♪
[Dramatic music plays]
♪
Attenborough: Much of our planet still remains unexplored...
♪
...for most of it is covered by water.
♪
Every journey below the surface
can reveal something extraordinary.
♪
More than 1,000 new species are discovered here every year.
♪
The ocean is home to 80% of all animal life
on planet Earth.
♪
But today, thriving in this varied world
sometimes demands the most surprising behavior.
♪
The shallow seas of the tropics.
[Water rushing]
This may look like a paradise.
But beneath the surface, it is an arena
for constant life and death struggles,
where not everything is quite as it seems.
[Dramatic music plays]
♪
A predatory lionfish...
♪
...on the hunt for shrimp and small fish.
♪
With so many places for its prey to hide,
the lionfish has to be patient.
♪
This shrimp appears tempting.
♪
As the lionfish closes in,
it fans out its fins to disorientate its prey.
♪
The hunter becomes the hunted.
♪
Tricked by one of the shallow seas'
most extraordinary predators...
♪
...a clown frogfish.
♪
On its head, it carries a fishing rod,
a modified dorsal fin baited with a lure
easily mistaken for a shrimp.
♪
But when the fish stop biting,
it's time to pack the rod away and move on.
♪
And for a frogfish, that takes time.
♪
Rather than swim, frogfish walk.
♪
Its fins have, in effect, become feet.
♪
It may not look pretty, but what appears to be coral
living on its skin is actually camouflage.
♪
As every good angler knows,
picking the right spot is important.
♪
Jigging the rod sends out pressure waves
to attract the attention of possible prey.
These dragonets are certainly interested.
Almost there.
[Dramatic music plays]
♪
Hook, line and sinker.
♪
-Do you know this place? -It's the old Mayfair house.
-What do you know about it? -It's famous for its witches.
What?
I don't understand anything that's happening.
Ciprien: I'm assigned to observe the unexplained.
Your gift is thestrongest thing I've ever felt.
Woman: The devil forms.
Man: You know you're special, don't you?
Can you feel it?
♪♪
Like all shallow seas,
the cold waters off the coast of North America benefit
from the intensity of the sunshine.
♪
Here, that fuels one of the fastest-growing organisms
on the planet...
giant kelp.
♪
Towering forests can eventually reach the height
of a 12-story building.
♪
These forests are nurseries for young horn sharks.
As the sun begins to set, they leave their daytime shelter
and set off into the heart of the kelp forest
to find food.
♪
Barely half a meter long,
this little shark is extremely vulnerable.
♪
There are monsters here --
a giant sea bass weighing over 200 kilograms.
♪
And wolf eels with big teeth
that can crush little red sea urchins.
♪
But the biggest danger comes from other sharks...
♪
...hound sharks.
♪
And huge broadnose sevengills.
♪
In this forest, it pays to keep a low profile.
♪
An angel shark...
♪
...one of the most deadly sharks in the kelp forest,
and certainly the best camouflaged.
♪
An angel shark will lie in wait for days.
♪
Now, this one
has already attracted
too much attention.
♪
It's not welcome here.
♪
Now the coast is clear.
But angel sharks hunt around the clock.
♪
Openings for breathing called spiracles
blow out sand that helps cover its body.
♪
The trap is set.
♪
Staying close to the seabed
is a good way to avoid most predators.
♪
Faster than the blink of an eye.
But it's not over yet.
♪
Horn sharks have a secret weapon...
♪
...sharp spikes keep them very much off the menu for most.
♪
So this young horn shark can hunt in safety...
for now.
♪
Violent winter storms batter these kelp forests.
♪
The plants can be ripped from the sea floor...
♪
...and carried away far out to sea.
♪
The open ocean is a vast, featureless desert.
♪
Even a small piece of drifting kelp can become valuable.
♪
It's just what these fish have been searching for.
♪
Here, shelter where eggs can be laid unobtrusively is rare,
so they make the most of it.
♪
Each female produces up to 1,000 eggs,
and the males rush in to fertilize them.
♪
All this activity attracts the attention of blue sharks.
♪
They can travel thousands of miles through the ocean
in search of food...
♪
...and they may not have eaten for weeks.
♪
It seems that they're in luck.
♪
But these fish are no easy meal.
♪
They are flying fish.
♪
The blue shark, however, are not here for the fish.
They have come for the caviar.
But flying fish lay so many eggs
that the sharks' feasts hardly make an impact.
♪
And in a few months time,
a new generation will take to the skies.
♪
Floating islands of weed are always attractive to creatures
looking for shelter out in the big blue.
But in today's ocean,
they're being replaced by something else...
plastic.
12 million tons of it end up in the ocean every year.
The deadliest kind are discarded fishing lines and nets.
Each year, it's likely over half a million animals
are ensnared and killed by these ghost nets.
But some animals are learning
how to take advantage of the plastic rafts...
and use them for shelter or even as a home.
♪
This male Columbus crab,
barely bigger than your thumbnail, is a castaway.
♪
Clinging to his net,
he may have been drifting on ocean currents for months.
♪
Now fully grown, he needs to find a partner.
But where?
[Dolphins calling]
♪
Certainly not here, alone on the net.
♪
Columbus crabs are not good swimmers.
So this male is marooned.
♪
Perhaps a passing loggerhead turtle
could be the chance to hitch a lift.
♪
Made it.
♪
But there is more than one passenger here --
a female Columbus Crab.
♪
They waste no time in getting acquainted.
♪
And start to mate.
♪
This pair may well stay together for the rest of their lives.
♪
The turtle, after all, makes an excellent home.
♪
In return, the crabs provide an onboard grooming service.
♪
Finding a partner in the vast ocean is not easy.
♪
Dawn in the Sea of Cortez.
♪
Mobula rays.
♪
They're gathering here most likely to breed.
♪
No one is sure why they leap,
but the loud splashes certainly seem to attract more rays.
♪
Other creatures, however, are also listening.
♪
Orca have heard the splashes.
♪
This female specializes in hunting rays.
♪
But today, she is teaching two youngsters
the finer points of mobula ray hunting.
♪
The rays are fast and can outmaneuver an orca.
[Orca calling]
♪
She knows she needs to herd the prey into a tight group.
♪
But she can't do that on her own.
It'll take teamwork.
And that is today's lesson.
♪
The young orca are quick to catch on.
♪
The rays are surrounded.
♪
They dive...
♪
...only to be forced back up again
by the experienced female.
♪
And now, with the exhausted rays
trapped against the surface, she attacks.
♪
And the young ones follow her lead.
♪
This family are the only orca known to hunt whales like this,
and they are lethally efficient.
♪
But it appears that school is over for today.
♪
For a few battle-scarred survivors,
it's a lucky reprieve.
♪
With the orca gone, the rays can resume their courtship.
♪
And they do so in astounding numbers.
♪
Tens of thousands of rays in a single show.
♪
Vast areas of our ocean are yet to be explored.
The least known parts of it are its great depths.
[Radio chatter]
Only highly specialized vessels can take you there.
As you descend, the sunlight rapidly fades.
♪
200 meters down, you enter the twilight zone..
♪
...an alien world inhabited by creatures beyond imagination.
♪
The Siphonophore.
With a cloak of lethal stinging tentacles...
♪
...Siphonophores repeatedly clone themselves and so grow
to immense lengths.
♪
This one measures 45 meters
and is the longest animal ever recorded.
♪
With such deadly predators around,
creatures here go to great lengths to hide.
♪
A glass squid,
completely transparent except for its eyes...
♪
...and stomach.
So it is extremely difficult to find in the gloom.
♪
Below 1,000 meters,
all traces of sunlight have disappeared.
♪
This is the midnight zone.
♪
Catching food in the perpetual darkness is not easy.
♪
A gulper eel.
♪
Its giant, extendable mouth
can engulf prey larger than its own body.
♪
Two miles down,
you finally reach the ocean floor.
♪
We know more about the surface of Mars.
♪
The pressure of the water is 300 times greater
than at the surface, and it's freezing cold.
Yet, amazingly, there are animals living here.
♪
Muusoctopus robustus, nicknamed the Pearl octopus.
♪
Breeding in these extreme conditions
poses a particular problem for these animals.
♪
At these low temperatures,
this female's eggs could take over ten years to develop.
♪
So she travels to a very special place.
♪
This is the largest known gathering of octopus
in the world.
♪
She joins 20,000 other females,
all here to lay their eggs.
♪
Water heated deep in the Earth's crust
rises through cracks in the seabed,
raising the temperature to as much as 10 degrees Celsius --
a deep sea thermal spa.
♪
This warmth significantly speeds up
the development of their eggs.
Even so, they will still take nearly two years to hatch.
♪
Once a female is settled, she won't move from her spot,
not even to feed.
♪
She will constantly tend to her brood, keeping them clean
and oxygenating them with jets of water.
♪
Pearl octopus mothers
must surely be amongst the most devoted.
♪
After almost two years, the ordeal takes its toll.
♪
But the vigil is almost over.
♪
The last of the brood are gently encouraged to leave.
♪
But this will be a final act.
Like all the mothers here,
this octopus is starved and exhausted.
♪
Her life will soon be over.
♪
But this devotion means that her offspring are among the largest
and most developed of any octopus
and have the best chance of survival
in the demanding world of the deep.
♪
We are finding more of these strange hot springs every year.
♪
In some places, they can be astonishingly violent.
Superheated water hot enough to melt lead
spouts from the sea floor.
Dissolved minerals condense around them to form
towering chimneys known as hydrothermal vents.
♪
They are home to unique communities of animals
that all rely on the nutrients in the scalding water.
♪
Some suggest that vents like these could be the places
where life on Earth first began 4 billion years ago.
♪
And there is now evidence of hydrothermal vents
on the moons of Jupiter and Saturn.
Could they too be supporting life?
♪
Here on Earth, the influence of these vents
extends far beyond their chimneys.
The essential nutrients carried in these plumes
can rise all the way to the surface two miles above.
♪
Here, they stimulate the rapid growth of tiny marine plants
on an astronomic scale.
♪
This phytoplankton is so abundant
that it produces half of all the oxygen on Earth.
♪
It's also food for a host of minute animals --
zooplankton.
♪
Together, they are the basis of the food chains
that sustain nearly all life in the ocean.
♪
In the Pacific waters off South America,
they feed anchovy that gather here in billions.
♪
This is one of the world's most productive ecosystems.
♪
These South American sea lions are on the hunt.
♪
But the anchovy shoal has already been located...
♪
...by the planet's most efficient hunters.
♪
A net over half a mile long encircles the shoal.
♪
It can trap over a million fish.
[Seagulls calling]
But the sea lions aren't about to go hungry.
They have learned to look for holes in the net.
Why waste energy when food comes to you as easily as this?
As more and more sea lions arrive,
some change their tactics.
♪
They line up on both sides of the net
and wait.
♪
As the net tightens, the anchovy panic and rush for the surface.
♪
[Sea lions barking]
This is the moment the sea lions have been waiting for.
♪
It's such an effective way of hunting
that the sea lions here are changing
their natural behavior...
♪
...and are raiding the fishing nets
in their thousands.
♪
With the net almost drawn in,
the fishermen beat out a warning signal.
[Banging]
Time is up.
♪
[Banging, men shouting]
♪
[Sea lions barking]
♪
In the confusion, not everyone manages to escape.
♪
The trapped sea lions are in danger of being drowned.
♪
Pups are separated from their mothers.
♪
[Sea lions calling]
♪
Then, at the last minute,
the fisherman briefly drop their net.
♪
And the trapped sea lions can escape.
♪
But many are not so lucky.
♪
Around the world,
millions of animals are accidentally caught and die
in fishing nets every day.
♪
And this bycatch, as it's known,
is pushing many species toward extinction.
♪
Animals have evolved in remarkable ways
to the demands of life in the ocean.
♪
But can they now adapt to the new challenge --
living alongside us?
♪
Attenborough: The open ocean is home
to some of the largest and most extraordinary animals
on Earth.
But here, off the Canary Islands,
the "Planet Earth" team are searching for one
of its smaller and less familiar residents.
We're looking for a tiny creature called a Columbus Crab,
which is only about the size of your thumbnail,
which live on floating objects in the open ocean.
Columbus crabs were once
only found on natural debris like driftwood or seaweed.
But the oceans are changing,
and they've been forced to adapt.
♪
One of the most common items they find
is discarded fishing gear.
Over a million tons is left adrift in the ocean each year,
and Columbus crabs are now making their homes
on these unnatural materials.
Surprisingly, Columbus crabs
are thriving on this new habitat.
But for larger ocean creatures, these nets can be lethal.
Loggerhead sea turtles are especially vulnerable.
Many times, they are very injured, and many times,
they don't even survive.
It's a sad situation.
As a rule, wildlife filmmakers
observe natural behavior and do not interfere.
But this is far from natural.
The team feel they must take action.
[Man shushing]
It seems that the turtle is quite okay.
We'll just finish to cut the plastic,
and then we release it.
♪
[Conversing in native language]
♪
It's a bittersweet moment, as this is one of eight turtles
they rescued whilst filming here.
This situation is not natural. It's something that is being
caused by human beings.
♪
Sadly, the crew now face dilemmas like this
on many of their filming expeditions.
Including when they traveled to the Pacific coast of Chile
to show how sea lions are competing for food
with one of the biggest fisheries on Earth.
♪
Expedition leader Fernando Olivares
takes the team to the fleet.
♪
Diving near fishing nets is extremely dangerous,
so the crew must ensure
they have the full cooperation of the fisherman.
♪
Pretty hazardous place to dive.
Just a case of trying to keep an eye on the divers.
But the sea lions also like to go down and blow bubbles.
So you'll think you're following the divers,
and then a sea lion will pop up.
♪
Taking the utmost care, the divers get a close up view
of the sheer scale of the operation.
♪
This one there must have about 15 tons of fish in it,
and there's 8 or 9 boats in this one little bay.
And these are just the small boats out there.
There are huge factory ships
that are taking even bigger catches.
How much fish a year from -- just from here?
From a million tons a year, more or less.
♪
The catches are so vast,
that sea lions have changed their natural behavior
to collect anchovies directly from the nets.
♪
It's a risky strategy.
The crew witnessed sea lions caught in nets multiple times.
Whoa. It's intense, mate. There's so many in there.
[Fishermen shouting]
[Sea lions calling]
There's a pup stuck in the net, calling to its mother,
and its mother is just on the outside of the net,
calling back.
♪
That's really hard to watch.
[Men shouting indistinctly]
♪
The pup's really panicking now.
♪
Sometimes, fishermen are able to release trapped sea lions.
But not this time.
♪
The pup is in serious danger.
Once again, the crew decide to step in.
[Sea lions calling]
♪
Wow.
[Laughs]
♪
Nice. Really nice.
♪
It's a relief this time.
♪
But it highlights the new realities of filming wildlife
in today's changing ocean.
♪
♪♪
Attenborough: Here, life is forced to do things differently
and nature is at its most spectacular.
♪♪
♪ Close your eyes [Elephant trumpets]
This is...