All language subtitles for BBC.Secrets.of.our.Living.Planet.2of4.The.Secret.of.the.Savannah.XviD.AC3.MVGroup.org.eng

Ten million species live on planet Earth-

Each one is remarkable-

But none can survive on its own-

All life depends upon connections...

...unexpected, invariably complex,

beautiful relationships between
millions of plants and animals.

This time, in our grasslands,

1 want to show you
why these antelope need these rhino---

---why this lone wolf---

needs an ant---

(SNARLS)

---and the incredible secret
that lies buried beneath them all-

Connections like these create
the planet's great ecosystems-

They're vital for all life-

I want to show you our world
as you've never seen it before.

Central Kenya---

---and this is whistling acacia grassland-

The whistling actually
comes from the breeze

blowing across the holes
in these hollow galls---

---and they're home to one of
the grasslands'most intriguing creatures-

This lizard is
the aptly named dwarf gecko,

and this one has laid a couple of eggs
down here in this gall on the tree.

The perfect place for a nest,
you might think.

But this tiny lizard
can only safely lay its eggs here

thanks to one of Africa's largest,
most iconic and bizarre animals,

the giraffe.

The story of why the gecko
needs the giraffe is wonderful,

and it will take us on a journey
across the world,

to some of our most
breathtaking grasslands-

They are habitats which occupy a quarter
of the land surface of our planet-

They support some
of our most spectacular wildlife---

---and yet grasslands lack
one of the basic ingredients for life---

---a truly precious element-

1t's this---

---nitrogen,

a colourless, tasteless gas-

It's only when we chill it
down to 1 96 degrees below zero...

- (CLINK)
- ...that we can actually see it.

I can tell you

that almost everything that happens
out here in this grassland ecosystem

is governed by a craving
for this rare resource.

In fact, I'd go so far as to say
that grasslands can only function

because they can cope so ingeniously
with so little of it.

So, for once, perhaps this will make
the ecologist's job a little easier,

because to understand
how grasslands work,

all we need to do is
follow the nitrogen.

Australia-

The grasslands here have some of the
lowest levels of nitrogen on the planet,

which makes the local wildlife perfect
for demonstrating why it's so important-

Nitrogen is the magic ingredient.

When you add it to carbohydrate,
you get protein.

And protein is what you need
to make living tissue.

Protein is the building block for life,
all life.

A baby eastern grey kangaroo-

When he was born, he weighed
less than a one-pence piece-

His dad, on the other hand, is one
of the heaviest marsupials in the world---

---which means that joey
has a lot of growing up to do-

1n fact, from birth to adulthood,

he'll increase his body size
by 1 OO,OOO times---

---and all of that
will be built with protein---

---and you can't make protein
without nitrogen-

Right now, he gets most
of his protein from his mother,

and she gets all of her protein
from a diet of grass-

At the moment,
these kangaroos are just hanging out,

and they look like
a typical population of kangaroos,

but I can assure you they're not.

Because this is not
your typical Australian grassland-

1t's Anglesea Golf Club near Melbourne-

Kangaroos were here when
the golf course was built 6O years ago,

but since then,
their population has boomed-

At a recent count, there were 359 of them-

That's nearly 2O for each hole-

And the secret of their success
is down to these immaculate fairways-

This grass is so green and so lush
because it's had something added to it.

This.

Nitrogen fertilizer.

And I know it's a product
of the industrial revolution

that's therefore led
to all of this lushness,

but it certainly proves a point -
the power of nitrogen in a grassland.

1t's added once a month-

1t seeps into the soil,
is quickly taken up by the roots

and then converted into proteins
for stronger, healthier grass---

---great for golf
but perfect for the joey-

The extra protein means
that he can grow faster,

become healthier and live longer---

---and that's the power of nitrogen-

On the plains of East Africa,
there's an animal

that you might think
is the least likely to be affected

by nitrogen levels in the grassland-

(SNARLING)

Nitrogen, or indeed the lack of it,

plays a decisive role
in any grassland ecosystem.

It's even intrinsically entwined
with the ecology of large predators

like these lions.

(GR0WLING)

This close, and 1'm in no doubt

that these animals are
at the very top of their food chain-

But to find out
how nitrogen affects predators,

1 need to start at the bottom
of the food chain---

---and it all begins
with a very special plant---

---one of the great unsung heroes
of our planet,

grass-

The really great thing about grass
is that it's simple.

Compared to other flowering plants,
shrubs and trees,

it requires minimal protein to build.

So it can take all of the nitrogen
from its roots

and put it not into bulky structures
but organise it efficiently, yet simply,

to maximise photosynthesis
to produce its food.

So grass leaves have protein
at much lower concentrations-

But this gives grazing animals
a real problem-

1mpala are one of Africa's commonest
antelope, a favourite prey of big cats-

But their biggest challenge
is a much more basic one---

---how to survive
on nothing more than grass-

The key is being very fussy
about the sort of grass you eat,

because some grass is richer
in nitrogen than other grass-

This impala

is actually cherry-picking the leaves with
the highest concentration of nitrogen-

Even so, she'll have to work hard
to extract it-

Just watch her neck closely-

Any moment now,
she's going to regurgitate

a ball of partially digested grass---

---and she'll process it all over again-

1t's called chewing the cud-

By digesting grass not once---

---but twice,

these animals can extract
as much of the nitrogen as possible,

but it still only works
on the very best grass-

Antelope, like these impala,

can only survive on a diet of grass
which is relatively high in nitrogen -

grass like this. We call it sweet grass.

This long grass, on the other hand,
is known as sour grass,

because the nitrogen in its leaves
occurs at even lower concentrations-

Antelope can't live here-

They simply can't get enough nitrogen
out of sour grass to survive-

But there is an animal here
that can change that---

---a very rare one-

This is what I've been looking for.

The animal that has deposited this dung

processes grass through its gut
in a very different way than antelope,

and I'm sure I can demonstrate that.

Here is some antelope poo,

and if I take just one of these
and break it open here,

you can see that what remains
is pretty much nothing more than dust...

...whereas this, on the other hand,
is very different.

If I break this one in half...

...the grass is still very visible.

(RHIN0 SN0RTS)

The white rhino.

What an animal!

Their sheer scale...

I mean, they're the closest thing
perhaps that we have on the planet

to mammalian dinosaurs.

And of course, they have a reputation
for being pretty feisty,

so I'm being very careful and not moving
too quickly and keeping my voice down.

In fact, this one's getting
a little bit close,

so I'm going to stop moving
and talk...talking altogether.

Their eyesight is poor,
so if 1'm still, they may not notice me-

But they do have a great sense of smell-

1f the wind changes, they could charge-

Absolutely fabulous things.

Now, one of these animals
has got no horns.

It hasn't lost them in a scrap.

They've been deliberately removed
by the park rangers here,

as these horns can have
a tremendous value.

Rhinos with horns
are prized by poachers-

The month before 1 arrived,
they killed one in this very park-

Cutting off her horn could save her life,

and it's hoped that this practice
will save the entire species-

Losing a species like this

would have a drastic impact
on the entire grassland ecosystem-

Her huge size allows her to live on grass
where antelope just can't-

Her body houses a massive gut,
a fermentation chamber,

so she can make up
for the low quality of sour grass

by digesting vast quantities of it-

All of which means
she produces a lot of dung---

---which she drops
in a very specific place -

a midden-

For rhinos, this is important-
1t's how they communicate-

Rhinos come here from far and wide-

By smelling the pile,
they can tell who's around,

how they're doing
and who is ready to mate-

1t's a sort of faecal Facebook
but with added value-

1t brings nitrogen-rich manure
from all over the grassland to one place-

So the grass growing here
becomes increasingly sweeter

until, as if by magic, rhinos have created
a grazing lawn of sweet grass,

perfect for fussy eaters like impala-

Rhinos are ecosystem engineers
upon which many other animals depend-

That, surely, is their true value-

That's why they're worth
much more alive than dead-

Right across the world,

it's sweet grass that is crucial
for most grassland grazers---

---and it's this quest for sweet grass

that drives one of the largest movements
of animals on our planet-

Every year, one and a half million
wildebeest migrate 3,OOO kilometres,

all because of nitrogen-

And this is when its impact
reaches the top of the food chain-

(INSECTS BUZZING)

(B0NES CRUNCHING)

So, what has a lion kill
got to do with nitrogen?

Well, basically two things.

You see, the lions here have identified

the richest source of nitrogen
available out here in the grassland -

large herbivores.

You see, their bodies
are made up of principally proteins,

and that protein is where the nitrogen is.

Then it's the sweet grass
which dictates where lions like to hunt-

(PURRS)

King of beasts they may be,
but their lives are ruled by nitrogen-

But how would a grassland predator
survive

if there were no sweet grass to hunt in?

Depending on where you are in the world,
the grassland always has a special name.

In Africa, the savannah.

In the US, it's the prairies.

Here in South America, it's the cerrado.

There's one animal that lives here
that I'd love to show you.

It's...it's really special.

I've never seen one in the wild,

but it's a truly fantastic animal
by anyone's standards.

This is Emas National Park-

The name comes from the Brazilian
for this bird---

---the rhea-

(BIRDS0NG)

But it's not a rhea that 1'm after-

What 1'm after is a wolf-

Maned wolves are one of the largest
predators in South America,

but their home ranges,
their territories, are huge,

so they're not easy to find or see.

This wolf has a problem on her paws-

You see, these grasslands
are so low in nitrogen

that they can't support
herds of grazing animals,

like impala or wildebeest-

1n fact, the wolfs survival here

is all thanks to a relationship with one
of the cerrado's smallest inhabitants-

It's this, an ant.

And the story of why the wolf
needs the ant is an amazing one,

and it's all down to the way

that grassland ecosystems
survive against the odds.

Other species of canids -
dogs, wolves - hunt in packs,

but her life is a lonely one-

There's just not enough nitrogen here
for even two maned wolves,

so one of them has to go-

Hunting on her own means
that even the odd deer is off the menu-

1nstead, she has to catch
more modest prey-

She may have walked miles
just for that mouse---

---and such meagre pickings
won't sustain a wolf-

So she has put herself
on a bizarre dietary supplement-

This is a lobeira fruit, from
the word ''lobo'', which means wolf,

and wolves love these things.

They make the perfect midnight snack-

Lobeira fruit make up
about half of her diet-

True, they don't have much nitrogen,

but they are packed with vitamins
and carbohydrates-

So eating fruit means
she needs to catch fewer mice-

(SNIFFING)

And that actually means
that she can survive

in this nitrogen-starved grassland-

But it gets even better-

The maned wolf is also helping the fruit-

Wolves like to mark their territory,
and maned wolves are no exception,

and they like to choose
high spots to do so.

But, of course, here on the flat cerrado,
such places are in short supply.

So, the one they turn to is this,

and this mound of soil here
is the nest of leaf-cutter ants.

When the wolf poos on the mound,
it has an immediate effect-

Soon most of the colony are out in force-

The ants will salvage anything-

They'll even try what's left of a mouse-

But one of them
has just found the real prize---

---a seed from the lobeira fruit-

The nutrient-rich coating from these seeds
will be fed to the ant larvae-

And, buried in the safety of the nest,
those seeds will germinate-

They've even got added fertilizer-

So what we have here is an interaction
between three totally disparate species -

the ant, the fruit and the wolf.

Now, the ants, they get food
delivered straight to their door.

The fruit has found something
to disperse its seeds

and something else to ensure
that they germinate perfectly.

And the wolves? Well, they're
effectively farming their own food.

What a story. What a story!

It's stories like that

that mean that you can always entertain
a lifelong fascination with nature.

And, you know, every single leaf-cutter
ant nest out here on the cerrado

has a lobeira fruit tree
growing next to it.

It works.

And, you know,
the most exciting thing for me

is that none of the players in this
system, the ant, the fruit or the wolf,

has any knowledge or regard
for what it's doing,

and yet it works perfectly.

Fantastic.

These connections are not just important
for the creatures concerned-

Because of the way they move
precious nitrogen around,

they are crucial
for the entire grassland ecosystem-

Relationships between species
evolve over millennia,

but they can be destroyed
in just a matter of years-

And it's happened a lot
in Australia's grasslands-

This is Mount Rothwell
Research Centre in Victoria-

1t's 4OO hectares
of high-security grassland-

Scientists here are trying
to restore animal relationships

and thus mend a broken ecosystem-

1t's surrounded
by 1 1 kilometres of fencing-

7,5OO volts protect the perimeter---

---and it's patrolled every day-

I'm feeling a little imprisoned.

But then, this fence
is not designed to keep things in.

It's actually designed to keep things out.

You see, in here

is the largest piece of native Australian
grassland left in this region,

and this fence is helping keep out

a whole load of animals
that they don't want in here.

(CAT MIA0WS)

This moggy is, or was, someone's pet,

but she's also an alien predator
that didn't evolve in this ecosystem-

(CAT MIA0WS)

You see, Australia
has no native cats of any kind-

Down under, she's an unstoppable killer
along with feral dogs and foxes-

These carnivores would do anything to get
theirjaws and claws on what's in here-

This is a brush-tailed rock wallaby-

And because of
these introduced predators,

he is now one of the rarest mammals
in the world,

and the extinction
ofjust a few key creatures like him

has had a catastrophic impact-

Crucial ecological relationships
are in tatters here,

and as a result, this native grassland

is now far more endangered
than any tropical rainforest-

The question is, if you remove
all of the alien animals

and reintroduce the key native ones,

could Australia's grasslands
be brought back to life?

0n the inside of this fence,

a relatively small community
of animals and plants has been saved,

and I've got to say,
some of them really are pretty odd,

and to stand any chance of seeing them,

I'm going to have to wait
until after dark.

(INSECTS DR0NE)

Welcome to the weird world
of the native Aussie night-

This is a southern brown bandicoot...

...and I'm getting a superb view of it.

I'm so close that I can actually see
the saliva glistening in its mouth

as it's chewing its food.

It's one of about 20
different species of bandicoot,

and they all come equipped with
this long, pointed and sensitive snout.

And they're principally insectivores,
meat eaters,

but they do play a very important role

when it comes to maintaining
the plant community in this ecosystem.

He spends all of his time
digging for food-

By the end of the night,
he'll have covered the grassland

with lots of snout-shaped conical pits-

Here's one of the pits, here.

And when the wind blows,
grass seeds are caught in here

along with a lot of other detritus,
all of which is rich in nitrogen.

So they become a perfect place
for germination.

This is a bettong,
otherwise known as a rat kangaroo.

They're herbivores.

At the moment, if you listen carefully,

you can hear it munching on some roots
or tubers that it's eating.

All of these animals are so tame

that's it's no wonder foreign cats
and foxes have almost wiped them out-

As it feeds, it effectively ploughs
this hard soil, allowing air and water in,

vital for the plants that live here-

But so that the herbivores
don't do too much damage,

this miniature Serengeti
also has its own mini lion-

(SNIFFING)

This is an eastern quoll...

...a pocket-sized marsupial predator.

Don't be fooled by his size-

He can take prey
much larger than himself-

What's important is that
unlike cats and foxes,

quolls have co-evolved with their prey

so they are a critical part
of this ecosystem-

The Rothwell experiment is working-

Rare species of plants, birds
and mammals, the entire grassland,

is making a comeback here-

The secret to healthy grasslands is having
the right species in the right place---

---and there's one animal that benefits
grasslands more than any other on Earth-

These monoliths dominate
the cerrado in South America-

There can be as many as 4O,OOO
in one square kilometre-

From the outside,
these things appear entirely lifeless.

In fact, you could sit down here alongside
one and see nothing move all day.

But living on the inside

is perhaps the most important animal
in this entire ecosystem.

They are grasslands'secret weapon
in the battle for nitrogen-

Termites, half-blind
distant cousins of cockroaches-

There are so many millions
living in this grassland

that their combined weight is far greater

than that of all of the mammals
living here put together-

And yet you would have no idea
they were even here

if they didn't build these huge mounds-

They build them as cooling towers,

to keep the temperature
of the colony on the inside

at an optimum 30 degrees centigrade,

and they are remarkably efficient,

normally accurate
plus or minus a single degree.

Not bad for a colony of primitive insects.

But then, building these mounds
all over the landscape

is the least of their accomplishments.

(CAWING)

Because, one way or another,

termites are fundamentally important
to almost all life here-

Especially the strangest of all,
the giant anteater-

These animals are related
to armadillos and sloths-

They're part of a group called edentates,
which basically means ''without teeth''-

But whilst armadillos and sloths
do have rudimentary teeth,

if you were to perform a dental
examination on one of these guys,

which would be difficult
because their mouth is so small,

you'd find no teeth at all.

But it's not teeth he needs
to unlock the termites'secret-

If you look at its front feet,

you can see it's got these two huge claws
on each one of them,

and they can break into
just about any substrate.

It also uses them for defence.

It's said that if it's attacked
by a larger predator,

it will stand back on its tail
and lash out with those claws.

He uses his tongue,
which is over 5Ocm long,

flicking it in and out
at around 1 5O times a minute-

Giant anteaters
eat 35,000 termites a day.

Nevertheless,
you could be forgiven for thinking

that no matter how many
they hoover up, or how quickly,

they could never sustain
an animal this size.

But they do.

By weight, termites are the most
protein-rich food that you can find.

There's more protein
in these little insects

than there is in beans, nuts,
cheese, chicken, even roast beef.

And what's interesting is that termites
occur in ecosystems all over the world,

and wherever they do,
there are creatures like this

that have evolved to feed
exclusively on termites.

The reason
termites are so rich in protein

is all down to some
very intimate relationships-

The first is with a fungus-

Deep within the mound,

the fungus breaks down dead grass
so the termites can digest it-

Not much else could eke
a living out of this stuff-

The second is more remarkable still-

You see, termites can obtain nitrogen

directly from the air-

And they achieve this through
another symbiotic relationship,

an even more intimate one.

Because living inside
their digestive systems

are amazing nitrogen-trapping bacteria,

and it's this that gives termites
their special powers-

So using the nitrogen
they get from that bacteria,

the nutrients they get from the fungus,

they're able to turn...

...this dead, woody material
into a productive food source.

This stuff, which is so low in nitrogen,
so low in protein,

they can turn into edible protein,

and that's how they can form
these vast colonies.

The termite mound
becomes a nitrogen hot spot-

That's good for anteaters

but also for all the surrounding plants
and for all the other animals living here-

The incredible actions of termites
nurture grasslands all over the world---

---including Kenya's
whistling acacia savannah-

Here, the impact of termites
goes right to the top---

---all the way
to the world's tallest land animal-

When 1 was a child, we thought
there was just one type of giraffe,

but now we know
there are six different species-

This one's a reticulated giraffe-

He can reach anything,

but of all the plants here, he's chosen
to eat the whistling acacia tree-

But just look at it-

1t's one of the best-defended plants
in the whole of Africa-

But why are these trees so well armed

against browsing animals
like these giraffes?

Well, the answer, you won't be surprised,
comes down to nitrogen.

You see, these trees' leaves
are absolutely packed with nitrogen.

That's why they are
the botanical equivalent of Fort Knox.

At the base of many of these acacias
are colonies of African termites-

The acacias'roots
are boring under the mounds,

tapping into a rich well of nitrogen-

As a result, these acacias become
an oasis in a nitrogen desert-

So it's really no wonder

that the thorns alone
don't deter giraffes from tucking in-

So, not to be beaten, the tree
employs another line of defence,

its own private army.

Now, just watch this.

I'm going to pretend to be a giraffe
browsing on this branch here.

So I'm going to pull at the leaves,
shake it about a bit,

try and not get jabbed by the thorns here.

But just look at this.

Very quickly,

a whole mass of these Crematogaster ants
swarms out and covers my hand.

And I can tell you that,
if you were a giraffe browsing on this,

you wouldn't want these things
all over your tongue.

Each ant is armed
with a chemical weapon-

1t's capable of squirting venom-

Each gall houses
a separate colony of ants,

and each branch might have
a dozen or more of these galls-

So the only way a giraffe
can get an ant-free meal

is to grab a quick snack and then move on-

The tree has evolved
to produce these hollow thorns,

and they are the perfect structures for
the ants to make their colonies inside.

And in return for the plant's investment,

it gets these insects
as vigorous defenders.

But this is just the beginning
of a truly amazing web of relationships-

These are patas monkeys-

As grassland specialists, they're
the fastest-running primates in the world-

1n the 1 OO-metre sprint, they'd beat
any Olympian by three seconds-

To fuel their energetic lifestyles,

their favourite food
is Crematogaster ants and their larvae-

The trick is finding them
in just the right position-

He could easily have his eye out
on those thorns-

Once ripped open,
the ants abandon the gall,

but this act of primate vandalism
only serves to enrich this mini ecosystem-

You see, a short while later,
a new occupant has moved in-

Here, protected from predators
and the harsh sun,

a dwarf gecko has laid two eggs-

Because she isn't a threat to either them
or the acacia, the ants mostly ignore her-

After four months,
a perfect miniature gecko hatches out-

1t's completely defenceless,

but luckily, it's found itself
in the perfect nest-

1t couldn't possibly appreciate
all of the creatures here on the grassland

that have come together
to put a safe roof over its head-

The giraffe eats the acacia tree,

so it continually produces those galls
which form the geckos' home.

The acacia tree needs the ants
to protect its leaves and keep it healthy,

and in turn, the patas monkey
needs those ants and their larvae as food.

And all of this can only happen

because the tree
has managed to accumulate nitrogen

from a grassland that's evolved to prosper

despite the fact that this element
is always in short supply.

1t's often said that you can only tell who
your real friends are in times of need-

This is also true in nature-

You might ask if it really matters
if an animal becomes extinct-

Well, so intricate are the connections
in the natural world

that there's no way to predict the impact
of adding or removing species

until it's too late-

Who would have thought
that a bettong would need a bandicoot,

that a leaf-cutter ant
would need a maned wolf,

or, indeed, that a gecko
would need a giraffe?

Now, the complex web
of relationships that we've seen

have evolved over millions of years,

but we've only scratched the surface
of a myriad of stories

that, when they come together, make
these grasslands functional ecosystems,

and it's here that I've learned
to see the real beauty in nature.

You see, for me,
it's not in the minute detail.

It's in the bigger picture.

Because this works perfectly,
and that is beautiful.

If you'd like to know more about the
fascinating web of links between species,

the 0pen University has produced some
material both to inform and inspire you.

For your free copy,

or to find out more about
0pen University programmes, ring...

0r go to the website...

And then follow the links
to 0pen University.

And join me next time,

when 1'll be travelling
to the world's greatest seasonal forest-