0:00:59 > 0:01:04You might think this orang-utan is washing socks as some circus trick
0:01:04 > 0:01:08for which she's been specially trained - but not so.
0:01:08 > 0:01:12She is doing this on her own initiative.
0:01:12 > 0:01:16She's seen others doing it and she's copying.
0:01:16 > 0:01:22That ability to imitate, as well as to use tools, started among monkeys,
0:01:22 > 0:01:26but has been brought to a much greater level among the apes.
0:01:26 > 0:01:28Those two talents
0:01:28 > 0:01:32ultimately led to the transformation of the world.
0:01:40 > 0:01:45Camp Leakey in Borneo is home to a special group of orangs,
0:01:45 > 0:01:49rescued from captivity and returned to the wild.
0:01:49 > 0:01:53Because they've lived partly in OUR world,
0:01:53 > 0:01:55they can show what we have in common.
0:01:55 > 0:01:58This old lady loves DIY.
0:02:10 > 0:02:14So does her son, who was born in the wild.
0:02:15 > 0:02:18Even her infant is interested.
0:02:24 > 0:02:30It's very striking when you sit as close to an orang-utan as this
0:02:30 > 0:02:34to see how similar they are to human beings.
0:02:34 > 0:02:38We are both, of course, great apes.
0:02:38 > 0:02:42But look how human her hand is,
0:02:42 > 0:02:45the skill with which she picks things up,
0:02:45 > 0:02:50the way that she can grasp a tool like that.
0:02:50 > 0:02:55How she uses her brain to imitate what she's seen others do,
0:02:55 > 0:02:59and oddly, the fact that she is clearly left-handed.
0:02:59 > 0:03:02Great apes share with human beings
0:03:02 > 0:03:06a predilection to use either the right or left hand,
0:03:06 > 0:03:08and she's left-handed.
0:03:09 > 0:03:13But the most important thing we share is our big brain.
0:03:13 > 0:03:18THAT has produced so many of the talents and abilities
0:03:18 > 0:03:20that we have in common.
0:03:24 > 0:03:29All apes have a love of one kind of food - fruit.
0:03:35 > 0:03:41But getting fruit in the South-East Asian forests has its problems.
0:03:41 > 0:03:43GROWLS
0:03:45 > 0:03:48There are powerful predators on the ground,
0:03:48 > 0:03:51so orangs seldom come down from the trees.
0:03:53 > 0:03:56They're the heaviest animal up in the branches,
0:03:56 > 0:04:02but they've worked out an ingenious way of exploiting their weight.
0:04:02 > 0:04:04They pole-vault.
0:04:07 > 0:04:13But getting about is tiring, and as fruiting trees are widely scattered,
0:04:13 > 0:04:17orangs need to take the most direct path between them.
0:04:18 > 0:04:21But they seldom take wrong turns.
0:04:21 > 0:04:25It seems that they have a map of the forest in their minds.
0:04:29 > 0:04:35They must have mental calendars, for they miraculously appear in a tree
0:04:35 > 0:04:39at exactly the time its fruit is ready for picking.
0:04:42 > 0:04:47It requires a lot of skill to travel around in this way,
0:04:47 > 0:04:49and youngsters take many years
0:04:49 > 0:04:55to match their parents' expertise in route-finding and aerial gymnastics.
0:05:02 > 0:05:05Mothers keep an eye on their young,
0:05:05 > 0:05:11ready when needed to provide a helping hand...or an arm or a leg.
0:05:13 > 0:05:16It takes up to 13 years
0:05:16 > 0:05:21for a youngster to match its mother's knowledge of the forest.
0:05:21 > 0:05:26This may be why young orangs spend longer with their mothers
0:05:26 > 0:05:28than any other ape except humans.
0:05:30 > 0:05:35But eventually, this close tie has to be broken.
0:05:37 > 0:05:41Orang-utan, as adults, are famed as loners.
0:05:41 > 0:05:46But this doesn't mean that they're necessarily anti-social.
0:05:50 > 0:05:54Back at Camp Leakey, it's feeding time.
0:05:54 > 0:05:58There's a lot of food, and here orang-utan assemble
0:05:58 > 0:06:03and show that, at heart, they're really quite sociable animals.
0:06:03 > 0:06:08Scenes like these suggest that it's only the scarcity of food
0:06:08 > 0:06:11that compels them to live apart.
0:06:11 > 0:06:14A group as big as this would starve
0:06:14 > 0:06:15if they lived together in the wild.
0:06:21 > 0:06:27But just occasionally, the forest creates its own food bonanza.
0:06:29 > 0:06:34Every four or five years, many fruit trees ripen simultaneously,
0:06:34 > 0:06:37producing a brief glut of food,
0:06:37 > 0:06:41which attracts orangs from miles around.
0:06:44 > 0:06:49They show how sociable they can be, 20 of them in just one tree.
0:06:49 > 0:06:54The fruit will soon end, so friends make the most of their time together.
0:06:55 > 0:07:00But some individuals do cause trouble.
0:07:00 > 0:07:05The highly-sexed male clambering up the tree is not after fruit.
0:07:05 > 0:07:08He drives off a female's chosen partner
0:07:08 > 0:07:11and tries to force himself on her.
0:07:12 > 0:07:15SQUEALS
0:07:18 > 0:07:21SCREAMS
0:07:27 > 0:07:29A bellowing call
0:07:29 > 0:07:35announces the arrival of the most powerful orang in the whole forest.
0:07:36 > 0:07:39He hasn't visited the area for years.
0:07:39 > 0:07:42The others recognise him instantly.
0:07:45 > 0:07:50The mere threat of his presence sends the smaller male into retreat.
0:07:50 > 0:07:53BELLOWS
0:07:58 > 0:08:04He takes up his dominant position in the group and the rest settle again.
0:08:04 > 0:08:09In the same way that we can take up relationships...
0:08:09 > 0:08:11sometimes after years of separation,
0:08:11 > 0:08:17so orang-utans can slot back quickly into their own social circle.
0:08:17 > 0:08:22That requires a brain that can keep track of different individuals
0:08:22 > 0:08:25over long periods of time and distances.
0:08:25 > 0:08:31There's one place where interactions happen between orang-utans
0:08:31 > 0:08:33more frequently than anywhere else
0:08:33 > 0:08:38that has produced extraordinary examples of intelligence.
0:08:40 > 0:08:43The swamp forests of northern Sumatra.
0:08:45 > 0:08:48This is a paradise for orang-utan.
0:08:50 > 0:08:55It floods regularly, and the waters bring in a rich supply of nutrients,
0:08:55 > 0:08:59so there's a great deal of food to be had.
0:08:59 > 0:09:05Orangs can travel and feed together in groups throughout the year.
0:09:10 > 0:09:13They eat insects as well as fruit.
0:09:17 > 0:09:20Termites are a particular favourite.
0:09:20 > 0:09:26Collecting them from a rotten trunk doesn't need much ingenuity.
0:09:26 > 0:09:31Extracting from a hole in a LIVING tree is a different matter,
0:09:31 > 0:09:35even for a powerful male like this one.
0:09:35 > 0:09:38But the orangs here have solved such problems.
0:09:38 > 0:09:42They make tools. First, they select a twig.
0:09:44 > 0:09:47Next, they trim it to length.
0:09:47 > 0:09:50Then they whittle it into shape...
0:09:50 > 0:09:54and carefully insert it into the tree
0:09:54 > 0:09:58to reach whatever they want from inside.
0:10:00 > 0:10:05This ingenious male is probing into a bees' nest
0:10:05 > 0:10:09with an instrument which lets him lick honey from one end
0:10:09 > 0:10:12while collecting more with the other.
0:10:18 > 0:10:22Younger members of the group watch and learn.
0:10:22 > 0:10:27So a tradition grows that will be passed on to new generations.
0:10:27 > 0:10:30BUZZING
0:10:30 > 0:10:33If there's an abundance of food,
0:10:33 > 0:10:38orang-utan can live in high densities and so form a community.
0:10:38 > 0:10:40If one individual gets a bright idea,
0:10:40 > 0:10:44others will copy it and so form a culture.
0:10:44 > 0:10:49To see an even more complex ape culture,
0:10:49 > 0:10:51we have to go to another continent.
0:10:51 > 0:10:57This is Africa - a mangrove-covered island near the mouth of the Congo.
0:10:57 > 0:11:01It's home to a remarkable and revealing community
0:11:01 > 0:11:06of a different great ape - chimpanzees.
0:11:07 > 0:11:10These chimps are orphans.
0:11:11 > 0:11:15Their parents were killed for the bush-meat trade,
0:11:15 > 0:11:19and many were pets kept in unsuitable conditions.
0:11:19 > 0:11:23And now they are part of a unique experiment.
0:11:23 > 0:11:26They're being taught the skills they'll need
0:11:26 > 0:11:31to survive by themselves in the wild.
0:11:31 > 0:11:34THEY CHATTER AND SQUEAL
0:11:49 > 0:11:52Several of them, as youngsters,
0:11:52 > 0:11:56acquired some skills by watching humans.
0:11:56 > 0:11:58Some know how to crack nuts.
0:11:58 > 0:12:04But it takes a chimp years to work out how to place the nut in a socket
0:12:04 > 0:12:07and then how to wield a hammer.
0:12:08 > 0:12:11This chimp, Balinga, is an expert.
0:12:11 > 0:12:14His companion, Flo, watches attentively.
0:12:20 > 0:12:26Puck is struggling. He started watching nutcracking when he was six,
0:12:26 > 0:12:30two years too late for a chimp to learn new skills.
0:12:30 > 0:12:35You really can't teach an old ape new tricks.
0:12:46 > 0:12:50D'you want this? D'you want one of these?
0:12:50 > 0:12:52Want one?
0:12:54 > 0:12:56Mind your fingers!
0:13:13 > 0:13:18Of course, there are many different ways of cracking a nut.
0:13:19 > 0:13:23Come to that, there are many different kinds of nuts,
0:13:23 > 0:13:26and so different groups of chimps
0:13:26 > 0:13:31have developed different ways of dealing with the problem.
0:13:31 > 0:13:34THAT is the beginning of a culture.
0:13:34 > 0:13:39Of course, a culture has many things in it apart from cracking nuts.
0:13:41 > 0:13:47These rainforests lie 1,000 miles away, east of the Congo, in Uganda.
0:13:47 > 0:13:51The chimps here have a very different culture
0:13:51 > 0:13:55and they have never been filmed before.
0:13:55 > 0:13:58Their communities are the biggest known
0:13:58 > 0:14:01and contain the most adult males.
0:14:03 > 0:14:08As elsewhere, cultural traditions extend to social etiquette.
0:14:13 > 0:14:17Here, they practise a style of grooming
0:14:17 > 0:14:19known as the grooming hand clasp.
0:14:19 > 0:14:22Most of the time, life is peaceful.
0:14:22 > 0:14:27But the males, although they live alongside one another, are rivals.
0:14:27 > 0:14:30Occasionally, tempers flare.
0:14:30 > 0:14:33THEY SCREAM AND WHOOP
0:14:59 > 0:15:04These displays are ways by which males establish their dominance
0:15:04 > 0:15:06without physically wounding others
0:15:06 > 0:15:11who would be needed as comrades, were the group to be attacked.
0:15:11 > 0:15:16After a quarrel, they embrace to re-establish bonds of friendship.
0:15:17 > 0:15:21But sometimes, rivalries become more serious.
0:15:27 > 0:15:31Young male Grapelli is being ferociously beaten
0:15:31 > 0:15:35by an unusually large gang of adult males.
0:15:35 > 0:15:38THEY GRUNT AND SQUEAL
0:15:48 > 0:15:53Battles between rival groups from neighbouring communities
0:15:53 > 0:15:56have been seen elsewhere in Africa,
0:15:56 > 0:16:01but attacks like this on a single male within the group are VERY rare.
0:16:09 > 0:16:13This is the last that was seen of Grapelli.
0:16:13 > 0:16:19He was very seriously wounded and it's almost certain that he died.
0:16:24 > 0:16:28His body has not yet been found.
0:16:30 > 0:16:35What is happening at Ngogo that causes these savage attacks?
0:16:35 > 0:16:40One theory is that young males find it particularly hard
0:16:40 > 0:16:45to establish a place within such a large group of powerful adult males,
0:16:45 > 0:16:50whose lives are ruled by social bonds we have yet to understand.
0:16:52 > 0:16:56Even these apparently simple acts of grooming
0:16:56 > 0:16:59can have great social significance.
0:17:01 > 0:17:04Grooming is important for health.
0:17:04 > 0:17:07It's a service males perform for relatives,
0:17:07 > 0:17:10as these two brothers are doing.
0:17:11 > 0:17:16It's also a way of creating and maintaining good relationships
0:17:16 > 0:17:19between allies and males in the same peer group.
0:17:25 > 0:17:27This young male, Pork Pie,
0:17:27 > 0:17:32seems to be more successful socially than Grapelli was.
0:17:35 > 0:17:40But these males have other things than grooming on their mind.
0:17:40 > 0:17:44Their attention has turned to the tree tops.
0:17:44 > 0:17:47It's time to hunt.
0:17:47 > 0:17:51A large group of like-minded males are assembling.
0:17:52 > 0:17:55One of them drums.
0:17:55 > 0:17:58It's a signal telling others nearby
0:17:58 > 0:18:00that a hunt is about to start.
0:18:02 > 0:18:08Chimps usually hunt when they see a good opportunity, but here in Ngogo,
0:18:08 > 0:18:14hunts often start whether or not suitable prey has been spotted.
0:18:15 > 0:18:18The males set off through the forest.
0:18:18 > 0:18:24They travel for up to four hours at a time, searching for likely victims.
0:18:24 > 0:18:29Pork Pie tags along. He's not yet an accepted member of the hunting group.
0:18:32 > 0:18:38This is what they are looking for - a troop of red colobus monkeys.
0:18:44 > 0:18:49The hunters take up their positions in the surrounding trees,
0:18:49 > 0:18:53ready to pounce on any monkeys that try to escape.
0:19:08 > 0:19:13They are closing in on the most vulnerable target -
0:19:13 > 0:19:16a female with her young.
0:19:45 > 0:19:49The colobus males do their best to fight back,
0:19:49 > 0:19:52but the chimps are much bigger and stronger.
0:20:13 > 0:20:18Some of the infants have been separated from their mothers.
0:20:19 > 0:20:21They're now easy prey.
0:20:21 > 0:20:24SCREAMING
0:20:30 > 0:20:36It's not over yet. The male colobus fight to defend their families...
0:20:36 > 0:20:39SCREAMS
0:20:40 > 0:20:43..but they couldn't save this infant.
0:20:46 > 0:20:49The hunters crowd round the kill.
0:20:49 > 0:20:51The rest of the group join them.
0:20:55 > 0:20:58The males are the first to eat.
0:20:58 > 0:21:01They supplement the flesh with a few leaves,
0:21:01 > 0:21:05just as humans take vegetables with their meat.
0:21:06 > 0:21:10But some of the male hunters now share their kill
0:21:10 > 0:21:14with other group members, including the females.
0:21:16 > 0:21:20Do they get anything in exchange? Sex?
0:21:20 > 0:21:25This male is certainly mating with one of the females.
0:21:29 > 0:21:34But he then allows a different female to take some of his meat.
0:21:39 > 0:21:43Perhaps the meat is given to those who beg the hardest.
0:21:43 > 0:21:49Pork Pie is certainly trying his luck with one hunter after another.
0:21:49 > 0:21:52Time after time, he is spurned...
0:21:54 > 0:21:59..but eventually, his persistence pays off.
0:22:01 > 0:22:06But the Ngogo chimps have another possible motive for meat-sharing.
0:22:06 > 0:22:10Males give more meat to their allies than to others.
0:22:10 > 0:22:15It seems that they are using meat as a way of strengthening such bonds.
0:22:15 > 0:22:22The hope of collecting some meat may be why others join in the hunt.
0:22:24 > 0:22:27Chimpanzees have much in common with humans.
0:22:27 > 0:22:33They are, after all, thought to be our closest living relatives.
0:22:33 > 0:22:37They're clever, social, political creatures...
0:22:38 > 0:22:40..and apparently, they even dream.
0:22:42 > 0:22:45But in prehistory, the dreams and ambitions of the ape
0:22:45 > 0:22:49whose descendants took over the planet
0:22:49 > 0:22:53must have taken a very different direction.
0:22:54 > 0:22:56More discoveries about that creature
0:22:56 > 0:23:02have been made here at Olduvai Gorge in Tanzania than anywhere else.
0:23:02 > 0:23:04Perhaps here we can find clues
0:23:04 > 0:23:08as to why our ancestors took such a different path.
0:23:08 > 0:23:103.5 million years ago,
0:23:10 > 0:23:14the volcano behind me was belching out ash,
0:23:14 > 0:23:16which covered the entire landscape,
0:23:16 > 0:23:22and it was in that ash that the most evocative discovery of all was made.
0:23:22 > 0:23:25These are the fossilised tracks
0:23:25 > 0:23:27of ancient rhino and antelope,
0:23:27 > 0:23:30here at Laetoli in Tanzania,
0:23:30 > 0:23:33and among them are the footprints of an ape -
0:23:33 > 0:23:36a very remarkable ape.
0:23:37 > 0:23:41Scientists say they can deduce from the shape of bones
0:23:41 > 0:23:46the posture of the animal, but there will always be arguments.
0:23:46 > 0:23:51Here, however, is proof positive that 3.5 million years ago,
0:23:51 > 0:23:55mankind's ancestors were walking on two feet, upright.
0:23:55 > 0:24:00Here's the dent made by the heel as it hit the ground. The raised instep.
0:24:00 > 0:24:03The big toe, instead of pointing outwards,
0:24:03 > 0:24:07as is needed if you're going to climb trees,
0:24:07 > 0:24:11is aligned forward to give the final push-off.
0:24:11 > 0:24:16But the exciting thing is that there is a whole track-way of prints.
0:24:16 > 0:24:21They have fossilised behaviour and revealed family life
0:24:21 > 0:24:25in a way that is almost disturbingly familiar.
0:24:27 > 0:24:32Two individuals, one larger than the other - perhaps male and female -
0:24:32 > 0:24:37appear to have been walking beside one another, maybe even arm in arm.
0:24:37 > 0:24:41The male's footprints are scuffed by smaller prints,
0:24:41 > 0:24:46perhaps made by a child walking through the ash,
0:24:46 > 0:24:49treading in the steps of its father.
0:24:50 > 0:24:53The big question is - why did they stand upright?
0:24:53 > 0:24:56There are a number of suggestions.
0:24:56 > 0:25:01One is that it was to get a better view to spot for danger or for prey.
0:25:01 > 0:25:05Maybe it was to release the hands to use tools,
0:25:05 > 0:25:07or pick up food or hold a baby.
0:25:07 > 0:25:11There's a third, more controversial suggestion.
0:25:11 > 0:25:14About six million years ago,
0:25:14 > 0:25:18the climate of the Earth became very erratic.
0:25:21 > 0:25:25The great African forests began to die back.
0:25:25 > 0:25:29The trees became broken by scrub and grassland.
0:25:29 > 0:25:33There is evidence that slow movements in the Earth's crust
0:25:33 > 0:25:35caused areas of East Africa to flood.
0:25:35 > 0:25:39A new habitat had appeared for the apes.
0:25:39 > 0:25:42Using their long, chimp-like arms,
0:25:42 > 0:25:45they still climbed trees to find food,
0:25:45 > 0:25:48but as the forests diminished,
0:25:48 > 0:25:52it was farther from one tree to the next.
0:25:52 > 0:25:57They had to cross open spaces covered with grass or even water.
0:25:57 > 0:26:02And to do that, they travelled upright on two feet as I am doing.
0:26:54 > 0:27:00Suddenly, an image from our remote past comes vividly to light -
0:27:00 > 0:27:05the time when our ancestors, to keep up with a changing environment,
0:27:05 > 0:27:10had to wade and keep their heads above water to find food.
0:27:10 > 0:27:12That crucial moment,
0:27:12 > 0:27:17when our distant ancestors took a step away from being apes
0:27:17 > 0:27:19and a step towards humanity.
0:27:23 > 0:27:27Apes are primarily adapted for a life in the trees,
0:27:27 > 0:27:30so they waddle if they walk upright.
0:27:30 > 0:27:35It is tiring for them to stand on two feet for any length of time.
0:27:35 > 0:27:41But water supports their bodies and takes strain off their leg muscles,
0:27:41 > 0:27:44so they can stay upright longer.
0:27:55 > 0:28:01Maybe a life at the water's edge encouraged anatomical change.
0:28:01 > 0:28:04At this time, their hip bones altered
0:28:04 > 0:28:09and our ancestors adopted an upright existence.
0:28:13 > 0:28:18There are places in the Congo which give us a clue
0:28:18 > 0:28:23as to what the ape-men might have found to eat in the swamps.
0:28:25 > 0:28:27These are lowland gorillas.
0:28:36 > 0:28:39They're collecting marsh plants.
0:28:40 > 0:28:46Our ancestors may well have come to such places to feed in a similar way.
0:28:46 > 0:28:48We know from other evidence
0:28:48 > 0:28:54that nutritious roots and tubers were indeed eaten by early humans.
0:28:57 > 0:29:03There was another kind of food that our ancestors might have found here.
0:29:03 > 0:29:06Gorillas today are exclusively vegetarian,
0:29:06 > 0:29:12but our ancestors, judging by their teeth, also ate meat as chimps do.
0:29:14 > 0:29:20So although gorillas seem to ignore other animals visiting these swamps,
0:29:20 > 0:29:24their presence may not have gone unnoticed by early ape-men.
0:29:26 > 0:29:29But to kill such fast and wary prey,
0:29:29 > 0:29:33which so easily take to flight and run faster than apes,
0:29:33 > 0:29:36would require the skill
0:29:36 > 0:29:38to follow their tracks.
0:29:38 > 0:29:44Linking marks with an animal that passed that way hours or days before,
0:29:44 > 0:29:48requires a profound leap of the imagination.
0:29:48 > 0:29:52As far as we know, only human beings have done that.
0:29:52 > 0:29:57But once it's been done, identifying the tracks simply is not difficult.
0:29:57 > 0:30:01- Even- I- know those are an eland's tracks.
0:30:01 > 0:30:06But some people can interpret even the faintest of marks on the ground.
0:30:08 > 0:30:11They hunt in silence.
0:30:11 > 0:30:16The hand-sign indicates that he has found the track of a group of kudu.
0:30:16 > 0:30:20These are the San people of the Kalahari Desert,
0:30:20 > 0:30:27the last tribe on Earth to use the most ancient hunting technique - the persistence hunt.
0:30:29 > 0:30:31They run down their prey.
0:30:38 > 0:30:43They feel the rhythm of the animals' movements from the spacing of tracks.
0:30:43 > 0:30:45The group is not moving fast.
0:30:55 > 0:30:58The animals have taken fright.
0:31:02 > 0:31:04They will concentrate on the bull.
0:31:04 > 0:31:07He's carrying a heavy set of horns
0:31:07 > 0:31:09and therefore will tire more quickly.
0:31:10 > 0:31:14To do that, they must separate him from the herd,
0:31:14 > 0:31:18so his tracks aren't confused by others'.
0:31:22 > 0:31:28The sun is overhead, and the men sense a change in the kudu's pace.
0:31:28 > 0:31:31He's slowing.
0:31:32 > 0:31:35After hours of tracking,
0:31:35 > 0:31:39they are in a trance-like state of concentration.
0:31:43 > 0:31:47At times, it's impossible to see the kudu's tracks,
0:31:47 > 0:31:51and they must imagine the path it has taken.
0:31:59 > 0:32:02The heat is hard on the hunters,
0:32:02 > 0:32:07but they are close enough for the next stage - the chase.
0:32:15 > 0:32:18This is the signal for it to begin.
0:32:25 > 0:32:30But only one man will undertake it - Karohe, the runner.
0:32:44 > 0:32:47He must be relentless.
0:32:52 > 0:32:55It's now a test of endurance.
0:32:55 > 0:32:59Who will collapse first - the man or the animal?
0:33:03 > 0:33:07This was how men hunted before weapons,
0:33:07 > 0:33:12when a hunter had only his physical endurance to gain his prize.
0:33:15 > 0:33:19Running on two feet is more efficient over long distances
0:33:19 > 0:33:21than running on four.
0:33:23 > 0:33:28A man sweats from glands all over his body and so cools himself.
0:33:28 > 0:33:33A kudu sweats much less and has to find shade if it's to cool down.
0:33:38 > 0:33:41A man has hands with which to carry water,
0:33:41 > 0:33:47so during the chase he can replenish the liquid he loses as sweat.
0:34:11 > 0:34:16Hours pass and Karohe is getting closer.
0:34:16 > 0:34:20But then the kudu runs into thick cover.
0:34:24 > 0:34:26The tracks have disappeared.
0:34:32 > 0:34:37Karohe puts himself into the mind of the kudu and re-enacts the moment
0:34:37 > 0:34:42when it heard him approaching as it rested in the shade.
0:34:48 > 0:34:52He deduces the direction in which it must have fled.
0:34:52 > 0:34:55It's close by.
0:35:08 > 0:35:11The chase has lasted eight hours.
0:35:11 > 0:35:14Hunter and hunted are both at the end of their strength.
0:35:14 > 0:35:17Neither can go on much longer.
0:35:31 > 0:35:34And then the kudu collapses...
0:35:34 > 0:35:37from sheer exhaustion.
0:35:43 > 0:35:46It's close to death.
0:35:52 > 0:35:56Karohe's spear-throw is scarcely more than a symbolic gesture.
0:36:24 > 0:36:29The hunter pays tribute to his quarry's courage and strength
0:36:29 > 0:36:32with ceremonial gestures that ensure
0:36:32 > 0:36:37that its spirit returns to the desert sands from which it came.
0:36:40 > 0:36:44While it was alive, he lived and breathed with it
0:36:44 > 0:36:47and felt its every movement in his own body.
0:36:50 > 0:36:54And at the moment of death, he shared its pain.
0:36:56 > 0:36:59He rubs its saliva into his own legs
0:36:59 > 0:37:04to relieve the agony of his burning muscles.
0:37:04 > 0:37:06He gives thanks for the life he took,
0:37:06 > 0:37:09so that he may sustain his family,
0:37:09 > 0:37:12waiting for him in their settlement.
0:37:16 > 0:37:21While the men were away, the women have collected tubers and roots.
0:37:21 > 0:37:27But Karohe has brought them the much more nutritious, energy-giving meat.
0:37:35 > 0:37:37The dogs are given a share.
0:37:37 > 0:37:41Wild dogs must have followed hunters for scraps since prehistory.
0:37:41 > 0:37:46Men chose the least savage pups to help with tracking.
0:37:46 > 0:37:49The character of their dogs began to change.
0:37:51 > 0:37:55Cattle were domesticated by a similar process,
0:37:55 > 0:37:59choosing docile calves and hand-rearing them.
0:37:59 > 0:38:07The Fulani people of Mali lay claim to the half-wild herds that roam the savannahs,
0:38:07 > 0:38:09and mark them accordingly.
0:38:18 > 0:38:21But grazing animals, wild or tame,
0:38:21 > 0:38:25may have to migrate with the seasons to find pasture,
0:38:25 > 0:38:28and then the people must follow.
0:38:34 > 0:38:39People all over the world have tried to domesticate animals,
0:38:39 > 0:38:42but very few species are actually suitable.
0:38:42 > 0:38:47To be any good, an animal has to be relatively docile,
0:38:47 > 0:38:52to eat an easily available food, to breed easily in captivity
0:38:52 > 0:38:55and to live in packs or herds -
0:38:55 > 0:38:59groups in which individuals recognise one dominant animal
0:38:59 > 0:39:02to which all the rest are submissive.
0:39:02 > 0:39:07Then a human can take over the place of that dominant animal
0:39:07 > 0:39:09and so control his flocks and herds.
0:39:09 > 0:39:11GUNSHOT
0:39:11 > 0:39:14A gunshot drives the cattle forward.
0:39:19 > 0:39:21The herds must be guided
0:39:21 > 0:39:26to survive this most challenging part of their long, annual journey.
0:39:26 > 0:39:32So every year, grazing animals, both domesticated and wild,
0:39:32 > 0:39:37have to risk their lives in treacherous waters to reach food.
0:39:50 > 0:39:54The tamed and subservient cattle, however,
0:39:54 > 0:39:57are guided and protected by the men.
0:40:01 > 0:40:06If the animals don't stay together, they may be swept away by currents.
0:40:09 > 0:40:13Herding cattle is by no means the easy option.
0:40:13 > 0:40:16Just keeping them alive is difficult.
0:40:16 > 0:40:21But in spite of all the problems, humans have become so good at it
0:40:21 > 0:40:27that today, domesticated cattle far outnumber their wild relatives.
0:40:40 > 0:40:44Relying on herds that must migrate in search of pasture
0:40:44 > 0:40:48makes it impossible for people to settle in one place.
0:40:48 > 0:40:53But in more fertile areas, cattle can be confined
0:40:53 > 0:40:58and then they can provide not only milk and meat, but power.
0:40:58 > 0:41:02Once people settle down, then they can plant crops.
0:41:02 > 0:41:04They can become farmers.
0:41:04 > 0:41:09All over the world, woodlands and grasslands began to disappear,
0:41:09 > 0:41:14to be replaced by fields in which to grow crops of domesticated plants.
0:41:16 > 0:41:20People began to select those plants that gave good yields,
0:41:20 > 0:41:24and so plants also changed, just as animals had done.
0:41:26 > 0:41:28In Africa, in Europe, in Asia,
0:41:28 > 0:41:32people started to settle down in villages.
0:41:32 > 0:41:36Hitherto, the population of every species of animal
0:41:36 > 0:41:40was limited by the amount of food available to it.
0:41:40 > 0:41:42But human beings now changed that.
0:41:42 > 0:41:46They'd learned how to increase the food supply
0:41:46 > 0:41:50far beyond that which occurred naturally.
0:41:51 > 0:41:55It was a crucial moment in the history of this planet.
0:41:55 > 0:41:59The number of human beings began to increase.
0:42:04 > 0:42:10This strange, miniature house wasn't built for occupation by human beings.
0:42:10 > 0:42:14Instead, it shelters the most important commodity
0:42:14 > 0:42:16in this Dogon village in Mali.
0:42:16 > 0:42:19It's a granary. It contains millet.
0:42:20 > 0:42:25Millet is the most important thing in Dogon life.
0:42:25 > 0:42:29The year revolves around planting and harvesting it.
0:42:29 > 0:42:33There are more houses for it in a village
0:42:33 > 0:42:35than there are houses for humans.
0:42:35 > 0:42:40The first music that a baby in Dogonland is likely to hear
0:42:40 > 0:42:43is its mother pounding millet.
0:42:52 > 0:42:58Now that people did not have to be permanently on the move to find food,
0:42:58 > 0:43:01they had more time for other things.
0:43:01 > 0:43:06Ritual and the arts flourished as never before.
0:43:21 > 0:43:23For the Dogon, harvest is finished.
0:43:23 > 0:43:26The granaries are full.
0:43:26 > 0:43:28It's time to celebrate.
0:43:41 > 0:43:45As more food became more easily available,
0:43:45 > 0:43:49so the human population continued to increase.
0:43:49 > 0:43:52Villages grew into towns.
0:43:52 > 0:43:54Towns became cities.
0:44:06 > 0:44:12This immense, low mound may look as though it's covered with gravel,
0:44:12 > 0:44:17but if you look closely, it is composed of fragments of pottery.
0:44:17 > 0:44:22It's the site of the oldest city in Africa below the Sahara,
0:44:22 > 0:44:29and this is the remains of 2,000 years of continuous human occupation.
0:44:29 > 0:44:32To make things even MORE remarkable,
0:44:32 > 0:44:36the city itself is still flourishing over there.
0:44:36 > 0:44:38This is Djenne.
0:44:38 > 0:44:41In its heart stands the mosque,
0:44:41 > 0:44:45the oldest and largest mud building in the world.
0:44:47 > 0:44:53And around it, a market that has been held here since medieval times.
0:44:55 > 0:45:00Djenne's growth was closely tied to that of a neighbouring city,
0:45:00 > 0:45:04the fabulous Timbuktu that lay farther up the Niger.
0:45:04 > 0:45:09Between them, the two dominated the trade across the Sahara.
0:45:09 > 0:45:12Into these markets
0:45:12 > 0:45:17came traders from North Africa who crossed the Sahara by camel caravan
0:45:17 > 0:45:19to look for slaves, gold and ivory.
0:45:19 > 0:45:22And trade still dominates the city.
0:45:27 > 0:45:32Quelle poisson? ..De la fleuve? ..Oh. INDISTINCT REPLY
0:45:33 > 0:45:36Great numbers of people living together
0:45:36 > 0:45:41meant some could avoid the daily chore of producing food.
0:45:41 > 0:45:46They could become craftsmen and exchange what they produce for food.
0:45:46 > 0:45:51So it became possible for technologies to develop,
0:45:51 > 0:45:56for arts and sciences to flourish, for people to put up huge buildings.
0:46:06 > 0:46:11This is Tikal, the capital of the Maya people,
0:46:11 > 0:46:15who built the tallest constructions in the whole of the New World,
0:46:15 > 0:46:18until skyscrapers were put up in New York
0:46:18 > 0:46:21at the beginning of the 20th century.
0:46:26 > 0:46:30At the height of Tikal's glory, about 1,300 years ago,
0:46:30 > 0:46:36the city covered a vast area, at least double that of ancient Rome.
0:46:38 > 0:46:43The city centre was filled by thousands of temples and houses,
0:46:43 > 0:46:46only a fraction of which can be seen today.
0:46:48 > 0:46:54The inhabitants excelled at every form of civilised activity.
0:46:54 > 0:46:59They were accomplished builders, superb sculptors and painters.
0:46:59 > 0:47:04Expert astronomers, they measured the solar cycle with great precision.
0:47:08 > 0:47:10They constructed complex calendars
0:47:10 > 0:47:14to which their religious beliefs were tied.
0:47:14 > 0:47:16And they devised a system of writing
0:47:16 > 0:47:21that was, in its time, the most advanced in the Americas.
0:47:23 > 0:47:26Having achieved such skills and knowledge,
0:47:26 > 0:47:29when and why were their cities abandoned?
0:47:30 > 0:47:35Fortunately, we do have some clues, certainly as to date.
0:47:35 > 0:47:41The Maya recorded their history in great detail on stones like this.
0:47:41 > 0:47:46The latest inscription to be found in the ruins of city
0:47:46 > 0:47:49can be dated to 869AD.
0:47:49 > 0:47:51After that, the city falls silent,
0:47:51 > 0:47:54the inhabitants disappear
0:47:54 > 0:47:58and classic Maya civilisation is coming to an end.
0:47:58 > 0:48:03The explanation of why Tikal and all the other Maya cities collapsed
0:48:03 > 0:48:06is the subject of hot debate.
0:48:06 > 0:48:09But now new evidence has been found.
0:48:09 > 0:48:12To see it, you need to get above the city.
0:48:23 > 0:48:27From there, you can see hints of occupation
0:48:27 > 0:48:32that extend far beyond the jungle-covered ruins of today.
0:48:32 > 0:48:36Cameras in space have revealed aqueducts, canals
0:48:36 > 0:48:39and fields buried under the soil -
0:48:39 > 0:48:42proof that when temples were built,
0:48:42 > 0:48:45the forest had already been felled
0:48:45 > 0:48:49and replaced by a great expanse of cultivated fields.
0:48:51 > 0:48:55As the population of the city grew, probably to 60,000,
0:48:55 > 0:48:58farmers struggled to produce enough food.
0:48:58 > 0:49:04The fertility of the fields was exhausted. Soon people were starving.
0:49:04 > 0:49:09They drifted away from the city, and gradually the jungle returned.
0:49:11 > 0:49:15But how is the fate of Tikal relevant to us today?
0:49:16 > 0:49:19When the Maya built their cities,
0:49:19 > 0:49:24there were only about 50 million people on the entire planet.
0:49:25 > 0:49:29But the Maya were unable to sustain their population
0:49:29 > 0:49:34with the technology they'd developed, sophisticated though it was.
0:49:35 > 0:49:38Then, a few centuries later,
0:49:38 > 0:49:42human beings elsewhere, with new techniques,
0:49:42 > 0:49:47began to build on a scale that dwarfed even Tikal's skyscrapers.
0:50:06 > 0:50:09Today, there are not just 50 million,
0:50:09 > 0:50:13but 6,000 million people on Earth.
0:50:13 > 0:50:16Nearly half of that vast number
0:50:16 > 0:50:20live in cities which are still growing fast.
0:50:20 > 0:50:23And all these people need food.
0:50:23 > 0:50:25We have long since utilised
0:50:25 > 0:50:29the best fertile places to grow our food.
0:50:29 > 0:50:33Now, we are having to try to do so elsewhere.
0:50:39 > 0:50:42In a desert like this one in Arizona,
0:50:42 > 0:50:46trying to cultivate anything would seem to be futile.
0:50:46 > 0:50:51With just a few centimetres of rain a year, there is no use for this
0:50:51 > 0:50:54and little enough water for thirsty plants.
0:50:54 > 0:50:57But appearances can be deceptive.
0:50:58 > 0:51:04With the right technology, even the desert can yield edible crops.
0:51:04 > 0:51:07These lush fields can only exist
0:51:07 > 0:51:12because of humanity's unique capacity to innovate and to learn.
0:51:12 > 0:51:15Our big brains have enabled us
0:51:15 > 0:51:19to discover how to add fertiliser to poor soil,
0:51:19 > 0:51:24to deal with pests with insecticide, and even bring rain to the desert.
0:51:28 > 0:51:32This "rain" has been pumped along hundreds of miles of pipes
0:51:32 > 0:51:35from a far distant water supply.
0:51:35 > 0:51:40Every year, human beings displace the equivalent of entire rivers
0:51:40 > 0:51:42to water their crops.
0:51:44 > 0:51:47In just a few thousand years,
0:51:47 > 0:51:52the revolution of agriculture has spread to nearly all human societies.
0:51:52 > 0:51:55Today, over a third of the surface of the land
0:51:55 > 0:51:59is devoted to producing food for humans.
0:51:59 > 0:52:03That has changed some landscapes in the most dramatic way.
0:52:12 > 0:52:16The rich variety of the world's natural ecosystems
0:52:16 > 0:52:19has been replaced by uniformity.
0:52:19 > 0:52:24Complex communities eliminated and changed to monocultures.
0:52:24 > 0:52:26The intricate embroideries of nature
0:52:26 > 0:52:31have been replaced by a geometric landscape of straight lines.
0:52:31 > 0:52:36All this was made possible by the technological revolution
0:52:36 > 0:52:40which started when our hands were freed,
0:52:40 > 0:52:44and we could manipulate our surroundings.
0:52:45 > 0:52:47Our ingenuity has now enabled us
0:52:47 > 0:52:52to utilise the most unlikely and unpromising corners of the Earth.
0:52:52 > 0:52:56We're even beginning to farm the oceans.
0:53:03 > 0:53:07The changes we have wrought on the surface of our planet
0:53:07 > 0:53:11are so wholesale, they're visible from space.
0:53:11 > 0:53:16As we increase, so there is less land for other animals and plants.
0:53:16 > 0:53:21But humanity can't expand its numbers indefinitely.
0:53:21 > 0:53:25Will our civilisation crumble as did that of the Maya?
0:53:27 > 0:53:30This has been the launch pad
0:53:30 > 0:53:34for humanity's greatest, most complex achievements
0:53:34 > 0:53:39and highest hopes, from space shuttles to space stations.
0:53:39 > 0:53:42And it's from here, in the year 2020,
0:53:42 > 0:53:47that our species may launch its most ambitious project yet -
0:53:47 > 0:53:52to settle on another planet, to send a mission to Mars.
0:53:53 > 0:53:57'Six, five, four, three,
0:53:57 > 0:53:59'two, one...'
0:54:10 > 0:54:16The ape that stood up on its hind legs has outgrown its planet.
0:54:16 > 0:54:21Now it seeks to travel through space to look for another.
0:54:27 > 0:54:32Could it really add Mars to its empire?
0:54:32 > 0:54:35Conditions there could hardly be more hostile
0:54:35 > 0:54:38for life that evolved on Earth.
0:54:38 > 0:54:42There, the energy-giving sunlight is only half as intense.
0:54:42 > 0:54:46Temperatures fall to more than 100 degrees below freezing.
0:54:47 > 0:54:51Will our technology be able to meet THIS challenge?
0:54:58 > 0:55:03Colonising another planet might sound like science fiction,
0:55:03 > 0:55:08but, in fact, work on solving the problems of living on Mars
0:55:08 > 0:55:11is going on right now, here on Earth.
0:55:15 > 0:55:20The first problem for those that seek to settle there
0:55:20 > 0:55:23will be, as always, to find food.
0:55:23 > 0:55:27To do that, they will have to grow plants - the basis of all our food.
0:55:27 > 0:55:30On Earth, we're beginning to realise
0:55:30 > 0:55:35that we may now be over-reliant on the few species of plant
0:55:35 > 0:55:39which provided food for 10,000 years.
0:55:39 > 0:55:43We are at last taking steps to conserve wild species
0:55:43 > 0:55:48that we have been destroying so carelessly for centuries.
0:55:50 > 0:55:55Giant greenhouses like this are astonishing technical achievements,
0:55:55 > 0:56:00but they're also proof that we now have the skill and the knowledge
0:56:00 > 0:56:05to create artificial environments almost anywhere - even on Mars.
0:56:06 > 0:56:11If we did build such structures on another planet,
0:56:11 > 0:56:15might we then contemplate spreading our species still further
0:56:15 > 0:56:18to other more distant worlds?
0:56:22 > 0:56:28This new era of exploration began when human beings landed on the moon.
0:56:28 > 0:56:33Is that as far as our species will reach? Or SHOULD reach?
0:56:33 > 0:56:38Or will our incurable urge to explore, and our growing numbers,
0:56:38 > 0:56:42lead us to print our feet on yet more new worlds?
0:56:45 > 0:56:48'The Eagle has landed.
0:56:50 > 0:56:53'It's one small step for man...
0:56:54 > 0:56:57'..one giant leap for mankind.'
0:57:02 > 0:57:053.5 million years separate the individual
0:57:05 > 0:57:09who left these prints in the sands of Africa
0:57:09 > 0:57:13from the one who left them on the moon.
0:57:13 > 0:57:15A mere blink in the eye of evolution.
0:57:15 > 0:57:18Using his burgeoning intelligence,
0:57:18 > 0:57:22this most successful mammal has exploited the environment
0:57:22 > 0:57:25to produce food for an increasing population.
0:57:25 > 0:57:29Despite disasters when civilisations overreach themselves,
0:57:29 > 0:57:34that process continues, indeed accelerates, today.
0:57:34 > 0:57:39Now mankind is looking for food, not just on THIS planet but on others.
0:57:39 > 0:57:44Perhaps the time has come to put that process into reverse.
0:57:44 > 0:57:48Instead of controlling the environment for the population,
0:57:48 > 0:57:52perhaps it's time we control the population
0:57:52 > 0:57:55to allow the environment's survival.
0:58:14 > 0:58:18Subtitles by BBC Broadcast
0:58:18 > 0:58:21E-mail subtitling@bbc.co.uk