The Hunt (2015): Season 1, Episode 4 - Hunger at Sea (Oceans) - full transcript
The open ocean.
It covers more than half
the surface of our planet.
Yet, for the most part
it's a watery desert, empty of life.
Hunters here spend their lives
in a constant search
for scarce and elusive prey.
Remarkably, this seemingly
is home to the largest hunter
of them all.
The blue whale.
Weighing 200 tonnes and 30 metres long,
these are the biggest animals ever
to have lived.
Despite their immense size
blue whales are one of the most
and energy-efficient of all swimmers.
Their food is so scarce
and widely spread
that blue whales
must journey across whole oceans
just to find a single meal.
They can travel over a hundred miles
a day, for weeks at a time.
The ocean's largest animal
feeds on one of its smallest.
Krill, small shrimp-like crustaceans.
Opening its gigantic mouth
takes so much effort
that they only do so when the swarms
of krill are rich and concentrated.
The krill here is too scattered,
not even worth slowing down for.
This blue whale's lonely search for food
must go on.
Out here feeding opportunities
are always few and far between.
And they never last long.
Prey is devoured within minutes.
When it's all over the hunters
must resume their endless search.
the pirates of the high seas.
on the gentle trade winds,
they can scan vast tracts
of ocean for food.
Frigates must be so lightweight
that they can't afford the heavy oils
that waterproof the plumage
of other sea birds.
So getting wet would be lethal.
This may seem an impossible limitation
for a seafaring hunter.
But frigate birds overcome this handicap
with help from others.
One of the fastest
and most voracious of ocean predators.
They patrol close to the surface,
searching for prey.
Little fish try to hide amidst
the undulating swell of the ocean,
the only cover there is.
It's a game of hide and seek
played out amongst the waves.
Their cover blown,
escape seems impossible.
But these particular fish
have a unique ability.
They're flying fish.
With an extra thrust from their tails,
the flying fish get airborne
With a good wind,
they can glide for hundreds of metres.
But this is just what the frigate birds
have been waiting for.
When frigates join the hunt,
the flying fish are literally
caught between the devil
and the deep blue sea.
If the flying fish get too much lift
they become easy prey for the frigates.
If they dive to evade attack from above,
they could fall into the mouths
of the dorado.
With the help of the dorado
the wily frigate bird has
become a flying fish specialist,
and without getting
a single feather wet.
Not all open ocean hunters are able
to travel in search of their food...
Some have no choice,
but wait for a meal to come to them.
A mat of sargassum weed
drifts in the middle of the Atlantic.
Sargassum is the only seaweed
to live entirely at the surface,
it never attaches to the sea floor.
This floating tangle of fronds
is home to a surprising open
The sargassum fish.
Every part of his body mimics the weed.
His fins are more suited
to walking than swimming.
In fact, he can barely swim at all.
He will spend his entire life
marooned on this weedy raft.
This sargassum fish must lie in wait
for those seeking shelter
amongst the weed.
his mat is empty for now,
but at least he's not wasting
valuable energy searching for food.
In the featureless ocean,
these mats are much sought
after sanctuary for juvenile fish.
his first opportunity for weeks.
He must get closer.
He can only strike when he's within
a few centimetres of his prey.
Trusting his perfect camouflage,
he hides in the weed.
Still not close enough.
Hunger is clearly getting
the better of him.
Surely this time.
It may be weeks
before he gets another chance.
The open ocean is so vast
that some hunters
can only find enough prey
by searching as a team.
Dolphins live in highly sophisticated
Working together they can cover
a huge area of ocean.
These are spinner dolphins.
Why they make these twisting leaps
is still debatable.
Perhaps it's a form of communication.
Or perhaps it’s just fun.
Small groups sometimes come together,
five thousand strong.
And these are on the hunt.
Spinners are the most vocal
of all the dolphins.
They use echolocation, a kind of sonar,
to find their prey.
Each hunter sends out a series of clicks
and then listens for returning echoes.
Allowing them to scan for distant prey,
hundreds of metres away.
The super-pod spreads out
into a wide hunting line
up to a mile across,
producing a wall of sound.
for their favourite prey.
They are the most numerous fish
on the planet.
But these small fish spend most of their
time down in the deep ocean,
way beyond the reach of dolphins.
It's only when they come up
to the surface to feed
that they become prey.
Once they've found a shoal
the dolphins use their sonar
in a different way.
They stun the fish with loud blasts,
then simply gather them up.
As they feed, the dolphins work
the underside of the shoal
to stop their prey from escaping
back into the safety of the deep.
Within a few minutes,
all that's left is a shower of scales
drifting downwards to the ocean depths.
The deep ocean is by far the largest
habitat for life on earth.
And home to some of the most
bizarre hunters of all.
Down here, food is much scarcer
than at the surface,
so deep-sea predators
must do all they can
to save precious energy.
Waiting patiently, a viper fish,
special light-producing organs
on its head
entice prey towards fearsome teeth.
Strange, yet deadly,
jelly hunters also live here.
Most simply drift,
loaded with lethal stings.
Others, propelled by lines
of beating hairs,
glide gently through the darkness.
Beroe, the top deep-sea jelly predator.
They actively hunt other jellies.
Like this ctenophore.
To grasp its gelatinous prey,
beroe has special teeth-like
spikes in its mouth.
Many deep-sea hunters
just hang in the abyss,
saving their energy,
luring their prey to come to them.
This deep-sea squid fishes for prey
using long sticky tentacles.
Each has a glowing lure
pulsing to attract passing prey.
A gentle twitch adds to the temptation.
Down here in the darkness
this meal is a rare bonanza.
The open ocean may be
a vast blue desert,
but like all deserts it has oases.
across this endless space
are thousands of small islands.
These are the summits
of underwater mountains,
which rise up from the sea floor
many miles below.
The sea mounts deflect deep
ocean currents upwards,
forcing nutrient laden water
to the surface.
A busy oasis in the emptiness
of the big blue.
For potential prey
there's plenty of shelter
amongst the coral.
And in the caves that are hidden
beneath the reef itself.
Small fish take refuge here,
out of the reach
of most of their predators.
But not all.
They're not built for speed...
Success here depends on
Their strategy is to hide
in plain sight,
lulling their prey
into a false sense of security.
The lion fish’s stripes
are visually confusing,
making it difficult for their prey
to judge how close it is.
Using its extravagant fins
to hide slow and deliberate
it edges ever closer.
It must get to within a few centimetres,
close enough for a sudden strike.
The deep-water currents
that sustain so many residents
also attract visitors to these oases.
They journey hundreds of miles
between sea mounts,
using them as gathering places
in the featureless ocean.
They’re joined by hammerheads.
Both these sharks constantly
travel between the Galápagos
and other isolated sea mounts
in the Eastern Pacific.
No one knows for sure why they
gather in such numbers,
but some certainly come
to these oases in search of food.
A school of resident silver sides
cloaks the sea mount.
If these little fish
stay close to the coral
the sharks won't be able to get at them.
Other more agile visitors are attracted
by the potential feast.
And golden trevally.
To get a meal they'll need to drive
their prey up and away from the reef
into open water.
As long as the silver sides
stick close to the sea floor
they should evade their predators.
This time the frustrated hunters
will have to search elsewhere.
There's never an easy meal
in the open ocean.
The Southern Ocean,
The wildest seas on our planet.
Here, it's these storm-tossed waters
that bring nutrients to the surface,
creating isolated patches of richness.
Far from the calm tropics,
this weather-beaten ocean
is home to the albatross.
Black browed albatross
are the same size as frigate birds,
but three times as heavy,
and so they need
a totally different flying technique.
Albatross have the longest wingspan
of any bird
and that enables them to exploit
the power of the Southern Ocean winds.
First, they glide into the wind,
harnessing its energy to give them lift.
Then they turn and descend downwind,
picking up speed.
Soaring on wind fronts like this
an albatross can travel
hundreds of miles of ocean in a day,
barely beating its wings.
They often spend weeks at sea
searching for prey
without ever returning to land.
Food at last...
A patch of krill close to the surface.
Because the winds are so strong here
albatrosses can afford
the extra weight of waterproofing oils
on their feathers.
They can duck dive
to no more than a meter
so they rely on the churning
of the Southern Ocean
to bring their prey up into range.
Like all birds,
albatross have to breed on land,
but suitable islands
are so few in the South Atlantic
that most are heavily overcrowded.
Steeple Jason, one of the largest
albatross colonies in the world.
Nearly half a million come back here
each year to raise their young.
Adults share parenting duties,
returning every few days
to feed their chick.
it's time to head out to sea.
They need to make their way
to the edge of the packed colony
where there's more room for take-off.
Albatrosses are so heavy
that they can only get airborne in
places where the wind is strong enough.
Using a special runway,
with a good head wind...
From the air
the ocean may appear featureless,
but beneath the surface
a network of powerful currents
is constantly on the move.
It's these currents,
more than any other force,
that determine the distribution
of life out here.
A whole community of ocean drifters
on these rivers in the sea.
Pelagic red crabs.
They've gathered to feed on
tiny floating plants and animals,
a bloom of plankton
fueled by the currents.
Fine hairs on their legs
slow their descent,
and then with a few flicks of the tail
they swim back up
to continue feeding.
The currents that carry
these wandering crabs
also serve as highways
for the ocean's larger predators.
they can travel huge distances
with minimum effort.
These hunters patrol the boundaries
between ocean currents,
where their prey often gathers.
has an incredible sense of smell,
able to detect faint trails
left by their prey.
Somewhere out here is the big prize...
And hunters of all kinds
are looking for it.
Great shoals of fish
are attracted to a plankton bloom.
A single school of sardines
can be many miles long.
The fish swim tightly together.
There's safety in numbers.
Their defense relies on coordination.
When attacked, the sardines move as one.
Each fish instantly matches
the movements of its neighbour
and the whole shoal moves in synchrony.
A lone sea lion can't keep up
with their rapid reactions.
Even when more sea lions arrive
they can't seem to break down
the sardines' coordinated defenses.
The shoal this big,
the sea lions need to isolate
a smaller more manageable group of fish.
But with so few predators
the fish still have the advantage.
All the sea lions can do
is keep the sardines at the surface
and wait for others to join them.
Their arrival changes everything.
Tuna attack from below
cutting off the sardines' escape route
down to deeper water.
Next to appear, shear waters,
but also surprisingly agile underwater.
With so many predators
attacking from all sides,
the advantage starts to shift away
from the sardines.
As the fish pack ever tighter
their shoaling strategy
now makes it easier for the hunters.
They've scented blood in the water.
Surprisingly, perhaps, the predators
never attack one another,
they work together to corral
the ball of fish,
taking turns to grab a mouthful.
As the shoal gets ever smaller
each sardine scrambles desperately
to hide in the middle,
but now there's no escape.
A Bryde's whale
finishes off the feast...
Tonnes of sardines
devoured in less than an hour.
The predators melt away into the blue,
going their separate ways once more.
This blue whale
is still searching for a meal
to satisfy its giant hunger.
Being so large it must catch
an average of four tonnes of food a day.
But many days may pass
without feeding at all.
It is their great size
that enables blue whales to travel
roaming every ocean
from the tropics to the poles.
Trapped against the surface by fish
a dense patch of krill.
This blue has finally found what it's
been searching for, for so long.
A meal big enough to make opening
its massive mouth worthwhile.
The krill swarm
is hundreds of metres across
and packed tight.
The whale lines up on its prey,
targeting the densest part of the shoal.
It takes so much effort to swim
with a fully extended throat
that the whale
virtually comes to a standstill.
The whale uses its tongue
to force the water out of its mouth,
trapping the krill on plates
of hairy bristles that line its jaw.
But it takes time to sieve
so much water.
And that gives more nimble hunters
Blue whales may not be
as agile as other hunters,
but they don't need to be.
In one giant mouthful
they can swallow whole swarms of krill.
No other predator is better suited
to exploit these scattered riches
that the open ocean can provide.
The blue whale,
the greatest hunter
in all the world's oceans.
The open ocean created
many challenges for The Hunt team.
But none came bigger than trying to film
blue whales underwater.
Achieving this was to turn
into a two-year mission.
The crew teamed up
with John Calambokidis,
the world's foremost
blue whale scientist.
John gets crucial information
from these harmless tags.
But he can only observe blue whales
for the brief time they surface.
Well, part of this research
and part of the reason that, uh,
we're working with filmmakers is that
it gives us a unique chance to get,
uh, scientific information
we wouldn't be able to otherwise.
So we are doing this under our
research permit to get an insight
into what they're doing underwater,
how they're diving,
how they're swimming,
how they're feeding.
Pictures of blue whales are rare,
they're the biggest animal
ever to live on the planet,
but there are only a few
underwater pictures that exist today.
A few where you can actually
see the animal.
First, they have to find a blue whale.
Well, I always feel really embarrassed,
you know, because how can you lose
the biggest animal
that's ever lived,
but, uh, while the whale is big,
the ocean is even bigger.
Just over there.
The team's success
will depend on good water visibility.
Too murky and the whale
literally disappears into the gloom.
The first year
was blighted by poor visibility
and the shoot ended in failure.
and the sea conditions are much better.
Oh, here he is, right there.
Blue whales only surface
for two to three minutes at a time
before diving for up to 15 minutes.
It's a narrow window
for everything to come together.
There's a bit of tricky
maneuvering here for John.
And he's got to try and get the boat
ahead of the whale,
but not in front of it.
Then, David has to swim out
and hope the whale passes
close enough to get a shot.
It's too far.
It's a little too far that time.
This year the water
is exceptionally clear,
but getting David in the right position
still takes time.
He went by, I definitely got a shot,
it's not one of our best.
After weeks of effort
all the elements finally come together
giving David the chance of a lifetime.
Once I got down about 25 feet
I knew that whale was out there.
But, uh, he just came out of the blue,
right to me.
I could see his eye,
the details of his mouth,
every scratch on his skin,
and he cruised on by, it took forever.
You know, they're so big
it just went by like a freight train.
I saw his tail slide by.
It slipped back into the blue.
It was awesome.
That is awesome, I have never...
Of all my years of doing this,
I've never got a shot like that.
That was amazing.
Images of blue whales
underwater are so rare
that this shot, one simply swimming by
is a major success.
But the crew need more.
This series is all about hunting,
and so nice though it is to have
that shot to make a sequence
we've got to get shots
of blue whales eating krill.
And what we've got to wait for
is when the krill
actually comes to the surface.
It might happen once,
maybe twice a month.
The crew come across
an encouraging sign
from a rather unsavory source.
That's a whale faeces.
So we've found a big
whale poo in the water,
um, it's a good sign for us,
we know that they're feeding here,
so maybe they'll stick around.
Finally the crew find
what they've been looking for.
Krill at the surface.
Look at those birds in the water.
So, there's a small krill ball.
We're going to go take a look at it.
All right, John, remember,
don't put me right on top of it.
All right, ready?
Okay, the ball's right here.
- Right here, right here.
- Is it on the surface?
- Yep. Right at the top.
- Good red?
Yeah, got it.
No one was prepared
for what happened next.
It's right behind you.
Hey, Hugh, here it comes!
That's a shot I bet you got it.
I bet you got it.
God, they're beautiful,
What you guys get?
What you guys get?
Oh, my God.
Oh, my God.
I still, I can't actually quite get
my head around what I just saw.
We were down there,
Dave was filming the krill balls
and I just noticed, literally,
between his fins
great whale just loomed out.
David saw it climb down,
I don't know where it came from.
Well, when I first looked down
I saw this whale,
of course, I was a little bit
stressed out because
95 feet of blue whale
is going between my fins.
He hooks around, comes up
and just grabs a big mouthful.
They're called blue whales
for a reason,
but you just see them underwater,
this bright iridescent cobalt blue just
pops out of the blue of the ocean.
And then finally I get round
to the other side
and I go, "Okay, he left, " and then,
that is pretty intense.
So I'm up
trying to just get another shot
of the krill and sure enough,
wide open he comes to one last time.
I was, kind of, in the wrong spot,
I had to do some serious,
but he comes through, closes his mouth,
it was just amazing.
The whole thing probably
lasted 10 minutes,
but it was hands down, without a doubt,
no questions, was the most intense,
amazing thing that I've ever seen.
To share the water and to look
eye to eye with a blue whale
is something I will never ever forget.
give John a unique insight
into the feeding behaviour
of blue whales.
Let's just look at the
side of his mouth there, uh, basically
the water flow you'd expect
to be coming out the back there.
Yeah, look at that little fold
there, that is really interesting.
Oh, that's a great view.
And notice the full rotation there.
Oh, that is... And the full inversion.
Okay, that's again a unique chance to
see a perspective we don't get to see.
With this close collaboration
the team have filmed
blue whales as never before
and at last have started to reveal
the secret life
of the ocean's greatest hunter.
Next time the hunt is on
out in the open.
On the deserts and grasslands.
Where hunters and hunted
have nowhere to hide.
For a free interactive
Open University poster
or go to bbc.co.uk/the hunt
and follow the links
to the Open University.