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This is the great
wildebeest migration
as you've never seen it before.

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The story of Africa's
greatest travellers

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is captured by
state-of-the-art spycams.

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Only cameras concealed in
the most unlikely places

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could capture such intimate images.

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Here, they spy on the moment the
wildebeest cross Kenya's Mara River.

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Their greatest challenge on
the astonishing 2,000 mile journey
they make each year.

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The hidden cameras immerse us
in the action,

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experiencing the drama
as the wildebeest see it.

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They show what it's like
to be on the hit list
of every African predator.

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Wildebeest undertake
the largest migration of
land mammals on the planet.

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Their epic march creates a spectacle
that's beyond compare.

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Over one and a quarter million
wildebeest

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participate in the migration,

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but each individual has its own
incredible story of survival.

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The adult females
carry new life inside them.

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These yet-to-be-born calves
will be the focus of this story.

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We will see how they overcome
the greatest dangers,

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whether from predators...
or from their journey.

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Hundreds of individuals were filmed
to recreate the calf's story

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as it makes the most challenging
trek that any mammal
ever undertakes.

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After crossing the Mara River,

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the herds follow the seasonal rains

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and head south to the lush plains

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of Tanzania's Serengeti.

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Here, volcanic soils create pasture
rich in both minerals and nutrients.

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And it's here that wildebeest
make their longest stop

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on a journey that takes a year
to go full circle.

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Their appearance
has been eagerly anticipated.

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For lush pasture is not the only
reason for this annual get-together.

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Africa's top predators are
assembling for a very special event.

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Each February,
these plains experience
the world's largest baby boom.

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In just three short weeks, over
half a million calves will be born.

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It's with this moment of birth
that our story begins.

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Delivery is quick,
every minute counts.

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Mother and calf
must form a lasting bond

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based on smell, taste and sight.

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It's this relationship
that will sustain them
on the long journey that lies ahead.

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This is his most vulnerable time.

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Hyenas - they may
commute the distance of
two marathons to get here,

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but for such easy pickings,
the rewards are worth it.

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Vulnerable newborns
are just what they're looking for.

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Other antelopes
hide their young away,

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but wildebeest calves must be ready
to follow their mother from birth.

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He has just minutes
to find his feet.

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Hyenas prefer the easy option,

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and prey doesn't come
much easier than this.

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To survive,
the calf must master in minutes what
a human baby takes a year to learn.

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Hyenas separate
as they move through the herds.

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In this way,
they cover more ground.

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They hunt with both sight
and sense of smell.

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The calf learns to use his legs
faster than any other mammal.

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He's up and walking
in under four minutes.

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It's not a moment too soon.

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He faces his first deadly challenge.

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He's already proving his strength,

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few calves can outrun a hyena
on their first day.

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And he's taken the first steps on
a journey that will last a lifetime.

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Danger past,
he suckles for the first time.

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This begins the unbreakable bond
between mother and offspring.

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One that will last the whole journey
until they return here next year.

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Tortoise-cam
is just one of 20 different cameras

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used to film the calf's story.

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Between them, they will record
over 500 hours of behaviour.

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Tortoise-cam's harmless appearance

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lets him infiltrate the herd.

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Protected by a hard shell, he's
never afraid to stick his neck out.

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Helped by other
undercover agents,

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he will spy on the calf
every step of the way.

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Dawn brings no respite from danger.

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Having young together helps
spread the risk posed by predators.

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The mothers form nursery herds,
where newborns are hidden
among the older calves.

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A territorial male attaches himself
to these nursing mothers

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and drives out
any males older than a year.

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Ousting the males creates
small secure nursing herds

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within the super herd.

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The calf may sometimes
get caught in the chase,

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but having a male around
adds to his security.

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Lions are an ever-present danger
and when the calves are born,

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nomadic lions
swell the enemy's ranks.

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As the male tries to keep control,
the herd easily becomes distracted.

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To increase their chances,
pride lions often hunt as a team.

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One lioness stalks directly forward.

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Her aim is to close the gap
as quickly as possible
without being seen.

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Another attempts
a flanking manoeuvre.

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They will try to stalk to within
30 metres before risking an attack.

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Lions find it hard to outrun
their prey,

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so every inch nearer
tips the odds in their favour.

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One lioness finds a target...

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the calf.

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But the herd panics across her path,

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and she spots a new victim.

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Both calf and mother escape.

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But in the chaos, the calf
is separated from his mother.

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He desperately needs to find her
if he is to survive.

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But the mother is just one
among thousands.

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He checks every wildebeest he meets,
but the females reject any calf
that's not their own.

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Without the herd,
he is hopelessly vulnerable,

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and the lions are not far away.

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The lions may be distracted now,
but they have many mouths to feed.

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The birth of their cubs
coincides with this bumper harvest.

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The calf's smell is unfamiliar.

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He will never be adopted
by another mother,

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even if she has lost her own calf.

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The herd drifts away.

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His call is unique,
if his mother hears his cries,
she will react instantly.

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Vultures keep an eye on everything
that happens in the migration.

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They react quickly
to any new opportunity.

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Lions don't give up their kill
easily, but with bellies full,

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it's easier to take a more
relaxed view of scroungers.

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But for some,
it's simply a matter of principle.

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The vultures are used to this game.

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They make their living
stealing food from lions.

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Time is on the vultures' side.

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He may be frustrated,
but he's just wasting his energy.

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As the day heats up, the desire
to defend the carcass cools down.

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This is a battle that vultures
invariably win.

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Lost calves are so desperate
for company,

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they will attempt to befriend
any likely animal.

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Even zebra are better than nothing.

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But there is no warm welcome here
for a lonely stranger.

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Hyenas have now picked up
the scent of the carcass.

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But a lone calf
makes a more tempting alternative.

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Instinctively, he heads for
the centre of the nearest herd.

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It may not be his herd,
or even his own kind,

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but this was a fortunate move.

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Zebras often tackle a threat
head-on and a raging stallion,

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at full throttle,
is a force to be reckoned with.

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By comparison,
the carcass is easy meat,

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even if it means battling it out
with the vultures.

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Between them, they will quickly
polish off the lot.

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It's midday, and the lost calf
is feeling the heat.

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Even his reluctant companions
leave him.

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Starved of his mother's milk,
he's close to exhaustion.

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No calf below six months old
will survive on its own.

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But there is still hope
on the horizon.

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The herd returns.

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Whilst there is fresh grass to eat,
herds don't move far.

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He searches again,
but even to a calf,

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all adult wildebeest look the same.

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Sound is a more reliable guide,

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he can recognise his mother's call
among a thousand others.

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A glimmer of recognition,**

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but smell is the final confirmation
as the pair are reunited.

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Remarkably, 95% of lost calves
become reunited with their mothers.

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Suckling reinforces the strong bond
between them.

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Once more, the herd provides
security and protection,

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especially against an old enemy.

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Now, a lost eland calf
has become a target.

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The wildebeest calf was lucky
that he didn't suffer the same fate.

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Dung-cam, a camera modelled
on a pile of elephant dung,

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is soon capturing some
rarely seen behaviour.

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Hyenas have devised a method
of extending the shelf life

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of their surplus food.

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The eland calf is destined for
the same underwater larder,

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as are the remnants
of the wildebeest carcass.

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Water not only hides the food,

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but conceals the smell
from other scavengers.

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Skull-cam is in dangerous company.

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Hyenas spend the hottest
part of the day cooling off,

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but this is also the time

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when thirsty calves
urgently need a drink.

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They have no choice
but to face off the enemy.

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Dung-cam takes up battle stations,

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but a gorged and lazy hyena
has other things on his mind.

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Wildebeest have learnt to live
alongside their troublesome
neighbours,

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making the most of
the hyenas' off-duty moments.

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But a calf is never
truly out of danger.

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Hyenas can turn nasty at any moment.

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But then
something remarkable happens,

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the wildebeest go on the offensive.

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The mother, defending her calf,
sends the hyena packing.

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The hyena has deadly enemies
of its own.

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This is the worst mistake
of its life.

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Hyenas will steal food from lions
and kill their cubs.

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This looks like revenge.

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A lioness vents her anger too,
but all she gets is a bloody nose.

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The war between lions and hyenas
over food never ends.

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Even for a whole pride,
a hyena is a tough adversary.

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It's late April, and the lush
green plains have been eaten away

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and become a barren wasteland.

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Dust devils whip the dust
into a swirling column.

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A new and puzzling sight
for a three-month-old calf.

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As the choking clouds
make life difficult,

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the herd treks southwards

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seeking greener pasture
and fresh water.

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Our spy-cams travel with them.

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Meet dragonfly-cam.

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Small and quiet, it can fly close
to the herd without causing alarm.

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It tracks the wildebeest south
as they follow the seasonal rains.

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For higher views,
stealth-cam takes over.

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It can zoom into a detail
of the herd.

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Ahead lies Lake Ndutu,
in the far south of the Serengeti.

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By now, the calf is used to being
on the move.

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but as the herd approaches the lake,

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he is about to encounter
a new challenge.

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Lake Ndutu is a soda lake
loaded with corrosive minerals.

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Although the calf must be thirsty,

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he has no alternative but to
cross it as quickly as possible.

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The calf needs to hurry.

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Too long in the water,
and the soda can burn.

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The calf's first experience
of deep water is traumatic,

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and he still has a way to go.

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A mile across, the lake is
a true test of the calf's stamina.

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Fortunately, there are
no crocodiles to worry about,

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and he's taken to swimming
as easily as he took up walking.

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Powerful strokes drive him forward.

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Guided by his mother,
the calf makes it to the shallows.

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This ordeal by water
is just a taste of things to come.

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Having crossed the lake,
the herd veers westwards

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into new fresh pasture, where the
seasonal rains have recently fallen.

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Grass-cam is there to greet them.

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But it's natural grass
that revitalises the herd.

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Replenished by these lush meadows,

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there's even time
for a game of chase.

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It's not only calves
that are expert at this game.

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Cheetahs are the fastest running
mammals on earth,

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and one in every two of their hunts
are successful.

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For the calves,
playing is a form of training,
it hones their escaping skills.

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But for all their speed, cheetahs
still need the element of surprise.

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A cheetah cannot sustain top speed
for more than 15 seconds
without overheating.

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Spotting the predator before he ran
gave the calf a vital head start.

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In a few weeks, following the yearly
cycle of the rains,

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the calf's herd
moves northwestwards.

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They finally reach the acacia
woodlands of the western Serengeti.

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It's taken the calf
four months to get here.

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Here, the calf will find
welcome shade

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and good grazing
between the trees.

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But here lurks Africa's
most elusive predator.

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Leopards are the stealth hunters
of the trek.

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Masters of surprise,
ambush is their modus operandi.

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But for a six-month-old cub,
a stone curlew is more his size.

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The bird's distraction display
is a tactic to lure the leopard
away from its nest.

234
00:37:07,840 --> 00:37:12,160
Today, the cub only manages
to ruffle a few feathers.

235
00:37:12,160 --> 00:37:16,160
It will be at least a year
before he becomes a serious threat.

236
00:37:32,200 --> 00:37:35,480
It's June, and midsummer madness

237
00:37:35,480 --> 00:37:37,720
seems to have gone
to the bulls' heads.

238
00:37:40,880 --> 00:37:45,840
This tree-rubbing
is a way to vent their aggression.

239
00:37:45,840 --> 00:37:50,400
The thrashing of young saplings
by a quarter of a million bulls

240
00:37:50,400 --> 00:37:52,520
helps stop the spread
of the woodlands.

241
00:37:52,520 --> 00:37:56,800
The destruction inadvertently
preserves their precious grasslands.

242
00:38:01,000 --> 00:38:08,240
As well as needing good pasture,
the wildebeest must make
a daily trip to water.

243
00:38:08,240 --> 00:38:11,760
Simply waiting for a meal to arrive

244
00:38:11,760 --> 00:38:14,760
is the lazy lion's approach
to hunting.

245
00:38:19,060 --> 00:38:23,720
It's just a matter of remembering
to wake up on time.

246
00:38:26,840 --> 00:38:33,360
The calf has every reason
to be wary, for this
is when most ambushes occur.

247
00:38:43,840 --> 00:38:47,960
The need for daily water
helps drive the great trek.

248
00:38:51,040 --> 00:38:58,200
The entire population drinks three
Olympic-sized swimming pools of it
each day.

249
00:39:11,760 --> 00:39:14,840
No longer dependent
solely on mother's milk,

250
00:39:14,840 --> 00:39:16,560
the calf guzzles his fair share.

251
00:39:17,560 --> 00:39:21,680
Head down,
he is at his most vulnerable.

252
00:39:27,200 --> 00:39:31,240
They sense danger.
The lioness must make her move.

253
00:39:32,880 --> 00:39:36,520
She isolates the calf,
but he's more sure-footed now...

254
00:39:41,440 --> 00:39:45,400
..and dust creates
the perfect smokescreen.

255
00:39:53,160 --> 00:39:57,040
Only one in five hunts
are ever successful.

256
00:40:18,800 --> 00:40:22,640
The trek moves on northwards
through the woodlands.

257
00:40:28,320 --> 00:40:32,560
The herd will soon arrive
at one of the most dangerous spots

258
00:40:32,560 --> 00:40:35,440
in the whole of Africa.

259
00:40:37,680 --> 00:40:42,480
The calm waters of the
Grumeti River are deceptive.

260
00:40:42,480 --> 00:40:44,680
To capture the upcoming drama,

261
00:40:44,680 --> 00:40:49,040
the river has been staked out
with a variety of spy-cams.

262
00:40:59,920 --> 00:41:03,240
A new camera makes an appearance.

263
00:41:05,600 --> 00:41:10,560
Hippo-cam is designed to blend in
with the local residents.

264
00:41:27,880 --> 00:41:33,120
Hippos can be aggressive,
but something far more
sinister lurks here.

265
00:41:36,760 --> 00:41:40,560
These are the biggest
crocodiles in Africa.

266
00:41:48,760 --> 00:41:53,080
Even Africa's biggest mammal
gives them a wide berth.

267
00:42:01,480 --> 00:42:06,120
Some are over 20 feet long
and weigh more than a tonne.

268
00:42:08,880 --> 00:42:12,520
They may not have eaten
for a whole year.

269
00:42:12,520 --> 00:42:15,720
But food is about to arrive.

270
00:42:21,040 --> 00:42:23,680
It's rush hour, and for a baboon,

271
00:42:23,680 --> 00:42:26,560
the traffic to the river
can become quite a hazard.

272
00:42:35,640 --> 00:42:38,040
It's best to look both ways!

273
00:42:42,800 --> 00:42:47,440
The crocodile's long hungry wait
is now over.

274
00:43:31,760 --> 00:43:37,040
Wildebeest are always nervous facing
new situations and in this case,

275
00:43:37,040 --> 00:43:39,720
who can blame them?

276
00:43:39,720 --> 00:43:44,200
For the calf,
it's a totally new experience,

277
00:43:44,200 --> 00:43:47,880
but the confidence of others
boosts his own confidence.

278
00:43:53,480 --> 00:43:59,120
If undisturbed, wildebeest can drink
eight litres in a single session.

279
00:44:15,640 --> 00:44:21,600
As his confidence builds,
he is oblivious to what lurks
beneath the surface.

280
00:44:33,880 --> 00:44:38,920
The herd is bewildered. Some have
never seen a crocodile before.

281
00:44:46,760 --> 00:44:49,560
Even as the full horror unfurls,

282
00:44:49,560 --> 00:44:53,400
there is great confusion
about just what is going on.

283
00:45:04,360 --> 00:45:07,640
And that was just the first attack.

284
00:45:14,720 --> 00:45:19,160
300 hungry crocodiles
live in the Grumeti River.

285
00:45:29,160 --> 00:45:33,440
Wildebeest react differently
to crocodiles than other predators.

286
00:45:33,440 --> 00:45:38,280
Even the adults seem unsure of
just how much danger they're in.

287
00:45:40,560 --> 00:45:43,760
The calf's desire
to quench his thirst

288
00:45:43,760 --> 00:45:47,200
overcomes any fear he may have.

289
00:45:58,500 --> 00:46:02,340
The crocodiles manoeuvre
around them with surprising ease.

290
00:46:03,980 --> 00:46:06,060
They are intelligent hunters,

291
00:46:06,060 --> 00:46:08,260
plotting their attack
with precision.

292
00:46:20,460 --> 00:46:23,060
A strike can happen at any time.

293
00:46:43,860 --> 00:46:46,900
Despite the carnage,
the mother and calf survive.

294
00:46:46,900 --> 00:46:50,100
They stampede back onto the plains.

295
00:46:59,700 --> 00:47:04,340
For the baboons,
it's more like a spectator sport.

296
00:47:04,340 --> 00:47:08,180
They might as well settle down,
a single croc

297
00:47:08,180 --> 00:47:11,820
can take some time
to overpower its victim.

298
00:47:21,060 --> 00:47:25,140
But crocodiles are co-operative
feeders, they work together.

299
00:47:31,140 --> 00:47:36,220
The death roll breaks the prey
into bite-sized chunks,

300
00:47:36,220 --> 00:47:38,940
but aggression can spill over.

301
00:47:52,180 --> 00:47:56,220
The calf has survived
his first day at the Grumeti,

302
00:47:56,220 --> 00:47:59,780
but as the river is
the only water for 30 miles,

303
00:47:59,780 --> 00:48:02,700
tomorrow,
he must run the gauntlet again.

304
00:48:13,220 --> 00:48:17,820
Meanwhile, our tortoise-cam
has found a friend.

305
00:48:56,660 --> 00:49:00,220
For tortoise-cam,
it's soon back to business.

306
00:49:06,220 --> 00:49:10,460
And these bulls
are not to be messed with.

307
00:49:10,460 --> 00:49:12,500
It's the rutting season.

308
00:49:12,500 --> 00:49:17,780
Three weeks of mayhem in which
the males fight over the females.

309
00:49:17,780 --> 00:49:21,780
Not the time to be stuck
in the danger zone.

310
00:49:37,900 --> 00:49:42,740
It's a test of
real strength and stamina.

311
00:49:44,820 --> 00:49:49,020
The winner returns to the females.

312
00:49:49,020 --> 00:49:54,340
At this time, a collective madness
appears to infect the males.

313
00:49:54,340 --> 00:49:56,380
The clashes can be quite violent.

314
00:50:05,780 --> 00:50:10,500
Each bull tries to round up
as many cows as possible.

315
00:50:13,060 --> 00:50:15,860
The calf gets caught up
in the confusion,

316
00:50:15,860 --> 00:50:18,300
as his mother
is corralled by the bull.

317
00:50:25,060 --> 00:50:29,020
It's a chaotic and confusing time
for the calf.

318
00:50:38,860 --> 00:50:42,340
During the rut,
bulls barely eat or sleep,

319
00:50:42,340 --> 00:50:44,780
they're so charged up
with testosterone.

320
00:50:46,460 --> 00:50:50,620
They have to stay on guard
for cattle rustlers.

321
00:50:52,420 --> 00:50:56,220
It's total pandemonium
as these rival males

322
00:50:56,220 --> 00:50:59,940
try to steal the females.

323
00:51:04,500 --> 00:51:07,260
They run through other males'
territories

324
00:51:07,260 --> 00:51:12,140
scattering the herd
in an attempt to abduct their cows.

325
00:51:17,420 --> 00:51:21,700
Troublemakers
are challenged to a duel.

326
00:51:27,780 --> 00:51:33,060
For the calf, it must be a relief
when things finally calm down.

327
00:51:44,660 --> 00:51:49,380
But for a male guarding females,
there's no respite.

328
00:51:49,380 --> 00:51:52,140
Challengers are always on the prowl.

329
00:51:57,460 --> 00:52:01,220
The calf can only
snatch a moment's rest.

330
00:52:01,220 --> 00:52:04,180
He soon becomes caught up
in more cattle-rustling.

331
00:52:08,180 --> 00:52:10,180
The bull springs into action.

332
00:52:18,660 --> 00:52:21,780
He sees off his rival
and claims his prize.

333
00:52:23,380 --> 00:52:27,700
Matings are more successful in
this species than any other mammal.

334
00:52:27,700 --> 00:52:29,260
95% succeed.

335
00:52:35,620 --> 00:52:39,660
After all that activity,
the herds head back to the river.

336
00:52:42,660 --> 00:52:46,940
But dragonfly-cam is experiencing
technical difficulties.

337
00:52:48,820 --> 00:52:52,420
Its transmitter
has mysteriously lost contact.

338
00:53:00,380 --> 00:53:03,940
Dragonfly-cam refuses to die.

339
00:53:03,940 --> 00:53:06,100
It gamely tries to continue
its mission.

340
00:53:16,260 --> 00:53:20,140
Even grounded, it keeps on filming.

341
00:53:22,220 --> 00:53:24,980
The rut has proved thirsty work.

342
00:53:31,020 --> 00:53:34,940
This time,
the herds are more cautious.

343
00:53:37,300 --> 00:53:41,740
Sensing danger, the calf holds back.

344
00:53:41,740 --> 00:53:47,020
But crocodiles still seem
more of a curiosity than a danger,

345
00:53:47,020 --> 00:53:50,180
and other animals
don't seem too concerned.

346
00:53:52,620 --> 00:53:58,100
Guinea fowl seem remarkably happy
to tempt fate.

347
00:54:11,700 --> 00:54:15,540
A yellow-billed stork
plays a game of dare.

348
00:54:19,620 --> 00:54:22,260
All the signals are reassuring.

349
00:54:22,260 --> 00:54:24,540
A baboon with young appears relaxed,

350
00:54:24,540 --> 00:54:28,300
even with a crocodile
just a stone's throw away.

351
00:54:37,580 --> 00:54:41,540
Wildebeest are highly tuned to the
signals given off by other animals.

352
00:54:41,540 --> 00:54:44,580
Apparently,
there's nothing to worry about.

353
00:55:05,980 --> 00:55:09,780
But a glossy starling
still gives them the jitters.

354
00:55:20,340 --> 00:55:23,740
The calf takes his cue
from the confidence of others.

355
00:55:32,140 --> 00:55:36,820
He can still stare death in the face
and not even know it.

356
00:55:40,860 --> 00:55:46,660
A crocodile's low profile
is its secret weapon.

357
00:55:46,660 --> 00:55:50,340
It isn't seen as a threat.

358
00:56:13,860 --> 00:56:15,460
Nose to nose,

359
00:56:15,460 --> 00:56:19,060
but the calf is still oblivious
to the clear and present danger.

360
00:56:46,060 --> 00:56:48,700
The teeth miss by inches.

361
00:56:54,820 --> 00:56:58,020
He may have escaped
the jaws of death,

362
00:56:58,420 --> 00:57:01,660
but his mother is not so lucky.

363
00:57:07,780 --> 00:57:10,860
Without her, the calf is doomed.

364
00:57:15,380 --> 00:57:18,140
But the croc can't keep his grip.

365
00:57:27,540 --> 00:57:34,260
The bond between mother and calf has
carried them through the first leg
of their epic journey,

366
00:57:34,260 --> 00:57:38,660
but will it be enough to overcome
the ordeals that lie ahead of them?

367
00:57:38,660 --> 00:57:42,860
In the next programme, the calf
reaches Kenya's Masai Mara,

368
00:57:42,860 --> 00:57:48,100
where he faces the greatest
challenges of his epic trek.

369
00:57:54,540 --> 00:57:58,780
Subtitles by Red Bee Media Ltd - 2007

370
00:57:58,780 --> 00:58:01,820
E-mail subtitling@bbc.co.uk