Nature (1982–…): Season 23, Episode 2 - Shark Mountain - full transcript
Narrator: THOUSANDS OF SHARKS...
SILKIES,
WHITE TIPS,
HAMMERHEADS,
HUNT ALONG THE VOLCANIC REEFS OF
THIS TINY ISLAND IN THE PACIFIC.
ACCLAIMED FILM MAKER
HOWARD HALL AND HIS CREW
HAVE BEEN DIVING AT COCOS
ISLAND FOR MORE THAN A DECADE.
Man: NOW THIS MAY
NOT BE ENTIRELY SAFE.
OOH, LOOK AT THOSE BIG BOYS!
THERE'S 50 SHARKS DOWN THERE!
GO! YEAH, GO...
YEAH, GO. GO?
PUSH HIM IN!
Narrator: IT TAKES ALL OF THEIR
EXPERIENCE AND KNOWLEDGE
TO DIVE IN THESE
TREACHEROUS WATERS.
WELCOME... TO SHARK MOUNTAIN.
The beach, San
Diego, California.
This is the edge of our world.
Along this thin line,
America slips quietly into
the vast Pacific Ocean.
It's no place for
humans out here,
but it calls to us all the same.
Yet only one percent of the
ocean has truly been explored.
Just an extraordinary
few have risked its dangers
and delved into its mysteries.
Two of them are
Howard and Michele Hall.
Their hours underwater in
the most remote places on earth
add up to years.
After more than 50 films,
they're considered
the best in the business.
But even for pros, the work of
exploring begins on the phone.
All right, three weeks...
Three weeks of diving.
No, no, I never said two weeks,
it's always been three weeks.
As Michele
tackles the logistics,
Howard organizes the gear,
and he never travels light:
Two cameras and nearly
40 cases of equipment
must all be packed and shipped
to one remote
location or another.
But lately, he's been finding
that no place is quite as remote
as it used to be.
You know, there's really
no place on the planet
that's not being
affected in some way
by human population growth.
So, we feel like we're
sort of on a quest
to discover as much as we
can, learn as much as we can
about the marine environment
and capture this... beautiful
wilderness on videotape
while we still can.
We understand that we're
sort of the privileged few
that get to go there and
see these things firsthand,
and it's wonderful.
And being able to share
that with the rest of the world,
uh... we think that's important.
This time, Howard and
Michele have agreed to show us
how they do it.
They've chosen a special spot,
a tiny outpost 300
miles into the Pacific
off the coast of Central
America, Cocos Island.
Cocos was once
the haunt of pirates.
Now, Howard and
Michele are seeking
their own brand of treasure.
Cocos is world-famous
for sharks.
Cocos is a bit like
Conan Doyle's Lost World,
not the island itself, but
just beneath the waves.
In an age where
90% of the large fish
have been taken from the sea,
you can still come to Cocos
and find the ocean
like it used to be.
Hundreds, even
thousands of sharks gather
in the currents
around the island.
There's no place
like it in the world.
For some ten weeks of filming,
our home will be the research
vessel Undersea Hunter.
It's a comfortable boat,
but you'd better be good
friends with your crew.
Besides, your life
depends on them.
25 years ago, Bob Cranston and I
began filming sharks
together off the California coast.
He's been with me ever since.
His diving and camera
skills are extraordinary.
Peter Kragh spent years as
a dive master in these waters
and knows the
treacherous currents
that sweep past the island.
I'll be relying on Peter
to keep us out of trouble.
Michele seems an
improbable undersea explorer.
At barely 100 pounds,
she's undersized for the heavy
diving gear she must carry.
In addition to organizing
our expeditions,
Michele is a talented
underwater still photographer
and marine naturalist.
Ocean life is so rich at Cocos
that the island and a
12-mile zone all around it
has been designated
a Costa Rican national
park and World Heritage Site.
No fishing is permitted here.
Many of the large animals
at Cocos are visitors,
but most of the smaller
species are permanent residents,
like this pair of
courting puffer fish.
Another resident, this
blue spotted jawfish,
seldom ventures
far from her den...
Ocean currents bring
her everything she needs.
Because of these currents,
almost every inch
here is covered with life,
and that makes Cocos both
spectacular and dangerous.
This is why divers
come to Cocos.
Often when I'm looking
down at some small creature,
a shadow is suddenly
cast over the reef.
A chill always
goes down my spine
before I raise my head
to discover legions
of hammerhead sharks
passing overhead
in schools so dense
they blot out the sun.
It's an experience that goes
beyond awe... it's magical.
Howard and his crew don't
rely on ordinary scuba here.
Instead, they use a
more sophisticated system
that emits no bubbles
and won't run out of air.
This is the diving gear
we'll be using for the film.
It's very different than
standard scuba equipment.
This is a closed-circuit
mixed-gas rebreather.
It's very similar to the
systems the astronauts use
when they're in outer space.
Basically it takes the
gas that you're breathing,
purifies it and recycles it.
And then you just rebreathe
it, hence the name "rebreather."
This thing makes
filming wildlife
much more efficient underwater.
It's very, very silent.
It allows you to get
closer to the marine life
and you can stay down
for a very long time.
Besides, it's got
communications in it.
So this is the push-to-talk.
It's kind of like talking
with a bunch of
marbles in your mouth,
but Howard can understand me.
I can usually understand him.
Nobody can understand us.
Exactly... and that's it.
Cocos lies directly in the
path of deep ocean currents.
Their collision with the island
can churn the waters
into an undersea storm.
The currents around Cocos
behave a lot like turbulent winds.
Even when the surface is calm,
the currents below can be
unpredictable and dangerous,
threatening to sweep
us far out to sea.
But there's no way around
it... The most exciting dives
are usually where the
currents are most treacherous.
The only way to test
these waters is to jump in.
If we're able to
work in the current,
we might stay down for
two or three hours at a time,
or as long as our
camera batteries last.
Current is often our nemesis,
but it's also our guide to
the most spectacular animals.
Eagle rays fly over the reef.
But to feed, they drop down
on the deep, sandy plain
and scan for animals
hidden beneath the surface.
To film them, Howard stops
swimming and starts walking.
I often take my fins off while
filming animals in the sand.
When I leave my fins
on, I risk ruining the shot
by kicking up big
clouds of silt and sand,
and then you'd never see
how this ray makes a living.
Rays and sharks
are close cousins
and share the same
sensory abilities.
They both detect
the electric fields
produced by living things.
It's this special sense
that allows sharks to
find prey in total darkness
or hiding beneath the sand...
if they pass close enough.
The peacock flounder's
camouflage won't work
unless it keeps perfectly still.
But camouflage
helps the flounder
ambush its own tiny prey.
These white-tip sharks
are simply resting
here on the bottom,
but when they hunt,
extraordinary senses
come into play.
Their vision is pretty
good in low light,
but their sense of smell
is far more powerful.
They can also track
prey moving in the water
by following subtle
changes in water pressure.
The tiny spots on
his face are organs
that can sense
minute electrical fields
generated by the twitch
of a prey animal's muscle.
But not everything
interesting here is a shark.
Well, this little guy
wasn't on my agenda,
but it's certainly
one of the strangest
I've ever seen.
Everything about this
fish is just, well, weird.
It's a red-lipped batfish.
Instead of really swimming,
it walks on fins
modified to work like feet.
It also has a strange
horn on its head,
which conceals an odd lure.
How it uses this lure
is not really known.
This is the weird-looking
fish I was hoping to find.
It's a frogfish pretending to
be a harmless orange sponge.
Like the batfish, it uses
its fins more like feet.
To move in for close-ups,
I bring a heavy tripod to
keep the camera steady.
The frogfish is
waiting patiently
to deploy its second
trick of deception.
It attracts prey with a tiny
lure it uses like a fishing pole
attached to the top of its head.
While Michele and I are
hoping something will happen,
Bob discovers some real
action about a quarter mile away.
A swarm of male white-tip
sharks were attacking
a single exhausted female.
It's one of the most
violent courtships
in the animal kingdom.
Male sharks have to
hold on while they mate.
They can only do
that with their mouths.
So they bite the female
on the gills or pectoral fin.
In no time, the female's
gills are lacerated.
In 35 years of observing
and filming sharks,
I've seen courtship
behavior only four times,
and never have I seen
the entire act start to finish,
and at such close range.
It was unbelievably
violent and brutal.
When it's over, the
female swims away
exhausted and bleeding.
Above the water, Cocos
seems a more peaceful place.
Seabirds nest on the
island by the thousands;
there are no natural
predators here to disturb them.
The fairy tern wastes no
energy building elaborate nests.
Instead, she lays
her single delicate egg
on a round tree branch.
It's an incredible
balancing act.
The slightest mistake
and the egg will fall.
Brown boobies prefer
to nest on the ground,
where gravity is less likely
to cause a tragic mishap.
And the red-footed booby
prefers to make crude nests
in low-growing trees, where
they raise down-covered chicks.
But this idyllic island
life is only half the story.
All these birds make
their living from the sea,
where they are eager
players in a truly violent event.
Howard and his crew call it
a "bait ball feeding frenzy."
Beneath the diving birds,
predators herd a school of
green jacks and triggerfish
into a tight ball
and then pin them
against the surface.
The fish are attacked
from above and below.
The crew takes turns on lookout
for birds beginning to gather.
When they see birds diving in
to feed, they have to move fast...
A bait ball frenzy
doesn't last long.
Looks pretty good,
Howard, there's...
Okay, slow down a little bit.
Slow down.
Don't want to get too close.
We'll scoot out of the way.
Okay, cut the power.
Let's go in here.
Looks good.
Let's go.
Silkies and black-tip sharks
cut through the school,
devouring fish as
fast as they can.
Yellowfin tuna
streak in like missiles,
attacking at incredible speed.
And bottle-nose dolphins
gather by the dozen.
The buzzing sounds of their
echolocation fills the water.
We hang back, careful not
to get too close to the frenzy
and risk being
attacked by the sharks.
Many of the jacks are
injured and bleeding,
and that only intensifies
the sharks' excitement.
Fish gather around anything
that might serve as refuge.
They even gather around
the sharks themselves.
Some fish begin
gathering around us.
It's not a good thing.
Injured triggerfish
begin following Michele.
Then they surround Bob, seeking
a place to hide from the sharks.
He can't get rid of them.
Anything reflective could
be mistaken by a shark
for an injured fish.
Suddenly it's become dangerous.
But just as suddenly,
the bait ball breaks up...
The school of fish is gone.
Pretty equal mix,
dolphins, yellowfin tuna,
silky sharks, black-tip sharks.
And the poor little fish.
"Live fast, die young."
Man, the whole bait ball was
gone in about ten minutes.
You jump in and stare at
it, you can actually see it
getting smaller and
smaller and smaller.
Especially with the tuna.
The tuna are the... the
fastest predators out there.
They just... go through
it like a meat grinder.
Howard, I didn't
like that at all.
All those fish came
right around my head,
I was slapping
them off like this.
Sharks came right by
my ear, I could feel them.
I think I got hit by one.
Next time I'm wearing a hood.
The weather at Cocos
is as turbulent as the sea.
Beneath the surface,
strong ocean currents play
the part of wind and rain.
As the currents collide
with undersea escarpments,
they rise and swirl
around the island.
We often struggle
against a current flowing
north at the surface
only to struggle against one
flowing south on the bottom.
But hammerheads hover like
birds of prey on a mountain wind,
and marble stingrays
soar the current
like living hang gliders.
The currents also cause
optical problems for the crew.
As dense cold
waters rise and mix
with surface layers ten
to 15 degrees warmer,
they create a strange
"heat haze" effect.
It's like diving in a
mixture of oil and vinegar.
Images blur, making
camerawork impossible
as animals move
through the mixing layers.
But it's current that
brings life to Cocos.
Garden eels never
leave their burrows.
They rely on current to
deliver drifting planktonic prey.
The plankton, nourished by
this cold, nutrient-rich water,
is food for many
species of fish here...
as well as some of the ocean's
most spectacular leviathans:
the manta ray.
The whale shark.
The island's reefs provide
another place for fish to feed.
Schools of Moorish
idols swim over the reef
feeding on tiny sponges.
A hawksbill turtle grazes on
algae that clings to the rocks.
Her hard shell protects her
from most species of sharks.
And the white-tips
show no interest.
The hawksbill finds a
sea cucumber to eat.
To me, it seems even
less appetizing than algae.
A sea cucumber has
the consistency of rubber,
and I suspect it doesn't
taste much better,
but the turtle seems to like it.
Suddenly I find myself
being pulled away...
The current has struck again.
The boat anchor has
broken loose from the reef,
pulling the movie-light
cable off station
and me along with it.
Of course, the
turtle doesn't care.
Naturally, by the time
I secured the cables,
the turtle had finished its
meal and decided to leave.
Typical.
Fortunately, Bob was
there to get the last shot
as the turtle ascended through
a school of hammerheads.
The film crew is fond of saying
that there are only two
kinds of weather at Cocos:
Either it's raining
or it's about to.
The island receives more
than 24 feet of rain each year.
Oh, man, it's getting
wet faster than...
It's raining.
Here, just a second.
Just a second here.
These water absorbers
are getting wet
before we even get in the water.
Okay, I think the towel's
not doing much anymore.
It's pretty saturated.
Okay, you all set?
I'm set.
We've been coming to
Cocos for ten years now,
and despite all our
experience and preparation,
the work's not
getting any easier.
I know this place gets
24 feet of rain a year,
but I don't know why it all has
to come down the same day.
Because we're here.
I think all this mud
will drift away...
The fact is,
some of the creatures
we've always counted on here
are becoming
much harder to find.
Cocos is changing, and I'm
beginning to worry about it.
But there is one sequence
I'm sure we can get...
Something that still happens
every night on the reef.
Night is when sharks go hunting.
Howard is determined to
film white-tips working the reef.
Did you see some
action down there, Peter?
There were some silkies
right behind the boat.
Oh, the silkies?
So it's not just
white-tips tonight.
Oh... what happened?
Oh, dear.
Everybody to the rescue.
Michele, you're missing a...
See the tank here?
I need help.
You know, with a little luck,
this is going to
be on television.
It's a typical night dive.
Oh, man.
Hold still, hold still.
I hope the rest of the
night goes better than this.
Hold still.
Okay, there you go.
By the time we were
ready, I was shocked to see
how many large silky sharks
had gathered beneath the boat.
I see at least
seven of them here
right now.
Ooh, look at those big boys.
Oh, man, look at
the size of that guy.
This may not be entirely safe.
If we jumped in and
just descend right away...
hopefully they won't follow us.
I don't think you want
to stay on the surface
any longer than possible.
Okay.
When we start splashing,
they're probably going
to come in like crazy.
Go.
Yeah, go... yeah, go!
I know.
Go.
Go?
We're thinking about it.
Go... push them in, Peter.
I didn't like that.
Thought you guys
were going diving.
Oh... those silkies
scared me out of the water.
I've never been scared out
of the water like that before.
It was like a bait
ball without the bait.
They were knocking
into my feet...
knocking my legs.
I wasn't sure... at first I
thought it was Howard kicking.
It just spooked me, but
the fog finally cleared
and it wasn't Howard kicking me.
It was the silkies
knocking into me.
There's 50 sharks down there.
I'm not talking
about white-tips;
I'm talking about the big guys.
Yeah... I don't think we're
going to do this tonight.
Michele, could you kind
of crawl out of the way?
I'm trying.
Sometimes we use
bait to attract sharks.
But we never once used
bait while making this film,
and certainly not at night.
So I don't know why these
sharks were so aggressive.
That's what really
freaked me out.
I know that Howard will want
to try this night dive again.
I'm really not
looking forward to it.
The next day,
they try filming animals a bit
less threatening than sharks.
One of our goals was to
develop a time-lapse system
for capturing
high-definition images
of animals that move
very slowly in real time.
The system was
developed largely by Peter,
and this will be our first
dive to test the camera.
At normal viewing speeds,
these cushion sea stars
seem about as alive as
the rocks they cling to.
But, in fact, they are moving.
If we get this right, you'll
see that these animals exhibit
some interesting behavior,
and even some character.
It's all set up;
now we just wait.
When we speed up the action,
you can see that these
animals have a lot of personality.
They twist, bend and
even glide over the reef.
Cushion stars feed
mainly on algae,
and we've discovered
that they graze across the
sand in a very organized way.
They form a front that's
continually on the march.
But some of the stars
appear to be injured.
I couldn't imagine what
might eat a cushion star.
They're about as tough
as an old tennis shoe.
Then, as we explored
some small caves,
we saw lobsters
approaching a cushion star.
At first they were scared off
by a shark swimming overhead.
But it soon became
clear what was happening.
Lobsters are nocturnal.
During the day, they
stay close to their dens.
They may be
afraid to venture out
for something more
interesting to eat,
so they pick up a cushion star
and start gnawing on the legs.
The lobsters seldom
finish their meal
since the cushion
star is so tough,
and so the stars survive with
only some minor leg damage.
And cushion stars aren't
the only daytime snack
the lobsters indulge in.
It turns out
that lobsters will also feed
on venomous sea urchins.
Eating an urchin isn't easy.
The lobster has to carefully
break off the poisonous spines
before feeding on
the tasty meat inside.
Most underwater animals
have more respect for urchins.
Baby cardinal fish are
hiding in this forest of spines
for protection from predators.
But in this world,
no defense is perfect.
Leather bass have
their own clever tactic.
Several attack one
side of this urchin cluster,
driving the cardinal fish
into the waiting mouths of
leather bass on the other side.
Then they return the favor,
and all the leather bass
get something to eat.
But a brush with urchin
spines is trouble for Howard.
The sting from an
urchin burns like fire.
It hurts like the devil
for ten minutes or so
and leaves a mark on your
skin that can last for months.
It's a little humbling
to see a hogfish tackle
an urchin so easily.
They're completely
immune to the venom.
The motto on the reef is often
thought to be "eat or be eaten."
And though predation is a big
part of what happens down here,
it's far from the whole story.
Life down here is
amazingly complicated
and sometimes
surprisingly gentle.
We've observed that courtship
between male and female
is seldom limited to
the simple act of mating.
Bigeye jacks pair
up every evening
and swim together for hours.
They signal that they're a pair
by displaying
contrasting colors.
And these more gentle
behaviors even extend
to relationships
between species.
Courting jacks
descend to the reef
and are met by
yellow barberfish.
Although barberfish are
a perfect-sized
prey for the jacks,
no predation takes place.
Instead, the barberfish
pluck parasites from the jacks.
Even the fiercest
predators of Cocos
will engage in gentle cleaning.
Moray eels like
to be cleaned, too,
though it can be a
bit uncomfortable.
An alternate method
of removing parasites
is to use a rubbing rock.
And if no rubbing rock is
handy, a turtle shell will do.
But not all of this behavior
is so easy to understand
and at this very
ordinary-looking rock,
a real Cocos mystery plays out.
The spectacular silver-tip
shark, a rare species here,
comes to this single rock to be
cleaned by tiny rainbow wrasse.
The wrasse are everywhere
but the silver-tips
only visit them here.
Why the silver-tips at
Cocos come to this one rock
and nowhere else is
a complete unknown.
Silver-tips were never
common here, but in recent years
the numbers of all sharks
seem to have declined.
The cause hangs from
the mouth of this silky shark.
It's a long-line hook,
a dark harbinger for
the future of Cocos.
Fishing boats have
anchored at Cocos.
Fishing is illegal for a 12-
mile zone all around the island,
but 12 miles is just a two-hour
swim for a migrating shark.
These boats and others like them
kill dozens of sharks every day.
But Howard's work continues.
He and the team have
just one more week
to capture the story of Cocos.
As evening approaches,
this male peacock flounder
abandons his camouflage.
He risks exposure
as he swims across the
reef towards the sandy plain.
He's looking for love.
Once he spots a female,
he begins an elaborate courtship
that lasts more than 30 minutes.
When she's ready,
the female will follow the
male up toward the surface.
At the top of their ascent,
they simultaneously
release their spawn.
Capturing the courtship
of large marble stingrays
is like filming a ballet.
The dance of the marble rays
is certainly the most beautiful
courtship we see at Cocos.
Dozens of males pursue
a single large female.
Most of the time, she
wants nothing to do
with her gaggle of suitors.
When she stops, the
males hover overhead,
surrounding Bob and me.
We're careful
with these animals.
The tail of each ray is armed
with a venomous stinger
nearly eight inches long.
Constantly bumped and
nibbled at by the anxious males,
the female begins moving again.
The procession resumes,
gliding gracefully over the reef.
Occasionally the
female will double back,
trying to throw her
followers off the trail.
Once it starts, this
behavior can go on for days.
I've witnessed this graceful
display many times at Cocos,
but how these gatherings
culminate has always eluded me.
I'd like to get one good
shot of that female leaving.
That's the only thing.
She just, uh...
she just laid there.
She wasn't combatant.
Think the marble ray is
going to be there tomorrow?
I hope so.
I'd love to see, actually,
what the mating looks like,
because I've never seen that.
All the time we've seen
the marble rays, you know,
doing these aggregations,
do you notice the males
will come up off the bottom?
When you're hovering up high,
they come up,
like, to investigate.
And I think maybe they
think you're a female up there.
And then they'd come up,
and so it may be that the mating
actually goes on
near the surface.
So when she's ready,
maybe she just ascends,
and all the males come up.
I'm only guessing, though.
I've never seen, you
know, the actual act.
The dive masters
here have seen it.
They've seen them?
Do they go up?
They've seen it, yeah.
The female comes
up off the bottom.
The males come up
underneath, belly to belly,
and then insert
their claspers in.
It is sort of like
the white-tips.
Once one is done, the
second comes and takes over
and then takes off.
Wow, I'd love to see that.
Our time at Cocos is
rapidly coming to an end.
But there is one last
dive we need to make,
and I think we're ready.
Here we go.
Another night dive.
I don't know who
invented the night dive,
and I don't know who
invited all the sharks
off the back end of the boat,
but I guess we're going
to go down and find out.
The silky sharks will probably
stay high off the bottom.
There's no bait in the water,
so there's no reason
for these sharks to bite.
I just need to get
down quickly...
Down to the bottom
where it should be safe.
Okay, ready?
I feel much better
when I see the glow of
lights on the sand below.
The silky sharks are
staying well above us now
as Howard begins
leading us across the sand
and toward the reef.
When we reach the reef,
we find it swarming
with activity.
Hundreds of white-tip sharks
are hunting like a pack of wolves.
No bait was used to
cause this gathering.
Like the leather bass
attacking cardinal fish
in the urchin spines,
these sharks have learned the
advantage of hunting together.
The sharks all seem to
dive into the reef at once,
but with each attack, only
one shark emerges with a fish.
Soon we begin to
see a pattern emerge.
This pack strategy is more
efficient than hunting alone.
Sleeping fish take
shelter in the reef.
In the darkness,
the sharks only sense their
prey if the sleeping fish moves.
Once a shark discovers a fish,
it chases it deeper
into the reef.
Other sharks
immediately rush in.
If the first shark was
alone, the fish might escape.
But when the
sharks hunt in a pack,
the fish often blunders into the
waiting jaws of another shark.
As a pack, the sharks
are more successful.
The fear I felt earlier
seems a distant memory now.
I'm thrilled to witness
a nightly drama unfold,
just as it has for
thousands of years
before divers ever
discovered this world.
You might think all this
wildness would be safe,
hidden away at
this little island.
I only wish that were true.
We're at the dock
here in Puntarenas,
where the Undersea
Hunter ties up between trips,
and right next door is the
Taiwanese fishing fleet.
You can see these
long-line fishing boats here.
There's probably 30
or 40 of them tied up
at this particular dock,
and there's numerous other
docks here in Costa Rica,
and, uh, it's all rather secret,
because they don't really
want the bad publicity
that comes with the
outrage over shark fishing.
They recently put
this wall up here
so that people like us couldn't
film the operation of them
offloading the sharks
and processing the sharks.
It's all sort of out of sight
and therefore out of mind,
but this is where
the sharks are going.
Every night these boats go out,
set literally hundreds
of miles of long lines,
and the sharks that migrate up
and down the coast of Costa Rica
and migrate to and
from Cocos Island
have to run the gauntlet
through these long lines,
and of course many
of them don't make it.
It's a very sad thing.
I think for filmmakers
like myself,
we're perhaps
the last generation
to see large numbers
of sharks in the wild.
Ten years ago there were so
many more sharks than there are now
that it's really alarming,
and I know that
ten years from now,
especially with the
constantly increasing size
of these fishing fleets,
a cameraman is not going to
be able to come out to Costa Rica
and, uh... and film sharks.
They're just going
to be all gone.
For now the sharks
are still coming
to their island
outpost at Cocos.
For 400 million years,
sharks have been
the ultimate survivors.
They've outlasted
dinosaurs and ice ages,
but humans will prove to
be their greatest challenge.
Yet the deep ocean
still offers them a chance,
a refuge beyond our reach,
a last retreat in its dark
blue mysterious depths.
TO LEARN MORE ABOUT
WHAT YOU'VE SEEN ON
THIS "NATURE" PROGRAM,
VISIT pbs. org.
SILKIES,
WHITE TIPS,
HAMMERHEADS,
HUNT ALONG THE VOLCANIC REEFS OF
THIS TINY ISLAND IN THE PACIFIC.
ACCLAIMED FILM MAKER
HOWARD HALL AND HIS CREW
HAVE BEEN DIVING AT COCOS
ISLAND FOR MORE THAN A DECADE.
Man: NOW THIS MAY
NOT BE ENTIRELY SAFE.
OOH, LOOK AT THOSE BIG BOYS!
THERE'S 50 SHARKS DOWN THERE!
GO! YEAH, GO...
YEAH, GO. GO?
PUSH HIM IN!
Narrator: IT TAKES ALL OF THEIR
EXPERIENCE AND KNOWLEDGE
TO DIVE IN THESE
TREACHEROUS WATERS.
WELCOME... TO SHARK MOUNTAIN.
The beach, San
Diego, California.
This is the edge of our world.
Along this thin line,
America slips quietly into
the vast Pacific Ocean.
It's no place for
humans out here,
but it calls to us all the same.
Yet only one percent of the
ocean has truly been explored.
Just an extraordinary
few have risked its dangers
and delved into its mysteries.
Two of them are
Howard and Michele Hall.
Their hours underwater in
the most remote places on earth
add up to years.
After more than 50 films,
they're considered
the best in the business.
But even for pros, the work of
exploring begins on the phone.
All right, three weeks...
Three weeks of diving.
No, no, I never said two weeks,
it's always been three weeks.
As Michele
tackles the logistics,
Howard organizes the gear,
and he never travels light:
Two cameras and nearly
40 cases of equipment
must all be packed and shipped
to one remote
location or another.
But lately, he's been finding
that no place is quite as remote
as it used to be.
You know, there's really
no place on the planet
that's not being
affected in some way
by human population growth.
So, we feel like we're
sort of on a quest
to discover as much as we
can, learn as much as we can
about the marine environment
and capture this... beautiful
wilderness on videotape
while we still can.
We understand that we're
sort of the privileged few
that get to go there and
see these things firsthand,
and it's wonderful.
And being able to share
that with the rest of the world,
uh... we think that's important.
This time, Howard and
Michele have agreed to show us
how they do it.
They've chosen a special spot,
a tiny outpost 300
miles into the Pacific
off the coast of Central
America, Cocos Island.
Cocos was once
the haunt of pirates.
Now, Howard and
Michele are seeking
their own brand of treasure.
Cocos is world-famous
for sharks.
Cocos is a bit like
Conan Doyle's Lost World,
not the island itself, but
just beneath the waves.
In an age where
90% of the large fish
have been taken from the sea,
you can still come to Cocos
and find the ocean
like it used to be.
Hundreds, even
thousands of sharks gather
in the currents
around the island.
There's no place
like it in the world.
For some ten weeks of filming,
our home will be the research
vessel Undersea Hunter.
It's a comfortable boat,
but you'd better be good
friends with your crew.
Besides, your life
depends on them.
25 years ago, Bob Cranston and I
began filming sharks
together off the California coast.
He's been with me ever since.
His diving and camera
skills are extraordinary.
Peter Kragh spent years as
a dive master in these waters
and knows the
treacherous currents
that sweep past the island.
I'll be relying on Peter
to keep us out of trouble.
Michele seems an
improbable undersea explorer.
At barely 100 pounds,
she's undersized for the heavy
diving gear she must carry.
In addition to organizing
our expeditions,
Michele is a talented
underwater still photographer
and marine naturalist.
Ocean life is so rich at Cocos
that the island and a
12-mile zone all around it
has been designated
a Costa Rican national
park and World Heritage Site.
No fishing is permitted here.
Many of the large animals
at Cocos are visitors,
but most of the smaller
species are permanent residents,
like this pair of
courting puffer fish.
Another resident, this
blue spotted jawfish,
seldom ventures
far from her den...
Ocean currents bring
her everything she needs.
Because of these currents,
almost every inch
here is covered with life,
and that makes Cocos both
spectacular and dangerous.
This is why divers
come to Cocos.
Often when I'm looking
down at some small creature,
a shadow is suddenly
cast over the reef.
A chill always
goes down my spine
before I raise my head
to discover legions
of hammerhead sharks
passing overhead
in schools so dense
they blot out the sun.
It's an experience that goes
beyond awe... it's magical.
Howard and his crew don't
rely on ordinary scuba here.
Instead, they use a
more sophisticated system
that emits no bubbles
and won't run out of air.
This is the diving gear
we'll be using for the film.
It's very different than
standard scuba equipment.
This is a closed-circuit
mixed-gas rebreather.
It's very similar to the
systems the astronauts use
when they're in outer space.
Basically it takes the
gas that you're breathing,
purifies it and recycles it.
And then you just rebreathe
it, hence the name "rebreather."
This thing makes
filming wildlife
much more efficient underwater.
It's very, very silent.
It allows you to get
closer to the marine life
and you can stay down
for a very long time.
Besides, it's got
communications in it.
So this is the push-to-talk.
It's kind of like talking
with a bunch of
marbles in your mouth,
but Howard can understand me.
I can usually understand him.
Nobody can understand us.
Exactly... and that's it.
Cocos lies directly in the
path of deep ocean currents.
Their collision with the island
can churn the waters
into an undersea storm.
The currents around Cocos
behave a lot like turbulent winds.
Even when the surface is calm,
the currents below can be
unpredictable and dangerous,
threatening to sweep
us far out to sea.
But there's no way around
it... The most exciting dives
are usually where the
currents are most treacherous.
The only way to test
these waters is to jump in.
If we're able to
work in the current,
we might stay down for
two or three hours at a time,
or as long as our
camera batteries last.
Current is often our nemesis,
but it's also our guide to
the most spectacular animals.
Eagle rays fly over the reef.
But to feed, they drop down
on the deep, sandy plain
and scan for animals
hidden beneath the surface.
To film them, Howard stops
swimming and starts walking.
I often take my fins off while
filming animals in the sand.
When I leave my fins
on, I risk ruining the shot
by kicking up big
clouds of silt and sand,
and then you'd never see
how this ray makes a living.
Rays and sharks
are close cousins
and share the same
sensory abilities.
They both detect
the electric fields
produced by living things.
It's this special sense
that allows sharks to
find prey in total darkness
or hiding beneath the sand...
if they pass close enough.
The peacock flounder's
camouflage won't work
unless it keeps perfectly still.
But camouflage
helps the flounder
ambush its own tiny prey.
These white-tip sharks
are simply resting
here on the bottom,
but when they hunt,
extraordinary senses
come into play.
Their vision is pretty
good in low light,
but their sense of smell
is far more powerful.
They can also track
prey moving in the water
by following subtle
changes in water pressure.
The tiny spots on
his face are organs
that can sense
minute electrical fields
generated by the twitch
of a prey animal's muscle.
But not everything
interesting here is a shark.
Well, this little guy
wasn't on my agenda,
but it's certainly
one of the strangest
I've ever seen.
Everything about this
fish is just, well, weird.
It's a red-lipped batfish.
Instead of really swimming,
it walks on fins
modified to work like feet.
It also has a strange
horn on its head,
which conceals an odd lure.
How it uses this lure
is not really known.
This is the weird-looking
fish I was hoping to find.
It's a frogfish pretending to
be a harmless orange sponge.
Like the batfish, it uses
its fins more like feet.
To move in for close-ups,
I bring a heavy tripod to
keep the camera steady.
The frogfish is
waiting patiently
to deploy its second
trick of deception.
It attracts prey with a tiny
lure it uses like a fishing pole
attached to the top of its head.
While Michele and I are
hoping something will happen,
Bob discovers some real
action about a quarter mile away.
A swarm of male white-tip
sharks were attacking
a single exhausted female.
It's one of the most
violent courtships
in the animal kingdom.
Male sharks have to
hold on while they mate.
They can only do
that with their mouths.
So they bite the female
on the gills or pectoral fin.
In no time, the female's
gills are lacerated.
In 35 years of observing
and filming sharks,
I've seen courtship
behavior only four times,
and never have I seen
the entire act start to finish,
and at such close range.
It was unbelievably
violent and brutal.
When it's over, the
female swims away
exhausted and bleeding.
Above the water, Cocos
seems a more peaceful place.
Seabirds nest on the
island by the thousands;
there are no natural
predators here to disturb them.
The fairy tern wastes no
energy building elaborate nests.
Instead, she lays
her single delicate egg
on a round tree branch.
It's an incredible
balancing act.
The slightest mistake
and the egg will fall.
Brown boobies prefer
to nest on the ground,
where gravity is less likely
to cause a tragic mishap.
And the red-footed booby
prefers to make crude nests
in low-growing trees, where
they raise down-covered chicks.
But this idyllic island
life is only half the story.
All these birds make
their living from the sea,
where they are eager
players in a truly violent event.
Howard and his crew call it
a "bait ball feeding frenzy."
Beneath the diving birds,
predators herd a school of
green jacks and triggerfish
into a tight ball
and then pin them
against the surface.
The fish are attacked
from above and below.
The crew takes turns on lookout
for birds beginning to gather.
When they see birds diving in
to feed, they have to move fast...
A bait ball frenzy
doesn't last long.
Looks pretty good,
Howard, there's...
Okay, slow down a little bit.
Slow down.
Don't want to get too close.
We'll scoot out of the way.
Okay, cut the power.
Let's go in here.
Looks good.
Let's go.
Silkies and black-tip sharks
cut through the school,
devouring fish as
fast as they can.
Yellowfin tuna
streak in like missiles,
attacking at incredible speed.
And bottle-nose dolphins
gather by the dozen.
The buzzing sounds of their
echolocation fills the water.
We hang back, careful not
to get too close to the frenzy
and risk being
attacked by the sharks.
Many of the jacks are
injured and bleeding,
and that only intensifies
the sharks' excitement.
Fish gather around anything
that might serve as refuge.
They even gather around
the sharks themselves.
Some fish begin
gathering around us.
It's not a good thing.
Injured triggerfish
begin following Michele.
Then they surround Bob, seeking
a place to hide from the sharks.
He can't get rid of them.
Anything reflective could
be mistaken by a shark
for an injured fish.
Suddenly it's become dangerous.
But just as suddenly,
the bait ball breaks up...
The school of fish is gone.
Pretty equal mix,
dolphins, yellowfin tuna,
silky sharks, black-tip sharks.
And the poor little fish.
"Live fast, die young."
Man, the whole bait ball was
gone in about ten minutes.
You jump in and stare at
it, you can actually see it
getting smaller and
smaller and smaller.
Especially with the tuna.
The tuna are the... the
fastest predators out there.
They just... go through
it like a meat grinder.
Howard, I didn't
like that at all.
All those fish came
right around my head,
I was slapping
them off like this.
Sharks came right by
my ear, I could feel them.
I think I got hit by one.
Next time I'm wearing a hood.
The weather at Cocos
is as turbulent as the sea.
Beneath the surface,
strong ocean currents play
the part of wind and rain.
As the currents collide
with undersea escarpments,
they rise and swirl
around the island.
We often struggle
against a current flowing
north at the surface
only to struggle against one
flowing south on the bottom.
But hammerheads hover like
birds of prey on a mountain wind,
and marble stingrays
soar the current
like living hang gliders.
The currents also cause
optical problems for the crew.
As dense cold
waters rise and mix
with surface layers ten
to 15 degrees warmer,
they create a strange
"heat haze" effect.
It's like diving in a
mixture of oil and vinegar.
Images blur, making
camerawork impossible
as animals move
through the mixing layers.
But it's current that
brings life to Cocos.
Garden eels never
leave their burrows.
They rely on current to
deliver drifting planktonic prey.
The plankton, nourished by
this cold, nutrient-rich water,
is food for many
species of fish here...
as well as some of the ocean's
most spectacular leviathans:
the manta ray.
The whale shark.
The island's reefs provide
another place for fish to feed.
Schools of Moorish
idols swim over the reef
feeding on tiny sponges.
A hawksbill turtle grazes on
algae that clings to the rocks.
Her hard shell protects her
from most species of sharks.
And the white-tips
show no interest.
The hawksbill finds a
sea cucumber to eat.
To me, it seems even
less appetizing than algae.
A sea cucumber has
the consistency of rubber,
and I suspect it doesn't
taste much better,
but the turtle seems to like it.
Suddenly I find myself
being pulled away...
The current has struck again.
The boat anchor has
broken loose from the reef,
pulling the movie-light
cable off station
and me along with it.
Of course, the
turtle doesn't care.
Naturally, by the time
I secured the cables,
the turtle had finished its
meal and decided to leave.
Typical.
Fortunately, Bob was
there to get the last shot
as the turtle ascended through
a school of hammerheads.
The film crew is fond of saying
that there are only two
kinds of weather at Cocos:
Either it's raining
or it's about to.
The island receives more
than 24 feet of rain each year.
Oh, man, it's getting
wet faster than...
It's raining.
Here, just a second.
Just a second here.
These water absorbers
are getting wet
before we even get in the water.
Okay, I think the towel's
not doing much anymore.
It's pretty saturated.
Okay, you all set?
I'm set.
We've been coming to
Cocos for ten years now,
and despite all our
experience and preparation,
the work's not
getting any easier.
I know this place gets
24 feet of rain a year,
but I don't know why it all has
to come down the same day.
Because we're here.
I think all this mud
will drift away...
The fact is,
some of the creatures
we've always counted on here
are becoming
much harder to find.
Cocos is changing, and I'm
beginning to worry about it.
But there is one sequence
I'm sure we can get...
Something that still happens
every night on the reef.
Night is when sharks go hunting.
Howard is determined to
film white-tips working the reef.
Did you see some
action down there, Peter?
There were some silkies
right behind the boat.
Oh, the silkies?
So it's not just
white-tips tonight.
Oh... what happened?
Oh, dear.
Everybody to the rescue.
Michele, you're missing a...
See the tank here?
I need help.
You know, with a little luck,
this is going to
be on television.
It's a typical night dive.
Oh, man.
Hold still, hold still.
I hope the rest of the
night goes better than this.
Hold still.
Okay, there you go.
By the time we were
ready, I was shocked to see
how many large silky sharks
had gathered beneath the boat.
I see at least
seven of them here
right now.
Ooh, look at those big boys.
Oh, man, look at
the size of that guy.
This may not be entirely safe.
If we jumped in and
just descend right away...
hopefully they won't follow us.
I don't think you want
to stay on the surface
any longer than possible.
Okay.
When we start splashing,
they're probably going
to come in like crazy.
Go.
Yeah, go... yeah, go!
I know.
Go.
Go?
We're thinking about it.
Go... push them in, Peter.
I didn't like that.
Thought you guys
were going diving.
Oh... those silkies
scared me out of the water.
I've never been scared out
of the water like that before.
It was like a bait
ball without the bait.
They were knocking
into my feet...
knocking my legs.
I wasn't sure... at first I
thought it was Howard kicking.
It just spooked me, but
the fog finally cleared
and it wasn't Howard kicking me.
It was the silkies
knocking into me.
There's 50 sharks down there.
I'm not talking
about white-tips;
I'm talking about the big guys.
Yeah... I don't think we're
going to do this tonight.
Michele, could you kind
of crawl out of the way?
I'm trying.
Sometimes we use
bait to attract sharks.
But we never once used
bait while making this film,
and certainly not at night.
So I don't know why these
sharks were so aggressive.
That's what really
freaked me out.
I know that Howard will want
to try this night dive again.
I'm really not
looking forward to it.
The next day,
they try filming animals a bit
less threatening than sharks.
One of our goals was to
develop a time-lapse system
for capturing
high-definition images
of animals that move
very slowly in real time.
The system was
developed largely by Peter,
and this will be our first
dive to test the camera.
At normal viewing speeds,
these cushion sea stars
seem about as alive as
the rocks they cling to.
But, in fact, they are moving.
If we get this right, you'll
see that these animals exhibit
some interesting behavior,
and even some character.
It's all set up;
now we just wait.
When we speed up the action,
you can see that these
animals have a lot of personality.
They twist, bend and
even glide over the reef.
Cushion stars feed
mainly on algae,
and we've discovered
that they graze across the
sand in a very organized way.
They form a front that's
continually on the march.
But some of the stars
appear to be injured.
I couldn't imagine what
might eat a cushion star.
They're about as tough
as an old tennis shoe.
Then, as we explored
some small caves,
we saw lobsters
approaching a cushion star.
At first they were scared off
by a shark swimming overhead.
But it soon became
clear what was happening.
Lobsters are nocturnal.
During the day, they
stay close to their dens.
They may be
afraid to venture out
for something more
interesting to eat,
so they pick up a cushion star
and start gnawing on the legs.
The lobsters seldom
finish their meal
since the cushion
star is so tough,
and so the stars survive with
only some minor leg damage.
And cushion stars aren't
the only daytime snack
the lobsters indulge in.
It turns out
that lobsters will also feed
on venomous sea urchins.
Eating an urchin isn't easy.
The lobster has to carefully
break off the poisonous spines
before feeding on
the tasty meat inside.
Most underwater animals
have more respect for urchins.
Baby cardinal fish are
hiding in this forest of spines
for protection from predators.
But in this world,
no defense is perfect.
Leather bass have
their own clever tactic.
Several attack one
side of this urchin cluster,
driving the cardinal fish
into the waiting mouths of
leather bass on the other side.
Then they return the favor,
and all the leather bass
get something to eat.
But a brush with urchin
spines is trouble for Howard.
The sting from an
urchin burns like fire.
It hurts like the devil
for ten minutes or so
and leaves a mark on your
skin that can last for months.
It's a little humbling
to see a hogfish tackle
an urchin so easily.
They're completely
immune to the venom.
The motto on the reef is often
thought to be "eat or be eaten."
And though predation is a big
part of what happens down here,
it's far from the whole story.
Life down here is
amazingly complicated
and sometimes
surprisingly gentle.
We've observed that courtship
between male and female
is seldom limited to
the simple act of mating.
Bigeye jacks pair
up every evening
and swim together for hours.
They signal that they're a pair
by displaying
contrasting colors.
And these more gentle
behaviors even extend
to relationships
between species.
Courting jacks
descend to the reef
and are met by
yellow barberfish.
Although barberfish are
a perfect-sized
prey for the jacks,
no predation takes place.
Instead, the barberfish
pluck parasites from the jacks.
Even the fiercest
predators of Cocos
will engage in gentle cleaning.
Moray eels like
to be cleaned, too,
though it can be a
bit uncomfortable.
An alternate method
of removing parasites
is to use a rubbing rock.
And if no rubbing rock is
handy, a turtle shell will do.
But not all of this behavior
is so easy to understand
and at this very
ordinary-looking rock,
a real Cocos mystery plays out.
The spectacular silver-tip
shark, a rare species here,
comes to this single rock to be
cleaned by tiny rainbow wrasse.
The wrasse are everywhere
but the silver-tips
only visit them here.
Why the silver-tips at
Cocos come to this one rock
and nowhere else is
a complete unknown.
Silver-tips were never
common here, but in recent years
the numbers of all sharks
seem to have declined.
The cause hangs from
the mouth of this silky shark.
It's a long-line hook,
a dark harbinger for
the future of Cocos.
Fishing boats have
anchored at Cocos.
Fishing is illegal for a 12-
mile zone all around the island,
but 12 miles is just a two-hour
swim for a migrating shark.
These boats and others like them
kill dozens of sharks every day.
But Howard's work continues.
He and the team have
just one more week
to capture the story of Cocos.
As evening approaches,
this male peacock flounder
abandons his camouflage.
He risks exposure
as he swims across the
reef towards the sandy plain.
He's looking for love.
Once he spots a female,
he begins an elaborate courtship
that lasts more than 30 minutes.
When she's ready,
the female will follow the
male up toward the surface.
At the top of their ascent,
they simultaneously
release their spawn.
Capturing the courtship
of large marble stingrays
is like filming a ballet.
The dance of the marble rays
is certainly the most beautiful
courtship we see at Cocos.
Dozens of males pursue
a single large female.
Most of the time, she
wants nothing to do
with her gaggle of suitors.
When she stops, the
males hover overhead,
surrounding Bob and me.
We're careful
with these animals.
The tail of each ray is armed
with a venomous stinger
nearly eight inches long.
Constantly bumped and
nibbled at by the anxious males,
the female begins moving again.
The procession resumes,
gliding gracefully over the reef.
Occasionally the
female will double back,
trying to throw her
followers off the trail.
Once it starts, this
behavior can go on for days.
I've witnessed this graceful
display many times at Cocos,
but how these gatherings
culminate has always eluded me.
I'd like to get one good
shot of that female leaving.
That's the only thing.
She just, uh...
she just laid there.
She wasn't combatant.
Think the marble ray is
going to be there tomorrow?
I hope so.
I'd love to see, actually,
what the mating looks like,
because I've never seen that.
All the time we've seen
the marble rays, you know,
doing these aggregations,
do you notice the males
will come up off the bottom?
When you're hovering up high,
they come up,
like, to investigate.
And I think maybe they
think you're a female up there.
And then they'd come up,
and so it may be that the mating
actually goes on
near the surface.
So when she's ready,
maybe she just ascends,
and all the males come up.
I'm only guessing, though.
I've never seen, you
know, the actual act.
The dive masters
here have seen it.
They've seen them?
Do they go up?
They've seen it, yeah.
The female comes
up off the bottom.
The males come up
underneath, belly to belly,
and then insert
their claspers in.
It is sort of like
the white-tips.
Once one is done, the
second comes and takes over
and then takes off.
Wow, I'd love to see that.
Our time at Cocos is
rapidly coming to an end.
But there is one last
dive we need to make,
and I think we're ready.
Here we go.
Another night dive.
I don't know who
invented the night dive,
and I don't know who
invited all the sharks
off the back end of the boat,
but I guess we're going
to go down and find out.
The silky sharks will probably
stay high off the bottom.
There's no bait in the water,
so there's no reason
for these sharks to bite.
I just need to get
down quickly...
Down to the bottom
where it should be safe.
Okay, ready?
I feel much better
when I see the glow of
lights on the sand below.
The silky sharks are
staying well above us now
as Howard begins
leading us across the sand
and toward the reef.
When we reach the reef,
we find it swarming
with activity.
Hundreds of white-tip sharks
are hunting like a pack of wolves.
No bait was used to
cause this gathering.
Like the leather bass
attacking cardinal fish
in the urchin spines,
these sharks have learned the
advantage of hunting together.
The sharks all seem to
dive into the reef at once,
but with each attack, only
one shark emerges with a fish.
Soon we begin to
see a pattern emerge.
This pack strategy is more
efficient than hunting alone.
Sleeping fish take
shelter in the reef.
In the darkness,
the sharks only sense their
prey if the sleeping fish moves.
Once a shark discovers a fish,
it chases it deeper
into the reef.
Other sharks
immediately rush in.
If the first shark was
alone, the fish might escape.
But when the
sharks hunt in a pack,
the fish often blunders into the
waiting jaws of another shark.
As a pack, the sharks
are more successful.
The fear I felt earlier
seems a distant memory now.
I'm thrilled to witness
a nightly drama unfold,
just as it has for
thousands of years
before divers ever
discovered this world.
You might think all this
wildness would be safe,
hidden away at
this little island.
I only wish that were true.
We're at the dock
here in Puntarenas,
where the Undersea
Hunter ties up between trips,
and right next door is the
Taiwanese fishing fleet.
You can see these
long-line fishing boats here.
There's probably 30
or 40 of them tied up
at this particular dock,
and there's numerous other
docks here in Costa Rica,
and, uh, it's all rather secret,
because they don't really
want the bad publicity
that comes with the
outrage over shark fishing.
They recently put
this wall up here
so that people like us couldn't
film the operation of them
offloading the sharks
and processing the sharks.
It's all sort of out of sight
and therefore out of mind,
but this is where
the sharks are going.
Every night these boats go out,
set literally hundreds
of miles of long lines,
and the sharks that migrate up
and down the coast of Costa Rica
and migrate to and
from Cocos Island
have to run the gauntlet
through these long lines,
and of course many
of them don't make it.
It's a very sad thing.
I think for filmmakers
like myself,
we're perhaps
the last generation
to see large numbers
of sharks in the wild.
Ten years ago there were so
many more sharks than there are now
that it's really alarming,
and I know that
ten years from now,
especially with the
constantly increasing size
of these fishing fleets,
a cameraman is not going to
be able to come out to Costa Rica
and, uh... and film sharks.
They're just going
to be all gone.
For now the sharks
are still coming
to their island
outpost at Cocos.
For 400 million years,
sharks have been
the ultimate survivors.
They've outlasted
dinosaurs and ice ages,
but humans will prove to
be their greatest challenge.
Yet the deep ocean
still offers them a chance,
a refuge beyond our reach,
a last retreat in its dark
blue mysterious depths.
TO LEARN MORE ABOUT
WHAT YOU'VE SEEN ON
THIS "NATURE" PROGRAM,
VISIT pbs. org.