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00:07Africa. Two million years before your time. And life on Earth has a brand new face.
00:25First, our ancestors walked on two legs and stood out from all other animals.
00:34Now we'll meet creatures who took the next vital step from ancient apes to us.
00:42Creatures perhaps like him.
00:53I'm traveling back in time.
01:00With science we can build a picture of our past.
01:05And bring our dead ancestors to life.
01:11Join me on a journey through our human story.
01:31We've arrived at a critical moment in our story. A crossroads in our evolution.
01:39I'm right here, where there's not just one species of ape man on the savannah, but several.
01:45One of them could be our ancient ancestor. But which? Meet Paranthropus boisei. Boisei for short.
01:55You know, you can sometimes discover an enormous amount about how a species behaves from just one or two simple
02:03observations.
02:04And these boisei are no exception. If you had to pick one species from modern times from the 21st century
02:13that they remind me of, it would be a gorilla.
02:21This is a full grown adult male. And this, an adult female.
02:31He's taller than her at around four and a half feet. And he weighs nearly twice as much.
02:38This difference tells us about how they live. He's the dominant male of his troop. His share bulk and power
02:45holds the rest together.
02:47And he alone mates with all the females. And she's not just any female. She's the most senior in his
02:56harem.
02:58But that position could be under threat. It's a young female looking for a new troop to join.
03:12But a stranger, with their capacity to upset the balance of power, is always a disturbing sight for a settled
03:20troop of apes.
03:25To win herself a place in the group, the newcomer must be accepted by both the dominant male and, to
03:31an extent, the other females.
03:45Whatever the potential of trouble, the dominant male is already interested.
03:57He seems keen to add to his harem, whatever the consequences.
04:10By piecing together what we know about these creatures from the bones they will one day leave behind,
04:16modern scientists think they have an idea of the part they play in the evolution of you and me.
04:25But by being here, in East Africa, two million years ago, we can also do something else.
04:33We can actually see for ourselves the everyday lives of individual ape-men.
04:40And we can discover what it is about them which lives on in us.
04:47And to do that, we're going to need to follow the lives of more than just one type of ape
04:52-man, the Boisei.
05:06We're also going to have to take a close look at the lives of ape-men like these, Homo habilis.
05:14And it doesn't remind me of anything alive in the 21st century.
05:29The Africa of two million years ago is one of the most diverse habitats on Earth, with creatures both familiar
05:38and strange.
05:41Dynophilis, the full saber-tooth.
05:46The giant elephant-like dynotherium.
05:51The browsing and psilotherium.
05:56Unlike anything we can imagine in the 21st century, there are the many two-legged ape-men.
06:04There's the habilis, impish scavengers.
06:09Rudolfensis, their slightly bigger rivals.
06:15A gorilla-like Boisei.
06:23A whole range of upright apes.
06:26Each of them has a different strategy for survival.
06:30And from one, we've inherited our own way of life.
06:34The question is, which one?
06:37Who do you most recognize in yourself?
06:40Which one is our ape ancestor?
06:45To find out, we must first ask, why there are so many to choose from?
06:51Why, two million years ago, do we find so many different ape-men?
06:57Well, one explanation lies not on Earth, but in space.
07:02It turns out that it's all the fault of the Sun.
07:15As the Earth orbits the Sun, it's always on a slight angle. A tilt.
07:20And it's this that gives us our seasons. The bigger the tilt, the more severe they'll be.
07:27But the tilt is always changing.
07:30And around three million years before the 21st century, it was getting bigger.
07:36On Earth, the summers got colder.
07:40At the Poles, ice made during the winter didn't melt properly during the summer.
07:46Year by year, the polar ice caps grew.
07:49They locked up huge amounts of the planet's water.
07:55The Earth began to dry out.
07:59In East Africa, vast areas of rainforests and woodland died off, leaving a hodgepodge of scattered trees.
08:09And an alien species took hold.
08:18It's grass.
08:20And with alien plants came alien animals.
08:27With bizarre adaptations to exploit the new foods.
08:32Like the improbable four stomachs of an alien that can digest tough grass like a cow grass.
08:40And new animals create new food.
08:44And new creatures have evolved to eat it.
08:48And this is the key to the puzzle of why there's so much diversity of ape-man species at this
08:54time.
08:54Two million years before the 21st century.
08:59Africa now offers an incredible variety of things to eat and ways to live.
09:04And all kinds of animals have evolved to live here.
09:09From the Encilotherium to our ape-men.
09:15Take these reeds for example.
09:21I can't eat this kind of food, but there's a species of ape-man around here that can.
09:36The Poiseum.
09:38These magnificent creatures are adapted brilliantly to make the most of the foods that surround them.
09:48The Poiseum.
09:49Powerful mussels in their cheeks.
09:51An enormous jaw.
09:52And back teeth, four times the size of our own.
09:55Means that they can eat the toughest vegetation.
09:58Like the roots of these reeds.
10:05Their specialisms make the Poisei incredibly successful.
10:09We're months into an exceptionally long dry season.
10:13And many animals are finding the going hard.
10:16But for this troop, the pickings are easy.
10:19With ample food within easy reach, there's plenty of time left for any ape-man's favourite pastime.
10:27Sex.
10:34The new female is still hovering around the troop.
10:38Waiting for a chance to get close to the dominant male.
10:54For the existing queen of the harem, the newcomer could be a real threat.
11:06But the dominant male has a simpler view.
11:09A new female isn't a threat, but a challenge.
11:22Although almost entirely vegetarian, we know from tell-tale signs in their teeth that there's one kind of meat a
11:29Boisei can't resist.
11:33Termites.
11:40Doubly irresistible when on the menu of a romantic meal for two.
12:13Grooming is how all apes bond with each other.
12:17And the Boisei are no exception.
12:20A newcomer has become a new favourite.
12:32But whether she'll prove as popular with the rest of the troop remains to be seen.
12:39If the Boisei lead comfortable lives with mostly only domestic concerns,
12:45how are the other local ape-men fairies?
12:51These are the Homo habilis we met earlier.
12:53They are finding the long dry season considerably tougher than their Boisei neighbours.
13:04This is the habilis dominant male.
13:06And he's found a bee's nest.
13:09His position as leader depends mainly on his ability to find food.
13:13Though tricky to get at, and not really offering much of a meal,
13:18desperation has forced him to try a raid.
13:25That's one of the females the dominant male mates with.
13:29For the moment she'll stick with him.
13:31But unless the troop finds food soon, it'll begin to break up.
13:45This is our cheeky friend who attacked the car, eating his first meal for days.
13:54The truth is that habilis are struggling.
13:58And there's a simple reason why.
14:02They don't have the special adaptations of the Boisei.
14:06And without big teeth and powerful jaws,
14:09the habilis simply can't live off the kind of tough vegetation
14:12seen at the end of a dry season.
14:15A Boisei speciality like reed roots, or this hardened acacia pod,
14:20isn't exactly on their menu.
14:25To make up for their lack of specialist eating equipment,
14:28Habilis have had to take a very different tap.
14:32They developed into the archetypal jack of all trades.
14:37Inquisitive scavengers, prepared to try anything to survive.
14:42But it's a difficult way to live.
14:44Because while the Boisei know exactly where to find their food,
14:48a meal for habilis could be anywhere.
14:50To find it, you need to be a tireless investigator.
14:55But simply being inquisitive is no guarantee you're going to find a square meal.
15:01You also need a bit of luck.
15:08Oi, you!
15:16And good luck is something that this troop hasn't had much of recently.
15:23In fact, the troops' plight is desperate.
15:31But their inquisitive way of life has given Habilis a few tricks.
15:37Because if you're inquisitive, you investigate mysteries.
15:42Like, why do vultures gather together?
15:47The answer, of course, is that they've spotted food.
16:05An eland has been caught and killed on the savannah.
16:08Carcass is a godsend.
16:11Not only is it food, it's valuable protein and animal fat.
16:15Unlike the Boisei, Habilis eat meat.
16:24Normally, the dominant male would approach a carcass wearity.
16:28Particularly one so fresh.
16:30Whatever killed it could be still around.
16:38But today, his hunger and the troops' excitement outweighs any caution.
16:44But the young male seems quite wary.
16:57But other ape men have also spotted the vultures.
17:07Habilis aren't the only scavengers around.
17:10A rival species.
17:12Rudolfensis has also come for the meat.
17:22Habilis and Rudolfensis are remarkably similar.
17:25And are frequently driven to fight for food.
17:53It's the dominant male's moment of triumph.
17:57He's the dominant male's moment of triumph.
17:57He's led his troop to food.
17:59And thinks he's successfully defended it.
18:19The troop are distraught.
18:21Not only have they lost a valuable meat, they are now also leaders.
18:30With no obvious candidates to succeed the dominant male, the Habilis have reached their lowest point.
18:38There is little for the troop to do now but wait.
18:41And hope that their luck may change.
18:45And hope that their luck may change.
19:12The way the ид gap is also brought.
19:15There is little семь-还是 will be the latter.
19:19There is little for the troop to lead in.
19:22There is little one transmitted male.
19:29There is little one lies behind it.
19:30There is little one inside.
19:30There is little one inside.
19:33There is little one that has helped you save the human.
19:34To be good at the maximum of the troop to arrive.
19:37There is little one inside.
19:40There is little one inside.
19:53The long dry season is at last at an end.
20:02The onset of rain brings relief across the savannah.
20:13The Boisei sometimes display when it starts raining.
20:17No one knows exactly why.
20:23Perhaps it's out of sheer exhilaration.
20:33Or maybe they just hate getting wet.
20:36But it's common behaviour amongst apes in your own time.
20:43And sadly for Boisei, just like modern day gorillas, they're useless at building shelters.
20:57The Boisei and the Habilis embody two very different approaches to survival.
21:03Habilis are the jack of all trades, the Boisei the master of just one.
21:09But which trait will be passed on to future ape men?
21:13What will we inherit in two million years' time?
21:17Well, although the Boisei have a lifestyle that's incredibly successful, it's only a success
21:23as long as the world in which they live doesn't change.
21:27And if there's one thing you can bet on about the environment or the weather, is that nothing
21:32stays the same forever.
21:39Let's take a glimpse of what's to come.
21:49Over the next several hundred thousand years, the same forces which created the vast range
21:55of environments in Africa will continue to shape the continent.
22:06New habitats will appear, along with new animals to exploit them.
22:11While old ways of life will die, an old species of animal with them.
22:16Caught up in all this change, the Boisei will find themselves in a world they're simply unprepared for.
22:31But for the moment, all that lies hidden in their future.
22:49The dominant male Boisei rejoins his heart to find its number expanded by one.
23:00The dominant female has taken the newcomer under her wing and subtly shifted the balance
23:06of power.
23:17He may well find that he has some making up to do.
23:25Their successful way of life hides the fact that the Boisei have put all their evolutionary
23:31eggs in one basket.
23:33The trouble with being a specialist is that you end up getting left behind.
23:39Perhaps they won't be able to adapt to vegetation changes, or new animals will make their lives
23:45difficult.
23:47The truth is, were we to come back to this glade in a few hundred thousand years time,
23:52these magnificent creatures, the Boisei would have gone.
24:06The only legacy that these lovely animals will leave will be these, fossilized bones.
24:14nothing from these ape men will live on.
24:27But the part that Haberis plays in the story of you and I will be very different.
24:40Now that the vultures have had their fill, there will be precious little meat left on the
24:45carcass for anyone else.
24:48But the Haberis have a secret weapon.
24:51Their scavenging, inquisitive lifestyle has made them quick-witted and inventive.
24:57And it's led to a real breakthrough.
25:04Haberis are the first creatures on earth to be able to make stone tools.
25:09It's a hugely important leap forward.
25:13The stone tools mean that they can live off an amazing range of different foods.
25:22First, they have to be able to get to them.
25:29That's where Haberis' second secret weapon comes in.
25:35Eating meat has brought Haberis the essential protein and fat to allow the development of their brains.
25:43In fact, Haberis' brains are almost half as big again as those of the Boisei.
25:53In other words, meat has enabled them to grow smarter.
25:59Smart enough to know that you stand a much better chance of scaring off a lion if you work as
26:06a team.
26:09Welcome to the new world of ideas.
26:23Although the Elan carcass has almost been totally stripped of meat, there is one last meal left.
26:32Bone marrow, one of the most nutritious foods on the savannah.
26:37Neither lion nor vultures can reach it.
26:41Yet Haberis' new tools seem almost purpose-built for the job.
26:47The troop may have also solved their leadership problem.
26:51The young male's actions in getting food have given him a real status.
26:59It seems likely that he will now take over as the dominant male.
27:10Habilis' jack-of-all-trades way of life means that they have a chance of surviving in an ever-changing
27:17world.
27:18It's this trait that will live on and be essential in us.
27:26So it's Habilis which has taken the next step towards being you and I.
27:32By being able to live in different ways instead of being trapped in just one,
27:37it's begun to free itself from the rules governing all other life on Earth.
27:43Does this mean that it's Habilis which will dominate Africa in millennia to come?
27:49You might think so.
27:53But the end of our story has a strange twist.
27:57Round about now, two million years ago, an ape-man appears in East Africa
28:02which does what Habilis does, only better.
28:07But they have something else, which means that they could end up hounding Habilis out of existence.
28:16They are called Homo agaster.
28:25And they are the creatures we are going to meet next on the journey from apes to us.
28:47We'll see you next time.
28:48Bye.
28:59Bye.
29:00Bye.
29:04Bye.
29:08You