Food for Thought The Life of Mammals

You might think this orang-utan is washing socks as some circus trick

for which she's been specially trained - but not so.

She is doing this on her own initiative.

She's seen others doing it and she's copying.

That ability to imitate, as well as to use tools, started among monkeys,

but has been brought to a much greater level among the apes.

Those two talents

ultimately led to the transformation of the world.

Camp Leakey in Borneo is home to a special group of orangs,

rescued from captivity and returned to the wild.

Because they've lived partly in OUR world,

they can show what we have in common.

This old lady loves DIY.

So does her son, who was born in the wild.

Even her infant is interested.

It's very striking when you sit as close to an orang-utan as this

to see how similar they are to human beings.

We are both, of course, great apes.

But look how human her hand is,

the skill with which she picks things up,

the way that she can grasp a tool like that.

How she uses her brain to imitate what she's seen others do,

and oddly, the fact that she is clearly left-handed.

Great apes share with human beings

a predilection to use either the right or left hand,

and she's left-handed.

But the most important thing we share is our big brain.

THAT has produced so many of the talents and abilities

that we have in common.

All apes have a love of one kind of food - fruit.

But getting fruit in the South-East Asian forests has its problems.

GROWLS

There are powerful predators on the ground,

so orangs seldom come down from the trees.

They're the heaviest animal up in the branches,

but they've worked out an ingenious way of exploiting their weight.

They pole-vault.

But getting about is tiring, and as fruiting trees are widely scattered,

orangs need to take the most direct path between them.

But they seldom take wrong turns.

It seems that they have a map of the forest in their minds.

They must have mental calendars, for they miraculously appear in a tree

at exactly the time its fruit is ready for picking.

It requires a lot of skill to travel around in this way,

and youngsters take many years

to match their parents' expertise in route-finding and aerial gymnastics.

Mothers keep an eye on their young,

ready when needed to provide a helping hand...or an arm or a leg.

It takes up to 13 years

for a youngster to match its mother's knowledge of the forest.

This may be why young orangs spend longer with their mothers

than any other ape except humans.

But eventually, this close tie has to be broken.

Orang-utan, as adults, are famed as loners.

But this doesn't mean that they're necessarily anti-social.

Back at Camp Leakey, it's feeding time.

There's a lot of food, and here orang-utan assemble

and show that, at heart, they're really quite sociable animals.

Scenes like these suggest that it's only the scarcity of food

that compels them to live apart.

A group as big as this would starve

if they lived together in the wild.

But just occasionally, the forest creates its own food bonanza.

Every four or five years, many fruit trees ripen simultaneously,

producing a brief glut of food,

which attracts orangs from miles around.

They show how sociable they can be, 20 of them in just one tree.

The fruit will soon end, so friends make the most of their time together.

But some individuals do cause trouble.

The highly-sexed male clambering up the tree is not after fruit.

He drives off a female's chosen partner

and tries to force himself on her.

SQUEALS

SCREAMS

A bellowing call

announces the arrival of the most powerful orang in the whole forest.

He hasn't visited the area for years.

The others recognise him instantly.

The mere threat of his presence sends the smaller male into retreat.

BELLOWS

He takes up his dominant position in the group and the rest settle again.

In the same way that we can take up relationships...

sometimes after years of separation,

so orang-utans can slot back quickly into their own social circle.

That requires a brain that can keep track of different individuals

over long periods of time and distances.

There's one place where interactions happen between orang-utans

more frequently than anywhere else

that has produced extraordinary examples of intelligence.

The swamp forests of northern Sumatra.

This is a paradise for orang-utan.

It floods regularly, and the waters bring in a rich supply of nutrients,

so there's a great deal of food to be had.

Orangs can travel and feed together in groups throughout the year.

They eat insects as well as fruit.

Termites are a particular favourite.

Collecting them from a rotten trunk doesn't need much ingenuity.

Extracting from a hole in a LIVING tree is a different matter,

even for a powerful male like this one.

But the orangs here have solved such problems.

They make tools. First, they select a twig.

Next, they trim it to length.

Then they whittle it into shape...

and carefully insert it into the tree

to reach whatever they want from inside.

This ingenious male is probing into a bees' nest

with an instrument which lets him lick honey from one end

while collecting more with the other.

Younger members of the group watch and learn.

So a tradition grows that will be passed on to new generations.

BUZZING

If there's an abundance of food,

orang-utan can live in high densities and so form a community.

If one individual gets a bright idea,

others will copy it and so form a culture.

To see an even more complex ape culture,

we have to go to another continent.

This is Africa - a mangrove-covered island near the mouth of the Congo.

It's home to a remarkable and revealing community

of a different great ape - chimpanzees.

These chimps are orphans.

Their parents were killed for the bush-meat trade,

and many were pets kept in unsuitable conditions.

And now they are part of a unique experiment.

They're being taught the skills they'll need

to survive by themselves in the wild.

THEY CHATTER AND SQUEAL

Several of them, as youngsters,

acquired some skills by watching humans.

Some know how to crack nuts.

But it takes a chimp years to work out how to place the nut in a socket

and then how to wield a hammer.

This chimp, Balinga, is an expert.

His companion, Flo, watches attentively.

Puck is struggling. He started watching nutcracking when he was six,

two years too late for a chimp to learn new skills.

You really can't teach an old ape new tricks.

D'you want this? D'you want one of these?

Want one?

Mind your fingers!

Of course, there are many different ways of cracking a nut.

Come to that, there are many different kinds of nuts,

and so different groups of chimps

have developed different ways of dealing with the problem.

THAT is the beginning of a culture.

Of course, a culture has many things in it apart from cracking nuts.

These rainforests lie 1,000 miles away, east of the Congo, in Uganda.

The chimps here have a very different culture

and they have never been filmed before.

Their communities are the biggest known

and contain the most adult males.

As elsewhere, cultural traditions extend to social etiquette.

Here, they practise a style of grooming

known as the grooming hand clasp.

Most of the time, life is peaceful.

But the males, although they live alongside one another, are rivals.

Occasionally, tempers flare.

THEY SCREAM AND WHOOP

These displays are ways by which males establish their dominance

without physically wounding others

who would be needed as comrades, were the group to be attacked.

After a quarrel, they embrace to re-establish bonds of friendship.

But sometimes, rivalries become more serious.

Young male Grapelli is being ferociously beaten

by an unusually large gang of adult males.

THEY GRUNT AND SQUEAL

Battles between rival groups from neighbouring communities

have been seen elsewhere in Africa,

but attacks like this on a single male within the group are VERY rare.

This is the last that was seen of Grapelli.

He was very seriously wounded and it's almost certain that he died.

His body has not yet been found.

What is happening at Ngogo that causes these savage attacks?

One theory is that young males find it particularly hard

to establish a place within such a large group of powerful adult males,

whose lives are ruled by social bonds we have yet to understand.

Even these apparently simple acts of grooming

can have great social significance.

Grooming is important for health.

It's a service males perform for relatives,

as these two brothers are doing.

It's also a way of creating and maintaining good relationships

between allies and males in the same peer group.

This young male, Pork Pie,

seems to be more successful socially than Grapelli was.

But these males have other things than grooming on their mind.

Their attention has turned to the tree tops.

It's time to hunt.

A large group of like-minded males are assembling.

One of them drums.

It's a signal telling others nearby

that a hunt is about to start.

Chimps usually hunt when they see a good opportunity, but here in Ngogo,

hunts often start whether or not suitable prey has been spotted.

The males set off through the forest.

They travel for up to four hours at a time, searching for likely victims.

Pork Pie tags along. He's not yet an accepted member of the hunting group.

This is what they are looking for - a troop of red colobus monkeys.

The hunters take up their positions in the surrounding trees,

ready to pounce on any monkeys that try to escape.

They are closing in on the most vulnerable target -

a female with her young.

The colobus males do their best to fight back,

but the chimps are much bigger and stronger.

Some of the infants have been separated from their mothers.

They're now easy prey.

SCREAMING

It's not over yet. The male colobus fight to defend their families...

SCREAMS

..but they couldn't save this infant.

The hunters crowd round the kill.

The rest of the group join them.

The males are the first to eat.

They supplement the flesh with a few leaves,

just as humans take vegetables with their meat.

But some of the male hunters now share their kill

with other group members, including the females.

Do they get anything in exchange? Sex?

This male is certainly mating with one of the females.

But he then allows a different female to take some of his meat.

Perhaps the meat is given to those who beg the hardest.

Pork Pie is certainly trying his luck with one hunter after another.

Time after time, he is spurned...

..but eventually, his persistence pays off.

But the Ngogo chimps have another possible motive for meat-sharing.

Males give more meat to their allies than to others.

It seems that they are using meat as a way of strengthening such bonds.

The hope of collecting some meat may be why others join in the hunt.

Chimpanzees have much in common with humans.

They are, after all, thought to be our closest living relatives.

They're clever, social, political creatures...

..and apparently, they even dream.

But in prehistory, the dreams and ambitions of the ape

whose descendants took over the planet

must have taken a very different direction.

More discoveries about that creature

have been made here at Olduvai Gorge in Tanzania than anywhere else.

Perhaps here we can find clues

as to why our ancestors took such a different path.

3.5 million years ago,

the volcano behind me was belching out ash,

which covered the entire landscape,

and it was in that ash that the most evocative discovery of all was made.

These are the fossilised tracks

of ancient rhino and antelope,

here at Laetoli in Tanzania,

and among them are the footprints of an ape -

a very remarkable ape.

Scientists say they can deduce from the shape of bones

the posture of the animal, but there will always be arguments.

Here, however, is proof positive that 3.5 million years ago,

mankind's ancestors were walking on two feet, upright.

Here's the dent made by the heel as it hit the ground. The raised instep.

The big toe, instead of pointing outwards,

as is needed if you're going to climb trees,

is aligned forward to give the final push-off.

But the exciting thing is that there is a whole track-way of prints.

They have fossilised behaviour and revealed family life

in a way that is almost disturbingly familiar.

Two individuals, one larger than the other - perhaps male and female -

appear to have been walking beside one another, maybe even arm in arm.

The male's footprints are scuffed by smaller prints,

perhaps made by a child walking through the ash,

treading in the steps of its father.

The big question is - why did they stand upright?

There are a number of suggestions.

One is that it was to get a better view to spot for danger or for prey.

Maybe it was to release the hands to use tools,

or pick up food or hold a baby.

There's a third, more controversial suggestion.

About six million years ago,

the climate of the Earth became very erratic.

The great African forests began to die back.

The trees became broken by scrub and grassland.

There is evidence that slow movements in the Earth's crust

caused areas of East Africa to flood.

A new habitat had appeared for the apes.

Using their long, chimp-like arms,

they still climbed trees to find food,

but as the forests diminished,

it was farther from one tree to the next.

They had to cross open spaces covered with grass or even water.

And to do that, they travelled upright on two feet as I am doing.

Suddenly, an image from our remote past comes vividly to light -

the time when our ancestors, to keep up with a changing environment,

had to wade and keep their heads above water to find food.

That crucial moment,

when our distant ancestors took a step away from being apes

and a step towards humanity.

Apes are primarily adapted for a life in the trees,

so they waddle if they walk upright.

It is tiring for them to stand on two feet for any length of time.

But water supports their bodies and takes strain off their leg muscles,

so they can stay upright longer.

Maybe a life at the water's edge encouraged anatomical change.

At this time, their hip bones altered

and our ancestors adopted an upright existence.

There are places in the Congo which give us a clue

as to what the ape-men might have found to eat in the swamps.

These are lowland gorillas.

They're collecting marsh plants.

Our ancestors may well have come to such places to feed in a similar way.

We know from other evidence

that nutritious roots and tubers were indeed eaten by early humans.

There was another kind of food that our ancestors might have found here.

Gorillas today are exclusively vegetarian,

but our ancestors, judging by their teeth, also ate meat as chimps do.

So although gorillas seem to ignore other animals visiting these swamps,

their presence may not have gone unnoticed by early ape-men.

But to kill such fast and wary prey,

which so easily take to flight and run faster than apes,

would require the skill

to follow their tracks.

Linking marks with an animal that passed that way hours or days before,

requires a profound leap of the imagination.

As far as we know, only human beings have done that.

But once it's been done, identifying the tracks simply is not difficult.

-Even

-I

-know those are an eland's tracks.

But some people can interpret even the faintest of marks on the ground.

They hunt in silence.

The hand-sign indicates that he has found the track of a group of kudu.

These are the San people of the Kalahari Desert,

the last tribe on Earth to use the most ancient hunting technique - the persistence hunt.

They run down their prey.

They feel the rhythm of the animals' movements from the spacing of tracks.

The group is not moving fast.

The animals have taken fright.

They will concentrate on the bull.

He's carrying a heavy set of horns

and therefore will tire more quickly.

To do that, they must separate him from the herd,

so his tracks aren't confused by others'.

The sun is overhead, and the men sense a change in the kudu's pace.

He's slowing.

After hours of tracking,

they are in a trance-like state of concentration.

At times, it's impossible to see the kudu's tracks,

and they must imagine the path it has taken.

The heat is hard on the hunters,

but they are close enough for the next stage - the chase.

This is the signal for it to begin.

But only one man will undertake it - Karohe, the runner.

He must be relentless.

It's now a test of endurance.

Who will collapse first - the man or the animal?

This was how men hunted before weapons,

when a hunter had only his physical endurance to gain his prize.

Running on two feet is more efficient over long distances

than running on four.

A man sweats from glands all over his body and so cools himself.

A kudu sweats much less and has to find shade if it's to cool down.

A man has hands with which to carry water,

so during the chase he can replenish the liquid he loses as sweat.

Hours pass and Karohe is getting closer.

But then the kudu runs into thick cover.

The tracks have disappeared.

Karohe puts himself into the mind of the kudu and re-enacts the moment

when it heard him approaching as it rested in the shade.

He deduces the direction in which it must have fled.

It's close by.

The chase has lasted eight hours.

Hunter and hunted are both at the end of their strength.

Neither can go on much longer.

And then the kudu collapses...

from sheer exhaustion.

It's close to death.

Karohe's spear-throw is scarcely more than a symbolic gesture.

The hunter pays tribute to his quarry's courage and strength

with ceremonial gestures that ensure

that its spirit returns to the desert sands from which it came.

While it was alive, he lived and breathed with it

and felt its every movement in his own body.

And at the moment of death, he shared its pain.

He rubs its saliva into his own legs

to relieve the agony of his burning muscles.

He gives thanks for the life he took,

so that he may sustain his family,

waiting for him in their settlement.

While the men were away, the women have collected tubers and roots.

But Karohe has brought them the much more nutritious, energy-giving meat.

The dogs are given a share.

Wild dogs must have followed hunters for scraps since prehistory.

Men chose the least savage pups to help with tracking.

The character of their dogs began to change.

Cattle were domesticated by a similar process,

choosing docile calves and hand-rearing them.

The Fulani people of Mali lay claim to the half-wild herds that roam the savannahs,

and mark them accordingly.

But grazing animals, wild or tame,

may have to migrate with the seasons to find pasture,

and then the people must follow.

People all over the world have tried to domesticate animals,

but very few species are actually suitable.

To be any good, an animal has to be relatively docile,

to eat an easily available food, to breed easily in captivity

and to live in packs or herds -

groups in which individuals recognise one dominant animal

to which all the rest are submissive.

Then a human can take over the place of that dominant animal

and so control his flocks and herds.

GUNSHOT

A gunshot drives the cattle forward.

The herds must be guided

to survive this most challenging part of their long, annual journey.

So every year, grazing animals, both domesticated and wild,

have to risk their lives in treacherous waters to reach food.

The tamed and subservient cattle, however,

are guided and protected by the men.

If the animals don't stay together, they may be swept away by currents.

Herding cattle is by no means the easy option.

Just keeping them alive is difficult.

But in spite of all the problems, humans have become so good at it

that today, domesticated cattle far outnumber their wild relatives.

Relying on herds that must migrate in search of pasture

makes it impossible for people to settle in one place.

But in more fertile areas, cattle can be confined

and then they can provide not only milk and meat, but power.

Once people settle down, then they can plant crops.

They can become farmers.

All over the world, woodlands and grasslands began to disappear,

to be replaced by fields in which to grow crops of domesticated plants.

People began to select those plants that gave good yields,

and so plants also changed, just as animals had done.

In Africa, in Europe, in Asia,

people started to settle down in villages.

Hitherto, the population of every species of animal

was limited by the amount of food available to it.

But human beings now changed that.

They'd learned how to increase the food supply

far beyond that which occurred naturally.

It was a crucial moment in the history of this planet.

The number of human beings began to increase.

This strange, miniature house wasn't built for occupation by human beings.

Instead, it shelters the most important commodity

in this Dogon village in Mali.

It's a granary. It contains millet.

Millet is the most important thing in Dogon life.

The year revolves around planting and harvesting it.

There are more houses for it in a village

than there are houses for humans.

The first music that a baby in Dogonland is likely to hear

is its mother pounding millet.

Now that people did not have to be permanently on the move to find food,

they had more time for other things.

Ritual and the arts flourished as never before.

For the Dogon, harvest is finished.

The granaries are full.

It's time to celebrate.

As more food became more easily available,

so the human population continued to increase.

Villages grew into towns.

Towns became cities.

This immense, low mound may look as though it's covered with gravel,

but if you look closely, it is composed of fragments of pottery.

It's the site of the oldest city in Africa below the Sahara,

and this is the remains of 2,000 years of continuous human occupation.

To make things even MORE remarkable,

the city itself is still flourishing over there.

This is Djenne.

In its heart stands the mosque,

the oldest and largest mud building in the world.

And around it, a market that has been held here since medieval times.

Djenne's growth was closely tied to that of a neighbouring city,

the fabulous Timbuktu that lay farther up the Niger.

Between them, the two dominated the trade across the Sahara.

Into these markets

came traders from North Africa who crossed the Sahara by camel caravan

to look for slaves, gold and ivory.

And trade still dominates the city.

Quelle poisson? ..De la fleuve? ..Oh. INDISTINCT REPLY

Great numbers of people living together

meant some could avoid the daily chore of producing food.

They could become craftsmen and exchange what they produce for food.

So it became possible for technologies to develop,

for arts and sciences to flourish, for people to put up huge buildings.

This is Tikal, the capital of the Maya people,

who built the tallest constructions in the whole of the New World,

until skyscrapers were put up in New York

at the beginning of the 20th century.

At the height of Tikal's glory, about 1,300 years ago,

the city covered a vast area, at least double that of ancient Rome.

The city centre was filled by thousands of temples and houses,

only a fraction of which can be seen today.

The inhabitants excelled at every form of civilised activity.

They were accomplished builders, superb sculptors and painters.

Expert astronomers, they measured the solar cycle with great precision.

They constructed complex calendars

to which their religious beliefs were tied.

And they devised a system of writing

that was, in its time, the most advanced in the Americas.

Having achieved such skills and knowledge,

when and why were their cities abandoned?

Fortunately, we do have some clues, certainly as to date.

The Maya recorded their history in great detail on stones like this.

The latest inscription to be found in the ruins of city

can be dated to 869AD.

After that, the city falls silent,

the inhabitants disappear

and classic Maya civilisation is coming to an end.

The explanation of why Tikal and all the other Maya cities collapsed

is the subject of hot debate.

But now new evidence has been found.

To see it, you need to get above the city.

From there, you can see hints of occupation

that extend far beyond the jungle-covered ruins of today.

Cameras in space have revealed aqueducts, canals

and fields buried under the soil -

proof that when temples were built,

the forest had already been felled

and replaced by a great expanse of cultivated fields.

As the population of the city grew, probably to 60,000,

farmers struggled to produce enough food.

The fertility of the fields was exhausted. Soon people were starving.

They drifted away from the city, and gradually the jungle returned.

But how is the fate of Tikal relevant to us today?

When the Maya built their cities,

there were only about 50 million people on the entire planet.

But the Maya were unable to sustain their population

with the technology they'd developed, sophisticated though it was.

Then, a few centuries later,

human beings elsewhere, with new techniques,

began to build on a scale that dwarfed even Tikal's skyscrapers.

Today, there are not just 50 million,

but 6,000 million people on Earth.

Nearly half of that vast number

live in cities which are still growing fast.

And all these people need food.

We have long since utilised

the best fertile places to grow our food.

Now, we are having to try to do so elsewhere.

In a desert like this one in Arizona,

trying to cultivate anything would seem to be futile.

With just a few centimetres of rain a year, there is no use for this

and little enough water for thirsty plants.

But appearances can be deceptive.

With the right technology, even the desert can yield edible crops.

These lush fields can only exist

because of humanity's unique capacity to innovate and to learn.

Our big brains have enabled us

to discover how to add fertiliser to poor soil,

to deal with pests with insecticide, and even bring rain to the desert.

This "rain" has been pumped along hundreds of miles of pipes

from a far distant water supply.

Every year, human beings displace the equivalent of entire rivers

to water their crops.

In just a few thousand years,

the revolution of agriculture has spread to nearly all human societies.

Today, over a third of the surface of the land

is devoted to producing food for humans.

That has changed some landscapes in the most dramatic way.

The rich variety of the world's natural ecosystems

has been replaced by uniformity.

Complex communities eliminated and changed to monocultures.

The intricate embroideries of nature

have been replaced by a geometric landscape of straight lines.

All this was made possible by the technological revolution

which started when our hands were freed,

and we could manipulate our surroundings.

Our ingenuity has now enabled us

to utilise the most unlikely and unpromising corners of the Earth.

We're even beginning to farm the oceans.

The changes we have wrought on the surface of our planet

are so wholesale, they're visible from space.

As we increase, so there is less land for other animals and plants.

But humanity can't expand its numbers indefinitely.

Will our civilisation crumble as did that of the Maya?

This has been the launch pad

for humanity's greatest, most complex achievements

and highest hopes, from space shuttles to space stations.

And it's from here, in the year 2020,

that our species may launch its most ambitious project yet -

to settle on another planet, to send a mission to Mars.

'Six, five, four, three,

'two, one...'

The ape that stood up on its hind legs has outgrown its planet.

Now it seeks to travel through space to look for another.

Could it really add Mars to its empire?

Conditions there could hardly be more hostile

for life that evolved on Earth.

There, the energy-giving sunlight is only half as intense.

Temperatures fall to more than 100 degrees below freezing.

Will our technology be able to meet THIS challenge?

Colonising another planet might sound like science fiction,

but, in fact, work on solving the problems of living on Mars

is going on right now, here on Earth.

The first problem for those that seek to settle there

will be, as always, to find food.

To do that, they will have to grow plants - the basis of all our food.

On Earth, we're beginning to realise

that we may now be over-reliant on the few species of plant

which provided food for 10,000 years.

We are at last taking steps to conserve wild species

that we have been destroying so carelessly for centuries.

Giant greenhouses like this are astonishing technical achievements,

but they're also proof that we now have the skill and the knowledge

to create artificial environments almost anywhere - even on Mars.

If we did build such structures on another planet,

might we then contemplate spreading our species still further

to other more distant worlds?

This new era of exploration began when human beings landed on the moon.

Is that as far as our species will reach? Or SHOULD reach?

Or will our incurable urge to explore, and our growing numbers,

lead us to print our feet on yet more new worlds?

'The Eagle has landed.

'It's one small step for man...

'..one giant leap for mankind.'

3.5 million years separate the individual

who left these prints in the sands of Africa

from the one who left them on the moon.

A mere blink in the eye of evolution.

Using his burgeoning intelligence,

this most successful mammal has exploited the environment

to produce food for an increasing population.

Despite disasters when civilisations overreach themselves,

that process continues, indeed accelerates, today.

Now mankind is looking for food, not just on THIS planet but on others.

Perhaps the time has come to put that process into reverse.

Instead of controlling the environment for the population,

perhaps it's time we control the population

to allow the environment's survival.

Subtitles by BBC Broadcast

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