All language subtitles for BBC.Natural.World.2019.Hippos.Africas.River.Giants.1080p.HDTV.x265.AAC.MVGroup.org.eng

The hippopotamus is a paradox.

It's a vegetarian.

And it's also the most dangerous
animal in Africa.

It's an animal that cannot swim.

But one that is utterly
dependent on water.

In Botswana's Okavango Delta,

hippos face
an unparalleled challenge.

Here, deep water dries to dust
in a matter of months.

In one extraordinary season,
we will go beneath the surface...

..to see them
protect their families...

..face their enemies...

..and so reveal the true nature
of the hippo.

Courageous.

Sensitive.

And intelligent.

This is the life of the hippo

as never seen before.

The Okavango is one
of Southern Africa's great rivers.

It flows north to south
for almost 1,000 miles,

but never reaches the sea.

On its journey, it gathers
an abundance of life...

..and becomes laden with sand
and sediments

which drift in its current.

As it enters Botswana,

it confronts the dry sands
of the Kalahari Desert...

..and its main arteries
begin to slow.

Its rich sediments settle

and form the largest inland delta
in the world.

A multitude of species thrive here.

And all of these waterways rely
on one remarkable animal.

The hippopotamus.

Hippos cannot swim.

The dense structure of their bones

and the weight of their great bodies
makes them sink.

In the deep water,

they have to push themselves
off the bottom

in order to rise
and take a breath.

But then, they sink back down.

They then hold their breath,

and walk and run on the bottom.

As they move to the swamp
in search of fresh grazing,

they break pathways
through the weeds.

Where these pathways lead,
the clear water follows.

They link the big rivers
to the smaller pools...

..opening up channels as they go.

Soon, a complex web has been created
throughout the swamp...

..along which water flows
gently to nourish the land.

These animals are the architects
of the Okavango Delta.

Hippos are naturally sociable.

They bunch together, where they can
stand and form groups known as pods.

Each pod is defended
by a dominant bull.

But today, this one has other
matters on his mind.

A female hippo

is giving him the eye.

Courtship takes place in the water,

where such hefty bodies are better
supported than on land.

And now,
hippos reveal their sensitive side.

Nuzzling and touching seems
essential.

Much of this dance
happens under the surface.

Mating sometimes lasts
up to half an hour.

After eight months,

an expectant hippo really does
become heavily pregnant.

Experienced mothers
about to give birth

move away from the pod and find
a quiet and shallow pool.

The baby has to master life
in the water from its first breath.

This one, a male, seeks his mother's
nipple almost immediately.

And he has the ability
to suckle under water.

He instinctively folds back
his ears and closes his nostrils.

Weighing just 4% as much as an
adult,

a baby hippo is completely
dependent on its mother.

She keeps an ever-watchful
eye on him.

Isolation from the pod allows
the calf to imprint on his mother.

It's vital that they forge
a strong bond.

But her astute relatives
haven't missed a thing.

And curiosity draws them closer.

Her calf is still far too young
to meet the family.

She knows she will have to move
him away.

But this is a lot of effort
on his first day.

And he's tiring fast.

Now safe,
her baby begins to recover.

She creates a raft for him
to rest his weary head.

In only a few months' time,

the water here will cease to flow.

3,000 square miles of swamp
will dry and disappear.

And all the hippos of the Okavango
will face real hardship.

Water is the hippos' sanctuary.

It keeps them
cool in the baking heat

and provides the vegetation
on which they depend...

..and safety, away from predators.

But with all of this
slowly evaporating,

everyone will need to be prepared.

The calf is now several weeks
old and has built up his strength.

It's time for him to meet
the family.

Returning to the pod with a new baby
is inevitably risky.

A mother has to re-establish
that she's a member of the pod.

And, in the excitement,

a clumsy adult
could crush her calf.

The dominant bull is right
in her path.

If she stands her ground with him,

half her battle could be won.

But the real problem comes
from an unexpected place.

Her previous calf is showing
an unhealthy interest.

She's battle-scarred, and appears
to have a quarrelsome nature.

Whichever it is, it's dangerous.

Her calf is far too young
to be pushed around like this.

He's frightened,
and stays close to his mother.

This has turned into an attack,

and the mother
must put a stop to it.

The pair remain on the periphery
of the pod.

But the rest of the family
can still hear them.

Hippos are thought to be the closest
living relatives of whales.

And they, too, make most of their
vocalisations underwater.

Their head and jaw bones capture
vibrations

and transmit them directly into the
ear.

The vibrations become sound.

And in these quiet waters,

these can carry up to a mile.

Her calf emits a steady, pulsing
croak to stay in touch.

The others can hear it.

And this startles the pod.

Underwater, the pod move closer.

Mother and calf
are thoroughly inspected.

And, finally...

..they are accepted.

The calf is growing fast.

And life in the pod returns
to normal.

Eating over 30 kilos of grass a day
is what a hippo needs to do.

But the youngest
still need to learn how.

As the delta begins to dry,

all hippo pods will need
to follow the water.

And having joined
the rest of the family,

these two can now safely move on.

The season changes,

and many of the flood plains
have already disappeared.

The channels become more defined

as these fingers of water gradually
retract to the north.

With all the hippo pods on the move,

territories need to work
in a simple way.

When a group arrives at a new pool,

each family member is guarded
by their dominant bull.

And he must mark the new boundaries
of his transient territory.

He does this by splattering
his scent in spectacular fashion.

These signposts
of half-digested grass

proclaim that "this pool is mine."

A young male calf is intrigued.

One day, he may need to do
this for himself.

But owning a territory and a family

also means you need to defend it.

Dominant bulls are always vigilant.

As the land dries,
nomadic males are on the move,

seeking a new source of water.

An intruder tries to move
into the dominant bull's pool.

And the bull goes on the offensive.

He must hold his ground
and defend his pod.

A hippo's jaws have an enormous gape

which exposes
their formidable tusks.

And these are for fighting.

This is a full-on challenge.

The biggest gape wins.

He has protected his pod

and, very importantly,

his youngest calves.

New bulls kill the offspring
of their defeated rivals.

The loser escapes upriver.

Wounds like these can be fatal.

As winter hits,
the days become cooler.

The vegetation surrounding
the channels is drying out.

Over the next few months,

getting enough nutrients from the
grass will be a real challenge.

And it forces the hippos to leave
the edges of their channels

and venture into dry areas
in search of food.

Day and night,
they continue to graze.

But away from the water,
hippos are very vulnerable.

Dawn reveals a death.

Upriver, the intruder has
succumbed to his injuries.

And now,
his body is a feast for crocodiles.

The resident bull

clears the crocodiles away
from his fallen foe...

..and inspects the body.

Licking or mouthing may be a way
of collecting valuable nutrients.

Perhaps it's their intelligence
that drives this behaviour.

Maybe there is something here
to do with mourning.

Maybe it's a little
bit of all these things.

The stench of decay attracts lions.

The body of a hippo is a valuable
prize in this drying land

and everyone knows it.

Bull hippos are the only ones that
stand their ground against lions

and this bull wants them gone.

Two-tonne hippos are quite
capable of killing a lion.

He drives the predator
away from his old enemy.

In the darkness,
hyenas have pulled the body ashore.

And now, they're tucking in.
With teeth that can crack bones...

..nothing will be wasted.

CROCODILE ROARS

The crocodiles certainly
aren't giving up.

ROARS AGAIN

HYENAS SQUEAL

The fuss and the noise seems
to agitate the hippos.

HIPPOS GRUNT

It's time for a lesson
in defending your own.

And this youngster is learning fast.

ROARS

HYENAS WHIMPER

Out here, size does count.

Most of the water has now gone.

The channels carried little
more than trickles,

compared with what once flowed here.

Only the tracks of the departing
hippos remain.

Their paths, now dry,
still link the last remaining pools.

And the grasses they depend
on will soon wither and die.

Most hippos have headed north,
following their all-important water.

Some are still in search
of a refuge.

Only a few pools in the area

are still big enough to hold
a hippo pod.

And many pods are forced to share.

Large groups of up
to 200 hippos crowd

together in the last of the water.

The pressure is mounting.

And new arrivals just
stir things up.

The shrinking pools have
also trapped fish.

And they attract fishermen.

Pelicans arrive in their thousands.

This number of birds could clean out
a pool in just a few days.

So, the fish eagles need
to get in first.

The fish gather in shoals
around the hippos for safety.

But the fish eagles aren't
easily put off.

The hungry pelicans move in closer.

And a feeding frenzy begins.

The hippos are already stressed,

and this frenetic activity
is too much for some of them.

They become increasingly
territorial...

..and irritable.

One bull loses his temper
and overreacts.

The crocodiles make
a meal of the casualties.

Time is running out for the hippos.

Their dependence on water now
might be fatal.

This pool might disappear
before the annual flood returns.

And in the distance,
something worse is on its way.

When the Okavango is at its driest,
fires sweep across the land.

The flood plains are scoured
by flames,

destroying what
remains of the hippos' food.

Little water remains to stop it.

This is a disaster for the grazers.

In the smoky aftermath,
there's an ominous air.

Tensions rise.

The fire has consumed the little
food they had left.

Most of the grass on the land
surrounding them has vanished.

Only dust devils
swirl across their foraging paths.

The tough sedges surrounding
the remaining pools are fibrous

and inedible.

In these desperate times,

these hippos appear to do something
we've never seen before.

They seem to regurgitate grass from
their stomachs and chew it again.

Might this be
a way of extracting the last

particles of nourishment from the
grass that they've already eaten?

Could it be that when times
are tough, as they are now,

hippos develop the ability
to ruminate like cows?

The southern fingers of the delta
reach deep into the Kalahari Desert.

Thirsty animals trek across the dry,
dusty land...

..desperate for water.

With barely enough water
to cover them,

the hippos here are in real trouble.

The hide on a hippo's back
and rump is thick.

It helps to protect them
from the searing sun.

The skin on their underbelly,
however,

is thinner and must be kept moist.

But this water will not last.

More and more desperate
animals arrive.

Many hippos are expelled
from their pools.

Only bulls dare live in the farthest
reaches of this swamp.

Now they begin great overland
treks through the dry.

With no water to cool them down,

they rest in the shade
during the heat of the day,

confusing some of the residents.

This is not where a hippo
is meant to be.

The heat is overwhelming.

Hippos can't sweat, but they do
secrete a thick, oily reddish fluid.

This acts as a sunscreen and helps
protect against infection.

But he still needs to drink.

Water holes are dangerous
traps for thirsty animals.

This one is staked out by lions.

They're practised giant-killers.

Together, they can take
down an elephant.

He's dying of thirst.

But he stands firm.

A hippo could hold his ground,
if he needs to.

And he forces the lions
to allow him a share.

Finally, he gets his much-needed
drink.

Relief is on its way.

In the distance,
a flood is creeping slowly closer.

It travels along the hippos'
dry paths.

So, once again,

the hippos have determined the
course of the river's channels.

The face of the Okavango
changes once again.

And all that the hippos
had lost will soon return.

Their resilience, determination
and adaptability

have carried them
through the toughest of times.

Water once more flows along
the veins of the delta.

And life soon reappears.

As the land recovers and the flood
waters peak...

..the channels created by the hippos

carry the water
to its furthest limits.

It's they who perpetuate the watery
wonderland of the Okavango.

Everything and everyone
that lives here...

..owe their presence to the hippos.

Africa's river giants.

Hippos have a formidable reputation.

Across Africa,

they kill around 500 people
every year.

Few film-makers have attempted
to capture their lives in detail.

But director Brad Bestelink

was determined to take
up the challenge.

I was born to the delta,

brought into the swamp
when I was four days old.

I've always wanted to make a film
about hippos in Okavango,

simply because they are pivotal
to the way

the whole Okavango itself
functions.

With the best location for filming
identified from the air,

Brad and cameraman Mike Amos
head out in the boat.

It's very difficult.

You need to get really close
to animals on the water to be able

to get the footage and understand
what they're doing.

But you don't want to get
too close to them,

because they're that dangerous.

Brad has had personal experience
of this,

when he once accidentally
surprised a hippo.

He obviously got a hell
of a fright when he saw us.

He hit the side of the boat,
threw us off.

We caught him in the shallow.

He felt vulnerable, lashed out.

All the gear on the boat
just went to the bottom.

I've just spent the last hour
diving all the stuff out.

Quite a frightening experience.

To avoid a similar situation,

Brad hopes to plant a pole camera
directly in a hippo's path.

There's a hippo there. There's a
hippo there, coming this way.

OK, cool. It's coming that way.

Whoa, whoa, whoa, Mike!

Right here. What we're after.

Now, they need to set the camera
as quickly as possible.

Where is he?
There's another one here, somewhere.

As soon as this is in, we've got
to get on the other side of him. OK.

Let's go.

Camera in position,

it's a waiting game.

You'd be amazed at how subtle
a lot of the signs are of hippo.

I mean, it's such a big animal,
but it really just goes

really quietly and doesn't spend
too much time on the surface.

The hippos could be anywhere.

It's amazing that you can lose a
hippo.

Research suggests that hippos
can hold their breath for a maximum

of five minutes.

So, after ten minutes, Brad moves
in to collect the camera.

But the hippo is still there.

He's right here!

It seems that hippos can stay
under the water

much longer than anyone
thought possible.

Persisting with the pole-cam
pays off...

..getting them some beautiful shots
of the hippo

in their underwater world.

But Brad didn't want to stop there.

He wanted a deeper insight,
and that took a bit of creativity.

In our sort of pursuit
to film hippos,

we have had various iterations
of cameras.

We've had remote-controlled boats
that hippos have eaten.

We've got floating cameras which,
every time a hippo moves,

it tends to rock.

Even the underwater microphone
became a curiosity.

So, Brad had to come up
with something

that had never
been done before.

Basically, it's a underwater
remote-controlled car

and it's got to literally crawl its
way through the sand and vegetation.

Time for a test run.

Hey, look at that thing.

Look at that thing.

Go find them hippo!

With the test a success,

they now need to place the camera
near a hippo -

a somewhat bigger challenge.

Just going to have a look at this
pool

and see if it's got the right
entrance and the right current.

I think we could anchor
on it and send it down that channel.

Off he goes.

For days on end, they film
nothing but fish.

The pod is very aware of where
it is.

I can't tell you the amount of
hours I've spent

looking at this monitor, into murky
water and not seeing anything.

Looks like there's a couple
fairly close by.

Ooh, we've got a hippo.
Right on the nose.

He's coming in for a good look.

Straight looking into it.
"Oh, what is it?"

You see all the hairs, bristly hairs
off his nostrils with blood on.

Jeez, that's amazing.

BRAD GIGGLES

For Brad, it's the culmination
of a lot of hard work.

It's been, sort of, four years of
trial and error.

It's wonderful, really.

You actually feel like you're in the
water.

It's sort of nerve-racking,

having a hippo
walk up to this little camera.

Capturing such intimate footage

has given Brad a different
perspective

on these notorious animals.

It's a big, dangerous animal,

but they're also
very sensitive, very skittish.

I really think that an aggressive,
man-killing animal

is not an accurate
reflection of what they are.

I think that they're timid, sweet,
intelligent, very sensitive animals.

These unique images wouldn't
have been possible without Brad's

knowledge of the delta

and determination to tell
the hippo story.

To protect them,

you need to let people understand
it from nature.

They are, ultimately,
intrinsically important

to the functioning
of the entire swamp.