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There is only one planet
in the universe, as far as we know,
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where there is life.
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The Earth.
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Our home.
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The perfect planet.
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Life here is only possible
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because of a unique balance
of natural forces.
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Energy from the sun
powers the living world.
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GRUNTING
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THUNDER CRASHES
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Weather systems transport fresh
water around the globe.
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And powerful ocean currents
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circulate life's essential
nutrients.
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This series will reveal how these
global forces have worked together
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to create our planet's
fragile life-support system.
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One of these forces is so important
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that life would never have
even started without it.
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Across the surface of our planet,
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there are over 1,500 active
volcanoes.
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This is the most active -
Kilauea in Hawaii.
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Here, magma - liquid rock
from the planet's hot interior -
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bursts out through fractures
in the Earth's crust,
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and it's been flowing for months.
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Nothing can stand in the lava's way.
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Volcanoes are certainly destructive.
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But without these powerful
underground forces,
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there would be no breathable
atmosphere.
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No oceans.
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No land.
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No life.
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We can't control volcanoes,
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but they're vital for all living
things on Planet Earth.
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RUMBLING
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This is Ol Doinyo Lengai
in Tanzania.
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It's one of Africa's
most active volcanoes,
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and has erupted over 15 times
in the last 100 years.
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On its northern flank lies
Lake Natron,
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400 square miles in extent,
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and one of the world's most
corrosive bodies of water.
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The water wells up from deep below,
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carrying such a concentration of
chemicals that it can burn skin.
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But one animal thrives here.
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Volcano birds.
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Nearly two million lesser flamingos
live in East Africa
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and all of them come here to breed.
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FLAMINGOS CALL
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But they can only nest here
when the lake's level
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drops so far that in the centre,
its bed is exposed.
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And that rare moment is now.
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How they know when the conditions
are right is a mystery,
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but some have flown thousands
of miles to be here.
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The flamingos head for the
middle of the lake,
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where the intense evaporation
has created islands of salt.
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It's here that the birds
build their nests,
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over three miles from the
lake's edge
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and safe from land predators,
which are unable to cross
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the surrounding moat of
caustic soda.
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FLAMINGO CALLS
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The single egg is laid on a mount
of hardened salt
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built by the adults,
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its height an insurance against
a sudden rise in water level...
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...which often happens on
Lake Natron.
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As the centre dries and enlarges,
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more and more flamingos arrive
to nest on it.
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In good years, such as now,
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as many as half a million pairs
breed here.
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After 28 days of incubation,
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a chick emerges into Natron's
harsh glare.
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Here, temperatures can rise
to 55 degrees Celsius.
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Mother's wing, however,
can serve as a sun shield.
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CHICK CHIRPS
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The chick is fed a rich liquid
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made of the lake's
barely digested algae
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and traces of its parent's blood.
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After a few days, the chick is
strong enough to stretch its legs.
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CHIRPS
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CHIRPING
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It then joins a growing creche,
made up of chicks of different ages.
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Soon, the need for fresh water
will force the infant birds
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to trek to springs on the
lake's edge.
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A journey they have to make on foot,
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as their flight feathers
have yet to develop.
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Every day, the adults fly
to these springs to feed.
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Here, on the lake's margins,
they collect algae that flourish
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in the volcanic water -
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vital food for the flamingos.
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It's the algae that turn
the flamingos' feathers pink.
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It even colours their eyes.
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The adults spend most of their day
at the springs,
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and now their chicks
are going to join them there.
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CHIRPS
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No-one wants to get left behind.
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It's a three-mile march
over razor-sharp flakes of soda
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and sticky, caustic mud.
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A life-threatening trial,
especially for the youngest chicks.
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The groups merge into one
giant creche.
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CHIRPS
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For some, the challenges
are just too great.
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Exhaustion overcomes the weakest.
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And now, there is yet
another threat.
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Marabou storks.
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They have long legs like a flamingo,
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but a beak like a Roman sword.
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And they are patient,
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waiting for an easy target.
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Their very presence creates panic
among the chicks.
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The smallest avoid
being trampled underfoot
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by travelling on the outside
of the group.
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But that exposes them to attack.
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Their only defence is to run.
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But you have little chance
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when you're barely ankle-high
to your pursuer.
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FLAMINGOS SHRIEK
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Stragglers will almost
certainly be taken.
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But there comes a point
when every stork has had its fill.
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This little chick is very lucky.
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At last, the youngsters reach
the freshwater springs
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at the lake's margin
to rejoin their parents.
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Almost unbelievably,
each chick has a unique call
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that its parent can recognise.
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CHICK CHIRPS
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CHIRPING
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It's not just lesser flamingos
that depend on volcanoes.
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00:14:23,640 --> 00:14:27,440
Ultimately, so do all living things.
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00:14:34,400 --> 00:14:37,280
Over 80% of the Earth's surface
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is the result of magma bursting up
from the molten interior.
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BOOM
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00:14:49,800 --> 00:14:53,440
The process started
four billion years ago
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and it still continues today.
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00:15:01,240 --> 00:15:05,640
When lava cools, it solidifies
into rock,
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00:15:05,640 --> 00:15:10,640
and eventually weathers into land
that can support life.
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00:15:18,280 --> 00:15:23,520
All the Galapagos Islands
in the Pacific are volcanic,
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and Fernandina is the
youngest of them.
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And still growing.
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At its centre, a volcanic crater
four miles wide...
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...and over 800 metres deep.
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It seems dormant, but it was
erupting only two weeks ago.
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00:16:05,320 --> 00:16:10,640
Even so, there are some who depend
on the heat from this volcano.
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A female land iguana, heavy with
eggs, approaches the crater's rim.
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00:16:24,440 --> 00:16:27,840
It took her ten days
to climb up here,
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00:16:27,840 --> 00:16:31,360
but the toughest part of her
journey is still ahead.
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00:16:32,720 --> 00:16:36,280
She's going to descend
into the crater itself.
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00:16:49,000 --> 00:16:52,680
Frequent tremors
make the crater walls unstable.
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00:17:01,800 --> 00:17:04,400
More people have travelled in space
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than have visited the bottom
of Fernandina's crater.
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But instinct drives her on.
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The warm volcanic ash on
the crater floor
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has the perfect temperature
for incubating her eggs.
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But there are no clear paths down.
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00:17:31,160 --> 00:17:34,720
Any made last year have been
destroyed by rock falls.
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The slope is steep and unstable.
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Tumbling rocks
quickly become an avalanche.
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With the boulders falling down
away from her,
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she's not in immediate danger.
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00:18:25,640 --> 00:18:28,760
But behind her, higher up,
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two other females
have also started the descent.
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ROCKS RATTLE
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And now she is in the firing line.
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THUD
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She's safe.
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FLIES BUZZ
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Others before her
haven't been so lucky.
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But she's undeterred.
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At last, after an eight-hour
descent,
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she reaches the crater floor.
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00:19:58,520 --> 00:20:02,560
Now she must find a suitable
place to dig her nest.
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00:20:10,320 --> 00:20:13,080
The best sites are already taken.
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00:20:17,840 --> 00:20:21,280
And nesting females are very
aggressive.
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A nodding head means keep away.
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Push off!
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Ignored warnings are met with force.
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00:21:03,320 --> 00:21:07,160
But she's come a long way,
and she's not going to give up now.
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She, too, starts to dig a hole
in which to lay her eggs.
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That done, she will head back,
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leaving the volcano to provide
the warmth her eggs need
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if they are to hatch.
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00:21:36,400 --> 00:21:39,840
Sometimes, of course,
the volcano erupts
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and destroys not only eggs
but many nesting adults.
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But for the iguanas,
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the benefits of nesting in
the crater are so great
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that it's worth all the risks.
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Volcanic islands make up just 5%
of the planet's land,
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but they're home
to nearly 20% of its species.
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00:22:16,240 --> 00:22:20,560
Animals often evolve very
swiftly on islands,
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cut off from their mainland
relatives
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and faced with the challenges
of isolation.
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This is Wolf, an extinct volcano
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and one of the most remote islands
of the Galapagos,
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800 miles from
the nearest large landmass
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and over a million years old.
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A finch.
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A female.
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Its ancestors doubtless were blown
here by storms many centuries ago.
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00:22:59,520 --> 00:23:03,800
Like most finches, they feed on
seeds, nectar and insects.
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00:23:06,280 --> 00:23:09,480
But there's little food
of any kind on Wolf.
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00:23:09,480 --> 00:23:11,120
CHIRPS
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00:23:12,600 --> 00:23:15,880
And since they aren't strong enough
fliers to leave the island,
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00:23:15,880 --> 00:23:20,160
they've had to find food
from a very unusual source.
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00:23:22,920 --> 00:23:26,760
They depend on another
of the island's inhabitants.
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00:23:26,760 --> 00:23:28,080
BIRD CALLS
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00:23:33,200 --> 00:23:35,120
Nazca boobies.
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00:23:40,000 --> 00:23:43,120
Every day, these sea birds commute
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00:23:43,120 --> 00:23:46,680
between the island and their fishing
grounds out in the open ocean.
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00:23:50,560 --> 00:23:53,560
Each time a pair meet,
they renew their bond.
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00:23:56,520 --> 00:24:00,000
And then catch up with the
neighbours.
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00:24:00,000 --> 00:24:02,360
CAWING AND CHIRPING
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00:24:05,760 --> 00:24:07,200
Now is the time...
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00:24:08,560 --> 00:24:10,160
...to hop into action.
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00:24:19,360 --> 00:24:21,480
CHIRPING
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00:24:32,480 --> 00:24:33,800
Blood.
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They are vampire finches.
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00:24:44,440 --> 00:24:49,640
These little birds have become
one of the world's newest species.
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00:24:54,760 --> 00:24:57,120
She cuts the quill
of a large flight feather,
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00:24:57,120 --> 00:24:59,280
and the blood flows.
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00:25:02,680 --> 00:25:06,320
The sight of it attracts the
attention of others.
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00:25:08,280 --> 00:25:11,160
CAWING AND CHIRPING
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00:25:12,400 --> 00:25:17,480
Blood is very nutritious -
worth fighting for.
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00:25:30,520 --> 00:25:33,880
So with this never-ending supply
of food,
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00:25:33,880 --> 00:25:36,720
the vampire finches
can flourish on an island
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00:25:36,720 --> 00:25:39,920
where otherwise they could
not survive.
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00:25:45,040 --> 00:25:49,360
Why the boobies don't object,
nobody knows.
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00:25:52,520 --> 00:25:55,360
Perhaps the finches' behaviour
started
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00:25:55,360 --> 00:25:59,320
when they helped the boobies to
remove parasites from their plumage.
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00:26:02,120 --> 00:26:05,200
Maybe the boobies
think that the little vampires
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00:26:05,200 --> 00:26:07,640
are still providing a service.
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00:26:07,640 --> 00:26:09,240
Who can tell?
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00:26:14,800 --> 00:26:18,480
Volcanic islands don't last forever.
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00:26:18,480 --> 00:26:23,640
Changes deep in the Earth's crust
bring their eruptions to an end
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00:26:23,640 --> 00:26:27,440
and the forces of erosion
then begin to wear them down.
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00:26:34,680 --> 00:26:36,640
BIRDS TWEETING
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00:26:36,640 --> 00:26:40,000
But the coral around them
continues to grow,
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00:26:40,000 --> 00:26:43,880
sea levels change,
and eventually all that is left
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00:26:43,880 --> 00:26:49,840
is a ring-shaped island of coral
rock surrounding a lagoon.
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00:26:49,840 --> 00:26:51,560
An atoll.
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00:27:01,880 --> 00:27:05,520
There are hundreds of atolls
in tropical seas,
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all remnants of vanished volcanoes.
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00:27:15,880 --> 00:27:18,920
This is one of the largest
and most pristine -
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00:27:18,920 --> 00:27:21,960
Aldabra, in the Indian Ocean.
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00:27:24,640 --> 00:27:28,000
20 million years ago,
it was an island
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00:27:28,000 --> 00:27:30,640
with a volcanic crater in
its centre.
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00:27:36,080 --> 00:27:38,200
Now, it's an atoll.
242
00:27:39,560 --> 00:27:43,640
Mangroves took root
and sea birds came to nest.
243
00:27:46,320 --> 00:27:49,440
One land animal in particular...
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00:27:46,320 --> 00:27:49,440
GRUNTS
245
00:27:49,440 --> 00:27:51,520
..reached here before man.
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00:27:51,520 --> 00:27:53,520
GRUNTS
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00:27:55,000 --> 00:27:56,840
A giant tortoise.
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00:27:58,120 --> 00:28:00,120
These creatures can float
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00:28:00,120 --> 00:28:04,680
and live without food or fresh water
for long periods of time.
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00:28:08,920 --> 00:28:12,600
This isolated atoll is the
perfect refuge.
251
00:28:13,640 --> 00:28:16,200
Their only enemy is the sun.
252
00:28:21,920 --> 00:28:27,080
Without shade, a tortoise risks
being boiled in his shell.
253
00:28:31,400 --> 00:28:34,840
So, after feeding
in the cool of the morning,
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00:28:34,840 --> 00:28:38,040
and before the sun
becomes too crushingly hot,
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00:28:38,040 --> 00:28:39,880
they have to find cover.
256
00:28:41,240 --> 00:28:42,560
All of them.
257
00:28:48,760 --> 00:28:53,280
There is very little vegetation,
but caves in the coral rock
258
00:28:53,280 --> 00:28:55,880
can provide the shade
they so badly need.
259
00:29:03,920 --> 00:29:06,600
He's nearly there.
260
00:29:06,600 --> 00:29:11,760
All that is left is a white-knuckle
ride to the bottom.
261
00:29:11,760 --> 00:29:14,160
GRUNTS
262
00:29:15,440 --> 00:29:17,440
And he's in.
263
00:29:21,120 --> 00:29:23,680
Thousands of others
are still out in the sun.
264
00:29:25,240 --> 00:29:29,960
This tree could shade a couple
of hundred, if they pack tight.
265
00:29:45,240 --> 00:29:47,320
It's bumper-to-bumper parking.
266
00:29:53,160 --> 00:29:57,200
Within an hour or so,
all must find shade of some sort
267
00:29:57,200 --> 00:29:59,000
if they're to survive.
268
00:30:32,480 --> 00:30:34,120
Safe.
269
00:30:34,120 --> 00:30:36,320
GRUNTS
270
00:30:36,320 --> 00:30:41,240
But the future for Aldabra's
tortoises is far from certain.
271
00:30:42,720 --> 00:30:47,000
The climate is changing,
sea levels are rising,
272
00:30:47,000 --> 00:30:51,680
and Aldabra's tortoises may soon
have to find a new refuge,
273
00:30:51,680 --> 00:30:53,560
or drown.
274
00:30:59,880 --> 00:31:04,200
In some places, volcanoes erupt
not in the ocean
275
00:31:04,200 --> 00:31:07,240
but in the very middle
of a continent.
276
00:31:11,160 --> 00:31:13,120
North America.
277
00:31:13,120 --> 00:31:18,120
And in its very heart,
a volcanic hot spot - Yellowstone.
278
00:31:25,240 --> 00:31:27,760
The last major eruption here
279
00:31:27,760 --> 00:31:32,800
came to an end about
650,000 years ago,
280
00:31:32,800 --> 00:31:36,360
but this volcano is only sleeping.
281
00:31:38,160 --> 00:31:41,600
Not far below ground,
there is still magma.
282
00:31:43,040 --> 00:31:46,600
And that heats the ground water
to boiling point.
283
00:31:49,720 --> 00:31:51,520
BOOM
284
00:31:51,520 --> 00:31:53,360
Geysers.
285
00:31:56,400 --> 00:32:02,240
Some spout boiling water and steam
to heights of 90 metres or so.
286
00:32:04,120 --> 00:32:09,040
Elsewhere, the scalding waters
liquefy the ground sediments,
287
00:32:09,040 --> 00:32:11,960
creating pots of boiling mud.
288
00:32:17,880 --> 00:32:23,720
And this underground heating
has proved a lifeline for some.
289
00:32:29,880 --> 00:32:31,560
River otters.
290
00:32:31,560 --> 00:32:33,040
SQUEAKS
291
00:32:35,400 --> 00:32:39,000
They need a constant supply of food
if they're to keep warm
292
00:32:39,000 --> 00:32:41,840
in these freezing temperatures.
293
00:32:46,120 --> 00:32:50,480
And this close-knit family
know exactly where to find it.
294
00:33:07,720 --> 00:33:11,680
The springs are so hot that the
rivers never freeze,
295
00:33:11,680 --> 00:33:13,920
even in the coldest winters.
296
00:33:17,400 --> 00:33:18,800
SQUEAKS
297
00:33:18,800 --> 00:33:22,880
So the otter family can fish
the year round.
298
00:33:39,680 --> 00:33:42,000
GROWLING
299
00:33:42,000 --> 00:33:43,840
Trouble.
300
00:33:46,000 --> 00:33:48,840
This coyote knows that
in the middle of winter,
301
00:33:48,840 --> 00:33:52,200
a thermal river means otters,
302
00:33:52,200 --> 00:33:54,960
and otters mean fish.
303
00:34:00,000 --> 00:34:03,880
The question is
how to steal their catch.
304
00:34:27,880 --> 00:34:31,760
Perhaps the thing to do is to
pretend you're not interested...
305
00:34:33,280 --> 00:34:38,120
..and hope that they wander close
enough for a snatch-and-run raid.
306
00:34:50,280 --> 00:34:53,080
It seems the cool-under-fire otters
307
00:34:53,080 --> 00:34:56,720
can outwit the not-so-wily coyote.
308
00:35:08,000 --> 00:35:11,040
Many animals benefit
from the volcanic heat
309
00:35:11,040 --> 00:35:13,400
coming up from below.
310
00:35:13,400 --> 00:35:16,040
OTTERS CALL
311
00:35:16,040 --> 00:35:21,520
And we do as well, but not nearly
as much as we could.
312
00:35:24,280 --> 00:35:26,760
The volcanic heat could provide us
313
00:35:26,760 --> 00:35:29,400
with much of the energy
that we need,
314
00:35:29,400 --> 00:35:32,560
and then we could stop
burning gas and coal
315
00:35:32,560 --> 00:35:36,160
that is now changing the
climate worldwide.
316
00:35:47,120 --> 00:35:49,080
Deep in the Earth's crust,
317
00:35:49,080 --> 00:35:51,840
below both the oceans
and the continents,
318
00:35:51,840 --> 00:35:56,360
there are lines of weakness
along which rises liquid rock.
319
00:36:01,320 --> 00:36:05,640
The Kamchatka Peninsula
in the north-west Pacific
320
00:36:05,640 --> 00:36:07,640
lies along one of them.
321
00:36:22,040 --> 00:36:25,840
There are only a thousand known
geysers in the world,
322
00:36:25,840 --> 00:36:30,000
and many of them are here
in this isolated valley.
323
00:36:31,800 --> 00:36:34,520
BOOM
324
00:36:42,320 --> 00:36:46,080
Steam from superheated water
fills the air.
325
00:36:47,400 --> 00:36:51,600
But the danger from the scalding
pools does little to deter
326
00:36:51,600 --> 00:36:54,840
Kamchatka's most famous residents.
327
00:37:01,720 --> 00:37:03,600
GRUNTS
328
00:37:03,600 --> 00:37:08,280
In May, when the rest of Kamchatka
is still covered by snow,
329
00:37:08,280 --> 00:37:10,000
this valley is free of it,
330
00:37:10,000 --> 00:37:14,960
and bears, having just woken up from
their winter sleep, know that.
331
00:37:22,160 --> 00:37:25,800
The grass is fertilised
by mineral-rich water
332
00:37:25,800 --> 00:37:27,640
spraying from the geysers.
333
00:37:30,160 --> 00:37:33,400
Much-needed forage for
a large male bear
334
00:37:33,400 --> 00:37:36,520
that hasn't eaten for
several months.
335
00:37:42,000 --> 00:37:44,440
And he's not the only one.
336
00:37:55,480 --> 00:37:59,080
The bears haven't seen one another
for seven months,
337
00:37:59,080 --> 00:38:00,880
since the start of winter.
338
00:38:03,480 --> 00:38:07,800
And it seems that right now, they
would prefer to keep it that way.
339
00:38:09,280 --> 00:38:14,040
Nothing should come between a bear
and his first meal of the year.
340
00:38:19,080 --> 00:38:22,240
And in one place,
Kamchatka's underground forces
341
00:38:22,240 --> 00:38:25,880
provide its bears
with even more nutritious meals.
342
00:38:33,720 --> 00:38:37,720
Kurile Lake lies within the crater
of an immense volcano
343
00:38:37,720 --> 00:38:41,320
that long ago produced one of the
greatest eruptions
344
00:38:41,320 --> 00:38:43,080
in the planet's history.
345
00:38:46,480 --> 00:38:49,840
The lake is still circled
by active vents...
346
00:38:52,120 --> 00:38:55,880
..and mineral-rich ash
from their regular eruptions
347
00:38:55,880 --> 00:38:58,960
has made these waters
particularly fertile.
348
00:39:02,240 --> 00:39:05,600
Millions of salmon come
here from the Pacific Ocean
349
00:39:05,600 --> 00:39:08,480
in order to spawn in
these fertile waters,
350
00:39:08,480 --> 00:39:12,400
which will provide their newly
hatched young with abundant food.
351
00:39:18,680 --> 00:39:24,440
So, grass soon ceases to be top
of the menu for Kamchatka's bears.
352
00:39:27,600 --> 00:39:30,200
By the time spring
has turned to summer,
353
00:39:30,200 --> 00:39:34,760
Kurile Lake contains the
most dense assembly of bears
354
00:39:34,760 --> 00:39:37,520
to be found anywhere on Earth.
355
00:39:42,760 --> 00:39:45,200
All hungry for salmon.
356
00:39:53,000 --> 00:39:55,960
SEA BIRDS CALL
357
00:39:55,960 --> 00:40:01,200
But this early in the season,
the fish are still strong and swift.
358
00:40:17,160 --> 00:40:19,400
Nothing seems to work.
359
00:40:27,480 --> 00:40:30,840
But one old bear knows that,
right now,
360
00:40:30,840 --> 00:40:33,440
there is an easier meal to be had.
361
00:40:37,160 --> 00:40:40,560
He remembers that if he
paddles out into the lake,
362
00:40:40,560 --> 00:40:44,000
away from the shoals
of newly arrived salmon,
363
00:40:44,000 --> 00:40:47,480
there's food that
doesn't need chasing.
364
00:41:06,560 --> 00:41:09,680
Some of the first fish
to arrive have died,
365
00:41:09,680 --> 00:41:12,040
and their bodies can
be easily collected...
366
00:41:12,040 --> 00:41:13,440
BEAR GRUNTS
367
00:41:13,440 --> 00:41:15,240
..from the bottom of the lake.
368
00:41:21,280 --> 00:41:26,400
Diving for them at leisure
doesn't use many calories.
369
00:41:31,600 --> 00:41:34,360
And he can take his time.
370
00:41:47,000 --> 00:41:48,920
A couple of weeks later,
371
00:41:48,920 --> 00:41:52,640
the salmon are beginning
to spawn and are less wary.
372
00:41:55,280 --> 00:41:58,200
Now it's worth running.
373
00:42:14,760 --> 00:42:17,040
The fish are so abundant...
374
00:42:19,080 --> 00:42:21,040
..that there is plenty for all...
375
00:42:22,840 --> 00:42:25,760
..even those with no
previous experience.
376
00:42:29,800 --> 00:42:32,080
There are now so many fish,
377
00:42:32,080 --> 00:42:35,640
it's difficult to know
which one to chase.
378
00:42:50,720 --> 00:42:56,120
In a single day, a bear can
consume 100,000 calories,
379
00:42:56,120 --> 00:42:59,880
50 times more than the
average human being does.
380
00:43:01,200 --> 00:43:05,280
And one part is
particularly delicious...
381
00:43:09,480 --> 00:43:11,360
..caviar.
382
00:43:11,360 --> 00:43:14,080
80 calories in every mouthful.
383
00:43:19,800 --> 00:43:22,080
BEARS GRUNT
384
00:43:22,080 --> 00:43:25,880
By supporting huge
concentrations of salmon,
385
00:43:25,880 --> 00:43:29,760
mineral ash from
Kurile Lake's volcanoes
386
00:43:29,760 --> 00:43:33,520
has made life surprisingly
easy for these bears.
387
00:43:37,920 --> 00:43:40,120
EXPLOSIVE BOOM
388
00:43:47,480 --> 00:43:51,960
Our planet depends on minerals
brought up by volcanoes
389
00:43:51,960 --> 00:43:54,320
from the Earth's molten core.
390
00:43:57,760 --> 00:44:02,880
A single ash cloud can carry
billions of tonnes of minerals.
391
00:44:16,400 --> 00:44:20,280
And as a consequence,
the lands surrounding volcanoes
392
00:44:20,280 --> 00:44:22,680
are among the world's most fertile.
393
00:44:28,200 --> 00:44:30,960
Those in East Africa's Rift Valley
394
00:44:30,960 --> 00:44:34,760
support the most dynamic
ecosystem on Earth.
395
00:44:40,160 --> 00:44:42,000
The Serengeti.
396
00:44:46,200 --> 00:44:51,320
This is the most productive of
all natural grasslands anywhere.
397
00:44:53,360 --> 00:44:56,080
Every year, over a
million wildebeest
398
00:44:56,080 --> 00:44:59,600
assemble in this particular
corner of the Serengeti
399
00:44:59,600 --> 00:45:05,160
to feed on grass especially
rich in calcium and phosphorus,
400
00:45:05,160 --> 00:45:08,800
essential minerals
for the pregnant females.
401
00:45:11,360 --> 00:45:15,200
In just three weeks,
half a million calves are born
402
00:45:15,200 --> 00:45:17,920
on these ash-rich plains.
403
00:45:20,040 --> 00:45:23,560
That's 24,000 a day...
404
00:45:23,560 --> 00:45:26,120
..a thousand an hour.
405
00:45:29,800 --> 00:45:33,200
Calves stand up within a
few minutes of being born.
406
00:45:36,960 --> 00:45:40,960
Though some need a little
more time to find their feet.
407
00:45:53,280 --> 00:45:55,760
But a mother won't
let her calf suckle
408
00:45:55,760 --> 00:45:59,280
until it's mastered
a few physical skills...
409
00:46:02,200 --> 00:46:03,960
..walking...
410
00:46:05,000 --> 00:46:06,240
..trotting...
411
00:46:08,160 --> 00:46:09,960
..and running.
412
00:46:15,320 --> 00:46:17,360
WILDEBEEST SNORT
413
00:46:19,440 --> 00:46:24,240
Wildebeest calves must run
if they're to stay alive.
414
00:46:26,920 --> 00:46:28,760
HYENA CACKLES
415
00:46:39,520 --> 00:46:42,160
For these plains also support
416
00:46:42,160 --> 00:46:46,840
the greatest assembly
of hunters on the planet.
417
00:46:49,960 --> 00:46:53,520
Each species has its own
special hunting technique.
418
00:46:54,800 --> 00:46:57,040
But all have the same aim...
419
00:46:59,640 --> 00:47:04,680
..to make the most of this
brief super-abundance of life.
420
00:47:33,400 --> 00:47:36,800
PANTING
421
00:47:38,960 --> 00:47:41,280
HEARTBEAT THUMPING
422
00:48:02,800 --> 00:48:09,560
Only one in ten wildebeest
calves will survive to adulthood.
423
00:48:09,560 --> 00:48:14,160
But that is enough to maintain the
million-strong herd of wildebeest...
424
00:48:14,160 --> 00:48:16,040
HYENA WAILS
425
00:48:16,040 --> 00:48:19,600
...AND the planet's highest
density of predators.
426
00:48:23,000 --> 00:48:25,720
Volcanoes fertilise the planet,
427
00:48:25,720 --> 00:48:28,880
but they're the source of
something else so important
428
00:48:28,880 --> 00:48:32,240
that life could not
have started without it.
429
00:48:37,080 --> 00:48:40,960
The first carbon dioxide
in the Earth's atmosphere
430
00:48:40,960 --> 00:48:45,520
was brought by volcanoes
from deep in the Earth's crust.
431
00:48:47,440 --> 00:48:49,040
BIRDS CALL
432
00:48:49,040 --> 00:48:53,160
And this gas is the
foundation of life.
433
00:48:53,160 --> 00:48:55,880
Every plant needs it to grow,
434
00:48:55,880 --> 00:48:58,480
and absorbs it from the air.
435
00:49:01,360 --> 00:49:05,280
Volcanoes continue to
release carbon dioxide today,
436
00:49:05,280 --> 00:49:08,000
and for the last 10,000 years,
437
00:49:08,000 --> 00:49:12,960
its presence in the atmosphere
has suited life perfectly.
438
00:49:15,800 --> 00:49:18,440
Its greenhouse properties have kept
439
00:49:18,440 --> 00:49:21,800
our planet's climate
stable and warm.
440
00:49:26,520 --> 00:49:28,680
EXPLOSIVE BOOM
441
00:49:28,680 --> 00:49:32,360
But too much carbon dioxide would
make the planet's temperature
442
00:49:32,360 --> 00:49:34,960
rise to levels that
would upset the Earth's
443
00:49:34,960 --> 00:49:39,320
long-established
ecological balances.
444
00:49:39,320 --> 00:49:41,040
EXPLOSIVE BOOM
445
00:49:54,560 --> 00:49:57,000
Today, humanity itself
446
00:49:57,000 --> 00:50:00,960
has become a new
kind of supervolcano.
447
00:50:00,960 --> 00:50:03,800
EXPLOSIVE BOOM
448
00:50:07,480 --> 00:50:12,560
Now, every year, we ourselves
release 100 times more carbon
449
00:50:12,560 --> 00:50:15,520
than all the Earth's
volcanoes combined.
450
00:50:17,080 --> 00:50:20,480
And that has brought climate chaos.
451
00:50:24,800 --> 00:50:27,800
We can't control volcanoes,
452
00:50:27,800 --> 00:50:32,960
but we can limit the amount of
carbon dioxide that we produce.
453
00:50:34,320 --> 00:50:37,440
And if we do that,
there will still be time
454
00:50:37,440 --> 00:50:40,320
to restore the ecological balance
455
00:50:40,320 --> 00:50:44,520
that once made this Earth
our perfect planet.
456
00:50:56,560 --> 00:50:58,680
DAVID ATTENBOROUGH:
Lake Natron, in Tanzania
457
00:50:58,680 --> 00:51:03,120
is one of the world's
most toxic bodies of water.
458
00:51:03,120 --> 00:51:06,720
Yet once every few years,
when the centre dries out,
459
00:51:06,720 --> 00:51:11,160
it's brought to life by
thousands of breeding flamingos.
460
00:51:15,160 --> 00:51:17,000
But to reach the colony,
461
00:51:17,000 --> 00:51:20,400
there's only one way to
cross this soft soda sludge.
462
00:51:22,760 --> 00:51:24,920
It's finally here.
463
00:51:24,920 --> 00:51:26,840
Our secret weapon...
464
00:51:26,840 --> 00:51:29,320
..is a hovercraft.
465
00:51:30,520 --> 00:51:32,680
And it's beautiful.
466
00:51:32,680 --> 00:51:34,640
Having shipped it from the UK,
467
00:51:34,640 --> 00:51:38,240
Darren's keen to test
that all systems are go.
468
00:51:38,240 --> 00:51:41,120
ENGINE REVS
469
00:51:41,120 --> 00:51:43,760
Getting it off the
trailer is one thing,
470
00:51:43,760 --> 00:51:46,520
but at least the hovercraft's fans,
that give it lift,
471
00:51:46,520 --> 00:51:48,480
are working well enough.
472
00:52:01,560 --> 00:52:04,040
COUGHING AND LAUGHTER
473
00:52:04,040 --> 00:52:06,120
Well, guys, what do you think?
474
00:52:06,120 --> 00:52:08,840
We know she works, but...
475
00:52:06,120 --> 00:52:08,840
COUGHING
476
00:52:08,840 --> 00:52:11,640
..maybe some of these
guys' lungs don't now.
477
00:52:11,640 --> 00:52:16,280
125 miles away,
on the edge of Lake Natron,
478
00:52:16,280 --> 00:52:20,200
cameraman Matt Aeberhard is
trying to camouflage his hides.
479
00:52:21,560 --> 00:52:23,480
Those are our blinds.
480
00:52:23,480 --> 00:52:26,000
So, you can't camouflage
those on the flats,
481
00:52:26,000 --> 00:52:28,400
and the best thing that
we can do is actually
482
00:52:28,400 --> 00:52:30,720
turn them into a little
cluster of flamingos.
483
00:52:36,640 --> 00:52:39,000
It's pretty cool, huh?
484
00:52:39,000 --> 00:52:44,160
Hide complete, all that's needed
is transport out to the colony.
485
00:52:44,160 --> 00:52:47,000
And after a ten-hour
cross-country journey,
486
00:52:47,000 --> 00:52:50,200
Darren arrives with
his secret weapon...
487
00:52:50,200 --> 00:52:53,080
..and it's an instant hit.
488
00:52:53,080 --> 00:52:55,080
It's the new local
tourist attraction.
489
00:52:56,560 --> 00:52:58,600
You like it?
490
00:52:58,600 --> 00:53:01,680
The first job is to get the
hovercraft into service
491
00:53:01,680 --> 00:53:04,840
and plot a route out to
the nesting flamingos.
492
00:53:20,160 --> 00:53:23,320
The volcanic spring water
is soon replaced
493
00:53:23,320 --> 00:53:26,120
by a crust of razor-sharp
salt crystals.
494
00:53:27,240 --> 00:53:31,680
And for a machine that relies
on a delicate blow-up bottom,
495
00:53:31,680 --> 00:53:33,440
that's a problem.
496
00:53:33,440 --> 00:53:36,280
So, what we have here are
the plates of dried out soda
497
00:53:36,280 --> 00:53:38,960
which form on the mud
substrate underneath,
498
00:53:38,960 --> 00:53:41,560
and it just batters the hovercraft.
499
00:53:41,560 --> 00:53:44,000
We just cannot travel
across this stuff.
500
00:53:44,000 --> 00:53:45,800
It's impossible.
501
00:53:45,800 --> 00:53:50,640
If I was to skim my hand across
that, I would cut it to shreds.
502
00:53:52,240 --> 00:53:56,240
But crossing the soda crust is the
only way out of to the colonies,
503
00:53:56,240 --> 00:53:59,240
and so Matt and Darren
have to hope for the best.
504
00:53:59,240 --> 00:54:01,600
DRILL WHIRS
505
00:54:01,600 --> 00:54:03,040
Unfortunately for Matt,
506
00:54:03,040 --> 00:54:05,800
the best position for his
flamingo-covered hide
507
00:54:05,800 --> 00:54:08,800
has a rather soggy floor.
508
00:54:08,800 --> 00:54:12,680
When the mud dries, it leaves
massive amounts of salt.
509
00:54:12,680 --> 00:54:16,480
Very scratchy, nasty
and aggressive salt.
510
00:54:18,120 --> 00:54:21,640
But sitting shin-deep
in toxic sludge
511
00:54:21,640 --> 00:54:25,440
is a price worth
paying for the view.
512
00:54:25,440 --> 00:54:28,760
And Matt is soon rewarded
with the birth of a chick
513
00:54:28,760 --> 00:54:31,240
right in front of his hide.
514
00:54:42,160 --> 00:54:44,440
CHICK CHIRPS
515
00:54:47,160 --> 00:54:49,120
The daily commute, however,
516
00:54:49,120 --> 00:54:52,160
is taking its toll
on the hovercraft...
517
00:54:52,160 --> 00:54:54,000
ENGINE STALLS
518
00:54:54,000 --> 00:54:56,440
Oh, come on!
519
00:54:56,440 --> 00:55:00,720
..and its blow-up bottom is
literally being ripped apart.
520
00:55:00,720 --> 00:55:05,440
We've trashed 52 of these
that now need to be repaired.
521
00:55:05,440 --> 00:55:07,920
It's like travelling over sandpaper.
522
00:55:07,920 --> 00:55:10,880
So, what do you do when
your hovercraft needs
523
00:55:10,880 --> 00:55:14,120
replacement skirts and you're
in the middle of nowhere?
524
00:55:16,000 --> 00:55:18,800
Enter the local Maasai tribe,
525
00:55:18,800 --> 00:55:21,680
well known for their
needlework skills.
526
00:55:21,680 --> 00:55:24,320
There are only a few places
in the world that specialise
527
00:55:24,320 --> 00:55:26,880
in hovercraft maintenance,
528
00:55:26,880 --> 00:55:30,200
and Lake Natron is now
officially one of those hot spots.
529
00:55:30,200 --> 00:55:32,600
So if you're in the need
of any hovercraft services,
530
00:55:32,600 --> 00:55:34,480
you know where to go.
531
00:55:36,440 --> 00:55:39,920
Two days later, and after
a lot of serious sewing,
532
00:55:39,920 --> 00:55:43,200
the hovercraft is
ready to ride again.
533
00:55:43,200 --> 00:55:46,240
ENGINE TURNS OVER
534
00:55:46,240 --> 00:55:49,400
You look like the new
Tanzanian bobsleigh team!
535
00:55:54,120 --> 00:55:57,760
And getting back on the lake
couldn't have come at a better time,
536
00:55:57,760 --> 00:56:00,040
as the chicks are now on the move.
537
00:56:01,880 --> 00:56:05,480
Sadly, the new hide
position is no drier.
538
00:56:08,040 --> 00:56:13,320
We have an enormous creche of
hundreds of thousands of birds
539
00:56:13,320 --> 00:56:16,800
just pouring into the lagoon
from the salt mud,
540
00:56:16,800 --> 00:56:19,640
just constantly
chatting to each other.
541
00:56:21,240 --> 00:56:25,440
But the massive creche attracts
some unwelcome visitors...
542
00:56:26,880 --> 00:56:30,440
...predators - marabou storks.
543
00:56:35,040 --> 00:56:38,560
These marabous, they know
exactly what they are doing.
544
00:56:42,560 --> 00:56:46,080
Soon, thousands of panicked
chicks are on the move,
545
00:56:46,080 --> 00:56:48,920
desperately trying
to avoid the predators.
546
00:57:03,480 --> 00:57:08,080
And it's a scene that will
live long in Matt's memory.
547
00:57:09,360 --> 00:57:12,680
I mean, it was literally like...
548
00:57:12,680 --> 00:57:14,400
..war had been declared.
549
00:57:15,480 --> 00:57:18,760
I mean, that's one of the...the...
550
00:57:18,760 --> 00:57:24,520
...most amazing and frightening
and freaky wildlife scenes
551
00:57:24,520 --> 00:57:26,920
I've ever, EVER seen.
552
00:57:26,920 --> 00:57:30,560
And believe me, I've seen a few.
553
00:57:30,560 --> 00:57:34,600
And few places are more
challenging than Lake Natron,
554
00:57:34,600 --> 00:57:37,440
but to quote Matt,
if you can deal with
555
00:57:37,440 --> 00:57:40,560
the acrid and sulphurous
stink of the soda,
556
00:57:40,560 --> 00:57:44,800
the stinging eyes and the
chemical attack on your legs,
557
00:57:44,800 --> 00:57:50,200
then you could be rewarded with one
of the greatest spectacles on Earth.
558
00:57:54,760 --> 00:57:56,760
Next time...
559
00:57:56,760 --> 00:57:59,160
..the sun.
560
00:57:59,160 --> 00:58:03,160
Life on our planet is
fuelled by its energy.
561
00:58:08,000 --> 00:58:10,800
Everything must be perfectly tuned
562
00:58:10,800 --> 00:58:15,840
to the daily and yearly
rhythms of this vital force.
563
00:58:19,640 --> 00:58:22,720
The Open University has
produced a free poster
564
00:58:22,720 --> 00:58:25,120
exploring our perfect planet.
565
00:58:25,120 --> 00:58:30,480
To order, please
call 0300 303 0901.
566
00:58:30,480 --> 00:58:35,040
Or go to bbc.co.uk/perfectplanet
567
00:58:35,040 --> 00:58:38,160
and follow the links
to the Open University.
41977
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