:27,850
But beaver security is always
on high alert.
916
01:42:32,250 --> 01:42:35,050
The alpha female
sounds the alarm...
917
01:42:49,490 --> 01:42:54,570
..and sends every beaver within
earshot bolting back to the water.
918
01:43:10,530 --> 01:43:13,530
Soon, it's like they
were never there at all.
919
01:43:18,930 --> 01:43:21,850
Black bears
prefer to eat meat, but they have
920
01:43:21,850 --> 01:43:23,090
plenty of other options.
921
01:43:27,250 --> 01:43:30,970
Unlike the bigger brown bear, they
evolved in these forests.
922
01:43:35,250 --> 01:43:38,330
Their ancestors were
consummate climbers.
923
01:43:39,410 --> 01:43:41,530
And it's a skill that's been handed
down.
924
01:43:50,130 --> 01:43:52,290
Cubs can climb as soon as they can
walk.
925
01:43:55,570 --> 01:43:59,410
It gives them access to forage that
other animals can't reach.
926
01:44:02,970 --> 01:44:06,770
Come autumn, there'll be a glut of
nuts and berries to choose from.
927
01:44:08,490 --> 01:44:12,650
Until then, aspen pods will curb
their hunger pangs.
928
01:44:15,450 --> 01:44:16,970
If they can keep hold of them.
929
01:44:22,450 --> 01:44:26,330
It's only a snack. But mum
knows where more
930
01:44:26,330 --> 01:44:28,450
emergency rations are.
931
01:44:29,850 --> 01:44:34,050
She'll need to make full use of
this forest if her cubs are going
932
01:44:34,050 --> 01:44:35,930
to make it through until autumn.
933
01:44:49,530 --> 01:44:54,290
About 17 million acres of forest
cloaks Alaska's southern coast.
934
01:44:57,570 --> 01:44:59,890
Where over 60 inches of
rain fall annually.
935
01:45:16,610 --> 01:45:19,210
Many plants are
green here, all year round.
936
01:45:23,530 --> 01:45:26,690
But summer adds a splash of colour
to the undergrowth.
937
01:45:43,570 --> 01:45:46,090
Plants take advantage of the long
days...
938
01:45:47,890 --> 01:45:49,330
..and burst into bloom.
939
01:45:52,650 --> 01:45:59,490
Drawing in pollinators, from both
near... and far.
940
01:46:12,170 --> 01:46:18,050
At just three inches long and
weighing little more than a penny
941
01:46:18,050 --> 01:46:20,810
this female rufous hummingbird has
942
01:46:20,810 --> 01:46:27,050
flown over 3,000 miles from
Mexico to nest in south-east Alaska.
943
01:46:28,770 --> 01:46:31,530
No other hummingbird breeds this far
north.
944
01:46:34,050 --> 01:46:36,410
Males play no part in raising
their young.
945
01:46:38,970 --> 01:46:41,090
She's raised this
chick all on her own.
946
01:46:44,570 --> 01:46:47,770
Hatched from an egg the size of a
jelly bean
947
01:46:47,770 --> 01:46:52,730
in just three weeks she's already
outgrown the nest.
948
01:46:58,210 --> 01:47:02,570
They require more than their own
body weight in nectar each day.
949
01:47:04,690 --> 01:47:08,890
And if this chick is to
fledge successfully, the next
950
01:47:08,890 --> 01:47:11,010
24 hours are critical.
951
01:47:18,150 --> 01:47:20,150
It's July in Alaska...
952
01:47:22,790 --> 01:47:26,230
..and the forest resonates with the
drone of tiny wings.
953
01:47:33,270 --> 01:47:37,190
Rufous hummingbirds must soon
depart for their wintering grounds
954
01:47:37,190 --> 01:47:38,190
in Mexico.
955
01:47:40,430 --> 01:47:44,350
But the trip of almost
3,000 miles can't begin...
956
01:47:45,950 --> 01:47:48,150
..until this year's youngsters have
fledged.
957
01:47:50,430 --> 01:47:51,950
By beating her wings at up
958
01:47:51,950 --> 01:47:56,950
to 60 times a second, a chick
warms up for her maiden flight...
959
01:48:04,630 --> 01:48:07,710
..whilst her mother hunts for more
fuel.
960
01:48:14,310 --> 01:48:16,590
Nectar is a precious
resource...
961
01:48:18,070 --> 01:48:21,030
..that other hummingbirds aren't
always willing to share.
962
01:48:30,990 --> 01:48:33,910
But this mum has a cunning plan.
963
01:48:36,630 --> 01:48:38,270
There are sapsuckers nearby.
964
01:48:41,230 --> 01:48:43,550
They're also busy
raising chicks.
965
01:48:50,070 --> 01:48:54,590
Adults drill into
trees, to release sap which they
966
01:48:54,590 --> 01:48:58,750
lap-up... along with any insects
stuck in it.
967
01:49:02,390 --> 01:49:04,510
It's rocket fuel for
growing chicks.
968
01:49:07,750 --> 01:49:09,190
So when no-one's looking...
969
01:49:13,230 --> 01:49:15,710
..the hummingbird launches a raid.
970
01:49:19,430 --> 01:49:24,070
She must drain as many wells as she
can, before the sapsucker returns.
971
01:49:34,950 --> 01:49:39,390
Hovering takes the youngsters
a little while to master.
972
01:49:39,390 --> 01:49:43,390
But in order to fledge she just has
to manage a straight line.
973
01:49:49,470 --> 01:49:52,870
The chick has a few more weeks to
strengthen her flight muscles...
974
01:49:54,630 --> 01:49:56,390
..before she flies all the
975
01:49:56,390 --> 01:49:58,790
way to Mexico on her own.
976
01:50:07,790 --> 01:50:10,630
At the end of July,
summer turns a corner.
977
01:50:14,630 --> 01:50:18,830
South-west Alaska loses half an hour
of sunlight every week.
978
01:50:21,310 --> 01:50:22,630
Temperatures plateau...
979
01:50:25,230 --> 01:50:26,710
..and start to drop off.
980
01:50:29,710 --> 01:50:31,710
Animals sense the change.
981
01:50:41,070 --> 01:50:44,670
Bear cubs are born with
very little fat.
982
01:50:44,670 --> 01:50:48,590
But they need a thick layer of it
in order to survive hibernation.
983
01:50:50,670 --> 01:50:54,590
Their mum's milk is rich but it's
not enough on its own.
984
01:50:57,470 --> 01:51:00,070
The whole family
needs solid food.
985
01:51:02,790 --> 01:51:04,030
Their fate, and
986
01:51:04,030 --> 01:51:08,910
the fate of all brown bears in
Katmai, depends on the salmon.
987
01:51:19,110 --> 01:51:23,030
Pacific salmon make one of the most
incredible journeys on Earth.
988
01:51:24,470 --> 01:51:27,870
Every year, over 300 million
of them
989
01:51:27,870 --> 01:51:30,030
head towards Alaska's shores.
990
01:51:34,510 --> 01:51:39,590
Often travelling thousands of miles
to spawn in one of 12,000
991
01:51:39,590 --> 01:51:40,870
wild rivers.
992
01:51:43,150 --> 01:51:47,310
The salmon must find the one that
will lead them to their birthplace.
993
01:51:50,350 --> 01:51:55,070
With a coastline that
stretches for 40,000 miles
994
01:51:55,070 --> 01:52:00,270
their journey demands stamina
and remarkable navigation skills.
995
01:52:03,790 --> 01:52:07,510
Predicting where they'll turn up
first is impossible.
996
01:52:14,150 --> 01:52:16,590
All the bears can do is wait.
997
01:52:21,950 --> 01:52:25,230
Mum checks for signs
but there's barely a ripple.
998
01:52:32,110 --> 01:52:35,150
Her cubs are eager to play.
999
01:52:35,150 --> 01:52:38,430
But their mum has put all her spare
energy into making milk.
1000
01:52:48,430 --> 01:52:52,630
For her, the
salmon run can't come soon enough.
1001
01:52:57,990 --> 01:53:01,230
But instead, her worst nightmare
arrives.
1002
01:53:05,470 --> 01:53:07,390
A big, hungry male.
1003
01:53:17,550 --> 01:53:19,070
He won't catch anything here.
1004
01:53:20,430 --> 01:53:22,270
And he's a real danger to the cubs.
1005
01:53:29,470 --> 01:53:33,150
It's rare but when males are
under pressure they can resort
1006
01:53:33,150 --> 01:53:35,270
to cannibalism.
1007
01:53:47,230 --> 01:53:49,830
She'll protect her cubs furiously.
1008
01:53:55,790 --> 01:53:58,190
But there's no fish worth
fighting for here.
1009
01:54:00,870 --> 01:54:03,870
Better to be of
sight and out of mind.
1010
01:54:22,950 --> 01:54:26,750
In summer bears leave their
favourite stomping grounds
1011
01:54:26,750 --> 01:54:33,070
and move towards shallow creeks,
where salmon will be easy to catch.
1012
01:54:35,310 --> 01:54:37,630
Leaving much of Katmai
deserted.
1013
01:54:44,110 --> 01:54:46,310
Solitude is what this mum needs.
1014
01:54:49,430 --> 01:54:51,310
The cubs learn by copying her.
1015
01:54:53,950 --> 01:54:57,870
She checks for danger.
And so do they.
1016
01:55:02,550 --> 01:55:04,070
There are no bears here...
1017
01:55:05,990 --> 01:55:08,190
..but she catches wind of something.
1018
01:55:15,310 --> 01:55:18,030
All she has to do is track it down.
1019
01:55:33,110 --> 01:55:35,230
The cubs sense her excitement.
1020
01:55:47,470 --> 01:55:49,790
Finally, it's a salmon.
1021
01:55:51,630 --> 01:55:53,430
The first the cubs have ever seen.
1022
01:56:00,670 --> 01:56:02,830
Self-preservation kicks in.
1023
01:56:07,390 --> 01:56:09,870
Fish like this provide essential
1024
01:56:09,870 --> 01:56:12,990
energy that bear cubs can convert
into fat.
1025
01:56:19,310 --> 01:56:21,630
One fish won't feed a family of
four.
1026
01:56:24,710 --> 01:56:29,310
But nearby, there's a sign
that it could be the first of many.
1027
01:56:34,030 --> 01:56:36,310
Just 100 miles from here,
1028
01:56:36,310 --> 01:56:40,630
but on the other side of the
Alaska Peninsula lies Bristol Bay...
1029
01:56:47,030 --> 01:56:51,710
..where a deadly combination of high
winds and high tide has left
1030
01:56:51,710 --> 01:56:54,030
an early run of salmon stranded.
1031
01:57:02,630 --> 01:57:05,150
Whimbrels are first
to discover the bounty.
1032
01:57:10,310 --> 01:57:11,830
Tender fish
1033
01:57:11,830 --> 01:57:16,150
is an easy treat for birds more used
to probing the sand for crustaceans.
1034
01:57:19,590 --> 01:57:23,350
Further up the bluff is a colony of
Arctic ground squirrels.
1035
01:57:28,070 --> 01:57:29,790
Most females have pups.
1036
01:57:32,910 --> 01:57:38,110
They're over six weeks old, fully
weaned and can't
1037
01:57:38,110 --> 01:57:40,030
rely on mum for food any more.
1038
01:57:43,150 --> 01:57:47,070
But they must double their weight
or they won't survive hibernation.
1039
01:57:50,750 --> 01:57:53,510
Males gather grass to stockpile in
their burrows...
1040
01:57:56,790 --> 01:57:59,990
..whilst youngsters munch through as
much seed as they can.
1041
01:58:02,550 --> 01:58:04,670
Nothing is wasted.
1042
01:58:07,030 --> 01:58:11,430
Even the skin of a dead relative is
valuable extra protein.
1043
01:58:17,430 --> 01:58:20,270
They don't like to wander too far
from their boltholes...
1044
01:58:22,550 --> 01:58:24,950
..but they can smell fish in the
air.
1045
01:58:28,150 --> 01:58:30,830
It's an opportunity too good
to miss.
1046
01:58:40,550 --> 01:58:42,830
They need to build-up their
fat reserves...
1047
01:58:44,230 --> 01:58:47,790
..and oily fish has a
lot more calories than grass seed.
1048
01:58:50,230 --> 01:58:52,510
Come autumn, young females will
1049
01:58:52,510 --> 01:58:54,630
settle down to sleep with their
mothers.
1050
01:58:56,830 --> 01:59:00,230
But young males must first
find a territory of their own.
1051
01:59:02,270 --> 01:59:05,030
They're going to need all the energy
they can muster.
1052
01:59:07,070 --> 01:59:09,830
And only the
fittest squirrels will survive.
1053
01:59:16,150 --> 01:59:20,310
Whilst a twist of fate has landed
the squirrels with welcome feast...
1054
01:59:22,230 --> 01:59:26,430
..it's nothing compared to what's
just arrived over 800 miles
1055
01:59:26,430 --> 01:59:28,790
away on the other side of the gulf.
1056
01:59:37,270 --> 01:59:40,150
After four years out in the open
ocean
1057
01:59:40,150 --> 01:59:43,030
thousands of Chum salmon have
finally
1058
01:59:43,030 --> 01:59:45,030
arrived in south-east Alaska.
1059
02:00:00,110 --> 02:00:01,870
Nothing will stop them now.
1060
02:00:10,790 --> 02:00:13,790
Their spawning ground
is in the mouth of a river,
1061
02:00:13,790 --> 02:00:15,550
just beyond the high-tide line.
1062
02:00:27,630 --> 02:00:29,110
They don't waste any time.
1063
02:00:32,630 --> 02:00:35,110
Each female makes a small
pit in the gravel...
1064
02:00:40,430 --> 02:00:42,390
..where she'll lay up to
4,000 eggs.
1065
02:00:49,950 --> 02:00:51,630
Once they've been fertilised...
1066
02:00:59,830 --> 02:01:01,150
..she covers them over...
1067
02:01:05,390 --> 02:01:09,790
..and stands guard
until she's too weak to continue.
1068
02:01:25,710 --> 02:01:31,190
A voyage that's all about life, ends
in the death of the salmon.
1069
02:01:45,270 --> 02:01:49,030
As soon as they enter
freshwater, salmon stop eating.
1070
02:01:52,590 --> 02:01:54,750
Their stomachs slowly disintegrate.
1071
02:01:59,390 --> 02:02:00,670
GULL SQUAWKS
1072
02:02:04,350 --> 02:02:06,950
And they finally succumb to the
inevitable.
1073
02:02:15,350 --> 02:02:18,190
All the gulls have to do is wait.
1074
02:02:40,710 --> 02:02:43,830
Whilst the journey is over
for some travellers
1075
02:02:43,830 --> 02:02:47,790
for others, the
advance continues upstream.
1076
02:02:57,590 --> 02:02:59,590
Pink salmon spawn further inland...
1077
02:03:05,190 --> 02:03:08,590
..where predators lurk, ready to
pounce.
1078
02:03:20,500 --> 02:03:22,020
It's the end of July...
1079
02:03:25,340 --> 02:03:28,660
..and a big wave
of salmon has just hit Alaska.
1080
02:03:32,700 --> 02:03:35,420
Thousands of fish fight their way
1081
02:03:35,420 --> 02:03:38,740
upstream, driven by an irresistible
1082
02:03:38,740 --> 02:03:41,180
urge to reach their spawning
grounds.
1083
02:03:48,940 --> 02:03:51,580
This is what brown bears
have been waiting for.
1084
02:03:54,980 --> 02:03:58,620
It may be this adolescent's first
season away from his mum.
1085
02:04:00,900 --> 02:04:04,020
The perfect opportunity to
hone his hunting skills...
1086
02:04:06,060 --> 02:04:08,580
..and take
advantage of the glut of food.
1087
02:04:17,020 --> 02:04:19,580
But his lack of experience quickly
shows.
1088
02:04:27,020 --> 02:04:29,980
Many young bears copy their
mother's fishing methods.
1089
02:04:32,220 --> 02:04:38,420
In his case it's the dash, splash
and grab technique.
1090
02:04:41,820 --> 02:04:43,660
It's one he's yet to master.
1091
02:04:58,020 --> 02:05:00,180
Perhaps gaining some height
will help?
1092
02:05:03,340 --> 02:05:04,700
Apparently not.
1093
02:05:28,380 --> 02:05:31,500
The snorkelling method is another
way to catch a salmon.
1094
02:05:33,340 --> 02:05:36,140
Especially when
they're in such large numbers.
1095
02:05:42,020 --> 02:05:44,260
But seeing them is one thing.
1096
02:05:47,540 --> 02:05:49,740
Catching them is another.
1097
02:05:53,100 --> 02:05:58,740
The deep water isn't helping. It
gives the salmon an easy getaway.
1098
02:06:02,460 --> 02:06:05,540
Eventually he spots
a carcass floating downstream...
1099
02:06:10,220 --> 02:06:14,380
..only to discover that the best
bits have already been eaten.
1100
02:06:19,300 --> 02:06:20,420
He craves fat...
1101
02:06:22,300 --> 02:06:27,860
..and the fattiest bits on a salmon
are the skin, brain and eggs.
1102
02:06:33,660 --> 02:06:38,300
With so much food about, anything
substandard is quickly rejected.
1103
02:06:51,300 --> 02:06:54,500
Eventually perseverance pays off...
1104
02:07:00,340 --> 02:07:04,020
..and he nets himself a large female
pink salmon.
1105
02:07:21,660 --> 02:07:24,220
Flush with success he
goes for another...
1106
02:07:27,260 --> 02:07:29,100
..and almost loses the first.
1107
02:07:33,940 --> 02:07:36,900
Perhaps he should learn
to finish what's on his plate,
1108
02:07:36,900 --> 02:07:39,060
before going in for seconds.
1109
02:08:01,780 --> 02:08:03,540
Summer arrived with the auks...
1110
02:08:07,020 --> 02:08:09,020
..and filled Alaska with light...
1111
02:08:11,260 --> 02:08:15,420
..warmth and improving prospects.
1112
02:08:18,940 --> 02:08:22,100
It was a season
rife with possibilities.
1113
02:08:24,300 --> 02:08:28,260
Where hard work and persistence paid
dividends.
1114
02:08:31,980 --> 02:08:37,060
And where the death of one
generation brought hope to another.
1115
02:08:42,700 --> 02:08:45,780
But now, change is in the air.
1116
02:08:49,140 --> 02:08:50,580
Autumn is coming.
1117
02:08:53,660 --> 02:08:55,100
Next time...
1118
02:08:58,220 --> 02:09:00,460
The salmon season goes into
overdrive.
1119
02:09:02,580 --> 02:09:05,700
And animals battle it out
for a share of the spoils.
1120
02:09:08,740 --> 02:09:15,140
Young must come of age before
winter puts Alaska in lockdown.
1121
02:09:18,180 --> 02:09:23,340
With freezing temperatures
imminent it's do or die for many
1122
02:09:23,340 --> 02:09:28,180
predators... including the biggest
killer of all.
1123
02:09:52,780 --> 02:09:55,180
Subtitles by Ericsson
1124
02:10:03,500 --> 02:10:04,620
Alaska.
1125
02:10:06,380 --> 02:10:08,740
America's last frontier...
1126
02:10:11,860 --> 02:10:13,740
..and greatest wilderness.
1127
02:10:16,580 --> 02:10:17,580
Immense.
1128
02:10:18,940 --> 02:10:19,940
Unspoiled.
1129
02:10:21,260 --> 02:10:22,500
Awe-inspiring.
1130
02:10:24,420 --> 02:10:28,260
Home to half the world's glaciers,
1131
02:10:28,260 --> 02:10:32,060
America's highest mountains
1132
02:10:32,060 --> 02:10:35,260
and ice sheets that stretch
to the North Pole.
1133
02:10:39,700 --> 02:10:44,940
Inhabited by the world's largest
land predators,
1134
02:10:44,940 --> 02:10:48,980
herds of ancient beasts
1135
02:10:48,980 --> 02:10:51,100
and leviathans from the deep.
1136
02:10:55,380 --> 02:10:58,100
The land is hostile,
1137
02:10:58,100 --> 02:11:00,340
but its richness and diversity
1138
02:11:00,340 --> 02:11:03,460
is unparalleled
in the northern hemisphere.
1139
02:11:05,780 --> 02:11:09,620
All must be resilient and adaptable
1140
02:11:09,620 --> 02:11:14,780
if they're to survive a year
in the wild of Alaska.
1141
02:11:30,940 --> 02:11:34,220
Autumn is the season
when Alaska's wildlife
1142
02:11:34,220 --> 02:11:37,700
must make the final preparations
before winter.
1143
02:11:42,100 --> 02:11:45,180
Summer saw the groundwork done
by the adults.
1144
02:11:48,580 --> 02:11:51,460
Time is now running out
for the youngsters.
1145
02:11:54,780 --> 02:11:56,540
Days are growing short.
1146
02:11:59,020 --> 02:12:02,180
Snow and freezing temperatures
are imminent.
1147
02:12:07,300 --> 02:12:10,700
Many young must soon
start their lives alone.
1148
02:12:13,180 --> 02:12:15,900
Those not prepared will perish.
1149
02:12:29,300 --> 02:12:32,980
Nowhere is the struggle for survival
more apparent
1150
02:12:32,980 --> 02:12:35,300
than in the
Katmai Wilderness Area.
1151
02:12:41,340 --> 02:12:43,940
Three million acres of wildness.
1152
02:12:50,660 --> 02:12:54,180
Home to the highest density
of brown bears in the world.
1153
02:13:06,700 --> 02:13:11,300
They're here to gorge
on the millions of salmon
1154
02:13:11,300 --> 02:13:14,340
that are coming to the end
of their epic migration.
1155
02:13:16,580 --> 02:13:21,300
A journey that takes them back
to the very same
1156
02:13:21,300 --> 02:13:24,300
rivers where they were born.
1157
02:13:24,300 --> 02:13:28,980
Having travelled thousands of miles
to spawn,
1158
02:13:28,980 --> 02:13:33,140
the final leg is by far
the most dangerous.
1159
02:13:40,620 --> 02:13:44,820
Brown bears need to build up a thick
layer of fat for hibernation.
1160
02:13:47,740 --> 02:13:50,180
The salmon are their salvation.
1161
02:13:56,100 --> 02:13:58,260
Competition is fierce.
1162
02:14:22,300 --> 02:14:24,980
But the salmon don't only
attract bears.
1163
02:14:30,540 --> 02:14:33,540
Katmai is also home
to American Wolves.
1164
02:14:39,460 --> 02:14:42,300
This adult female finds a good spot.
1165
02:14:51,620 --> 02:14:53,340
And starts to hunt.
1166
02:15:00,940 --> 02:15:02,540
But the salmon
are too quick for her.
1167
02:15:26,140 --> 02:15:28,580
Then she gets company.
1168
02:15:30,500 --> 02:15:37,140
A mother bear is also actively
hunting the same stretch of river.
1169
02:15:46,940 --> 02:15:49,380
Never stand in the way
of a mother bear...
1170
02:15:53,340 --> 02:15:56,900
..especially one with two hungry
cubs to feed.
1171
02:16:01,300 --> 02:16:03,980
The wolf may also have young.
1172
02:16:05,380 --> 02:16:07,980
She can't risk getting injured
in a fight...
1173
02:16:09,780 --> 02:16:12,980
..so reluctantly gives up her spot.
1174
02:16:18,340 --> 02:16:20,540
Back in the spring,
1175
02:16:20,540 --> 02:16:23,060
these two cubs emerged from
hibernation.
1176
02:16:25,780 --> 02:16:28,780
They scraped by on a diet of clams
and milk.
1177
02:16:37,220 --> 02:16:41,420
If they're going to survive winter,
they must start
1178
02:16:41,420 --> 02:16:43,580
packing on the pounds.
1179
02:16:46,780 --> 02:16:49,780
Their mother replaces the wolf
on the bank.
1180
02:17:05,420 --> 02:17:08,500
One lunge and she does
what the wolf couldn't.
1181
02:17:11,020 --> 02:17:14,100
The lump on the salmon's back
identifies it
1182
02:17:14,100 --> 02:17:15,780
as a male Humpy, or pink.
1183
02:17:24,620 --> 02:17:28,620
She quickly devours it
without sharing
1184
02:17:28,620 --> 02:17:31,060
and moves on,
1185
02:17:31,060 --> 02:17:33,180
the cubs dragging along behind...
1186
02:17:37,580 --> 02:17:40,340
..leaving the wolf to pick up
the scraps.
1187
02:17:50,980 --> 02:17:54,060
She now wants to fish the prime spot
at the river mouth.
1188
02:17:57,780 --> 02:18:00,180
But it's taken
1189
02:18:00,180 --> 02:18:05,020
by a 1.000 lb male,
1190
02:18:05,020 --> 02:18:07,700
over 200 lbs heavier than her.
1191
02:18:12,660 --> 02:18:17,380
Upstream, the river is deeper,
making fishing near impossible.
1192
02:18:20,140 --> 02:18:24,700
She must feed the cubs...
1193
02:18:24,700 --> 02:18:26,420
so puts herself in danger.
1194
02:18:37,340 --> 02:18:38,780
A growl
1195
02:18:38,780 --> 02:18:40,340
and a charge...
1196
02:18:44,540 --> 02:18:46,060
..but he's not budging.
1197
02:18:58,860 --> 02:19:01,180
Undeterred, she grabs a fish...
1198
02:19:10,300 --> 02:19:12,740
..which draws in the big male.
1199
02:19:39,900 --> 02:19:43,260
Fortunately, there's plenty of fatty
salmon in the river to go round.
1200
02:19:49,500 --> 02:19:52,740
But this won't be the case for long.
1201
02:19:52,740 --> 02:19:55,620
She must reap the harvest
while she can.
1202
02:20:01,660 --> 02:20:05,260
Brown bears are not the only ones
fishing in the Gulf of Alaska.
1203
02:20:07,580 --> 02:20:09,700
Humpback whales have returned.
1204
02:20:11,580 --> 02:20:15,460
They've adapted their hunting
technique especially for here,
1205
02:20:15,460 --> 02:20:18,180
and they're hungry.
1206
02:20:26,690 --> 02:20:28,570
It's autumn
1207
02:20:28,570 --> 02:20:32,730
and one of Alaska's most iconic
migrants has returned.
1208
02:20:45,290 --> 02:20:47,890
These humpback whales
spent the winter
1209
02:20:47,890 --> 02:20:52,690
in their calving and mating grounds
off Hawaii and the Gulf of Mexico.
1210
02:21:05,090 --> 02:21:08,170
Following their 3,000 mile
migration,
1211
02:21:08,170 --> 02:21:14,050
they've arrived at their feeding
grounds in the Gulf of Alaska.
1212
02:21:20,530 --> 02:21:23,530
They've not eaten for six months,
1213
02:21:23,530 --> 02:21:25,690
so waste little time.
1214
02:21:30,330 --> 02:21:33,090
They have a unique way of fishing,
1215
02:21:33,090 --> 02:21:36,770
one not seen anywhere else
in the world.
1216
02:21:57,770 --> 02:22:00,610
Herring shoal here
in their millions,
1217
02:22:00,610 --> 02:22:04,290
for protection from seals and
Steller sea lions.
1218
02:22:06,410 --> 02:22:09,530
But this shoaling actually works
against them
1219
02:22:09,530 --> 02:22:11,330
now the humpbacks are here.
1220
02:22:19,250 --> 02:22:23,570
Once the whales have their sights
on a shoal,
1221
02:22:23,570 --> 02:22:24,810
they dive.
1222
02:22:32,570 --> 02:22:33,850
And start to sing...
1223
02:22:36,650 --> 02:22:39,450
..as loud as a jet aircraft.
1224
02:22:42,930 --> 02:22:45,770
The sound panics the herring
1225
02:22:45,770 --> 02:22:48,370
and drives them up
towards the surface.
1226
02:22:53,370 --> 02:22:55,890
One whale starts blowing bubbles
1227
02:22:55,890 --> 02:22:57,770
surrounding the herring...
1228
02:23:01,370 --> 02:23:06,330
..a vertical barrier as high
as a four-storey house,
1229
02:23:06,330 --> 02:23:10,010
which the herring
won't swim through.
1230
02:23:14,610 --> 02:23:16,530
The trap is set,
1231
02:23:16,530 --> 02:23:19,730
the whales move in
for the kill.
1232
02:23:29,530 --> 02:23:34,010
Together, they devour thousands
of fish at a time.
1233
02:23:47,530 --> 02:23:52,490
At over 45 feet long
and nearly 30 tonnes,
1234
02:23:52,490 --> 02:23:55,690
they have quite an appetite,
1235
02:23:55,690 --> 02:23:59,490
so quickly regroup
to do it all over again.
1236
02:24:05,250 --> 02:24:09,090
This North America coast
is the only place in the world
1237
02:24:09,090 --> 02:24:12,890
where humpbacks combine
bubble netting with singing.
1238
02:24:16,650 --> 02:24:20,330
They've learned that by engaging
their feeding siren,
1239
02:24:20,330 --> 02:24:24,490
they can turn these waters
into the perfect place to hunt.
1240
02:24:48,650 --> 02:24:51,490
500 miles north-west of the whales,
1241
02:24:51,490 --> 02:24:55,090
on the northern edge
of the Gulf of Alaska
1242
02:24:55,090 --> 02:24:57,450
lies Prince William Sound.
1243
02:25:01,170 --> 02:25:04,810
3,500 miles of rugged coastline...
1244
02:25:13,570 --> 02:25:16,570
..home to one of the highest
concentrations
1245
02:25:16,570 --> 02:25:18,290
of sea otters in the world.
1246
02:25:25,010 --> 02:25:29,810
Here because these nutrient rich
waters provide them with an endless
1247
02:25:29,810 --> 02:25:33,690
supply of food, which is vital
for their survival...
1248
02:25:35,890 --> 02:25:38,530
..as unlike most marine mammals,
1249
02:25:38,530 --> 02:25:41,450
sea otters don't have
an insulating blubber layer.
1250
02:25:43,650 --> 02:25:46,850
Instead, they burn calories
to keep warm.
1251
02:25:50,730 --> 02:25:55,930
To do this, they must eat a quarter
of their body weight every day,
1252
02:25:55,930 --> 02:25:58,570
so regular feeding is essential.
1253
02:26:03,090 --> 02:26:05,410
They can dive for four minutes
at a time...
1254
02:26:11,330 --> 02:26:16,450
..feeding on clams, snails, starfish
and sea urchins.
1255
02:26:24,690 --> 02:26:29,170
But body heat alone is not enough
to survive out here,
1256
02:26:29,170 --> 02:26:32,290
so sea otters
have the added protection
1257
02:26:32,290 --> 02:26:34,690
of the thickest coat of any mammal.
1258
02:26:36,530 --> 02:26:42,050
Up to one million hairs crammed into
every square inch
1259
02:26:42,050 --> 02:26:44,570
compared to the average human,
1260
02:26:44,570 --> 02:26:48,890
that only has 100,000 hairs
on their entire head.
1261
02:26:52,210 --> 02:26:55,170
But looking after this coat takes
time and effort,
1262
02:26:55,170 --> 02:27:00,050
so when not foraging,
they spend hours grooming...
1263
02:27:04,410 --> 02:27:05,650
..drying their fur...
1264
02:27:09,730 --> 02:27:13,650
..removing salt and excess oil.
1265
02:27:19,730 --> 02:27:22,010
Fluffing it up traps air,
1266
02:27:22,010 --> 02:27:25,250
providing four times
as much insulation
1267
02:27:25,250 --> 02:27:27,490
as the same thickness of fat.
1268
02:27:29,770 --> 02:27:33,610
Essential, as it's the only thing
that lies between them
1269
02:27:33,610 --> 02:27:36,730
and the freezing cold
Alaskan water.
1270
02:27:54,290 --> 02:27:57,090
The next six months
are the most difficult,
1271
02:27:57,090 --> 02:27:59,730
especially for mothers with pups.
1272
02:28:01,970 --> 02:28:06,970
Calm days will soon be replaced
by storms,
1273
02:28:06,970 --> 02:28:11,210
disrupting feeding,
1274
02:28:11,210 --> 02:28:15,410
increasing the chance
of separation and drowning.
1275
02:28:21,530 --> 02:28:25,690
One in five sea otter pups
won't see their first birthday.
1276
02:28:28,050 --> 02:28:30,490
Starvation is the biggest killer.
1277
02:28:33,530 --> 02:28:37,010
They must stick close to Mum
if they're to survive.
1278
02:29:00,970 --> 02:29:05,210
As autumn advances,
parental guidance is crucial.
1279
02:29:10,690 --> 02:29:14,850
But for some it lasts much longer
than just one season.
1280
02:29:21,250 --> 02:29:23,450
Over the past three months,
1281
02:29:23,450 --> 02:29:28,090
this mum has kept her two cubs
secreted away in the forest.
1282
02:29:30,170 --> 02:29:33,970
Unlike brown bears,
black bear cubs don't rely
1283
02:29:33,970 --> 02:29:36,930
on a diet of salmon
for their survival.
1284
02:29:38,290 --> 02:29:41,130
Mother's milk and vegetation
is more than adequate.
1285
02:29:49,130 --> 02:29:53,970
But Mum can't resist the lure
of a salmon lunch
1286
02:29:53,970 --> 02:29:58,130
and it's the best way for her to
get nutrition to produce milk.
1287
02:30:02,090 --> 02:30:04,370
She leads them to the river
for the first time.
1288
02:30:09,210 --> 02:30:11,450
They're understandably cautious.
1289
02:30:13,610 --> 02:30:16,050
Brown bears also fish here
1290
02:30:16,050 --> 02:30:19,330
and pose a serious threat
to the cubs.
1291
02:30:30,810 --> 02:30:32,970
She expertly catches a fish...
1292
02:30:51,090 --> 02:30:54,490
..then slinks back into the safety
of the forest to feed.
1293
02:31:04,370 --> 02:31:07,570
They'll spend the next three years
by her side
1294
02:31:07,570 --> 02:31:10,130
before heading out on their own.
1295
02:31:21,930 --> 02:31:24,050
That break-up can be traumatic...
1296
02:31:27,170 --> 02:31:30,370
..with youngsters sometimes
reluctant to leave.
1297
02:31:35,050 --> 02:31:38,530
This three-year-old cub
nestled in the rocks
1298
02:31:38,530 --> 02:31:40,690
waits expectantly to be fed.
1299
02:31:51,250 --> 02:31:53,370
His mother rebuffs him.
1300
02:31:56,450 --> 02:32:00,730
A clear sign it's time
he started hunting for himself,
1301
02:32:00,730 --> 02:32:04,890
as she can no longer
catch enough fish to feed them both.
1302
02:32:09,210 --> 02:32:11,770
He's not going to give up
without a fight.
1303
02:32:22,690 --> 02:32:24,970
His begging becomes more aggressive.
1304
02:32:30,130 --> 02:32:32,250
But she stands her ground.
1305
02:32:53,250 --> 02:32:55,730
Eventually he gets the message...
1306
02:32:57,570 --> 02:32:59,290
..and the family breaks up.
1307
02:33:37,410 --> 02:33:43,490
Just 60 miles north of the bears
in the Tongass National Forest,
1308
02:33:43,490 --> 02:33:49,010
another youngster is about
to take a leap into the unknown.
1309
02:34:09,200 --> 02:34:12,840
It's mid-Autumn in the
Tongass National Forest.
1310
02:34:15,280 --> 02:34:18,840
And a very big day
for a young bald eagle.
1311
02:34:24,080 --> 02:34:26,200
He hatched in early June.
1312
02:34:29,840 --> 02:34:33,080
Since then, his parents
have worked tirelessly.
1313
02:34:35,920 --> 02:34:37,720
And he's grown quickly.
1314
02:34:42,600 --> 02:34:45,400
His fluffy white down turned grey.
1315
02:34:51,720 --> 02:34:53,440
He grew flight feathers.
1316
02:34:59,560 --> 02:35:01,320
And learned to feed himself.
1317
02:35:05,520 --> 02:35:08,360
He was fully feathered in 56 days...
1318
02:35:09,680 --> 02:35:12,080
..and almost as big as his parents.
1319
02:35:15,600 --> 02:35:17,920
With age came a change in attitude.
1320
02:35:19,640 --> 02:35:21,400
He no longer waits to be fed.
1321
02:35:26,880 --> 02:35:29,240
And drives them off to fetch more.
1322
02:35:36,520 --> 02:35:39,760
His parents continued to make food
deliveries.
1323
02:35:44,920 --> 02:35:46,560
But didn't hang about.
1324
02:35:54,000 --> 02:35:57,240
Now, he's starting
to explore his environment.
1325
02:35:57,240 --> 02:36:00,280
Stretching his wings
to strengthen his flight muscles.
1326
02:36:07,560 --> 02:36:10,080
He's about to make
his maiden flight.
1327
02:36:12,600 --> 02:36:14,520
A huge leap of faith.
1328
02:36:19,800 --> 02:36:23,200
The ground being 150 feet below.
1329
02:36:31,880 --> 02:36:33,720
After a brief hesitation...
1330
02:36:34,960 --> 02:36:35,960
..he's off.
1331
02:36:46,600 --> 02:36:47,880
He doesn't go far...
1332
02:36:51,480 --> 02:36:55,000
..returning to snatch food
from his parents.
1333
02:36:59,360 --> 02:37:01,520
Survival is instinctive.
1334
02:37:01,520 --> 02:37:03,840
Good manners are not.
1335
02:37:09,200 --> 02:37:12,480
Parental duties over, they leave...
1336
02:37:14,920 --> 02:37:18,520
..forcing the youngster to start
looking after himself.
1337
02:37:28,320 --> 02:37:33,440
Just as the first autumnal storm
approaches from the Arctic.
1338
02:37:55,560 --> 02:37:58,240
On the island of St Lawrence,
1339
02:37:58,240 --> 02:38:00,560
40 miles off the Russian coast...
1340
02:38:05,400 --> 02:38:08,520
..three Arctic Fox cubs play.
1341
02:38:14,680 --> 02:38:16,800
They're only 12 weeks old.
1342
02:38:17,960 --> 02:38:21,280
This den site has been their
refuge since they were born.
1343
02:38:23,000 --> 02:38:24,640
But not for much longer.
1344
02:38:28,640 --> 02:38:31,440
They've already grown
their thick adult coats.
1345
02:38:34,920 --> 02:38:37,240
And now resemble Mum...
1346
02:38:37,240 --> 02:38:38,440
.and Dad.
1347
02:38:43,040 --> 02:38:45,880
They're perfectly camouflaged
amongst the rocks.
1348
02:38:50,480 --> 02:38:53,200
At this age, life is simple.
1349
02:38:57,560 --> 02:39:00,200
They pass the days play fighting...
1350
02:39:06,960 --> 02:39:09,840
..which helps improve
hunting techniques.
1351
02:39:09,840 --> 02:39:12,120
Strength and speed.
1352
02:39:19,880 --> 02:39:23,120
The braver they become,
the further they venture.
1353
02:39:24,680 --> 02:39:29,440
The more adventurous of them,
even attacking and killing fungi.
1354
02:39:41,640 --> 02:39:43,200
All of which is vital.
1355
02:39:44,840 --> 02:39:47,720
Their lives have reached
a critical point.
1356
02:39:55,360 --> 02:39:58,120
The nesting sea birds
are starting to migrate.
1357
02:39:59,680 --> 02:40:02,520
Their parents are no longer
returning with food.
1358
02:40:04,080 --> 02:40:09,280
A clear sign that it's time
for them to start life alone.
1359
02:40:11,920 --> 02:40:14,720
One by one, they drift away.
1360
02:40:29,280 --> 02:40:31,840
And the den lies quiet
1361
02:40:31,840 --> 02:40:33,720
until next year.
1362
02:40:44,880 --> 02:40:47,800
It's not just on St Lawrence
that food is drying up.
1363
02:40:52,600 --> 02:40:57,120
In Katmai Wilderness area, the
salmon run is starting to dwindle...
1364
02:41:07,320 --> 02:41:12,520
..heaping pressure on this mum
and her three yearling cubs.
1365
02:41:17,160 --> 02:41:21,320
She watches as bears downstream
catch the last of the salmon.
1366
02:41:24,360 --> 02:41:28,160
But it's too dangerous for her
to take her cubs into the melee.
1367
02:41:28,160 --> 02:41:31,240
Nor can she leave them alone
on the beach.
1368
02:41:39,200 --> 02:41:40,640
She's trapped upstream...
1369
02:41:45,320 --> 02:41:48,280
..while the others
hold the best fishing spots.
1370
02:41:59,120 --> 02:42:01,000
Her cubs are hungry.
1371
02:42:22,720 --> 02:42:25,440
She must revert to plan B.
1372
02:42:30,200 --> 02:42:34,360
Low tide gives her access
to mussel beds and razor clams.
1373
02:42:36,560 --> 02:42:40,160
Slim pickings, compared to the
salmon the other bears are catching.
1374
02:42:48,000 --> 02:42:50,360
But every morsel is vital...
1375
02:42:52,440 --> 02:42:56,200
..if they're going to survive
their first Alaskan winter.
1376
02:43:18,120 --> 02:43:20,800
The sun tracks low
across the autumn sky.
1377
02:43:23,560 --> 02:43:25,680
Winter is fast approaching.
1378
02:43:28,200 --> 02:43:30,400
North facing mountain slopes
1379
02:43:30,400 --> 02:43:34,560
won't feel the warmth of the
sun's rays until spring.
1380
02:43:41,880 --> 02:43:45,320
Shaded rivers are already
coated in frost.
1381
02:43:50,440 --> 02:43:53,280
In the Chugach National Forest,
1382
02:43:53,280 --> 02:43:54,920
in Alaska's south,
1383
02:43:54,920 --> 02:43:59,080
Coho salmon have at last
reached their spawning grounds.
1384
02:44:05,560 --> 02:44:08,560
They haven't eaten
since returning to the river,
1385
02:44:08,560 --> 02:44:10,280
and are now close to death.
1386
02:44:12,320 --> 02:44:16,600
But they still have one final act
before they die.
1387
02:44:16,600 --> 02:44:18,880
And that is to breed.
1388
02:44:23,320 --> 02:44:27,040
The females dig deep depressions
in the gravel.
1389
02:44:30,000 --> 02:44:33,280
Called a redd, this will be
the nest for her eggs.
1390
02:44:38,800 --> 02:44:42,960
The males line up, waiting
for the moment she lays.
1391
02:44:45,200 --> 02:44:47,960
Then they will rush in
to fertilize them.
1392
02:44:50,400 --> 02:44:52,600
They may only get once chance...
1393
02:44:55,080 --> 02:44:58,400
..so fights are frequent
and violent.
1394
02:45:06,840 --> 02:45:09,920
Even the largest males
carry severe injuries.
1395
02:45:14,960 --> 02:45:19,240
Half starved, their bodies
are in a state of collapse.
1396
02:45:20,480 --> 02:45:21,680
Wounds fester.
1397
02:45:23,040 --> 02:45:26,480
But still, they battle
to keep control of a female.
1398
02:45:41,160 --> 02:45:45,640
Their attention elsewhere
leaves them vulnerable to attack.
1399
02:45:54,120 --> 02:45:55,640
At around 10lbs,
1400
02:45:55,640 --> 02:46:00,280
this Chum salmon weighs
roughly the same as the eagle.
1401
02:46:03,000 --> 02:46:05,280
It's far too heavy to carry away...
1402
02:46:06,560 --> 02:46:08,800
..so he drags it into the shallows.
1403
02:46:14,120 --> 02:46:15,720
But he's not alone.
1404
02:46:19,080 --> 02:46:23,320
And stealing a meal
is easier than catching one.
1405
02:46:33,400 --> 02:46:35,520
As winter draws ever closer...
1406
02:46:39,560 --> 02:46:41,680
..and food becomes scarce...
1407
02:46:45,800 --> 02:46:47,480
..tensions rise.
1408
02:46:52,600 --> 02:46:55,960
But Alaska still has one
last offering.
1409
02:46:58,160 --> 02:47:01,640
A spectacle that throws a lifeline
to eagles
1410
02:47:01,640 --> 02:47:04,280
from across much of north America.
1411
02:47:15,170 --> 02:47:16,850
Late October.
1412
02:47:16,850 --> 02:47:21,210
Clear skies reveal
the Aurora Borealis.
1413
02:47:34,890 --> 02:47:36,570
Temperatures drop...
1414
02:47:39,290 --> 02:47:41,970
..chilling both land and water.
1415
02:47:44,530 --> 02:47:48,290
Soon, most of Alaska's rivers
will freeze completely...
1416
02:47:49,730 --> 02:47:53,890
..locking away vital food
under a thick layer of ice.
1417
02:47:56,130 --> 02:47:57,290
But not here.
1418
02:47:58,370 --> 02:48:02,210
The Chilkat River in southeastern
Alaska is different.
1419
02:48:08,170 --> 02:48:12,330
Upstream, water trapped
underground is warmed.
1420
02:48:14,690 --> 02:48:16,530
It slowly percolates up...
1421
02:48:17,970 --> 02:48:19,770
..and seeps into the river.
1422
02:48:22,930 --> 02:48:27,410
Keeping a five-mile stretch
of the Chilkat free of ice.
1423
02:48:30,090 --> 02:48:32,530
Even during the coldest winter.
1424
02:48:42,770 --> 02:48:46,370
The warmer water means salmon
can spawn here later.
1425
02:48:52,090 --> 02:48:55,930
This attracts eagles
from thousands of miles away...
1426
02:48:57,050 --> 02:49:00,930
..for one final feast
before winter hits.
1427
02:49:18,370 --> 02:49:23,130
At 3,000 strong, this is the
world's largest gathering
1428
02:49:23,130 --> 02:49:24,650
of bald eagles.
1429
02:49:28,690 --> 02:49:33,130
Such a glut of food means there
is little reason to squabble.
1430
02:49:38,490 --> 02:49:41,010
And a chilling calm descends.
1431
02:50:08,810 --> 02:50:11,610
The salmon pay the ultimate price.
1432
02:50:17,210 --> 02:50:20,650
They've done what they came
all this way to do.
1433
02:50:24,930 --> 02:50:27,890
Their cycle of life is now complete.
1434
02:50:34,370 --> 02:50:38,330
Every year,
300 million returning salmon
1435
02:50:38,330 --> 02:50:41,130
bring life to much of Alaska.
1436
02:50:46,010 --> 02:50:50,490
Even in death, they fertilize
the land along river banks...
1437
02:50:53,770 --> 02:50:55,690
..nourishing the vegetation...
1438
02:50:57,210 --> 02:51:00,010
..providing food for grazers...
1439
02:51:02,690 --> 02:51:06,130
..that in-turn feed predators.
1440
02:51:11,370 --> 02:51:14,450
Nutrients from far out
in the Pacific Ocean...
1441
02:51:18,250 --> 02:51:21,930
..creating life
hundreds of miles inland.
1442
02:51:35,210 --> 02:51:37,050
With winter closing in...
1443
02:51:40,210 --> 02:51:43,410
..Alaska's wildlife
must steel itself...
1444
02:51:45,210 --> 02:51:48,050
..ahead of seven months
of ice and snow.
1445
02:52:02,090 --> 02:52:06,810
But it's these extreme conditions
that have helped transform them
1446
02:52:06,810 --> 02:52:10,290
into some of the most
resolute creatures on the planet.
1447
02:52:24,930 --> 02:52:28,170
So that when spring
finally returns...
1448
02:52:30,370 --> 02:52:36,170
..they'll be ready to face
another year in the wilds of Alaska.
1449
02:53:01,850 --> 02:53:06,130
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