Original subtitles

They're the closest we have to extraterrestrials on planet Earth.

No wonder the cephalopod family has captured our imagination.

Their alien appearance

comes with astonishing intelligence,

independence,

and invention.

And there's still so much to learn

about these rarely seen legends of the deep.

Animals that truly are stranger than fiction.

Nutrient-rich waters make this

one of the most productive seas on the planet.

A perfect place for new life to begin.

Hidden beneath the waves…

in a secret world…

100,000 precious eggs.

Each no bigger than a grain of rice.

For six months, they have been carefully tended

by Mom.

A giant Pacific octopus.

Her body,

their fortress.

She keeps the water moving

to prevent algae from smothering her babies.

Within each egg,

a tiny replica of an almost impossible creature.

Eight arms…

three hearts,

and blue blood.

Eventually, they will grow to be 250,000 times heavier…

and among the most cunning predators in the ocean.

But very few make it that far.

It's time to leave the safety of their nursery.

With one final exhalation from Mom…

this baby is cast away into the ocean currents.

She will never see her mother again.

Completely alone,

at the mercy of the sea.

If she survives,

she'll take her place

within one of the most incredible animal families on Earth.

Found in every ocean…

there are over 800 species of octopus,

squid,

and cuttlefish.

They are cephalopods…

which literally means "head-foot,"

thanks to their peculiar anatomy,

with limbs sprouting out of their faces.

But the earliest cephalopods looked more like this.

A nautilus.

It resembles its mollusk relative,

the snail.

It has remained unchanged for half a billion years…

while others were evolving in the most extraordinary ways.

They lost their shells,

making them more flexible, more nimble,

able to explore places that had been off-limits.

Their fluid form

is even capable of surviving the crushing pressures of the deep.

But with no shell for protection,

cephalopods became soft targets.

So they came up with an almost supernatural range of abilities

to stay safe.

Vital in a sea full of predators.

The ocean can be a daunting place…

if you're only the size of a matchbox.

It pays to keep a low profile.

But a little cuttlefish can't hide forever.

A high metabolism means he's always hungry.

His favorite food lives in the shallows…

just 20 meters away.

But when you're this small, it's an epic journey…

…full of danger.

He swims pretty well,

but fish are faster…

with sharp eyesight.

But blending in is a cephalopod specialty.

The cunning cuttlefish

takes his disguise one step further.

Special muscles in his skin

produce thousands of spiny outgrowths known as tubercles…

making him look like seaweed.

It seems to do the trick.

This isn't the only outfit in his collection.

In a fraction of a second, he can channel any look.

Snail…

coral…

or rock.

Cephalopods' amazing ability to change color

is all thanks to their chromatophores.

Millions of pixel-like cells filled with pigments,

they expand and contract like balloons…

to create rapid changes in color.

Perfect for merging into the background within a fraction of a second.

Cephalopods put chameleons to shame,

with the most sophisticated camouflage of any animal.

This disguise is usually enough to keep a tuberculate cuttlefish safe.

But when all else fails…

…a smoke screen.

Mucus-rich balls of ink,

mimicking his shape and size.

Decoys deployed,

he makes his escape.

Unlike octopuses,

cuttlefish have an internal shell.

A built-in buoyancy aid,

making them superior swimmers.

Even so, after such a long, eventful journey,

he's worked up quite an appetite.

Shape-shifting…

inking,

even regrowing their limbs…

cephalopods' superpowers help them survive in dangerous waters.

Back in Canada, a story of success

in the face of overwhelming odds.

The giant Pacific octopus is now a year old…

and already 2,000 times bigger.

But there's still a long way to grow.

Only one in 30,000 make it to adulthood.

To help her get there,

she'll need to rely on her extraordinary sight.

Each octopus eye

has a greater field of view than we have with two.

And when she uses both eyes…

nothing escapes her.

Unrestricted by a solid skull,

her eyes move independently,

so she can look forwards and backwards at the same time

for an almost 360-degree field of view.

Allowing her to scan for food…

and keep an eye out for danger.

Like all octopuses, she's almost pure protein.

So everyone wants a bite.

She's now big enough to survive rockfish attacks…

but there's always a bigger predator looking for a meal.

She needs to keep vigilant.

With no parents for protection,

young octopuses must balance their innate curiosity with caution.

And in a constantly changing ocean, they need to learn fast.

When the tide turns,

predators move in,

searching for prey caught out by the falling sea.

Stranded in a rock pool…

a nine-month-old Brazilian reef octopus.

Cut off from the retreating ocean,

she can't survive long here.

But this resourceful young octopus isn't done yet.

Up above,

this is the moment

an army of Sally Lightfoot crabs have been waiting for.

Low tide is their chance to feed on exposed rocks.

At first, they seem determined to keep dry…

leaping ten times their body length from rock to rock.

But if the gap's too big, they're forced to take the plunge.

This was no lucky strike. It was a carefully planned ambush.

The young octopus has learned the crabs' regular highway.

Her incredible ability to strategize…

is carried out by a very unusual brain,

distributed throughout her body,

two thirds of its neurons located within her limbs.

Self-taught, she knows when to hang back

and when to pursue.

She paralyzes it by injecting toxic saliva with her hidden beak,

then waits for her digestive enzymes to liquefy its insides.

A nutritious crab shake.

But she needs five a day to keep her growing,

and she's working against the clock.

The midday sun is shrinking her tidal pool…

threatening to leave her high and dry.

And, as she breathes through moistened gills,

she'll suffocate without water.

It's hours till the tide rises again…

…but she's developed a clever solution.

In a cavity behind her head, she stores water to let her breathe.

Enough to buy a few more minutes.

The breathing space she needs to do the unthinkable.

She becomes a land crawler.

She must move fast before she dries out.

Her fluid body is no longer weightless.

Her organs are in danger of failing.

Shifting pools is a risky strategy,

but with cunning and forethought,

she won't be caught out.

The tougher the challenge, the more inventive cephalopods become.

Barren sands with nowhere to hide.

Predatory puffer fish.

To survive here,

octopuses have adopted some of the strangest strategies on the planet.

The wunderpus baffles predators by acting downright weird.

The blue-ringed octopus signals his lethal venom.

Others are more innovative.

Veined octopuses seem to regret ditching their shells

all those millions of years ago.

When it comes to a replacement suit of armor,

getting the right fit is all-important.

Perfect protection from puffer fish.

Once assembled,

they carry their mobile homes wherever they go.

Not bad for a mollusk.

Octopuses,

among the sharpest minds in the ocean

and the greatest tool users of any invertebrate.

They are even thought to dream.

When such intelligence combines with sheer size,

something remarkable emerges.

A trail of destruction,

leading to a kraken

at the height of her power.

One of the fastest-growing animals on the planet,

she needs 20,000 calories a day.

That's a lot of time out hunting.

Now, as heavy as a human,

this three-year-old giant Pacific octopus

is a physiological phenomenon.

She has thick blue blood,

pumped around her body by her three hearts.

Swimming is strenuous.

Better save energy and walk.

Eight muscular arms, five meters across.

Powerful enough to tear human flesh.

Her arms see through touch.

Two thousand suckers feel the way,

tasting as they go.

Every meal brings her one step closer to her ultimate goal.

To pass on her genes to the next generation.

Piling on the pounds before she mates

is her best way of ensuring breeding success.

So she cleans her weapons to improve their sense of taste,

touch,

and grip.

A quick scrub…

and she's back on the hunt.

To most animals,

this is a trap.

But she's smarter than that.

And in the open,

easy pickings.

This is her final killing spree.

Her last play as a lone assassin.

Most cephalopods only get one chance to mate.

So they must be prepared to do whatever it takes.

Every winter, this quiet bay becomes a bustling cephalopod city.

250,000 giant cuttlefish,

all desperate to find a mate.

This male is late to the party.

Males can reach a meter in length,

but, at only 30 centimeters,

he's easily outgunned by the big boys.

They're already guarding the females,

who are outnumbered eleven to one.

Not easy for a newcomer to make his move.

The giants' kaleidoscopic skin

and huge arms

signal their masculinity.

The little guy simply can't compete.

When two giants are equally matched,

the inky decoy distracts and confuses the attacker.

Battle scars.

A reminder they'll risk everything.

The drive to mate is overwhelming.

The newcomer spots an opportunity.

Two large males so focused on fighting,

they've left a female unguarded.

He sneaks in.

Cuttlefish mate in a face-to-face embrace.

He attempts to get in position.

But now the giant's back on duty.

It's too risky.

It's time to go undercover.

He tucks up his large arms that give away his gender.

Spotting another female, held captive under a giant,

he finesses his disguise,

dulling his vibrant colors to mimic a mottled female cloak.

In full drag…

the newcomer slips in…

and gets to mate…

right under the giant's nose.

Proving brains can be just as attractive as brawn.

Perhaps lost in the moment, the newcomer drops his cover.

The game is up.

This mind-blowing deception

accounts for one third of all breeding successes.

This little cuttlefish's work is done.

But for many cephalopods,

mating is just the beginning of the battle to breed.

Predators are gathering.

Short-tailed stingrays…

Cape fur seals…

and ragged-tooth sharks…

all here for one thing.

The annual feast.

A squadron of chokka squid.

Unlike solitary octopuses,

they move in huge shoals…

seeking safety in numbers as they cruise the open ocean.

Already mated,

this female is being guarded by the larger male

to ensure she doesn't try to mate again.

She has to lay her eggs on the sandy bottom.

But first,

she must get through the predatory barricade below.

Her best chance

is to hide in the crowd.

She's made it…

laying her capsules amongst the mass already here.

Millions of eggs on this single site.

Prodigious reproduction

and amazing adaptability

have brought cephalopods huge success.

Even today,

as many other animals are in decline,

many squid,

cuttlefish,

and octopus

are not just surviving,

they're thriving.

Hidden from sight,

steadily increasing in numbers,

expanding their range.

But as sea temperatures and fishing practices change…

it's unclear what lies ahead for the generations to come.

One thing is certain.

Each has a supermom, ready to sacrifice herself for her young.

Now four years old,

this giant Pacific octopus is a true survivor.

She's spent her life alone,

an orphan since birth.

But now, her three hearts beat for a single purpose.

Her final act.

Tending her brood.

For almost a quarter of her life,

she does nothing else.

She no longer leaves her den,

no longer eats,

starving herself to give her babies the best start.

They are her legacy.

Unaware Mom laid down her life for them,

these tiny octopuses are ready to take on the world

and teach us more about these fantastic beasts.