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The Albertine Rift, features deep lakes, tall mountains, and rich montane forests that support rare wildlife...
非洲艾伯丁裂谷在非洲有个景致特殊,能让你视觉震憾万分的地方,这地区的生物多样性,让人啧啧称奇,那就是非洲的艾伯丁裂谷,在这里物种突变和演化狂野失控,创造出地
非洲艾伯丁裂谷在非洲有个景致特殊,能让你视觉震憾万分的地方,这地区的生物多样性,让人啧啧称奇,那就是非洲的艾伯丁裂谷,在这里物种突变和演化狂野失控,创造出地
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AnimalsTranscript
00:00The Albertine Rift, forged by fire and geological violence, generated mutants and evolutionary
00:10mysteries.
00:11It pushed up Africa's tallest mountain range, where unique creatures evolved to survive
00:17in an alien environment.
00:21In toxic swamps below are air-breathing fish and prehistoric-looking birds.
00:33The rift created the mighty Congo River, dividing our closest relatives into societies of love
00:41and lore.
00:44These powerful forces shape all life in the Albertine Rift, and may ultimately have driven
00:51our ancestors to evolve from tree-dwellers into upright walkers.
01:18Africa, a vast continent full of exotic and bizarre creatures.
01:23But one region boasts a richer diversity of life than anywhere else, the Albertine Rift.
01:32Here, mutation and evolution have gone wild, creating species found nowhere else on Earth.
01:47The Albertine Rift is the southern end of a massive scar that runs through Africa.
01:53Africa, one of the world's great geological wonders.
01:59Just one percent of Africa, this wildlife hotspot has more species of mammal, bird, reptile and
02:08fish than anywhere else in the continent.
02:15Geological fury has torn and twisted the Earth into a stunning variety of landscapes.
02:22Ice-capped mountains, dry savannah, dense jungles and toxic swamps.
02:38Each environment forces life to mutate and adapt to its unique challenges, or perish.
02:48To the west of the Albertine Rift lie vast jungles, crawling with life.
02:59This is a primate's paradise.
03:02In the area around the Albertine Rift, there are more species of monkey and ape than anywhere
03:09else on Earth.
03:14They have mutated and evolved to take advantage of the natural supermarket provided by hundreds
03:20of species of trees.
03:23The branches are their highways.
03:26It's safer to stay 40 meters off the ground than go down to the forest floor where predators
03:32lurk.
03:34But one species of monkey takes traveling through the trees to extreme lengths.
03:47The red colobus, unique to East Africa.
03:52They have learned to use branches as springboards, bouncing up and down on them to launch them further
03:59between trees.
04:12Using this trick, red colobus can jump gaps in the canopy over 16 times their own body length.
04:19The equivalent of a man leaping a whole basketball court.
04:31Young red colobus must soon learn to make these death-defying leaps if they want to keep
04:37up with the troop.
04:45It can take a little while to master the art.
04:54Red colobus need to be acrobats because there is another primate living in these trees.
05:00One that can turn from a peaceful vegetarian into a savage killer.
05:08Chimpanzees' favorite food is fruit, and they can feed on 300 different species of plant
05:13in a year.
05:15But these apes have a dark side.
05:19Sometimes fruit is not enough, and chimps get a taste for meat.
05:25And red colobus are their favorite prey.
05:36A brave few stay to fight to protect the females and babies.
05:46They stand no chance against the intelligent and well-drilled apes.
06:03With chilling ferocity, the chimpanzees tear the monkey carcass apart.
06:11Fights and arguments break out.
06:15The dominant males take the choicest cuts.
06:29In this primal world of life and death, there is one outstanding evolutionary survivor.
06:41A deadly clan that has prowled the undergrowth since the time of the dinosaurs.
06:50Known in Africa as Siafu, they are a fearsome predator.
07:02They are African driver ants.
07:14Siafu are ruthless killers.
07:16They devour almost anything they find.
07:26Each ant is tiny, but together they form a single super predator.
07:34There can be 20 million driver ants in a colony.
07:39All of the workers and huge soldiers are daughters of a single queen.
07:45This is the largest family on earth.
07:51Siafu are closely related to ants on other continents thousands of kilometers away.
07:57But how?
08:00Driver ants are evidence that Africa was once part of an ancient supercontinent.
08:06Gontwana was home to their ancestors before it fractured into many smaller continents.
08:13One of the largest fragments became Africa.
08:17As it drifted across the equator, the center of this huge land became covered in dense tropical jungle.
08:27The rich environment allowed mutation and evolution to go wild.
08:33The rainforest filled with bizarre creatures of all shapes and sizes.
08:39And all of them were potential prey.
08:43The original ants of Africa hid below ground.
08:47But one group, the Siafu, emerged from the depths to prey on the rich life of the forest floor.
08:55Here, the driver ants mutated into terrifying hunters.
08:59Their legs became longer to run down their unfortunate prey.
09:04Their heads and jaws grew larger to tear them to pieces.
09:11But there is one primitive feature they retain from their underground ancestors.
09:17Siafu have no eyes.
09:22The millions of blind ants communicate using only touch and scent.
09:27They obey simple traffic rules by following scent trails left by their co-workers.
09:36Constantly sharing information and helping each other, ants are the original social network.
09:49At certain times of the year, juicy insects known as sausage flies stumble into the path of these deadly predators.
10:00The helpless sausage fly seems doomed.
10:04But this is not food.
10:06It is a male of the same species.
10:13Sausage fly is another name for the male Siafu, one of the largest ants in the world.
10:21This male flew away from his colony soon after he hatched.
10:25Once he reaches sexual maturity, he is drawn back to the scent of a column of female ants.
10:33He runs across a raiding party and is quickly swarmed.
10:37The female workers kidnap him, chew off his wings, and carry him back to their underground nest.
10:45The sausage fly will spend the rest of his short life imprisoned as a sperm donor to the queen.
10:54Captive sausage flies father millions of larvae that form the next generation of the driver ant colony.
11:03Siafu shift their entire nest every few weeks.
11:08Security is on high alert when the new brood are moved.
11:12Thousands of huge soldiers stand ready to attack any threat.
11:18This new generation will require even more food, and so millions of marauders swarm across the jungle floor.
11:27But some creatures have evolved to fight back.
11:31This slimy slug seems like another helpless victim of the Siafu.
11:37The ants quickly attack the slug, and it seems done for.
11:43But it has a brilliant escape plan.
11:46The slug oozes extra sticky slime, which gums up the ants' jaws.
12:04Alone, it's outfoxed an army of predators.
12:08The slug casually cruises away, leaving the deadly ants glued together in its wake.
12:17For millions of years, the Siafu terrorized the jungles that covered the heart of Africa.
12:26The center of the entire continent was one big, flat rainforest.
12:33But massive geological forces were about to change the heart of Africa.
12:40Forever.
12:42Thirty million years ago, the Earth's tectonic plates beneath Africa began to drift apart.
12:49Over millions of years, a great rift in the crust spread from Ethiopia southwards for thousands of kilometers.
12:59In the center of Africa, the great rift split into two branches about 12 million years ago.
13:06The western one is known as the Albertine Rift.
13:12The giant fracture in the Earth changed the landscape and climate.
13:18It divided the center of Africa in half.
13:22One side dry, the other wet.
13:26Driving evolution in dramatically new directions.
13:34In the vast Congo basin, west of the rift, lies one of our planet's great forests.
13:42The Congo rainforest covers over 1.6 million square kilometers.
13:48Four times the size of California.
13:52In its depths, lives a mysterious mutant first discovered by European explorers only a century ago.
14:06A living fossil named the Okapi.
14:15Okapi are the size of a horse, brows like a deer, and have stripes on their legs like zebra.
14:25But their only living relative is an evolutionary puzzle.
14:34The vital clues to this family mystery are the lumps on top of the Okapi's head.
14:40They're not horns.
14:41They're fur-covered growths of cartilage called ossicones.
14:47There is only one other animal in the world with lumps on its head like this.
15:01Like the Okapi, the giraffe has ossicones, and they are even larger.
15:15Female giraffes have two.
15:19While males have an extra one in the middle.
15:27How can the Okapi and giraffe be so closely related, but so different?
15:32The answer lies deep in the past.
15:38The Okapi and giraffe are the only living survivors of an ancient group of mammals.
15:48Today, the giraffe is one of Africa's most iconic animals.
15:53Yet curiously, its ancestors lived in Europe and Asia.
16:01These original prototypes split into many bizarre forms.
16:10Some became giants, like the elephant-sized civithereum.
16:18They browsed the open grasslands of Asia, then moved into northern Africa.
16:24The many relatives of the civithereum spread across southern Europe, Asia, and Africa, until the climate began to change radically.
16:35As Asia and Europe dried up, they became extinct.
16:42Only those much further south, in the heart of Africa, survived.
16:47But as the great rift tore through their land, these survivors were forced into two very different evolutionary directions.
17:00In the dark and dense jungles of the West, the ancient mammals kept their short legs and compact body shape.
17:09That's why the Okapi is a living fossil.
17:12It has stayed unchanged for millions of years, and is still a solitary phantom of the deep forest.
17:21On the east of the rift, the climate became drier, and the jungles gave way to open grasslands.
17:29In this parched environment, vegetation was harder to find.
17:35Browsers with greater reach had an advantage, and so they evolved into the long-necked giraffe so familiar to us
17:42today.
17:46The great African rift separated these ancient survivors, creating two very different species.
17:59Only two of this bizarre family of mammals still walk the earth.
18:04But intriguing clues found in northern Africa hint that a third species survived into human times.
18:12A strange animal in ancient desert rock art is thought by many to be a species of civotherium.
18:20These giant creatures may have survived the climate change that drove most of their relatives into extinction,
18:27but vanished from the earth around 8,000 years ago.
18:36The formation of the Albertine Rift turned the flat jungles of central Africa into a tortured landscape,
18:43thrusting up completely new terrains.
18:49The most spectacular are the Rearwin Zoris, the tallest mountain range in Africa.
18:57These aren't volcanoes.
18:59They are a single slab of the earth's crust, pushed up out of the ground by titanic geological forces.
19:12As the rift tore through the continent, immense pressure on the edges squeezed up a block of ancient rock,
19:20120 kilometers long.
19:23The biggest rift mountains on earth.
19:33Ice, wind and rain have carved the uplifted rock into peaks over 5 kilometers high.
19:45The Rearwin Zoris are one of Africa's most unusual and challenging environments.
19:52Towering mountains, capped with ice and glaciers, sitting right on the equator.
20:03Moisture-filled air slams into the mountains and unloads its cargo of water.
20:10Every year, over two and a half meters of rain falls here.
20:14That's why, in local language, Rearwin Zori means the rainmaker.
20:23All this moisture cloaks the mountains in mist.
20:31And feeds lush cloud forest around their base.
20:38The mossy forest is home to one of the strangest creatures to live in these or any other mountains.
20:53The Rearwin Zori three-horned chameleon.
20:56A true evolutionary freak.
21:03This dinosaur-like lizard is found only in the foothills of this one mountain range.
21:15Only males have mutated to have triple horns, which they use to defend themselves in territorial battles.
21:27Above 3,800 meters, the vegetation of the Rearwin Zoris changes dramatically.
21:37This is an alien landscape, dominated by gigantic plants.
21:44These strange, otherworldly species grow bigger here than anywhere else in the world.
21:55Lobelias, which in other places only grow 50 centimeters high, tower 10 meters into the mist.
22:05These alpine giants must cope with extreme temperature ranges.
22:13The sun blazes during the day.
22:18But as soon as it sets, the temperature plummets below freezing.
22:26There are no real yearly seasons in the Rearwin Zoris.
22:30Up here, it is summer every day, and winter every night.
22:37Few animals can cope with this altitude and extreme temperature range.
22:45But one beautiful and tough little bird has learned to survive where most cannot.
22:53The scarlet-tufted malachite sunbird is a high-altitude specialist.
23:00Males feed on the nectar of giant Lobelias, the only animal that pollinates the giant plants.
23:08This environment is too windy and harsh for flying insects like bees to survive.
23:18Sunbirds need a lot of fuel to sustain this fast pace of life.
23:22A third of his day is spent feeding.
23:29The sunbird does not just randomly visit flowers.
23:33That would waste precious energy.
23:35He has a detailed mental map in his head of all the Lobelias in his territory,
23:40and uses it to find flowers that he hasn't visited recently.
23:50As the sun sets, the sunbird faces his greatest challenge.
23:56The temperature rapidly drops below freezing.
24:02Winter is coming, as it does every night up here.
24:08To conserve energy, the sunbird does something utterly surprising.
24:15He forces his body temperature and metabolic rate to crash,
24:20something no other bird in Africa can match.
24:26As the mountain air gets colder and colder,
24:30the sunbird's metabolic rate slows down by almost 70%.
24:35His body temperature plunges by 15 degrees,
24:39and he enters a kind of temporary hibernation called torpor.
24:45In this remarkable way, he conserves energy and is able to survive the bitter cold of the ruined Zori's night.
25:11As the sun creeps above the rugged peaks, the sunbird reactivates his metabolism,
25:17and his body temperature quickly returns to normal.
25:20He's ready to face another day.
25:29Below the towering Rirunzori Mountains is a very different environment that drives life to its limits.
25:40While the edge of the Albertine Rift was pushed up into mountains,
25:45the center sank and over time filled with water to form deep lakes.
25:53Around the edges of the lakes are murky swamps.
26:01Every creature that lives here must be highly specialized to survive.
26:07The Jakana has evolved mutant feet that spread its weight and let it walk across floating lily pads.
26:16Up here, it's easy to see where you're going.
26:20But below the surface, it's a dark and different world.
26:25The stagnant water is murky and often critically low in oxygen.
26:30Conditions are so toxic that some mutants have evolved astonishing adaptations.
26:47The African lungfish is a bizarre and primitive creature that has remained unchanged for 350 million years.
27:00It breathes through lungs, which allows it to survive on land.
27:05At least for a while.
27:15The lungfish will never win any beauty contests.
27:18But it is a hero in the evolution of life on Earth.
27:24Lungfish are the closest living relative to ancient creatures that made the leap from swimming in water to walking on
27:31land.
27:33Its long, tentacle-like fins look nothing like legs, but the African lungfish uses them to walk across the bottom
27:42of swamps.
27:43He inflates his lungs and floats the front of his body off the bottom, then moves his back fins and
27:50alternating steps to propel himself along.
27:53It's not exactly walking, but it is the first baby step in an evolutionary path that led to creatures of
28:02the water invading the land.
28:08It may be an evolutionary pioneer, but lungfish get no respect from a feathered monster that makes these swamps its
28:18home.
28:19The Shoebill, a prehistoric-looking bird unique to East Africa.
28:26The Shoebill prefers to hunt in these low-oxygen waters because it knows the one weakness of its favorite food.
28:38Lungfish must eventually come up for air.
29:11A vicious hook on the end of their enormous bill has evolved especially to seize hold of slippery fish.
29:23The lungfish are nutritious, but slimy.
29:26After it swallows one, the Shoebill always takes a mouthful of water to wash out the taste.
29:35This bizarre and rare swamp predator has no close relatives.
29:40It looks like a mixture of a stork, a pelican, and a heron.
29:44But it's an evolutionary oddity.
29:48There is nothing like the Shoebill anywhere else on Earth.
29:57The lungfish isn't the only fish in these toxic waters to evolve extreme survival strategies.
30:07Professor Lauren Chapman studies another unique group of swamp dwellers.
30:15The mormyrid fishes are a large and species-rich group of fishes that are found only in Africa, nowhere else
30:24in the world.
30:25For a long time, these fish were a mystery to science.
30:30How do they orientate themselves and find each other in swamps so dark and impenetrable?
30:37Scientists only recently discovered the answer.
30:41To survive here, mormyrids have evolved an extraordinary ability.
30:47They use pulses of electricity to hunt and communicate.
30:53And then we'll see if we can get a good signal here.
30:57Lauren and her research team use a clever technique to detect and measure this electric super sense.
31:04One thing that's really interesting is that we can translate the pulses into sounds.
31:12And to do that, we put paired electrodes under the water.
31:19And the electric pulses that the fish emits are translated into a sound that we can hear.
31:36A special organ at the base of their tail sends out an electric field that surrounds the fish.
31:44When other creatures enter this force field, they distort its shape.
31:48The mormyrid can detect these changes using sensitive electro-receptors all over its body.
31:57This electro-sense is so fine-tuned that it can tell the difference between predators, prey, or fish of the
32:04same species.
32:08The underwater microphone reveals the hidden world of the mormyrids.
32:14They may seem calm, but there is a constant battle of electric signals going on.
32:21Every species has a unique electric signature which it uses to battle for territory,
32:29signal its social status, and even impress prospective mates.
32:36This extraordinary mutation has enabled mormyrid fish to thrive in the extreme swamp environments of the rift.
32:50Africa's Albertine rift forced the hand of evolution and created unique species of animals found nowhere else.
33:02Some of them are our closest genetic relatives.
33:09Chimpanzees share over 99% of our DNA,
33:13and like humans, are noisy, curious, intelligent, and above all, social.
33:20They live in groups dominated by an alpha male and his gang of lieutenants.
33:31Each chimp group jealously defends its territory.
33:35Males form alliances and security patrols that will attack and kill any intruders they find.
33:44When the alpha male and his lieutenants hear a stranger on their turf,
33:49they scramble into action.
34:11The intruder quickly retreats.
34:13He is lucky to escape with his life.
34:19Not far away, another highly intelligent ape also makes its home in the jungles of Central Africa.
34:32At first glance, they look like chimpanzees, but they are a completely different species.
34:39These are bonobos, a mysterious and shy dweller of the deep jungle.
34:45Bonobos are similar to chimps in many ways.
34:49They both climb the canopy in search of fruit and live in tight social groups with strong family bonds.
34:56But there is one remarkable difference.
34:59Unlike the violent chimpanzees, bonobos are peaceful and caring.
35:10In fact, they are often described as the hippies of the primate world.
35:17These two species of ape live in the same jungle environment.
35:22How did they evolve such different behavior?
35:29The key to this mystery is raging water.
35:34Local tribes call it the river that swallows all rivers.
35:39But to us, it is known simply as the Congo.
35:45The mighty Congo River is 4,700 kilometers long and up to 13 kilometers wide.
35:55Before it formed, there was only one kind of chimpanzee in these jungles.
36:04But the awesome forces of the Albertine Rift, yet again, drove evolution in strange directions.
36:14For millions of years, the Congo Basin contained a huge lake fed by a river.
36:22As the Albertine Rift began to push up mountains and highlands on the eastern edge of the basin, the river
36:29slowly bent around into a horseshoe shape.
36:33Eventually, it reached the Atlantic Ocean and drained away the lake, leaving behind one of the world's great waterways.
36:47This impassable barrier split one ape species in two.
36:57Chimpanzees are spread across 22 African countries, all on the north side of the Congo River.
37:07Arguments in chimp groups are solved by aggressive threats and violence.
37:13Male chimps battle each other for food, mates, and social status.
37:20On the other side of the river, females rule a totally different society.
37:29Bonobos are only found in one small area south of the Congo River, in the forests of the Democratic Republic
37:36of Congo.
37:44Biologists only realized bonobos were a unique species in 1929, making them the last great ape to be discovered by
37:53science.
38:04Dr. Gottfried Hohmann of the Max Planck Society works with the Congolese Wildlife Authority to study these elusive apes.
38:14Bonobos are wild animals, and first they avoid the presence of human beings, they run away, they hide.
38:21But if you are persistent, after a couple of months, you are able to follow them at a certain distance,
38:28and after one or two years, you can walk with them through the forest.
38:34Bonobos are physically very similar to chimpanzees, but there is one profound difference between the two apes.
38:40Bonobos and chimpanzees are closely related, they share a long history of evolution, and still they are surprisingly different.
38:52And this difference is particularly obvious in the social domain.
38:57There is no alpha male in this troop of bonobos.
39:01The real power lies with a group of senior females.
39:06Violence is rare in the bonobos world.
39:09Instead, they use intimate contact and food sharing to avoid conflict and diffuse tension in the group.
39:18The formation of the Congo River split one species into two.
39:22But why do the apes end up so different?
39:30Why is there war on the North Bank, and peace on the South?
39:43One theory suggests that a third species of great ape could have been the cause.
39:50Ancestral gorillas had to share the same food resources with chimpanzee ancestors.
39:57Today, gorillas only exist in small pockets in Central Africa, but they were once far more widely spread.
40:06Some primatologists think that five million years ago, gorillas competed with the smaller jungle apes for food.
40:13It appears that as the Congo River was forming, the climate of Central Africa changed dramatically.
40:21A drought wiped out the favorite food plants of gorillas, and the giant apes disappeared from most of the Congo
40:28Basin.
40:29When the drought ended, the forests and food plants returned, but the newly formed Congo River prevented gorillas from recolonizing
40:39the South Bank.
40:40Here, smaller apes had the forest to themselves.
40:49They may have fed on a much wider range of plants all year round, without competition from gorillas or each
40:57other.
41:01They became less violent, and eventually evolved into a distinct species we call bonobos.
41:13On the north side of the river, the original chimpanzees still had to share their forests with gorillas and compete
41:20with them for food.
41:23They also had to compete with each other, and this led to a culture of rivalry and violence, dominated by
41:31the most aggressive males.
41:34It may even have changed their DNA.
41:40Scientists have recently discovered part of a gene that seems to promote social bonding.
41:49Caring, sharing bonobos have it, and so do humans.
41:58But the violent chimps do not.
42:01The radical differences between aggressive chimps and peaceful bonobos may ultimately be because of a genetic mutation.
42:15The Albertine Rift reshaped the mighty Congo River and split our closest relatives into two very different species.
42:25But it may also have forced our ancestors out of the trees and onto two lakes and led to the
42:33dawn of mankind.
42:36Chimpanzees and humans share over 99% of their DNA, but chimps evolved to spend most of their time high
42:44in the trees.
42:47Immense upper body strength enables them to haul themselves up with muscles four times more powerful than a human's.
42:56Chimps often come down from the canopy to move between food sources and patrol their territory.
43:03When they're on the ground, chimps still use all four limbs.
43:07They lean on their arms to prop them up as they move across the ground.
43:14This is called knuckle walking.
43:18Chimpanzees can walk like humans for short distances, but their weak back legs can't take the strain for long.
43:28Scientists always thought that our earliest direct ancestors, called hominids, were tree dwellers that looked like chimpanzees.
43:37When Africa's climate dried up and the forest disappeared, it was presumed these ancient hominids were forced down to the
43:46ground.
43:49On the open savannah, they evolved from traveling on four limbs to walking on two.
43:55This theory, known as the savannah hypothesis, has been suggested ever since Charles Darwin's time.
44:02But a stunning fossil discovery changed that idea forever.
44:08In 1994, a remarkable specimen was found on the floor of the Great Rift in Ethiopia.
44:16A female hominid who weighed about 50 kilograms and stood 120 centimeters tall.
44:25This was the oldest and most complete hominid ever found.
44:304.4 million years old.
44:37This new fossil, named Ardipithecus raminis, or Ardi for short, shattered our understanding of human evolution.
44:48Ardi's limbs and anatomy were different to both humans and chimps.
44:58She was still a creature of the forest canopy, with opposable digits on her hands and feet like chimps.
45:12But the structure of her skeleton showed that Ardi could also comfortably walk on two legs, like us.
45:23This suggests the ability to walk upright evolved before our ancestors came out of the trees.
45:30If this is the case, then the savannah hypothesis is wrong.
45:37There might be another reason our earliest hominid ancestors evolved to walk on two legs.
45:47The appearance of the earliest bipeds overlaps with the Great Rift tearing through East Africa 3.5 million years ago.
46:02An intriguing new theory proposes the driving force behind our ancestors learning to walk on two legs was the formation
46:10of the Great Rift itself.
46:13Could it be they came down from the trees and entered the hills?
46:19This theory suggests that as flat terrain was pushed up into mountains and blasted into craters,
46:26our ancestors would have benefited from moving into the new landscapes.
46:32Steep terrain would have offered protection from four-legged predators that could not climb,
46:37and created whole new environments and food resources.
46:41As the hominids conquered this new landscape, they could have evolved powerful legs and shorter arms to help them balance
46:49and grip.
46:52And so they became upright, like us.
46:57And as the rift altered the climate of East Africa,
47:00perhaps the brains of our ancestors grew larger and more complex to cope with the challenges of surviving in such
47:09a changeable environment.
47:15The titanic forces at work under the surface of Africa made our species what we are, the ultimate primate survivor.
47:26As the Albertine rift tore through the center of Africa, it transformed flat rainforest into landscapes of staggering variety, each
47:37with their own challenges for life.
47:42This forced the hand of evolution, creating mutants and unique life forms found nowhere else on our planet.
47:57The titanic forces at work under the surface of Africa, the
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