- 2 days ago
Earth's Greatest Spectacles
Category
🐳
AnimalsTranscript
00:04Our planet is a place of constant change.
00:08Each year, the seasons shift and life is transformed.
00:13But there are places where the changes are so epic in scale, they can be seen from space.
00:22In this series, we reveal three of the most miraculous transformations.
00:29The islands of Svalbard. Within a few weeks, frozen wastelands burst into life.
00:37The African Okavango, a desert transforms into a magical water world.
00:45And the mysterious forests of New England erupting in a blaze of seasonal colour.
00:54Life finds the most ingenious and surprising ways to thrive in the world's most fast-changing landscapes.
01:24The Kalahari Basin.
01:29Two and a half million square kilometres of flat sand and scrub.
01:36This desert stretches across southern Africa.
01:41But at its heart lies a river. A river that never reaches the sea.
01:46And once a year, it floods.
01:53Over five months, waters spread across a vast area of the Kalahari.
01:59Transforming it into a wonderland.
02:08The Akavango Delta.
02:21This is the story of how nature creates a unique, flourishing wetland out of one of Earth's great deserts.
02:30When under rivers turns, what will據 and which clouds strike itself there?
02:49It's best possible home is called by Mars.
02:52But you have to protect ocean waker from Earth.
02:53It's still through especially the sea.
02:53You're getting
02:54The bracket comes from the river that reminds me of.
02:55It's still Polish miningид.
02:58You're even missing heritage2015 against the city.
02:59The Kavango Delta通 되면
03:00Our story begins in the heart of the Delta.
03:06The dry season is well advanced and water is becoming scarcer by the day.
03:14At this time of year, predators rule.
03:33Animals have another six months to wait before the flood turns this land back into a lush wetland.
03:48Sable antelope.
03:50After grazing on dry grass, they have to drink at a stagnant pool.
03:58But they're nervous.
04:04Predators watch their every move.
04:16For a leopard though, a sable's size and lethal scimitar horns pose too much of a risk.
04:27There are plenty of easier targets.
04:41A family of warthogs.
04:46Where once there was a wide river, they used their tough snouts to truffle for bulbs.
04:55But it's hard work in this dry, sun-baked ground.
05:01And having your snout in the sand is decidedly risky.
05:05We'll be back in the sand.
05:08The End
05:09We'll be back in the sand.
05:12The End
05:22Oh, oh, oh, oh, oh.
05:48The leopard drags its kill to a hiding place where it can dine in peace.
06:00The warthog will keep it going for a week.
06:06The dry season means good hunting for top predators.
06:12For everyone else, food is scarce.
06:19Chacma baboons survive through their knowledge and eclectic taste.
06:27Elephant dung is a valuable source of seeds and insects.
06:46But it looks like there's an appealing alternative.
06:49A tree that fruits even in the dry season.
06:52A fan palm.
07:07The fruit is nutritious, if a bit tough and pithy.
07:16But what's this?
07:22Elephants will eat virtually any vegetation.
07:25And fruit is their favourite.
07:28They can smell it from several kilometres away.
07:45For the baboons, the feast is over.
07:54The fruit may be 20 metres up and out of reach.
07:58But the elephant's strategy is simple.
08:01Root force.
08:03And that's what works.
08:06I'm trying to do that.
08:32Um, I'm trying to treat them as well.
08:32I'm trying to leak.
08:32Let's go.
09:04For a crafty baboon, though, it sometimes pays to hang around.
09:13It's spotted one that the elephants missed.
09:28Nearby, at a shrinking pool, something agitates the water.
09:39Mouths gulp at the surface.
09:43It's crowded with giant catfish up to a metre and a half long.
09:50There's no oxygen left in the water for their gills to use.
09:54But these fish also have lung-like organs that breathe air.
10:04Every day, under the Kalahari sun, more water evaporates.
10:12African fish eagles gather expectantly for a banquet.
10:35In desperation, some catfish attempt to make a run for it, using their fins to propel them.
10:44Now exposed, they are easy targets for eagles and jackals.
11:16These catfish have run out of time.
11:22Within two weeks, the pool has vanished.
11:43When it floods, there will be plenty of water for everyone.
11:47But now, at the end of the dry season, elephants must keep walking in search of water.
12:04Her calf needs 15 litres of milk a day, so she must find over 100 litres of water for both
12:11of them.
12:14But elephants have a special technique to get at fresh water.
12:21No other animal has such power.
12:29Using their tusks, they pile-drive into the floodplain until they reach water beneath the surface.
12:53In doing so, elephants create a lifeline for others.
12:59A hyena and jackal wait their turn.
13:04Elephants with calves are not to be messed with, so they dive in when they can.
13:17But this jackal may have pushed its luck a little too far.
13:21Let's go!
13:25Let's go!
13:32Let's go!
13:49For insect-eating birds, food is increasingly hard to find.
13:59This mound makes a good lookout post, but if only it knew what's inside.
14:12It's a fortress for Macrotermes termites, a colony a million strong.
14:21A termite's mound is just the hub of an underground city, six kilometres of foraging tunnels.
14:30Here, the Macrotermes process dead vegetation into food.
14:36The mound is perfectly engineered to keep air at constant temperature and humidity,
14:42protecting the termites from drying out.
14:48But these mounds will also prove essential for the survival of many other species when
14:54the floods come.
15:05By the end of October, dryness and increasing temperatures turn the once lush Okavango Delta
15:12into a tinderbox.
15:25But these birds seem to be attracted to the flames.
15:38For the lilac-breasted roller and the fork-tailed drongo, it's a great opportunity, because
15:44the fire flushes out a bounty of insects.
16:12Up to a quarter of the Okavango floodplain can burn in a single year.
16:20For most of the plants and animals that live here, the end of the dry season can't come
16:25soon enough.
16:45November brings a little respite to the parched land, warm, humid air moves in from the tropics.
16:56Rain in the Kalahari.
17:05Just enough to green the delta.
17:32The baboon troop has grown in number.
17:57These youngsters were born just in time to enjoy what the rains bring.
18:05More trees have come into fruit.
18:07It makes for a delicious breakfast.
18:14But there's a downside to such a wonderful scent.
18:23Sure enough, elephants aren't far away.
18:43The troops scatters.
19:00Maybe it's time to move on.
19:06Mothers carry their newborns safely underneath, where they can keep suckling.
19:13But the older ones must learn to ride on top.
19:23On these open plains, the troop must stick together.
19:29Some have already lost limbs to leopards.
19:37All these animals will soon face a new world.
19:47The Kalahari rains may have provided some temporary relief, but a much greater change is on its way.
19:58In distant mountains beyond the Kalahari, the tropical air now brings much heavier downpours.
20:24Rain, from highlands to the north, cascades ultimately into one river, the Akavango River.
20:33It creates a pulse of high water, which takes two months to snake over a thousand kilometres to the top
20:41of the Akavango Delta.
20:59It will still be another month before the floodwaters reach the heart of the Delta.
21:05Here, the river always flows and is home to several thousand people, such as Sinabi.
21:13His people are descendants of both Kalahari nomads and fishermen from Central Africa.
21:24As the river rises, water spills onto the surrounding land, creating shallows ideal for spearfishing.
21:46The rising pulse of water continues onwards, south towards the dry heart of the Delta.
21:56But to understand what happens next, we have to go back in time.
22:03Two million years ago, great cracks ripped through the desert floor.
22:12The land warped to create the shape of the Delta we know today.
22:21The faults define the start and finish lines for the flood which is to come to the main Delta.
22:41The dry plains in the heart of the Delta will soon be transformed.
22:52Life here is about to be turned upside down.
23:09But for this family of warthogs, there's still a bit of time to get some truffling in.
23:20The last rains softened the ground, and now getting at those tubers is much easier.
23:29For the cunning baboons, it's an unmissable opportunity.
23:35They muscle in to enjoy the fruits of the warthog's hard work.
23:49The baboons may have no manners, but the warthogs don't really seem to mind.
23:55Perhaps it's because the baboons provide extra security.
24:03But this is one food source that will soon disappear.
24:17Hidden in the reeds, it starts as the tiniest trickle.
24:22The beginning of one of Africa's greatest floods.
24:27the own ones, the birds, and the birds show all the gold cost.
24:44It was the fire at the
24:46The birds are crazy, including the birds.
24:50The birds come for Definitely Sun!
24:57As rising water spills into the main delta, it slows and spreads into countless tiny rivulets.
25:28Travelling at barely a kilometre a day, the flood will take another four months to cover the delta.
25:39But straight away, wherever water touches the land, it makes a remarkable impact.
25:51Common sand frogs spend most of the year buried half a metre underground.
26:00But now, water floods their burrows and forces them to the surface.
26:06They inflate to scare off any predators.
26:13He's off to find a female.
26:23For tiny creatures whose homes are in the way, the trickle is more like a tsunami.
26:31Ants are forced to evacuate their nest.
26:39An easy snack for blacksmith lapwinds.
26:50Termites now face the flooding of their colony.
26:57They beat a hasty retreat to the safety of their mound as their tunnels start to flood and collapse.
27:07But in doing so, something miraculous happens.
27:11The tunnels seal themselves up.
27:16This blocks the flood's underground advance and forces the water back to the surface.
27:29Back inside the mound, the termites are safe.
27:37Incredibly, the flood provides just the opportunity they need.
27:44Their fragile castle, made of sand, requires constant maintenance and rebuilding.
27:50But the soil, now softened by flood water, is easy to transport to damaged parts of the mound.
28:03Gradually, thousands of termites reconstruct their fortress.
28:12Repairing these mounds isn't just good for the termites.
28:17These structures help to create something vital for all the Delta's wildlife.
28:24Its islands.
28:29And it all starts like this.
28:42Dung.
28:44Ready-made fertilizer laden with fruits and seeds.
28:50Flood water soaks up the dry side slopes of the mound to create the perfect bedding for new plants.
29:11Gradually, season by season, termite mounds become home to more and more plants.
29:28As they grow, they attract more animals, which in turn bring with them the seeds to grow even more plants.
29:36Sycamore fig.
29:38Sycamore fig.
29:39Fan palm.
29:40Marula.
29:41Until the termite mounds are barely recognizable under their lush green canopies.
29:55As it floods, raised areas around termite mounds become islands.
30:03They provide food, shelter and a refuge throughout the year for everything from elephants to baboons and birds.
30:15In the Delta, once featureless desert, there are now around 150,000 such islands.
30:33For a lot of thirsty animals, the floods simply mean sweet drinking water.
30:42Elephants no longer need to dig holes.
31:04Baboons, too, seem to delight in the precious liquid.
31:14Curious youngsters encountering the flood for the very first time don't seem to know quite what to make of it.
31:24We take care of it.
31:48There we go.
31:55The sand may look barren, but wherever the water touches it, something magical happens.
32:03Within a couple of days, billions of freshwater plankton begin to awake and hatch.
32:16Such tiny creatures are the delta's secret ingredients, the foundation of its food chain.
32:26Meanwhile, in a deeper channel, a mountain of foam has appeared.
32:33It has been created by a pair of African pike, notoriously aggressive, but caring parents
32:40that watch over their offspring.
32:48Hidden safely underneath the foam, hundreds of fish eggs are beginning to hatch.
32:56The fry remain attached to the foam until they are well developed.
33:00And now, the delta offers plenty for them to eat.
33:07The tiny pike fry join small hungry fish of 70 different species, swimming through the shallows
33:15in a nutritious soup of freshwater plankton.
33:35Before long, the skies fill with birds, one of Africa's greatest wildlife spectacles.
33:47The birds have a great place, travelling nomads from far and wide.
33:52The reason they're here?
33:54Wherever water covers the land, it fills up with little fish.
34:02Each of the birds has its own special technique for catching them.
34:09A saddle-billed stork jabs at its prey.
34:18African spoonbills have the perfect equipment for filtering out the finest morsels.
34:39Black egrets use their wings to form canopies over the water.
34:43The shade lures nervous fish, desperate for cover.
34:59Others attack directly from above.
35:04A pied kingfisher.
35:11At 25 centimetres long, it's the world's largest hovering bird.
35:29Hovering demands a lot of energy, so they have to catch a quarter of their weight in fish every day.
35:39Keeping its head perfectly still, about 10 metres above the water, it sees movement.
35:49Then drops in a controlled dive.
35:54If the fish sees it, the kingfisher can still abort and save energy.
35:58If not, it commits and dives rapidly.
36:04It's worth the effort.
36:07Hovering allows them to hunt in the middle of the plains, where the pickings are especially rich.
36:25The bird kills its prey with a blow to the head.
36:30But before it can swallow, it must flip the fish head first, or the spines will stick in its throat.
36:37Then...
37:17Within a few months, another type of organism vital to the delta breaks the surface. Dozens of species of aquatic
37:26grasses, sedges and water lilies.
37:50At dawn, day lilies open to attract pollinating bees and flies.
38:22Music
38:24As dusk approaches, the day lilies begin to close and give way to the night shift.
38:31Music
38:35Night lilies open their brilliant petals, bright enough to attract insects in the moonlight.
38:45Water lilies flourishing in the middle of the Kalahari desert.
38:56Perhaps the greatest miracle of the delta.
39:03And only possible thanks to one thing.
39:09Nature has found a unique way to keep the water of the delta pure, very low in toxic salts.
39:19Its secret lies with those extraordinary islands.
39:25Music
39:34Trees on the islands act as pumps, sucking in water from the surrounding swamp.
39:42As they do so, salts in the water are deposited in the sand of the islands.
39:51By extracting salt from the water, it's as though the islands are kidneys, removing waste from the bloodstream.
39:59Music
40:04This way, the islands keep the delta's waters fresh, and able to nurture abundant life.
40:14Music
40:22Music
40:35As the morning sun heats the ground, rising vapours everywhere reveal that water has spread right across this plain.
40:44It's a transformation that turns the tables between predator and prey.
40:53Red lechway appear in large numbers, looking for their favourite food.
40:59Tender aquatic plants.
41:09But a hyena hopes to take advantage of their distraction.
41:21It just needs to get a little closer.
41:31Time to run for it.
41:43Lechway have large splayed hooves that allow them to bound at speed through shallow water, giving them a big advantage
41:50over any predator.
42:08It's an adaptation that helps to protect them during the time of flood.
42:22Soon, the aquatic vegetation sprouts everywhere, and the water becomes impassable.
42:34But crisscrossing the flooded plains, highways through the reeds appear.
42:43And here's their creator, a hippopotamus.
42:50He's a grazer, and thinks nothing of bulldozing a way through.
42:56As he does so, he excavates a channel.
43:17And it's not only hippos that have to find a way through.
43:27In the north of the delta, Sanabi rose through dense beds of reeds.
43:36To get through, he seeks the help of the spirit of the river.
43:42He seeks the help of the river.
43:44He seeks the help of the river.
44:10Deep in the reeds, he discovers a hippo channel.
44:14It's a highway for fish, so the perfect place to rig a net.
44:19There's nothing so many footprints.
44:20To be alerted, his hand puts his finger tapi cev angels in their hand.
44:29By Tana Alton you don't Graham'll pull a net out of our ileus.
44:36Hmm, don't you see that, Tim!
44:37I'm sorry, your journey into the desert and hisHolaplicicksal complex as aFO is still forever
44:39to evacuate.
44:39Yes, we cannot treat.
44:48No, we don't have this,
44:48but whilst theyзя like racially mentioned.
45:04Sanabi's village is on the edge of the floodplain.
45:10His family know that as long as the delta provides,
45:14they will never go short of food.
45:19He smokes the bream to preserve it for days when the catch isn't quite as good.
45:26Meanwhile, his family weave baskets out of grass from the floodplains.
45:31Later in the year, they will be used for catching fish.
45:59By July, in the heart of the delta, the once dry savannah has become a lush water world.
46:08But this transformation has an odd effect on the baboons.
46:27Each has developed its own funny walk.
46:54All that is, except for the baby, who just gets a soaking.
47:16It seems likely that baboons don't much enjoy being in the water,
47:19or they may be nervous of something in it.
47:26Crocodiles are everywhere.
47:32For the troop, a flooded delta is a lawless place.
47:36But a threat worse even than a crocodile has appeared.
47:52The shrinking of territory on land forces the loners into contact with troops.
47:59They may fight the troops' alpha male for control.
48:04If the stranger wins, he may also kill the young and mate with the females.
48:11An incumbent alpha male must keep a close eye on any rival.
48:21To survive, it is crucial that he lay down his authority.
48:36To survive, it is lucky.
48:54To survive, it is a puppy.
48:55Oh, my God.
49:28Insurgents must be sent packing.
49:49As the delta floods, everywhere tension seems to be mounting.
49:56Not least in the hippo community,
49:58where their watery territories are expanding dramatically.
50:06Here, too, there is a young challenger.
50:13The territory's resident bull snorts a warning.
50:24The adversaries declare their ownership of the pool
50:28by vigorously spreading dung with their tails.
50:41They yawn to display their weaponry, huge ivory tusks.
50:57First, a test of strength.
51:06The old bull makes a temporary retreat.
51:12Females have a vested interest in the outcome.
51:16They will only be prepared to accept a mate
51:18that can hold his own in a fight.
51:28The resident bull retaliates brutally.
51:46Hippos will often fight for hours,
51:49and sometimes to the death.
52:08Finally, a brutal headlock, the coup de grace,
52:12that settles it for the older male,
52:15expelling the pretender from his territory.
52:28Which means the resident bull passes the test
52:31to sire this year's crop of baby hippos.
52:48The young male has been injured during the retreat,
52:51his flank exposed to his furious pursuer.
52:58At least nature has arranged for him to be nursed
53:01by these ox-peckers.
53:03They eat anything that might cause an infection.
53:08The pain is probably worth it,
53:10and he should survive to fight another day.
53:24By August, the flood waters finally reach the delta's southern fault line,
53:28its maximum extent.
53:37The Okavango is now one of the largest inland deltas in the world.
53:45The whole delta is linked by water,
53:48shallow flood plains, pools, and deeper channels
53:51all fed by the Okavango River.
54:07Billions of fish that fill the plains have grown rapidly.
54:20And Sanabi's wives and daughters are ready for them with their baskets.
54:24They all shout,
54:27and thekins.
54:32But if you feel the same way,
54:35they may be able to lose their wings a little,
54:38whose wings are the same way.
54:39The unknown people,
54:49and the pine trees are their wings.
54:55Bulldog fish will make a fine stew.
55:03In the main river, something strange is happening.
55:07The waters appear to be boiling.
55:17It's catfish taking gulps of air at the surface.
55:25And they are here in their millions.
55:31Before the flood recedes, they return from their hunting grounds
55:34in the far reaches of the delta to the safety of the deep channels.
55:43Amongst the papyrus, they hunt smaller fish.
56:05Flocks of egrets arrive to join in the feast.
56:29No one is safe in the mayhem.
56:42African fish eagles swarm and dive-bomb the catfish.
56:50Millions of fish that grew fat out in the flood plains
56:53bring life back to the river that brought them water.
57:13When it's needed most, the flood creates a vast oasis in the desert, a wonderland.
57:19It's 10,000 square kilometres of crystal waters
57:24attracting thousands of animals from all over the dry Kalahari desert.
57:56But these waters will never reach the sea.
57:59they will soon begin to evaporate or simply sink into the Kalahari sand as
58:05the Okavango Delta gradually returns to dry savanna.
58:29Something quite interesting next tonight, we learn the magic word to use if you're ever
58:34trying to jump a queue. Stay with us for QI here on BBC Two.