♪♪ ♪♪ NARRATOR: The king awakens... His domain is on the edge of one of the most extraordinary swamps in Africa.

♪♪ He knows his charges... ♪♪ ♪♪ He knows his riches... ♪♪ He knows his threats... ♪♪ Intruders -- young challengers.

♪♪ But today, there is trouble in paradise.

♪♪ The cuts and scars on his face are a roadmap of his past battles.

♪♪ Everyone is aware.

♪♪ [ Low roar ] ♪♪ ♪♪ ♪♪ ♪♪ The message is clear: This is not their dream.

It belongs to him.

[ Low roar ] ♪♪ ♪♪ But the river itself doesn't belong to him alone: everyone lays claim to their piece of the Okavango, this river of dreams.

MARILYN MANSON: ♪ Everybody's ♪ ♪ Lookin' for something' ♪ ♪ Some of them want to use you ♪ ♪ Some of them wanna get used by you ♪ ♪ Some of them want to abuse you ♪ ♪ Some of them want to be abused ♪ [ Instrumental ] ♪♪ ♪♪ [ Music fades ] NARRATOR: The second phase of the Okavango, in Southern Africa's Botswana, is, as it fans out into a delta, in limbo, before spilling out into the Kalahari Desert.

♪♪ The clues to why the delta changes its shape so radically here lie at the center of each of its uniquely formed islands.

♪♪ There are forces at work down here, building underground fortresses, blockades against the rising water table -- using a combination of saliva and hard calcrete.

There are over 2,700 species of termites, but just a single one of them influences everything here.

[ Lion roaring ] The male lion is not a loner.

Daily calls connect him and his brother.

[ Low roar ] ♪♪ All around them, life is erupting.

♪♪ Once a year, termites start their nuptial dances.

They flush from underground homes to fly, and within seconds find a mate, before they can be eaten.

[ Birds calling ] ♪♪ Millions don't make it...

But millions do.

♪♪ The mating dance fills the air and starts one of the most magical relationships in nature... one that dominates the entire story of the Okavango.

♪♪ ♪♪ They land at the feet of giants, find their soul mates, and burrow down into the soft Kalahari sands.

Then, they start a new cycle of building.

Towering castles rise up even above the heads of elephants.

♪♪ Trees attach themselves, forming platforms for all life here.

♪♪ In this flat landscape, any high ground forces the flood waters to spread around these islands, creating a sprawling delta across 9,000 square miles of Botswana.

♪♪ ♪♪ And at the foundation of each island in the Okavango is a termite colony.

[ Elephant trumpets ] ♪♪ In a place where water is abundant, it's the high ground that is precious and used by just about everything here.

When there are cubs, the male doesn't spend a lot of time with the pride.

It's an unfamiliar and sometimes tense relationship with them.

In this upside-down world, months after the rains end and just as the dry season starts, the flood begins to rise.

Rainwater from halfway across the continent is finally reaching the delta.

♪♪ Those that can adapt to this watery world have an advantage, especially if they can find just the right island.

Two Hyena sisters have found some abandoned aardvark holes to turn into a den.

Hyena family greetings may be a little curious, but these are some of the most caring mothers in the delta.

All their cuteness has been reserved for when they are very young.

They soon grow out of it.

The older cubs have already developed bone crushing habits, so the youngest dig secret chambers into the heart of the termite mound that only they can get into.

Someone else is eyeing one of their holes today.

♪♪ And quite simply moves into the spare chamber.

It's disconcerting for the cubs.

Hyenas can easily rip a warthog to pieces, but for some reason now, they extend a kind of welcome.

A working solution develops.

♪♪ Hyenas den during the day, and at night, when they are out hunting, the warthogs are in residence... And during the twilight hours, both families are at home.

♪♪ It's family bliss, but with lethal jaws-in-the-making.

♪♪ ♪♪ ♪♪ ♪♪ Both families keep a wary eye out for the odd neighbors.

♪♪ The male lion is patrolling his territory but takes a diversion to harass hyenas.

He's definitely also interested in the smell of hidden pigs.

The unlikely alliance between these two families sharing a den worked well today, and those extra eyes and ears served as early warning mechanisms.

This relationship works well on a deeper level for miniature piglets.

At last -- the two brothers have found each other.

Their bond is vital to both of them, their territory and their pride.

The teenagers have energy to burn.

The males watch them closely.

The first sign of small manes on the young lions has their father's attention.

In a year, the large males will have to chase them off.

Lions of any size on the move through the swamp send shock waves of panic through everyone.

Anyone caught out of water is fair game for the youngsters.

♪♪ And it turns into a game of cat and very large mouse.

♪♪ ♪♪ [ Grunting ] ♪♪ ♪♪ ♪♪ For some, safety is in the water.

For others, it is on the termite islands as the flood rises.

♪♪ As the young piglets emerge from their catacombs, they have a lot to thank the hyena family for.

But it's time to move out into the world.

Warthogs across the delta more than double in number in a few weeks, all because of their initial safe havens in the termite mound islands.

[ Grunting ] On one of the larger islands, they are being watched from above.

♪♪ ♪♪ ♪♪ ♪♪ ♪♪ ♪♪ [ Warthogs squealing ] The leopard can't choose, so grabs up two piglets.

But she can't carry both to the trees before the chaos attracts unwanted attention.

Now, the hyenas are interested in the smell of piglets for an entirely different reason.

♪♪ The males, on a territorial patrol together, stride right towards the leopard's island.

♪♪ She is saved by chance.

♪♪ Piglets on the wind.

♪♪ Right into the jaws of death...

But it's a slippery little thing.

And one that comes with a lot of attitude.

♪♪ ♪♪ For the largest of the African cats, being confronted by something this small is... a little confusing.

♪♪ ♪♪ ♪♪ These plains may favor the bold and the brave, but today the odds were just too great... ♪♪ And not enough to feed both brothers.

♪♪ By mid-flood, over 80% of the Okavango is under sheet water.

Much of it is shallow and crystal clear -- exactly what the kingfishers like best.

♪♪ But hovering takes a lot of energy.

♪♪ ♪♪ High protein fish and frogs are worth the effort, though.

Right across the delta, pied kingfisher splashes punctuate the peace and tranquility.

♪♪ Because the flood lags so far behind the local rains, it brings new water at just the right time for thousands of animals.

♪♪ ♪♪ This massive movement of wildlife is triggered by the rainwater pools drying up.

And it is the elephants that are most important to the way the entire delta functions.

It is a haven for them.

The expression of sheer elephant joy seems to erupt in their voices.

[ Elephants trumpeting, rumbling ] ♪♪ ♪♪ ♪♪ Giants like these could have a devastating impact in large numbers, but in truth, elephants perform a great service in this landscape sized theatre.

They are in fact the architects of the Okavango.

Where elephants lead, the flood follows, bringing new water down dormant channels to forgotten islands.

♪♪ But what brings elephants to this part of the delta now lies ahead of them, on those islands.

They can't reach these dates and don't want to destroy the tree itself, so they gently "harvest" the fruit.

Being crowned by rock-hard nuts seems to be worth it.

But it's a classic case of which came first: the palm, the nut, or the elephant.

The palms can only germinate if softened at the right temperature... the exact same heat as that inside an elephant's gut.

These vast palm islands so typical of the delta exist purely because of these long caravans of traveling elephants.

And the islands themselves are built on termite mounds right across the Okavango.

If you're not particularly finicky about the source, the softened nuts in elephant dung hold amazing riches.

And vervet monkeys are used to having sticky fingers.

Blacksmith lapwings don't signpost their nests -- they are the signposts.

But today, they have chicks that are just the opposite -- their job is to blend in.

That could be a problem along this path.

Lapwings are extremely bold: bold voices, bold colors, and bold attitudes.

[ Squawking ] But with a heavy army on the march, they take evasive action today.

[ Chirping ] [ Low growl ] You never know when an elephant may be on a sugar high after date palm foraging.

Like this bull, who doesn't extend the same "lapwing courtesy" to the painted dogs today.

A hunt starts with a sneeze.

It's the pack's version of a vote.

Enough sneezes gets them excited and carries the motion.

These flooded swamplands are ideal for the hunting dogs, one of the last strongholds in the world for these highly endangered animals.

♪♪ ♪♪ The incredible size difference between predator and prey doesn't bother painted dogs.

For them, it's all about stamina, and few can match theirs.

♪♪ Today, the kudu's almost playful message is that it is fit, young, and can bolt away at any time.

♪♪ It's just a test anyway -- a warm-up while the rest of the pack mobilizes for the main event... ♪♪ ♪♪ Wildebeest...

Dogs hunt by testing for weaknesses, forcing mistakes.

♪♪ Against hunting dogs, the best defense is a show of unity.

[ Wildebeest bellows ] The pack's technique is to divide and conquer.

Each retreat is actually a ploy to draw one wildebeest away, so that other pack members can surround it.

It's the ultimate bait and switch.

♪♪ ♪♪ ♪♪ The alpha male calls it off.

The amount of energy it'll take to complete this hunt is just too expensive.

♪♪ ♪♪ As quickly as it came in, the flood starts to shrink after a few months -- the first signs of change.

It leaves soft green grasses exposed, and highly nutritious -- well worth going in search of.

[ Rumbles ] But unfortunately, others have the same idea.

It's a three-way fight.

One backs up into a small termite mound and gains two advantages: the high ground and a protected rear end.

It's a winning combination in a species where fighting is both critical to claiming space and food, and is dangerous.

Tens of thousands of hippos dominate the waterways throughout the delta, making it as hazardous for other animals here.

In these flood waters, there is a single rare antelope on the move today.

He is so rare that he's one of a kind.

There has never been another like him seen anywhere in the world.

At first glance, he looks like a common red lechwe.

It's not surprising: his mother was a lechwe.

But his father was a waterbuck.

We'll call him a wachwe, in honor of both parents.

♪♪ ♪♪ Today, the wachwe is in deep trouble -- and the pack knows it.

♪♪ The wachwe is larger than any normal lechwe, and though that may confuse them, the painted dogs are not easily scared off by size.

♪♪ But he's not a complete loner: today he's found his half-brother, a real waterbuck.

♪♪ Their interesting and different genetics may be academic now.

The real threat may actually be in the water they are using for their escape.

♪♪ Hippos attack each other, so complete strangers are not welcome in this pool.

They're in trouble if they don't leave the water now.

But they're in trouble if they try to.

♪♪ ♪♪ ♪♪ ♪♪ The confidence of being born bigger and bolder than his siblings is paying off.

But today, the two antelopes find safety in limbo, somewhere between the river bank and the deeper water.

Even the hunting dogs wont risk offending the hippos.

It's a standoff between an endangered predator and an antelope that doesn't really exist.

♪♪ ♪♪ The intimate lives of these animals make up the complex web of the Okavango: touch it in one place and it shivers somewhere else.

♪♪ Someone's paradise is someone else's purgatory.

♪♪ In this world of winners and losers, there are sometimes simple working relationships, with no disadvantages.

Black egrets have a special technique of blocking out the shine on the water, to catch fish under their umbrella-like wings.

Small minnows come to forage, and craftily, black egrets use their bright yellow feet as lures.

It's such a good tactic that a glossy ibis poaches under the umbrella without any shame at all.

There is one problem -- when you have your head under your wings, things can creep up on you.

The pride is out hunting, and young lions are interested in anything that moves -- in particular, those that move slowly.

These lions have adapted to being in water.

The constant wading, from one termite island to the next through deep water, makes them fit, strong, and some of the largest lions in Africa.

The cool water allows them to forge through the delta, well into the heat of the day.

♪♪ ♪♪ In these mosquito-infested swamplands, they are after one species of prey above all else.

It's their favorite, but it's not easy... Buffalo.

♪♪ Being down in the water-grass can get confusing, so Okavango lions have to use any advantage they can get.

Elevation is a huge help.

♪♪ It's one of the few places in the world where lions do climb trees.

They also climb to get any cooling breeze... but these heavy-set lions have to get their balance just right.

♪♪ ♪♪ And it's not just the lionesses that can climb.

♪♪ ♪♪ The buffalo are heading this way.

So now, all that is needed is a hasty and elegant descent to circle into position... ♪♪ The time to attack buffalo is when they bunch up, when they are stressed by the deeper water crossings.

♪♪ But today, the pride waits and sets the ambush for just as the buffalo enter their termite island.

♪♪ He's eager to join in.

♪♪ ♪♪ ♪♪ ♪♪ ♪♪ With the pride in perfect position to ambush a lost calf, the trick would be to not spook the buffalo.

♪♪ ♪♪ A big bull senses something wrong.

Now it's important for the male to be still... Silent.

But the male's weight-to-agility ratio is just off.

♪♪ These are Cape buffalo.

They kill more lions than any other animal does, and today, there are nearly a thousand of them.

Suddenly a young bull elephant is in the mix... [ Trumpeting ] And he's irate.

Elephants are definitely the dominant species on these islands.

But the lions have artfully sneaked off... and he's been left with the full force of the buffalo herd.

This warrior elephant is up to the challenge.

[ Trumpets ] Some of the younger lions have their own troubles now.

♪♪ ♪♪ Treed by the buffalo, they have nowhere to hide, and the best elevation is just at buffalo horn height.

♪♪ ♪♪ The lions have learned a valuable lesson today, one that once again establishes the reputation of buffalo as one of the most dangerous animals in Africa.

♪♪ The pride is bruised and retreats to give the buffalo a wider berth.

As the evening air cools, tiny nymphs that have been waiting for a year under water start to hatch.

Luna mayflies fill the air.

♪♪ Little bee-eaters hawk on them frantically, as if the flush will be their last meal.

But here, there is no shortage of insects.

The Okavango keeps providing to those that are well adapted to use the moment.

♪♪ ♪♪ But the flood also creates problems.

As it arrives, it isolates one kind of small, primitive ape, on whatever termite island they happen to be on.

These temporary prisoners rely almost entirely on the insects that the flood forces to the high ground.

And they do that with special adaptations.

They have huge eyes that are locked in position.

So big, in fact, that to move its eyes, it has to move its entire head.

It's effective: they can see and leap around a very complex world in the high trees.

And to help, they urinate on their hands for that extra stickiness.

[ Squawking ] Their tools work well for them as they navigate their isolated tree top realm.

♪♪ So here, if you can adapt, you do well.

Baboons have similar, forward-facing eyes, but they aren't nocturnal, and spend their nights in the trees, asleep.

♪♪ Getting down is a delicate matter.

But these straight up and down palms are their gateway to the safest place for them to roost.

Nothing else can climb these vertical trunks.

♪♪ ♪♪ The buffalo herd is also awake, moving downstream.

♪♪ Perhaps it's the definition of insanity, but the pride has decided to regroup and try the exact same tactic again.

♪♪ ♪♪ ♪♪ ♪♪ They're going to need something different today, or it will all end up in the trees again.

It's going to take a hero... An unlikely hero after yesterday's performance.

♪♪ Male lions are just not designed to hunt.

Their manes are for display, for fighting.

♪♪ The pride is uncoordinated; the buffalo united.

♪♪ ♪♪ And then, just as the herd hits the first reeds, the second male flies into action alongside his brother.

♪♪ ♪♪ ♪♪ This is why prides often have more than one male: to bring down the difficult, heavy prey that the rest of the pride simply cannot conquer.

Their feast is short-lived.

Elephants have picked up the sound of death, the chaos, and they don't like it.

The mere presence of lions, the smell of blood, and the disturbance to their sedate lives offends these animals.

They thrive on peace and seem to just want to maintain that.

Outraged, they act as if the lions had killed one of their own, not a buffalo.

[ Snorting, trumpeting ] And for one of them, that may be true.

A tusk-less cow reacts as if she has lost a calf or family member of her own in the past.

Elephants hold that hurt and loss for a long time.

But the lions slip away into the long grass, frustrating her even more.

[ Elephants trumpeting ] And then, without any obvious reason at all, the female and her herd suddenly settle down and allow the pride to feed.

Forgiven perhaps, but not forgotten.

It's just one of the mysteries that define this river with so many faces.

♪♪ This strange but magical flood starts inland, adapts to meander around termite castles and down elephant paths, affecting millions of animals.

And then dribbles out into nothing.

The next phase of the river is an entirely different one.

Herds we see little of in the delta start to leave just when it is at its very best.

They take us out to the far reaches of the water, away from the realm of kings and farther down this strange river of dreams.

MANSON: ♪ Everybody's looking for something ♪ ♪ Some of them want to use you ♪ ♪ Some of them want to get used by you ♪ ♪ Some of them want to abuse you ♪ "Nature's" journey into the Okavango concludes...

The river has run its course... And everyone is on the move, from hardy survivors to exiled hunters.

Experience one of the last pl aces on Earth where giants can roam... ♪♪ ♪♪ ♪♪ ♪♪ ♪♪ To learn more about what you've seen on this "Nature" program, visit pbs.org.

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