Original subtitles

Arabia's coral reefs are home to some of nature's most impressive illusionists.

Animals that can transform themselves -

often in the blink of an eye.

The most flamboyant pulsate with color...

..and engage in enthralling displays of showmanship.

Camouflage helps others to become almost invisible.

Elaborate disguises and clever distractions

can favor the bold.

These are Arabia's Magicians Of The Reef.

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It's late May in the Gulf of Oman.

Temperatures are rising, as summer approaches.

The Gulf is situated off the east coast

of the Arabian Peninsula.

It borders the coasts of Oman, United Arab Emirates,

Iran and Pakistan.

It connects the shallow Arabian Gulf

to the northwest

to the deeper, cooler Arabian Sea further south.

In this underwater paradise,

conditions are now favorable for the brief, but intense,

breeding season of one extraordinary magician.

The cuttlefish.

Cuttlefish are members of the cephalopod family,

which also includes octopus and squid.

All of these highly intelligent mollusks

have three hearts, eight arms

and the largest brains of any living invertebrate.

Cephalopods are notorious masters of disguise.

They can change their appearance

to match their surroundings and escape detection.

These magicians are also able

to alter their body patterns and color,

to put on quite a show.

The breeding season in the Gulf

is the cuttlefish's chance to really show off.

These are pharaoh cuttlefish.

The larger of this pair is the male.

He can grow 16 inches long and weigh up to 11 pounds.

His stocky, oval body - called a mantle -

and his frilled fin edge

are similar to that of his close relative, the squid.

Like many other cephalopods,

cuttlefish can change color...

but they have taken it to extreme levels.

Their skin is covered in tiny color-changing cells,

called chromatophores.

This cuttlefish has a staggering 130,000

of these color-changing cells per square inch of skin.

These cells enable it to make these sophisticated changes

in color, tone and pattern.

A large male shadows a smaller female,

as she swims around the reef.

As he detects they have company,

he boosts his pattern and flashes dark spots

as a warning.

This female is his.

He follows her closely.

Raising his eight arms at her

doesn't appear to attract her attention.

In a split second,

he flexes tiny muscles under his skin,

to make it stand up.

These projections are called papillae.

They help him blend into the coral.

But cuttlefish also use them

during these courtship displays.

The female can perform the same tricks,

to also mimic the coral.

The male's efforts still draw no response.

He raises his game...

..splaying his tentacle arms

in an attention-grabbing display.

Still nothing.

He switches his color off.

Finally, she responds.

Their arms entwine,

as they lock in a face-to-face embrace.

The male uses a special arm called a hectocotylus

to transfer sperm directly into a cavity

near the female's mouth.

His top two arms drape over her head,

as he holds on to her.

Cuttlefish can stay locked together like this

for up to seven minutes at a time.

If the male can retain her interest

and protect her from other males,

they will mate again.

This love match is not over yet.

Not all cephalopods like to stand out

when it comes to mating.

Sometimes it's better to keep a low profile.

This creature has a disappearing trick.

The dark shape of a day octopus

can barely be seen in this coral crevice.

Without a skeleton,

this contortionist can squeeze itself

into extremely tight places.

Only an eye gives him away.

Day octopuses tend to breed year round,

but this one has good reason to avoid attention for now.

Mating can spell disaster for males.

Female octopuses can cannibalize their partners,

once they've mated.

If a female comes looking,

this male's vanishing-act rehearsal

may just save his life.

Like the octopus,

another of the reef's magicians

also breeds year round.

He can also make himself invisible.

The seahorse.

This master of disguise

blends perfectly against the coral wall...

..surrounded by colorful sea fans.

This is a great seahorse,

one of only two species found

in these enchanting Arabian waters.

Seahorses are famous for the male's role

during the breeding season.

When she is ready, the female deposits her eggs

into his distinct brood patch,

the smooth area seen here,

on the front of his body.

He fertilizes the eggs inside his pouch

and carries them for up to four weeks, as they develop.

Then he gives birth.

He's anchored to a sea fan by a prehensile tail,

but he's ready to find a new spot.

He swims upright, using his dorsal fin

to propel him forward.

This fin can beat 70 times a second,

the same as a hummingbird's wings.

Tiny pectoral fins behind his gills

enable him to steer and maintain stability,

even against the strong sea current.

Seahorses don't swim well, so they don't move often.

In his new location, the male simply floats horizontally,

moving in rhythm with the current.

A passing predator may be tricked into seeing it

as just another piece of coral hanging off the reef.

Above the reef, an enormous school of small fish

creates the illusion of a large, impenetrable mass.

But their trick doesn't guarantee their safety.

These silversides are important prey for sharks.

They also face attack from above.

The Damaniyat Islands

lie nine miles off the coast of Oman.

Sooty gulls and terns

use them to rest on and hunt from.

They take aim,

trying to pluck out individuals,

disguised in the mesmerizing blur.

The fish move, as one,

away from the surface, to avoid the danger.

Back on the reef,

having established his territory and found a mate...

..the male cuttlefish

tones down his elaborate displays...

for now.

The stakes are high.

Cuttlefish, like all cephalopods,

get just one season to pass on their genes.

In just a few weeks, those that mate will die.

This pair makes the most

of their one chance in life to breed.

Newly matched pairs mate repeatedly

during their short time together.

The female will fertilize her eggs

with the sperm passed to her from the male.

Females can delay fertilization

for several days after mating...

..but this one is ready to lay immediately.

She tightens her arms up into a fist-like shape,

to create a chamber near her mouth.

Here she breaks open the stored spermatophores

to fertilize her eggs.

The male is eager to mate again...

..but the female spurns his colorful advances.

She's looking for a suitable rock or a coral crevice

to tuck her eggs into.

It must be deep enough

to hide them away from hungry predators.

She deposits each tiny egg individually

into the crevice,

as she flutters her long fin more rapidly,

to control her movement.

Cuttlefish control their buoyancy

through a porous internal shell called a cuttlebone.

The pores in the bone enable the animal

to adjust the volume of air and water inside its body,

thereby changing its weight and position in the water.

The male switches his color off,

as he makes another play for her attention.

But she is on her own mission: to lay more eggs.

He has to settle for keeping a protective eye on her,

a behavior known as mate guarding.

He can't risk another male stealing his partner.

He must ensure that she has only his sperm

to fertilize her eggs.

For now, they are alone in their Arabian-reef romance...

..but pheromones released from their eggs

will soon attract other mature cuttlefish

into a mass spawning event,

increasing their chances of survival.

In Arabian waters,

the closest relative to the cuttlefish is the reef squid.

The two have plenty in common.

The same-shape mantle,

with its magical color-changing abilities.

The long fringing fin along its body.

Large eyes.

And the same bilateral symmetry, or mirror image,

of left and right side.

This one is known as a bigfin reef squid,

for rather obvious reasons.

These inquisitive magicians are common in these waters

and are extremely agile.

Like the octopus and the cuttlefish,

squid change color and mostly swim backwards.

They do this using jet propulsion.

The squid contracts the muscles in its mantle,

to force water through a funnel known as a hyponome.

The squid adjusts the position of the funnel...

..located between the head and mantle,

to change direction.

The faster the contraction,

the faster the squid can escape danger.

Unlike the cuttlefish,

squid do not have an internal bone

to control their buoyancy.

Instead, they manipulate the molecular composition

of their body fluids.

In slow motion...they become even more mesmerizing.

Some squid perform elaborate dances

when attracting a mate...

..but the bigfin reef squid are more subtle.

If two are interested in each other,

they may swim together side by side.

This male squid is on guard.

Beneath him, a female lays their eggs.

But they have company.

A second male loiters nearby.

He may try and mate with the female.

The guarding male quickly signals his annoyance

by rapidly changing color.

It's enough to halt the intruder in his tracks.

He turns the color on

by contracting his chromatophore muscles,

and relaxes them to turn it off.

This lack of color

causes his mantle and arms to turn white.

The intruder keeps his distance,

but doesn't give up.

Remarkably, the male is also able

to flash different colors on different sides of his body.

He shows brown to the female,

to signal everything is fine,

but flashes silver to intruders,

to say, "Keep away."

This is known as silver lateral display.

Pulsing dark blotches on his arms

and a stripe down his back reinforce the warning:

"I will defend my mate."

It's enough to drive his rival away.

Bold patterns, especially stripes,

serve as a warning in many animals.

Deadly sea snakes

commonly have banded patterns to communicate danger.

But this is no serpent.

It's another illusionist.

A harmless banded snake eel,

masquerading as a toxic sea snake.

The eel has a dorsal fin, but a real sea snake does not.

This clever deception is known as Batesian mimicry.

It allows the eel to trick predators

into believing it's more deadly than it is,

allowing it to move confidently around the reef,

as it hunts for small fish and crustaceans.

The cuttlefish couple has company.

They're in the midst of their breeding cycle,

but an intruder is shadowing their every move.

The male produces dark stripes on his mantle,

to warn off the rival male.

His opponent may be smaller,

but darkening his own stripes

signals his intention to get involved.

The male raises his arms to intimidate his rival...

..as his mate prepares to lay more eggs.

Females can, and will, mate with more than one male,

then select whose sperm to use.

This phenomenon is known as cryptic female choice.

The male must ensure

she doesn't mate with anyone else.

He turns on his rival.

He then conjures up his own silver lateral display -

bold warning stripes to the right,

calmer sandy brown to the left -

to reassure the female.

He mustn't let her slip out, into the arms of his rival.

The intruder may be outsized and out-striped,

but he's not about to give up.

As the female finishes laying...

..her protector makes his move.

He out-maneuvers his rival...

..but the little guy is ready.

He touches the larger male.

This is an uncommon provocation.

The bigger male sucks water into his body

and stretches his arms even wider, to appear much bigger.

If he can win this contest through visual display alone,

he may avoid a potentially damaging fight.

The smaller rival backs away...

..but he's not done yet.

The stand-off lasts several more minutes...

..before the rival eventually concedes defeat.

The male has won the right to keep his mate.

His dark head signals his victory.

Despite the dazzling displays,

remarkably, cuttlefish and squid

are almost certainly color-blind.

Recent scientific research suggests

that light-sensitive proteins in their skin

may help them sense their multi-colored world,

without actually seeing it.

The high contrast of colors may be enough.

The female squid seeks a safe place

to finish laying her eggs.

It will be tough getting past the sea urchins

hiding in this crevice.

Many species of squid

simply release their eggs into the water,

as most fish do...

..but, like cuttlefish,

these bigfin reef squid

seek to protect theirs in coral crevices.

Once their first batch of laying is complete,

the pair simply vanishes into the blue.

Squid and cuttlefish can both live at depths

of more than 300 feet.

Down there, color is less important,

as only blue light penetrates these depths.

During the breeding season,

they spend more time in the dazzling shallow reef waters

around the Damaniyat Islands.

But shallow waters bring shallow-water predators.

Black-spotted butterflyfish are opportunists.

Cuttlefish eggs are a nutritious treat...

..if they can reach them in the tight coral crevices.

The cuttlefish does nothing

to protect her eggs from the long-snouted predator.

The mouth on the end then sucks out a hidden egg.

A damselfish vacuums up the left-overs.

The female cuttlefish

hasn't chosen the best of hiding places.

The gaps between the algae-coated branches

expose the cluster of translucent white egg sacs,

which need 14 days to develop and hatch.

The persistent butterflyfish goes back for more,

but another quickly snatches the egg...

..resulting in an underwater tug-of-war.

All the cuttlefish can do is lay again.

There are at least 16 species of butterflyfish

in Arabian waters.

Black spotteds are the most common in the Gulf of Oman...

..but they are outshone by their dazzling relative...

..the Arabian butterflyfish.

They mate for life.

Despite their bright color,

these conspicuous fish are also masters of illusion.

Their dark tails are mirrored

with dark, vertical eye bands.

Predators look for eyes to target their attacks.

Striking the head...

..is a more effective kill than biting a tail.

If a predator can't see the eyes,

it's hard to know what to aim for,

and it may attack the wrong end...

..giving the butterflyfish a chance to escape.

Fish are the primary prey of the cuttlefish.

Here, one prowls the reef in search of a meal.

This ambush predator

becomes almost invisible in its preferred hunting ground,

the sea floor.

A cuttlefish fires out two long tentacles,

lined with suckers, from beneath its arms,

to catch prey.

A shoal of fusiliers provides plenty of opportunity.

The fusiliers' best defense is safety in numbers.

Some fish form schools,

meaning they swim in the same direction,

maintain an equal distance between them and move as one.

But other species form shoals...

..a looser group,

where the fish do not co-ordinate their movements.

Fusiliers do both.

When hunting, they will school,

but, more commonly,

they shoal in large numbers, for safety.

Their twists and turns make it hard for the cuttlefish

to focus on an individual.

But this master of disguise bides its time.

It appears to assess its strike range...

..adjusts its position...

..color and texture.

Success.

Its tentacles have suckered a fusilier.

Its arms hold the fish in position

and slowly direct it into its mouth.

The cuttlefish devours its prey,

using a hard beak buried at the base of its arms

and a flesh-scraping tongue.

It's rare to witness a cuttlefish take its prey.

These magicians more commonly hunt in these shallows

under the cover of darkness.

Octopuses will also grab fish swimming above them.

A dark, almost invisible head

protrudes just above the coral hideout.

A spinecheek hovers unwittingly above him.

The octopus remains perfectly still,

as a large grouper points to the lurking predator.

But it's too big to be at risk.

Smaller chromis dart overhead,

oblivious to the potential danger beneath them.

Now you see him, now you don't.

The octopus is back in his den,

with only an eye visible.

One chromis brushes its tail against the octopus,

as it attempts to court a female nearby.

This kind of mistake could prove fatal...

but octopuses usually prefer slower-moving prey,

like crustaceans...

or even a great seahorse.

Like the octopus,

the seahorse is an ambush predator.

It can capture a staggering 90% of its targeted prey,

when sea conditions are calm.

Its long snout and wide mouth

enable it to suck up tiny crustaceans.

This is a female.

Once her eggs are with the male,

she plays no further role in raising their young.

She's not feeding,

but she opens and closes her mouth,

to pump oxygenated water in

and push carbon dioxide out,

through gills behind her eyes.

Her best trick is the ability

to move each orbital eye independently,

giving her the power of almost 360-degree vision.

Her bony exoskeleton has protruding appendages,

known as cirri,

which add to her coral-like camouflage.

A fine coating of algae completes the look,

giving the seahorse a protective cloak

of near-invisibility

against a passing predatory moray eel.

A female hawksbill turtle is also out hunting.

She appears to know exactly what she's looking for.

Sea turtles have good eyesight underwater,

but they also have an acute sense of smell,

for detecting prey.

Hawksbills most commonly eat sponges in these waters,

but, at this time of year,

there's a different protein treasure to find.

She arrives at a large clump of coral

and immediately works her magic.

Her sharp, hawk-like beak is exceptionally strong.

Presto! Cuttlefish eggs.

The eggs are in small clusters,

making them easily removable.

Wrasse and damselfish are ready to grab any left-overs.

She uses her flippers to gain purchase,

as she tears the eggs from the coral.

These eggs are more developed

than the butterflyfish's earlier snack.

The turtle can no longer reach

the rest of the treasure.

The eggs were a good meal for both the turtle

and the hungry fish...

..but enough remain intact under the coral to hatch.

As summer begins to tighten its grip on the Gulf,

temperatures above and below water are rising.

It's now June.

The cuttlefish breeding season is well underway...

..and competition is getting fierce.

Time is running out.

Across the reef, pheromones,

released from the cuttlefish eggs

and drifting on the sea currents,

entice others to start

their once-in-a-lifetime chance to breed.

Couples pair up and establish bonds

for their own brief encounters.

The waters are teeming with protective males,

with bold blue stripes...

..each closely guarding a female

who could ensure his genetic legacy.

In amongst the melee of large characters,

smaller males try to get in on the action.

These so-called "sneaker males"

have a few tricks of their own to play.

Sneaker males tone down their color,

to create the illusion of being female,

to get past the bolder, protective males.

Having already successfully seen off his rivals,

the male cuttlefish and his mate

now have trouble of a different kind.

It seems the egg-laying pair

has strayed into the territory

of a damselfish...

..and he's not about to tolerate their presence

on his patch.

Damselfish are notorious for taking on intruders,

no matter how big or how many there are.

His best line of defense is attack.

The cuttlefish may struggle to magic himself

out of this tricky situation...

..and now there's double trouble.

A sneaker male loiters nearby.

If the sneaker male can take advantage

of the damselfish distraction,

he might be able to inseminate the female

right under the tentacles of the big male.

The big male can't shake the damselfish.

The sneaker makes his move.

Now the male is alert to the danger.

The sneaker male wasn't sneaky enough.

By keeping others at bay,

the bigger male ensures his partner lays her last eggs,

carrying only his genes.

Across the reef, males and females mate and lay eggs

in the dying days of the short,

but intense breeding season.

A cuttlebone is all that remains

of one adult cuttlefish.

Evidence of what will become of this year's mated couples.

Females each lay approximately 1,600 eggs

during a spawning season.

Some will fall prey to predators...

..but enough will survive, to ensure the next generation

of these extraordinary magicians of the reef.

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