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One continent on our planet changes

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more dramatically than any other.

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(THUNDER RUMBLES)

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North America.

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Whole landscapes here can be transformed
in a matter of minutes.

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And all life has to be ready
to seize the moment.

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Getting it wrong can be disastrous.

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But time it correctly,
and there can be great rewards.

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This is a land of opportunity.

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Over 100 times the size of Great Britain,

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North America stretches from just above
the equator almost to the North Pole.

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Temperatures can range
from 50 degrees Celsius to minus 40.

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The coldest wilderness of all
lies in the Arctic north.

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Here, in Canada's Yukon Territory,
winter is brutal.

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Many animals have travelled... south
to avoid the worst of the cold.

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For those which stay behind,

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life becomes very hard indeed.

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A Canadian lynx.

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No other kind of cat, anywhere,

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lives farther north than this one.

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The search for food could take him
hundreds of miles.

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(GROWLS)

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A snowshoe hare.

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This could be a chance.

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He's lost the element of surprise.

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And now there's a tangle of branches
between him and his prey.

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Missed again.

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More of his energy wasted.

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Another hare...

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...this time out in the open.

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And another failure.

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If he doesn't kill soon,
he may not survive these winter months.

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But in North America,

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change is never far away.

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April... and billions of tonnes of snow
and ice are starting to melt,

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bringing new opportunities.

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(SQUAWKING)

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Much of the water drains southwards.

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10,000 creeks join, forming
North America's biggest river system.

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The meltwaters-travel 2,000 miles
down the Mississippi,

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right through the heart of North America.

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In the streams of Tennessee,
river chub are getting ready to breed.

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This male is busy building
a mound of stones, in which,

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if he's lucky,
a female will lay her eggs.

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As the river flows faster,
the work gets harder.

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It's a good start,
but rivals are doing the same thing

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and want some of his pebbles.

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The intruder seen off,

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and it's back to business.

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A few finishing touches.

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And then, with the last
of some 7,000 stones,

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his nest is complete.

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And right on time, here is a female.

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But the mound now needs one last feature.

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A trench where she can lay her eggs.

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And with a gentle shimmy of his body,
he nudges her into position.

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And she deposits her eggs

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where they will be safe
from both currents and predators.

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His work is done.

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The eggs will hatch,

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and then his mound
will be slowly dismantled

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by the current.

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So next year,
he'll have to start all over again.

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Spring is now well on its way.

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North America is wonderfully rich
in wild flowers.

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There are over 10,000 species of them.

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Hummingbirds fly up from the south
to feast on the nectar.

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Along the North American coast,
the tides are the largest in the world.

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The fragmented shoreline
forces seawater to rush up narrow inlets.

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And each time the tide retreats,
it opens a freshly stocked larder.

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7,000 square miles of extra coastline

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is uncovered in the space of just
two hours.

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(WHIMPERS)

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(GRUNTS)

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A mother black bear is looking
for something suitable for her cubs.

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This is their first ever trip
to the seaside.

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In a few hours, the tide will return.

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So they must keep up with Mum.

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(WHIMPERS)

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(SQUEALS)

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Here's something tasty...

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crabs.

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Big crabs can give a nasty nip.

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So it's best to start off
with smaller ones.

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During spring, three quarters
of the bears' food comes from the beach.

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(SQUEALS)

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But now... this family is not alone.

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An adult male.

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He's double her size,
and they're in his territory.

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(GRUNTS)

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The cubs know that call.

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It's time to head for safety.

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Bears have poor eyesight,
but their sense of smell is acute,

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and the male has detected intruders.

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He knows exactly which tree they are in.

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If the cubs stay up there,
they'll be safe,

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but they're losing precious feeding time.

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For now,
he's content to leave his scent mark.

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A warning note for trespassers.

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The family moves on.

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For the cubs, lunch today
will have to be a takeaway.

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The tide comes in.

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And within minutes,
feeding time is over for another day.

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As the continent warms,

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on a few special nights,

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when the temperature is just right...

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...the forests of North America
put on a show.

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Male fireflies are taking to the air.

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These insects are not, in fact, flies,
they're a kind of beetle.

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The light produced by the males
is the most energy-efficient on Earth.

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Some species synchronise-their flashes

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to increase the visibility of the message.

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If a female sees something she likes,

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she returns the signal.

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It looks as if the message is working.

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But the forest is booby-trapped...

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...by orb-weaver spiders.

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The firefly continues to glow,
even in death.

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Other males see the flashes,
but not the dangers.

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The spider's larder is filling up.

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But for every firefly that gets caught,

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thousands avoid the traps.

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And this male is lucky.

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He's found a mate.

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And over the course of the night,

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millions will pair up.

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There are over 150 different species
of fireflies in North America,

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and each has its own flash code.

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Once they're mated, the females
deposit their eggs in the ground.

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And for those that didn't find a mate,

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their one chance has come and gone.

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Little rain reaches
the heart of the continent.

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For over a million square miles,
there's not a tree in sight.

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Many of those living here
spend much of their time underground.

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A prairie dog... a kind of
large, burrowing squirrel.

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(SQUEALS)

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Sentinels keep watch,
ready to warn others of any danger.

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And at this time of year
is a new generation to protect.

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This mother has six pups.

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The youngsters constantly beg for food.

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After all,
the pups aren't great at sharing.

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But the prairie dogs don't have
the prairies to themselves.

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(GROWLS)

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An American badger.

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The pups have never seen one before.

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And badgers eat pups.

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A burrowing owl.

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It also knows that badgers are dangerous.

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(SQUAWKS)

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It too has young and does not want
the badger anywhere near them.

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Eventually, the badger gives up.

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He sets off to look elsewhere.

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If he can find a place
where the grass is higher than he is,

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he will have a better chance.

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The mother sounds the alarm.

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(CHIRPS)

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Adults know the danger all too well.

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(CHIRPS)

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(SCREECHES)

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Four pups make it to safety below.

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But their mother dare not
wait above ground any longer.

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(GROWLING)

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(FLIES BUZZ)

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Half of all prairie dog pups
don't survive to adulthood.

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Predators are not the only problem
faced by animals

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living on these great plains.

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Warm air sweeps up from the Gulf of Mexico
and across the open prairies.

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And here, with no mountains to block it,

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it meets the frigid air from the Arctic.

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The results are spectacular.

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As the air currents mix and swirl,

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they build into one of nature's
most fearsome forces.

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(THUNDER CRASH ES)

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To Tornados.

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(WHOOSHING)

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These twisters spin at speeds
of up to 300 mph,

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the world's fastest wind.

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Over 1,000 tornadoes
touch down here every year.

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These drenching summer storms

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are prevented from spreading westwards
by the Rocky Mountains.

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Some peaks are over four kilometres-high,

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so, beyond them, to the west,
much of the land remains parched.

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The great American deserts
cover over a million square miles.

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Here, roasted by the sun and blasted
by the wind, the rocks disintegrate,

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and mountains, particle by particle,
are reduced to sand.

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These pillars are all that remain
of a plateau where dinosaurs once roamed.

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Few animals can now survive here.

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In summer, as in all deserts,

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the enemy is heat,

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and it returns every day.

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At seven in the morning

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the temperature
is already 25 degrees Celsius.

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The clock is ticking

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for one unusual descendant
of the dinosaurs.

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(WARBLES)

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(WARBLES)

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A roadrunner.

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00:29:44,160 --> 00:29:46,811
Found only in the deserts
of North America.

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Built for a life on the ground.

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00:29:53,720 --> 00:29:56,849
- He can run at over 20 mph.
- (WARBLES)

201
00:29:59,080 --> 00:30:02,050
But the prey he seeks are one step ahead.

202
00:30:11,880 --> 00:30:14,724
(WARBLES)

203
00:30:19,040 --> 00:30:21,247
(WARBLES)

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00:30:24,800 --> 00:30:28,600
The roadrunner's challenge
is picking the right target.

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(HISSES)

206
00:30:42,640 --> 00:30:45,484
A Gila monster...

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00:30:45,600 --> 00:30:46,886
too big.

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00:30:54,640 --> 00:30:59,646
By mid-morning,
it will be 40 degrees Celsius.

209
00:31:01,040 --> 00:31:04,522
Even the smallest lizards
will soon head for cover.

210
00:31:21,440 --> 00:31:22,930
A centipede.

211
00:31:24,720 --> 00:31:27,121
Slim pickings for a morning's work.

212
00:31:34,960 --> 00:31:36,610
Hunting should get easier

213
00:31:36,720 --> 00:31:38,529
and prey will stay out longer

214
00:31:38,640 --> 00:31:41,530
once the summer's peak begins to fade.

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00:31:57,200 --> 00:32:01,171
On the East Coast,
summer is coming to an end.

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00:32:03,080 --> 00:32:06,971
Cold currents are sweeping
along the coast of Florida.

217
00:32:12,880 --> 00:32:16,202
And with them
come grey... mullet on their migration

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00:32:16,320 --> 00:32:18,926
to their spawning grounds in the south.

219
00:32:28,480 --> 00:32:29,481
Millions of them...

220
00:32:29,600 --> 00:32:34,845
and packed so tightly,
they stain the water like an oil slick.

221
00:32:37,080 --> 00:32:40,129
Few people on the beach
are even aware of them.

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00:32:46,960 --> 00:32:51,090
The mullet keep as close
to the shore as possible,

223
00:32:51,200 --> 00:32:53,680
for, in deeper water, there are predators.

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00:32:58,080 --> 00:32:59,320
Close to the beach,

225
00:32:59,440 --> 00:33:02,364
they have to keep clear of human swimmers.

226
00:33:09,040 --> 00:33:13,284
But now hunters from the open ocean
have detected them.

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00:33:19,920 --> 00:33:24,801
Tarpon... over two metres long
and weighing over 100 kilograms.

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00:33:36,160 --> 00:33:38,606
To get close to the mullet
in the shallows,

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00:33:38,720 --> 00:33:40,882
the tarpon turn on their sides.

230
00:33:41,000 --> 00:33:44,243
Now the mullet can't see
their shining silver flanks

231
00:33:44,360 --> 00:33:46,089
until it's too late.

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00:33:54,840 --> 00:33:56,285
And feasting begins.

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00:34:14,560 --> 00:34:17,882
Black-tipped shark arrive.

234
00:34:19,480 --> 00:34:22,086
Pelicans join in.

235
00:34:43,800 --> 00:34:47,771
But these attacks have little effect
on the immense shoals.

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00:34:49,520 --> 00:34:54,003
The mullet outnumber their enemies
by 10,000 to one.

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So the great procession travels on,
into the Northern Atlantic Ocean,

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00:35:00,480 --> 00:35:04,201
where, at last,
they will be able to spawn in safety.

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00:35:09,880 --> 00:35:12,281
Autumn arrives in North America.

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00:35:14,960 --> 00:35:18,601
No mountain range spans the continent
from east to west,

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00:35:18,720 --> 00:35:22,202
so there is nothing to stop cold air
from the Arctic

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00:35:22,320 --> 00:35:25,847
sweeping down unhindered
as far south as Louisiana.

243
00:35:39,440 --> 00:35:42,489
Autumn brings colour-
to the southern swamps.

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00:36:08,320 --> 00:36:12,166
Here, it has been hot and humid
for most of the year,

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00:36:12,280 --> 00:36:16,365
and now these sub-zero temperatures
are something of a trial

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00:36:16,480 --> 00:36:18,050
for the local inhabitants.

247
00:36:20,480 --> 00:36:22,209
An American alligator.

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00:36:40,440 --> 00:36:44,729
The alligator reacts to the chill
by slowing its heart rate

249
00:36:44,840 --> 00:36:47,844
to barely one beat per minute.

250
00:36:47,960 --> 00:36:51,362
It's a kind of energy-saving winter sleep.

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00:36:55,720 --> 00:36:58,564
But other creatures
don't have this ability.

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00:37:00,560 --> 00:37:03,643
The largest inhabitants of the swamp.

253
00:37:05,680 --> 00:37:08,889
A relative of the elephant.

254
00:37:11,680 --> 00:37:12,841
A manatee.

255
00:37:15,400 --> 00:37:20,531
A female provides milk for her calf
from a teat behind her flipper.

256
00:37:25,680 --> 00:37:28,524
She might be able to survive the chill.

257
00:37:29,680 --> 00:37:32,206
But her calf cannot.

258
00:37:43,200 --> 00:37:48,081
So every autumn,
they need to find warmer waters.

259
00:37:51,160 --> 00:37:53,128
They have a long journey ahead...

260
00:37:53,240 --> 00:37:55,242
it could be hundreds of miles.

261
00:38:14,080 --> 00:38:16,481
And she is not alone.

262
00:38:32,080 --> 00:38:38,281
The warm waters they need to survive
come from an unusual source.

263
00:38:38,400 --> 00:38:41,051
An immense underground river

264
00:38:41,160 --> 00:38:45,484
flows through subterranean channels
in Florida's rocks.

265
00:38:47,320 --> 00:38:52,087
In places, it comes to the surface,
creating over 1,000 springs.

266
00:38:57,880 --> 00:38:58,961
Now, in winter,

267
00:38:59,080 --> 00:39:03,130
these springs are ten degrees warmer
than the surrounding waters.

268
00:39:06,840 --> 00:39:12,006
So manatees come here every year
from far and wide.

269
00:39:21,200 --> 00:39:23,441
And here they can relax.

270
00:39:29,760 --> 00:39:32,684
They can get their backs scrubbed.

271
00:39:36,760 --> 00:39:39,286
And they socialise-.

272
00:39:42,600 --> 00:39:45,524
No-one is in much of a hurry.

273
00:39:54,000 --> 00:39:59,530
And young manatees have a chance
to meet some surprising neighbours.

274
00:40:03,800 --> 00:40:09,011
In summer, playing with an alligator
might be a dangerous game.

275
00:40:13,640 --> 00:40:14,880
But now, at any rate,

276
00:40:15,000 --> 00:40:19,961
the giant reptiles are still too chilled
to react with any vigour-.

277
00:40:38,840 --> 00:40:41,047
Without these warm pools,

278
00:40:41,160 --> 00:40:45,370
few of Florida's manatees
would be able to survive the winter.

279
00:40:47,560 --> 00:40:52,487
But the waterways here
are now very popular with people, too,

280
00:40:52,600 --> 00:40:57,527
and many manatees carry scars inflicted
by the propellers of boats.

281
00:40:59,680 --> 00:41:03,082
Her calf has already had its first scrape.

282
00:41:04,680 --> 00:41:09,208
Every year, more than 100 manatees die
from human causes.

283
00:41:18,080 --> 00:41:20,890
As the human population of Florida grows,

284
00:41:21,000 --> 00:41:24,288
so wildlife is coming
under increasing pressure.

285
00:41:24,400 --> 00:41:27,006
(BOAT ENGINE E REVS)

286
00:41:27,120 --> 00:41:29,361
Across North America,

287
00:41:29,480 --> 00:41:33,007
a million acres of wilderness
are lost every decade.

288
00:41:49,760 --> 00:41:52,650
But it is in the far north
of the continent

289
00:41:52,760 --> 00:41:57,084
that human beings
are affecting wildlife most critically.

290
00:41:58,680 --> 00:42:03,049
Canada is warming faster
than any other country on Earth.

291
00:42:17,840 --> 00:42:22,721
Polar bears have always relied
on sea ice for their hunting.

292
00:42:27,640 --> 00:42:30,769
But summers are now getting longer
and hotter.

293
00:42:34,200 --> 00:42:35,531
For most polar bears,

294
00:42:35,640 --> 00:42:37,563
this is a time of starvation.

295
00:42:50,040 --> 00:42:51,769
On the shores of Hudson Bay,

296
00:42:51,880 --> 00:42:55,601
some bears are finding
a new source of food.

297
00:43:04,200 --> 00:43:07,488
They're all looking for the same thing,

298
00:43:07,600 --> 00:43:11,321
and they have their own ways
of catching it.

299
00:43:18,120 --> 00:43:21,363
First, they must find the right rock.

300
00:43:32,080 --> 00:43:33,923
Now they must wait.

301
00:43:44,640 --> 00:43:49,771
The tide comes in,
bringing with it other northern giants.

302
00:44:09,320 --> 00:44:11,084
Beluga whales.

303
00:44:12,400 --> 00:44:15,483
(SQUEAKING)

304
00:44:15,600 --> 00:44:17,443
Close to the shore,

305
00:44:17,560 --> 00:44:22,964
their calves should be safe
from ocean-going predators such as orca-.

306
00:44:25,200 --> 00:44:27,851
Over 3,000 whales have gathered here.

307
00:44:43,680 --> 00:44:46,001
A young male makes his move.

308
00:44:54,480 --> 00:44:58,007
Polar bears are skilled marine hunters...

309
00:45:00,800 --> 00:45:03,007
...and beluga are slow swimmers.

310
00:45:43,680 --> 00:45:47,048
As long as a whale
can keep an eye on a hunting bear,

311
00:45:47,160 --> 00:45:48,491
it should be safe.

312
00:46:03,240 --> 00:46:05,368
This young bear is still learning.

313
00:46:12,640 --> 00:46:16,725
More experienced bears
know to be patient.

314
00:46:31,640 --> 00:46:35,531
Success will depend
on split-second timing.

315
00:47:19,640 --> 00:47:24,168
A bite at the back of the head,
and the kill is swift.

316
00:47:32,880 --> 00:47:36,441
This extraordinary behaviour
has only been reported here,

317
00:47:36,560 --> 00:47:39,530
in this remote corner of North America...

318
00:47:42,400 --> 00:47:44,402
...and only in the last few years.

319
00:47:52,720 --> 00:47:57,203
This one small group of bears
has found an ingenious way

320
00:47:57,320 --> 00:48:00,563
of surviving the lean summer months.

321
00:48:14,320 --> 00:48:18,291
But for others, it is not so easy.

322
00:48:20,440 --> 00:48:23,922
We continue to transform our planet,

323
00:48:24,040 --> 00:48:27,249
and the seasons
are becoming less predictable.

324
00:48:30,600 --> 00:48:34,321
Will the wildlife of North America
be able to adapt?

325
00:48:35,560 --> 00:48:40,282
Not only on this continent,
known for its change,

326
00:48:40,400 --> 00:48:42,528
but in a rapidly changing world?

327
00:49:03,520 --> 00:49:05,807
DAVID ATTENBOROUGH:
The North America crew heard reports

328
00:49:05,920 --> 00:49:08,924
of a rarely seen
polar bear hunting behaviour.

329
00:49:11,240 --> 00:49:13,720
To film it, they set out in a small boat

330
00:49:13,840 --> 00:49:18,004
to navigate the far corners
of Canada's Hudson Bay.

331
00:49:20,680 --> 00:49:22,682
But the weather here,
on the Arctic Circle,

332
00:49:22,800 --> 00:49:24,325
can be unpredictable.

333
00:49:29,760 --> 00:49:35,369
We're out in the middle of Hudson Bay
and we have a thunderstorm approaching.

334
00:49:35,480 --> 00:49:40,168
The thing you don't want with
a thunderstorm is a metal boat

335
00:49:40,280 --> 00:49:41,486
and a big metal crane.

336
00:49:42,760 --> 00:49:47,209
Hundreds of miles from help,
there's no chance of rescue here,

337
00:49:47,320 --> 00:49:49,448
so the crew head for safety.

338
00:49:49,560 --> 00:49:51,244
- (THUNDER CRASHES)
- Whoa!

339
00:49:52,760 --> 00:49:57,368
CAPTAIN ON RADIO: Let's see...
30 K, and then gusting up to 50 or 60,

340
00:49:57,480 --> 00:49:59,881
so it's gonna get a little nasty.

341
00:50:02,160 --> 00:50:04,731
- (THUNDER CRASHES)
- Oh!

342
00:50:17,480 --> 00:50:20,609
DAVID ATTENBOROUGH BOROUGH:
On land they'll be safe from the storm,

343
00:50:20,720 --> 00:50:22,609
but they need to be armed.

344
00:50:25,400 --> 00:50:27,641
Polar bears have little fear of humans,

345
00:50:27,760 --> 00:50:30,604
and at this time of the year,
most are hungry.

346
00:50:32,840 --> 00:50:36,811
With the bears at a safe distance,
there's time for a quick moment

347
00:50:36,920 --> 00:50:40,208
to celebrate
cameraman John's 40th birthday.

348
00:50:40,320 --> 00:50:43,290


349
00:50:44,720 --> 00:50:47,087
We've come to what is probably
one of the windiest shoots

350
00:50:47,200 --> 00:50:49,168
I've ever done in my life.

351
00:50:49,280 --> 00:50:52,807
JOHN: This is the first time
I've had a birthday on the beach.

352
00:50:52,920 --> 00:50:54,524
- You're kidding?
- Yeah.

353
00:50:54,640 --> 00:50:56,085
And what a beach it is.

354
00:50:58,800 --> 00:51:00,689
At the first sign of calm weather,

355
00:51:00,800 --> 00:51:04,646
the crew head back out
to look for a key part of the story.

356
00:51:08,200 --> 00:51:10,521
Beluga whales.

357
00:51:16,720 --> 00:51:19,610
With frigid waters and strong currents,

358
00:51:19,720 --> 00:51:24,282
a thin rope will be
cameraman Bertie's only lifeline.

359
00:51:36,720 --> 00:51:38,085
(GRUNTING)

360
00:51:38,200 --> 00:51:42,250
Bertie can hear the belugas,
but he can't see them.

361
00:51:44,160 --> 00:51:45,161
To communicate,

362
00:51:45,280 --> 00:51:48,682
the whales sing to each other
through the murky water.

363
00:51:49,960 --> 00:51:52,691
So, with this underwater microphone,

364
00:51:52,800 --> 00:51:56,691
we're going to listen
to what these beluga whales are singing

365
00:51:56,800 --> 00:51:57,961
for Bertie.

366
00:51:58,080 --> 00:52:03,291
(WHALE SONG)

367
00:52:03,400 --> 00:52:07,166
Listening to their calls
gives the crew an idea.

368
00:52:07,280 --> 00:52:13,731
Bertie tries enticing the belugas closer
with some tunes of his own.

369
00:52:13,840 --> 00:52:18,641
(HUMS CHEERILY)

370
00:52:18,760 --> 00:52:21,730
Despite some questionable singing,

371
00:52:21,840 --> 00:52:24,320
it seems to be working.

372
00:52:24,440 --> 00:52:31,050
(CONTINUES HUMMING)

373
00:52:36,000 --> 00:52:38,367
Once reeled in, he shares the secret.

374
00:52:38,480 --> 00:52:43,088
The moment I started singing Adele,
they just went crazy.

375
00:52:43,200 --> 00:52:44,611
(LAUGHS)

376
00:52:46,920 --> 00:52:50,208
It's the chorus, that's what gets them...
every time.

377
00:52:52,400 --> 00:52:55,324
With their boat
the only feature for miles,

378
00:52:55,440 --> 00:52:58,967
it's not just beluga
that come to check them out.

379
00:53:00,040 --> 00:53:02,646
(WHISPERS) Here's a young guy,
really curious.

380
00:53:02,760 --> 00:53:07,687
That's about as close as you can get
to a polar bear.

381
00:53:20,880 --> 00:53:23,645
This bear is pulling our anchor
off the bottom, and we're drifting

382
00:53:23,760 --> 00:53:25,569
cos he's pulling... keeps pulling it up.

383
00:53:27,200 --> 00:53:29,885
Hey, leave that anchor alone. Leave it.

384
00:53:35,280 --> 00:53:36,725
With all eyes on the bear,

385
00:53:36,840 --> 00:53:40,208
the crew suddenly realise
they have a bigger problem to deal with.

386
00:53:40,320 --> 00:53:42,402
(CLANKING)

387
00:53:42,520 --> 00:53:44,602
Their boat has hit a rock.

388
00:53:44,720 --> 00:53:46,324
Do you know exactly where the rock is?

389
00:53:49,720 --> 00:53:50,960
Push it that way.

390
00:53:51,080 --> 00:53:53,242
Strong currents risk tipping the boat

391
00:53:53,360 --> 00:53:56,170
and putting the crew in serious danger.

392
00:54:05,960 --> 00:54:08,361
We're up on top of it, I think.

393
00:54:10,080 --> 00:54:11,491
The team doesn't have long

394
00:54:11,600 --> 00:54:15,241
before the falling tide
will leave them stranded on the rock.

395
00:54:15,360 --> 00:54:17,044
Is it moving or is it just swinging?

396
00:54:17,160 --> 00:54:20,084
- OK, push your end, push. Go on.
- See if we can...

397
00:54:20,200 --> 00:54:22,487
(CLANKING)

398
00:54:22,600 --> 00:54:24,284
- OK, we're off.
- We're off?

399
00:54:24,400 --> 00:54:25,890
Whoo!

400
00:54:26,000 --> 00:54:28,162
A narrow escape.

401
00:54:28,280 --> 00:54:32,046
Like all film crews,
we kept wanting more and more,

402
00:54:32,160 --> 00:54:34,766
and eventually the boat
got high-centred-on a rock.

403
00:54:36,480 --> 00:54:39,006
I didn't think about bears
until I was back on the boat.

404
00:54:39,120 --> 00:54:40,451
There was a bear in the water.

405
00:54:40,560 --> 00:54:42,642
Yeah, there are a couple right around us.

406
00:54:42,760 --> 00:54:43,921
Yeah.

407
00:54:49,520 --> 00:54:50,931
But with time running out,

408
00:54:51,040 --> 00:54:55,284
there's little sign
of the bears' unique hunting strategy.

409
00:54:57,840 --> 00:55:03,006
It's a waiting game,
for both the bears and the crew.

410
00:55:09,720 --> 00:55:12,485
Bear, bear, bear! Straight off the front.

411
00:55:12,600 --> 00:55:15,843
Finally, a big male
in a promising position.

412
00:55:20,160 --> 00:55:23,528
This is just the situation
they've been looking for.

413
00:55:23,640 --> 00:55:28,567
With one camera on the boat
and one in the air,

414
00:55:28,680 --> 00:55:31,763
the crew is hoping to cover the action
from all angles.

415
00:55:35,200 --> 00:55:38,090
Just waiting for the right one
in the right spot.

416
00:55:44,960 --> 00:55:49,249
He's got one. He's got one.
Let's get the anchor up, anchor up.

417
00:55:49,360 --> 00:55:51,601
He's got it.

418
00:55:56,040 --> 00:55:57,530
He's got it on the back of the head.

419
00:55:59,240 --> 00:56:00,890
He's got him by the tail now.

420
00:56:03,680 --> 00:56:08,242
For the team, witnessing
this life-and-death struggle is hard.

421
00:56:09,320 --> 00:56:11,049
Oh, it's kind of shocking

422
00:56:11,160 --> 00:56:14,004
when it just happens
in front of you like that.

423
00:56:15,360 --> 00:56:17,522
It's amazing how powerful the bear is...

424
00:56:17,640 --> 00:56:20,376
it just grabbed an animal that's designed
to be in the water and be powerful,

425
00:56:20,400 --> 00:56:21,925
and the bear just throws it around.

426
00:56:23,440 --> 00:56:27,570
To see an animal lose its life
is upsetting,

427
00:56:27,680 --> 00:56:31,287
and the crew are left with mixed feelings.

428
00:56:31,400 --> 00:56:33,926
We've really connected with these belugas,

429
00:56:34,040 --> 00:56:36,327
so it's sad to see them die,

430
00:56:36,440 --> 00:56:39,922
but that was a really spectacular bit
of nature right there.

431
00:56:41,560 --> 00:56:44,040
This footage adds to our understanding

432
00:56:44,160 --> 00:56:47,050
of these ingenious animals.

433
00:56:53,720 --> 00:56:55,848
In a changing world,

434
00:56:55,960 --> 00:56:59,487
one small group of polar bears has come up

435
00:56:59,600 --> 00:57:02,570
with a remarkable strategy for survival.

436
00:57:07,680 --> 00:57:08,886
Next time...

437
00:57:12,800 --> 00:57:16,850
...the continent where wildlife
puts on the greatest show on Earth.

438
00:57:19,240 --> 00:57:21,641
(GRUNTING)

439
00:57:27,600 --> 00:57:29,250
Africa.