Original subtitles

The islands that lie between Asia and Australia

were forged by fire.

Their great wealth of plants and animals

the result of a violent birth.

(whooping)

But there is a parallel world where the moon holds sway.

♪ ♪

A world where fish live inside trees

and run away from water.

Insects light up the darkest of nights,

and crabs dance.

The power of the moon is strongest along the coast

and in the shallow seas.

Here the moon reigns over her shadowy subjects.

♪ ♪

Every day the moon pulls on the oceans, creating the tides.

♪ ♪

Over millions of years,

the plants and animals of the coast

have evolved ways to survive the dramatic change

from salt water to dry land.

♪ ♪

The tide floods vast areas of the coastal mangrove forest.

♪ ♪

This is a world that moves to the rhythm of the moon.

♪ ♪

In places, salt water infiltrates miles inland

to the traditional sleeping trees of proboscis monkeys.

These 'monkeys of the moon' must wait for the tide to fall

before they can reach their favorite food.

So they're in no hurry.

The moon recedes

and slowly draws the water from the mangroves.

Fish are forced to leave.

For within hours, water will be replaced by air.

♪ ♪

With the morning stretching and scratching over,

the monkeys set off through the tops of the flooded forest.

In places the forest stretches for miles.

The monkeys face a long journey.

Their goal is the distant shoreline.

Each mangrove species has had to find ways to survive

in this extreme environment that would kill other trees.

The Rhizophora's trunk doesn't reach the ground.

Instead, a web of giant roots projects outward

to support the tree in the soft, gooey mud.

The Avicennia grows strange pencil roots

that stick up from the mud.

The pores breathe in air

to stop the buried roots from suffocating.

Only by extraordinary adaptations like these

can the trees survive in this strange amphibious world.

♪ ♪

The fish leave with the tide,

except for these gobies.

Just two centimeters long,

they've found a surprising way of staying in the mangroves.

Some tree trunks and logs are riddled with tunnels,

dug by sea snails.

As the water level falls, the fish swim into these holes.

The tide drops further, exposing the fallen tree trunk.

But the gobies are safe in the water-filled passageways.

Most fish may have fled, but the forest is not deserted for long.

A new cohort of air-breathing creatures

is waiting for the tide to retreat.

♪ ♪

At the feet of the mangroves live tiny fiddler crabs

measuring less than three centimeters.

They are dwarfed by the leaves

and pencil roots of the mangrove trees.

But like the trees, they have evolved over millions of years.

There may be as many as 10 species on one mudflat.

Each with its own particular way to survive between the tides.

This red fiddler crab claims the top of the tide.

He has a leisurely lunch,

since the water won't return here for 10 hours.

♪ ♪

But to breathe, he must keep his gills wet.

So he regularly returns to his burrow

and his subterranean pool of water.

♪ ♪

But a tiny crab must always be alert for danger.

Predators hang out in this ambiguous place

that is both sea and land.

♪ ♪

The skink hunts crabs.

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The crabs are quick and stay close to their burrows.

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But if the skink sneaks close enough,

it can outrun the crabs.

♪ ♪

High above the mud,

the monkeys of the moon keep pace with the falling tide.

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They're after something tasty to eat.

But it will be hours before they reach their goal.

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So for now the monkeys chew on dry mangrove leaves.

The most striking thing about an adult male

is his spectacular schnoz.

Nothing to do with nutrition,

but a lot to do with attracting a mate.

Females prefer nasally well-endowed males.

We have no idea why.

His nose isn't his only enlarged feature.

He also has a huge belly.

Proboscis monkeys have a chambered stomach

to help them break down the unpalatable, fibrous leaves.

♪ ♪

Some of these mangrove leaves are not very tasty.

They are full of salt water that would kill other plants.

But mangroves have evolved ways of surviving the salt attack.

The Aegiceras has leaves that excrete the noxious salt.

♪ ♪

Another kind of mangrove stores the salt

in its old yellow leaves.

It then discards the leaves,

ridding itself of the toxic salt.

Extreme ways to survive between the moon-driven tides.

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As the water leaves the mangroves, the monkeys follow.

♪ ♪

The tide has left the fallen tree trunk behind,

but for now water remains in its tunnels.

And the gobies push further into the labyrinth.

They are not completely safe, even here, deep inside the log.

A miniature octopus, its body less than three centimeters,

waits patiently for its dinner.

♪ ♪

At last, the tide departs the shadowy forest

and reaches the coast.

As the mudflats are exposed,

more creatures of the moon emerge.

Blue-spotted mudskippers spend half their lives

in mud burrows underwater.

(insect buzzing)

(insect buzzing)

These bizarre fish spend the other half of their lives

out of water, grazing algae on the muddy plains.

♪ ♪

They defend their patch of mud and microbes

with a display of banner-like fins

and rounds of jousting.

♪ ♪

The retreating tide has uncovered

the mudskippers' beach.

The monkeys can walk the final stretch to their goal--

a tree that grows along the beach.

♪ ♪

This is what they have traveled all this way for,

the flowers of the sea hibiscus.

After the dry, salty leaves of the mangroves,

the monkeys relish the sweet-tasting flowers.

♪ ♪

(barks)

While the adults eat their fill,

the youngsters take the opportunity to play.

(screeching)

(barks)

♪ ♪

The moon is far away, close to the horizon.

As the tide recedes, it uncovers more and more fiddler crabs.

♪ ♪

They feed by sifting the fine sediment

for tiny plants and animals.

The female has a major advantage.

She has two feeding claws.

The male, in contrast, has only one.

The other is monstrously enlarged.

So males can only feed at half the speed of females.

They are handicapped by a claw

that weighs half their bodyweight.

But the claw has a purpose.

One function is to protect their small patch of beach

from intruders.

Their lives depend on the food surrounding their burrows.

Each species of crab has a different display of ownership,

different gestures, claw size and color.

The displays are aimed at any intruder

no matter the species or size.

In most cases, a display is enough to resolve a conflict,

but sometimes the dispute escalates.

Weapons are prepared.

Warnings sent out.

♪ ♪

En garde!

And fight!

♪ ♪

While these combative crabs fight,

the tide slides further down the beach,

uncovering more strange subjects of the moon.

On the islands between Australia and Asia,

the tide recedes to reveal this species of fiddler crab

that lives in sticky clay

and specializes in sifting the fine particles.

♪ ♪

Even closer to the low water mark

lives a fiddler crab with the most extreme tidal life.

They have as little as two hours before the tide returns.

So they feed twice as fast as the red crabs

that live back among the mangroves.

All of these crabs have evolved over millions of years,

under the tropical moon.

The exposed fiddler crabs attract a hungry bearded pig.

♪ ♪

(snorts)

♪ ♪

The tiny crabs are no more than a snack to the pig,

so they must be tasty.

The pig's not alone.

♪ ♪

Long-tailed macaques search among the pencil roots.

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Unlike the pig, they have delicate fingers,

so they have to watch out for the crabs' claws.

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It's not just the attentions of pigs and monkeys

the crabs must survive.

The fierce sun can make the midday hours unbearable.

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The tiny gobies stay cool inside the fallen tree trunk.

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But the water is draining out.

Soon the tunnels will be dry

and it will be hours before the sea returns to the fallen trunk.

♪ ♪

All the creatures of the moon

are waiting for the tide to turn.

As the Earth rotates, the moon pulls up the seas,

and this bulge of water moves across the face of the Earth.

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At last the tide changes direction.

♪ ♪

Fiddler crabs evolved to breathe air,

but now they must prepare to spend time underwater.

The crabs closest to the low tide

are the first to disappear.

♪ ♪

As the water forces its way back up the beach,

the crabs disappear,

one after the other.

♪ ♪

There is just enough time for one last display of ownership,

before the blue-spotted mudskippers

flee down their burrows.

♪ ♪

Another type of mudskipper is more of a nomad.

They were feeding on the low tide.

But now these fish make the long march back up the beach,

racing the tides, trying to keep out of the water!

As the tide slithers back toward the mangroves,

the race is on for these mudskippers to reach safety.

♪ ♪

The monkeys of the moon

are forced to leave their sweet-tasting flowers.

Once they are safely back in the trees,

the youngsters start goofing off again.

♪ ♪

The tide pushes some of the nomadic mudskippers

into the mangrove forest.

♪ ♪

To avoid the advancing water, the fish climb into the trees!

♪ ♪

Here they will perch, safe from predatory fish,

until the water starts to drop,

and they once again become nomads of the moon-driven tides.

♪ ♪

The water pushes into the mangroves

and flows back into the tunnels of the fallen tree trunk.

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The tiny gobies stir.

Amazingly, these tough little fish

have survived six hours out of the water.

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The mangroves are once again a flooded forest.

♪ ♪

The strength of the tropical sun begins to fade.

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But the power of the moon remains...

undiminished, day or night.

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12 hours and 25 minutes after it left,

the salt water returns to its highest point.

A cycle of tides is complete.

Strange fish swim in on the high tide.

Weaver ants patrol the mangrove branches, looking for prey.

But the hunters will soon be the hunted.

♪ ♪

The high water brings the ants within range.

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The archerfish estimates the distance, and shoots.

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Archerfish can shoot a bullet of water

powerful enough to dislodge even the most tenacious grip.

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The salt water retreats from the dark forest,

leaving small isolated pools.

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Any fish trapped in the puddles are in great danger.

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A fishing owl's sharp vision pierces the gloom of the forest.

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Its talons are huge, the skin on its feet hard and ridged.

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The influence of the moon is felt wherever there is water.

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The tides have as much impact on the seas

as they do on the mangroves and the beaches.

Every day, tidal currents carry nutrient-rich waters

full of plankton.

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These tiny creatures are at the mercy of the tides

and are preyed on by the largest fish in the world.

Whale sharks are plankton-eating giants.

They can grow to 40 feet long and weigh 20 tons.

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They feed by forcing plankton-rich water

into their huge mouths.

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In places, there is so much food

the whale sharks don't have to travel far.

They just swim from one cloud of plankton to another.

The plankton support a wealth of life

in the waters between Asia and Australia.

♪ ♪

They're surrounded by warm, shallow water,

ideal for coral growth.

♪ ♪

These are the richest reefs in the world.

There are over 1,400 species of fish,

and many feed directly on the plankton.

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It's not just small fish that join in on the feast.

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Manta rays filter the plankton

as they fly through the water on their huge wings.

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The giants visit the reef for a very specific reason.

As the ray hovers, moon wrasse race up from the reef

to pick off parasites and nibble at old or damaged skin.

♪ ♪

The reef is a kind of maintenance station

where the mysterious giants can stop to be cleaned and serviced

before they resume their flights through the plankton-rich seas.

♪ ♪

The plankton support fish, big and small,

and in places, in vast numbers.

♪ ♪

Anchovies, which eat the plankton,

attract another set of hunters:

the swift and sleek mobula rays.

These rays hunt in packs,

herding the small fish and pressing them against the reef.

Once the anchovies are confined, the rays attack.

The rays plunge through the shoals, seizing the anchovies.

After the frenzy of attacks, the anchovies regroup.

And the sinister shepherding starts all over again.

The tides that create the ocean currents,

moving fish and plankton, are not constant.

As the moon goes through its monthly phases,

so the tides wax and wane.

♪ ♪

They are strongest at the full and new moon.

♪ ♪

The phase of the moon affects all its subjects,

both on the reefs and in the coastal forests.

The profound dark of the new moon

enhances the display of fireflies in the mangrove trees.

♪ ♪

All this flashing has something to do with courtship and mating.

But exactly why they create this luminous effect is a mystery.

♪ ♪

The ensuing show is mesmerizing.

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The fireflies are miniscule, less than a centimeter,

yet they are so bright

they can be seen from hundreds of feet away.

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Two weeks later, the moon is full

and the tide is once again at its highest.

♪ ♪

The bright moonlight has a dramatic effect on many fish.

All over the reef, bohar snappers congregate.

They swim toward a spot

where the tidal current is especially strong.

The fish form tight shoals and move up toward the surface.

There they spawn in a mass event.

Eggs and sperm are expelled and mix in the water

as they are swept away by the current.

Black snappers race in to eat the eggs.

But the sheer number of bohar snappers

means most eggs will drift safely away from the reef

and its many hungry mouths.

They will join the plankton, and after a few months,

some will return to the reef as baby fish.

♪ ♪

The impact of the full moon is felt all along the coast.

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It seems to make fiddler crabs frisky.

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A female sets out to select her mate.

Her options seem endless.

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The males display in synchrony.

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It may be that females go for the male that displays first.

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She makes her pick

and follows him down a burrow to mate.

♪ ♪

The moon has a mysterious power.

It rules the animals of the mangrove forests and the reefs.

♪ ♪

It stirs the oceans and creates plankton-laden currents.

And for many creatures,

it is the key to the continuation of their species.

Captioned by Nat Geo.