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♪♪

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NARRATOR: In the middle
of the Pacific Ocean,

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the world's most isolated
island chain

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is shark paradise.

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Some hunt in gangs,

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others ride the tides
to find food.

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The biggest are loners.

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But no matter
what their size...

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...or what they eat...

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...Hawaii has everything
sharks need.

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♪♪

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Shallow reefs here
are packed with fish.

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♪♪

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The deeper blue
offers different fare.

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The warm water calls to many.

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If it seems too perfect,
it just might be...

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for now.

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The biggest sharks
with the biggest needs

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may be moving here, too.

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♪♪

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♪♪

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♪♪

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NARRATOR: These humpback whales
are finally home.

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After feeding all summer
in the Gulf of Alaska,

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they've traveled
over 3,000 miles

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to return to Hawaii,
where they were born.

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♪♪

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Some females have journeyed
to these warm, clear waters

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to entertain a mate or two.

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And soon,
those that are pregnant

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will give birth
to their own calves here.

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♪♪

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The new mothers will be
extremely protective

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of their newborns.

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They have to be.

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Because while this place
looks idyllic,

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the whales have come back
to an age-old battleground.

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♪♪

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Tiger sharks are the apex
predators in Hawaiian waters,

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15 feet of clever camouflage

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constantly patrolling
the channels between islands.

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They prey on whale calves,

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a feast they've been
anticipating all year.

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♪♪

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Then, these mighty opponents
will come face-to-face,

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2,400 miles
from the nearest continent.

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♪♪

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Hawaii's archipelago
is the most remote on Earth.

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The eight main islands
are merely the summits

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of a vast,
submarine mountain chain

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stretching 1,500 miles
across the Pacific.

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♪♪

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They're all the result
of a deep-sea volcanic hot spot

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that builds new islands when the
tectonic plates above it move.

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♪♪

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Kilauea, on the Big Island,

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is the most active volcano
on Earth.

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It's been continuously erupting
for the past 40 years.

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♪♪

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♪♪

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Lava meanders down the slopes
in molten paths to the sea.

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♪♪

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♪♪

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These islands are primeval,

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but in Earth's
geologic timeline,

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Hawaii is a newcomer.

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The first island
rose above the sea

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a mere 5 million years ago.

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And, in the middle of nowhere,

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it became an anchor
for coral spawn

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drifting in from open water.

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♪♪

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♪♪

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Hawaii became a magnet
for life,

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sheltering thousands
of unique species

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found nowhere else
in the world.

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Hawaiian monk seals
and Hawaiian octopuses

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are natives here.

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♪♪

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But Tiger sharks are
much older than Hawaii.

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They somehow discovered
these islands

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in the course
of their migrations.

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These days, Hawaii's bays
and inlets

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offer year-round opportunities
for every palate.

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Both the massive
and the miniature

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enjoy the islands' embarrassment
of undersea riches...

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♪♪

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...including at least
40 species of sharks...

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♪♪

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...and their cousins, the rays.

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♪♪

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The volcanoes created stark
basaltic plains underwater,

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which were first colonized
by algae

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and then by tiny
coral polyps.

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Over time, life moved in,

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creating a stationary buffet
for carnivorous sharks,

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eels, tangs, and angelfishes,
just to name a few.

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At least 25% of Hawaii's
coral reef fishes are native

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and only live here.

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It seems impossible that
this delicate fairyland

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could spring from such violent
brimstone and fire.

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Hawaii's two active volcanoes
are the modern agents

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of a process
that is still unfolding.

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Kilauea and Mauna Loa are both
on the Big Island --

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also called Hawaii --

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which is the youngest island
in the chain.

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When super-heated magma
meets the cool ocean,

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a cauldron is born.

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As the lava cools,

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trapped air forms an undersea
labyrinth of tunnels and tubes,

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creating superb
miniature bunkers

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for those
that need sanctuary.

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They draw travelers in
from the open ocean.

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♪♪

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And even sharks need
to find a safe haven.

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♪♪

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The lava tubes are
a perfect retreat

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for nocturnal
whitetip reef sharks.

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♪♪

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Slender whitetips often escape
into the narrow passageways,

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thwarting more massive pursuers.

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♪♪

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♪♪

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These reef dwellers sometimes
become tiger shark prey

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because they're so much smaller.

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At five feet long,
they're right in the middle

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of a tiger shark's menu.

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This tiger cruises
just outside the maze,

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perhaps hoping to surprise
a whitetip away from home.

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♪♪

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Deep in their lairs,
whitetips can relax.

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They use specialized muscles

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to draw in oxygen-rich water
over their gills,

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making them one of the few
shark species

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that doesn't need to swim
in order to breathe.

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They cruise through
the murky lava jungle,

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always searching for
a better place to rest.

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Though they're able
to suspend activity

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in parts of their brain,

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they never actually sleep.

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They spend hours like this,
simply resting,

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sometimes alone,
sometimes together.

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♪♪

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Light doesn't reach
into most of the lava maze,

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but nocturnal whitetips
still wait for the dark of night

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to venture out.

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♪♪

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Carefully, cautiously,

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they'll morph from the hunted
into the hunters...

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...searching
their small territories

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for prey
that's also active at night.

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♪♪

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♪♪

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The reef during the day
is a different world,

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whether you're predator
or prey.

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♪♪

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Beyond the coral heads,
in open water,

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there's no place to hide.

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♪♪

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This silver flash is actually
a school of small mackerel

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called akule.

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As juveniles,
they lived on the reef,

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but as adults,
they've moved into deeper water.

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They gather
in the tens of thousands,

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seeking safety in numbers.

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♪♪

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When they sense danger,
the small fish react

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by crowding close together
in what's known as a bait ball.

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♪♪

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♪♪

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Instead of seeing individuals,

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predators confront a much
larger, confusing "creature."

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♪♪

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But sometimes
increasing their profile

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only attracts
more lethal attention.

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♪♪

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Bluefin trevallies,
3 feet in length,

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are some of Hawaii's
most efficient carnivores.

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♪♪

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Aggressive and sleek,
they can carve up a bait ball

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with exquisite precision.

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♪♪

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Akule caught in the rift
are the first to be devoured.

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The others try to flee.

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♪♪

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♪♪

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The sounds of plunder draw
gray reef sharks to the scene.

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♪♪

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Then, an elegant silky
comes in from the blue.

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They have the ability
to hear prey through open water.

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♪♪

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Now, the Akule have
drawn multiple sharks

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to the nearshore reef.

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Sharks may hunt cooperatively,

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but it's every individual for
itself when it comes to food.

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♪♪

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♪♪

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The hunters try to
corral the baitfish

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into more manageable masses.

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♪♪

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♪♪

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After enduring attack
after attack...

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the Akule are tiring...

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...but it won't be over
until the sharks are satiated.

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♪♪

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In the end, bottom dwellers
reap the last spoils of war.

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A blue pincher crab
is camouflaged

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by algae covering its claws...

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♪♪

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...allowing it to steal a prize,

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almost.

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Like a furtive ribbon,

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this undulated moray eel has
followed the scent of flesh.

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♪♪

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Needle-like teeth
shred the meal.

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♪♪

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Surviving Akule disperse

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with their casualty count
unknown.

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♪♪

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Back on the reef, there is
a constant kaleidoscope of color

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and danger.

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♪♪

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Every creature here has evolved
a strategy to meet its needs.

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The sharks are no exception.

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♪♪

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Blacktip reef sharks
are Hawaii's homebodies.

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♪♪

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They prefer shallow water,

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which suits their docile,
social nature.

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They often convene in groups.

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♪♪

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Around the Big Island,
these small sharks use the tides

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in order to hunt
ever closer to shore,

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the best place to find
tasty crustacean prey.

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♪♪

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And the tides
always 
deliver.

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♪♪

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The Big Island is also known
for its black sand beaches,

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formed by volcanic glass
that's rich in iron.

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But, it's not the color
of the sand

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that attracts green sea turtles
to Hawaii.

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This is the natal home

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of the largest hard-shelled
sea turtles in the world.

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♪♪

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Adults sport shells more
than four feet across

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and can weigh over 300 pounds.

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As juveniles, their diet
is quite eclectic,

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but adults graze
on algae and sea grass,

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which tints their internal fat
a pale shade of green.

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Female sea turtles
of all species

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come ashore
in order to lay their eggs.

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[ Moans ]

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But, this is the only place
in the world

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where males haul out
alongside females.

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No one knows why.

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The males don't guard the eggs
and the turtles don't mate here.

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This exceptional behavior
is a complete mystery.

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♪♪

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00:19:58,966 --> 00:20:00,600
Oceanic nomads,

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green sea turtles swim endlessly
until they reach maturity,

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somewhere
between 20 and 50 years.

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Scientists don't know

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00:20:11,566 --> 00:20:14,933
how long these prodigious
seafarers live,

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but they suspect
it's more than a century.

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♪♪

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Cruising through clouds
of plankton for decades

267
00:20:27,466 --> 00:20:29,700
allows algae and barnacles

268
00:20:29,733 --> 00:20:32,566
to grow on the platforms
of their broad shells.

269
00:20:32,600 --> 00:20:41,566
♪♪

270
00:20:41,600 --> 00:20:44,766
This provides great benefits
for the barnacles.

271
00:20:44,800 --> 00:20:46,700
But, as they accumulate,

272
00:20:46,733 --> 00:20:49,800
ferrying such a load
can slow turtles down.

273
00:20:49,833 --> 00:20:51,700
♪♪

274
00:20:51,733 --> 00:20:55,766
The barnacles attach themselves
with organic cement.

275
00:20:55,800 --> 00:20:57,666
They're permanent passengers.

276
00:20:57,700 --> 00:21:01,433
Unless knocked off
in the tussle of turtle sex.

277
00:21:01,466 --> 00:21:03,633
♪♪

278
00:21:03,666 --> 00:21:06,166
But there is a way
to limit their growth --

279
00:21:06,200 --> 00:21:08,766
with a little help
from some friends.

280
00:21:08,800 --> 00:21:16,966
♪♪

281
00:21:17,000 --> 00:21:19,400
♪♪

282
00:21:19,433 --> 00:21:23,066
These brown and yellow tangs
can digest tough marine algae

283
00:21:23,100 --> 00:21:25,133
that grows
along with the barnacles.

284
00:21:25,166 --> 00:21:33,566
♪♪

285
00:21:33,600 --> 00:21:37,000
This helps the turtles
by keeping their shells smooth,

286
00:21:37,033 --> 00:21:40,900
making it more difficult for new
barnacle larvae to attach.

287
00:21:40,933 --> 00:21:44,100
♪♪

288
00:21:44,133 --> 00:21:45,766
On Hawaii's reefs,

289
00:21:45,800 --> 00:21:47,933
sea turtles aren't
the only customers

290
00:21:47,966 --> 00:21:49,833
to benefit from a good cleaning.

291
00:21:49,866 --> 00:21:57,033
♪♪

292
00:21:57,066 --> 00:22:00,033
But it's more of a challenge
for grey reef sharks

293
00:22:00,066 --> 00:22:02,500
to take advantage of the tangs

294
00:22:02,533 --> 00:22:06,166
because they must keep swimming,
in order to breathe.

295
00:22:06,200 --> 00:22:14,000
♪♪

296
00:22:14,033 --> 00:22:17,666
They solve the problem
by adopting a vertical stance,

297
00:22:17,700 --> 00:22:21,700
with snout and gills facing
into the oxygen-rich current.

298
00:22:21,733 --> 00:22:28,966
♪♪

299
00:22:29,000 --> 00:22:38,900
♪♪

300
00:22:38,933 --> 00:22:45,733
♪♪

301
00:22:45,766 --> 00:22:49,100
Cleaner fish don't fear
their shark patrons

302
00:22:49,133 --> 00:22:51,066
because the symbiotic
relationship

303
00:22:51,100 --> 00:22:55,500
provides relief from parasites
for the predators.

304
00:22:55,533 --> 00:22:58,333
Both creatures benefit
from the alliance.

305
00:22:58,366 --> 00:23:04,866
♪♪

306
00:23:04,900 --> 00:23:09,033
Cleaner wrasse even follow their
customers in order to clean --

307
00:23:09,066 --> 00:23:12,733
and eat -- mucus from gills,
noses, and teeth.

308
00:23:12,766 --> 00:23:18,966
♪♪

309
00:23:19,000 --> 00:23:24,333
♪♪

310
00:23:24,366 --> 00:23:26,900
But this remarkable
upright dance

311
00:23:26,933 --> 00:23:29,566
is a lot more taxing
for the little fish.

312
00:23:29,600 --> 00:23:33,433
♪♪

313
00:23:33,466 --> 00:23:38,000
These humble janitors ensure
the health of many species,

314
00:23:38,033 --> 00:23:41,966
which makes
them 
one of the most
important fish on the reef.

315
00:23:42,000 --> 00:23:47,900
♪♪

316
00:23:47,933 --> 00:23:52,833
Like all urban places,
the reef is a bustling place.

317
00:23:52,866 --> 00:23:56,000
But, beyond Hawaii's
coral cities,

318
00:23:56,033 --> 00:24:00,233
the rural seascape
becomes stark, desert-like.

319
00:24:02,966 --> 00:24:06,300
It appears almost devoid of life

320
00:24:06,333 --> 00:24:09,833
and, yet, there is prey here,

321
00:24:09,866 --> 00:24:12,166
which an alien-looking
hammerhead

322
00:24:12,200 --> 00:24:14,433
has just the tools to detect.

323
00:24:14,466 --> 00:24:20,066
♪♪

324
00:24:20,100 --> 00:24:21,600
The bizarre shape of its head

325
00:24:21,633 --> 00:24:23,800
makes for an imposing
silhouette...

326
00:24:23,833 --> 00:24:27,200
♪♪

327
00:24:27,233 --> 00:24:30,633
...and enables those strange,
wide-set eyes

328
00:24:30,666 --> 00:24:34,600
to see a near 360° view
of its hunting grounds.

329
00:24:34,633 --> 00:24:44,466
♪♪

330
00:24:44,500 --> 00:24:45,766
Like all sharks,

331
00:24:45,800 --> 00:24:48,633
hammerheads use special
sensors to detect

332
00:24:48,666 --> 00:24:52,200
the bioelectrical fields
of creatures around them,

333
00:24:52,233 --> 00:24:57,600
but these peculiar beasts have
twice as many as other sharks.

334
00:24:57,633 --> 00:25:00,166
It's as though they
were especially designed

335
00:25:00,200 --> 00:25:02,133
for this stark hunting ground.

336
00:25:02,166 --> 00:25:06,933
♪♪

337
00:25:06,966 --> 00:25:08,300
The hammerhead is scanning

338
00:25:08,333 --> 00:25:10,833
for signals
from its favorite prey.

339
00:25:10,866 --> 00:25:16,133
♪♪

340
00:25:16,166 --> 00:25:17,966
But, stingrays are experts

341
00:25:18,000 --> 00:25:22,333
at hiding and escaping
in this sandy expanse,

342
00:25:22,366 --> 00:25:24,866
so the hunt continues.

343
00:25:24,900 --> 00:25:29,200
♪♪

344
00:25:35,633 --> 00:25:37,833
Off the island of Oahu,

345
00:25:37,866 --> 00:25:40,133
there's another
desolate expanse.

346
00:25:44,366 --> 00:25:46,566
But this is an undersea prairie,

347
00:25:46,600 --> 00:25:50,666
with its own waving strands
of garden eels.

348
00:25:50,700 --> 00:25:54,700
♪♪

349
00:25:54,733 --> 00:25:57,833
These native Hawaiians
are desperately shy...

350
00:25:57,866 --> 00:26:02,766
♪♪

351
00:26:02,800 --> 00:26:05,333
...partially emerging
from their burrows only

352
00:26:05,366 --> 00:26:08,366
to devour zooplankton.

353
00:26:08,400 --> 00:26:10,033
Hundreds plant themselves

354
00:26:10,066 --> 00:26:14,766
where strong currents
deliver food to their doors.

355
00:26:14,800 --> 00:26:18,233
This species is only found
in Hawaiian waters.

356
00:26:18,266 --> 00:26:23,133
♪♪

357
00:26:23,166 --> 00:26:27,900
Each will spend its entire
lifetime in the exact same spot.

358
00:26:27,933 --> 00:26:34,200
♪♪

359
00:26:34,233 --> 00:26:38,300
The eels' large eyes
spot this roving tiger shark.

360
00:26:38,333 --> 00:26:41,200
♪♪

361
00:26:41,233 --> 00:26:44,766
But any intruder will trigger
the group to disappear back

362
00:26:44,800 --> 00:26:46,300
into their sandy dens.

363
00:26:46,333 --> 00:26:54,900
♪♪

364
00:26:54,933 --> 00:26:58,800
♪♪

365
00:26:58,833 --> 00:27:02,166
The only creatures
garden eels need to fear

366
00:27:02,200 --> 00:27:03,800
are each other

367
00:27:03,833 --> 00:27:07,366
because males engage
in brutal territorial fights.

368
00:27:07,400 --> 00:27:16,100
♪♪

369
00:27:16,133 --> 00:27:20,066
The tiger shark has no interest
in the slender stalks below.

370
00:27:20,100 --> 00:27:28,500
♪♪

371
00:27:28,533 --> 00:27:32,000
It's headed some
500 miles northwest,

372
00:27:32,033 --> 00:27:33,366
for a proper meal.

373
00:27:33,400 --> 00:27:41,633
♪♪

374
00:27:41,666 --> 00:27:45,733
♪♪

375
00:27:45,766 --> 00:27:47,466
The tiger's destination is

376
00:27:47,500 --> 00:27:51,200
an eerie spit of sand
in the middle of nowhere,

377
00:27:51,233 --> 00:27:54,833
once a military airstrip
during the Second World War.

378
00:27:54,866 --> 00:27:57,900
[ Birds squawking ]

379
00:28:03,866 --> 00:28:07,133
Today, the only residents
are birds,

380
00:28:07,166 --> 00:28:08,200
monk seals,

381
00:28:08,233 --> 00:28:11,200
and, occasionally,
green sea turtles.

382
00:28:21,666 --> 00:28:23,133
Tern Island is part

383
00:28:23,166 --> 00:28:26,900
of the Hawaiian Islands
National Wildlife Refuge

384
00:28:26,933 --> 00:28:31,200
and it's a critical sanctuary
for millions of nesting seabirds

385
00:28:31,233 --> 00:28:33,766
and thousands
of wintering shorebirds.

386
00:28:42,300 --> 00:28:43,900
It's also a magnet

387
00:28:43,933 --> 00:28:46,933
for a maverick group
of tiger sharks

388
00:28:46,966 --> 00:28:49,066
searching for seal prey.

389
00:28:49,100 --> 00:28:58,266
♪♪

390
00:28:58,300 --> 00:29:01,466
Aside from a bat,
the Hawaiian monk seal

391
00:29:01,500 --> 00:29:05,433
is the only mammal endemic
to the islands

392
00:29:05,466 --> 00:29:08,766
and there are only
about 1,500 of them left.

393
00:29:08,800 --> 00:29:15,000
♪♪

394
00:29:15,033 --> 00:29:16,333
[ Snores ]

395
00:29:16,366 --> 00:29:19,133
♪♪

396
00:29:19,166 --> 00:29:23,433
Many show signs of lucky
escapes from shark jaws.

397
00:29:23,466 --> 00:29:32,966
♪♪

398
00:29:33,000 --> 00:29:36,933
♪♪

399
00:29:36,966 --> 00:29:41,033
Tigers will also take turtles,
and even dolphins.

400
00:29:41,066 --> 00:29:42,433
[ Whistling ]

401
00:29:42,466 --> 00:29:44,566
♪♪

402
00:29:44,600 --> 00:29:48,333
These hunters have
liberal tastes in prey.

403
00:29:48,366 --> 00:29:51,766
Anything and
everything 
is
on their menu

404
00:29:51,800 --> 00:29:55,100
and this far-flung outpost
of Hawaii

405
00:29:55,133 --> 00:29:56,966
offers them something unique.

406
00:29:57,000 --> 00:29:59,566
[ Chirping ]

407
00:29:59,600 --> 00:30:02,200
Laysan albatross parents
leave the island

408
00:30:02,233 --> 00:30:05,333
before their chicks'
transition from landlubbers

409
00:30:05,366 --> 00:30:07,366
to open ocean voyagers.

410
00:30:07,400 --> 00:30:10,433
[ Squawking ]

411
00:30:18,333 --> 00:30:21,766
Designed to glide
over an endless expanse,

412
00:30:21,800 --> 00:30:26,100
extra-long wings make learning
to use them extra challenging.

413
00:30:31,733 --> 00:30:34,100
Black-footed albatrosses
are here, too.

414
00:30:38,666 --> 00:30:40,666
Like the Laysans,

415
00:30:40,700 --> 00:30:43,633
they lay just one egg
every other year.

416
00:30:45,466 --> 00:30:48,666
The Northern Hawaiian Islands
host 90%

417
00:30:48,700 --> 00:30:51,066
of the breeding albatrosses
in the world.

418
00:30:53,733 --> 00:30:57,933
From terns to frigate birds,
albatrosses to gannets,

419
00:30:57,966 --> 00:31:02,666
18 species rely
on this tiny spit of land.

420
00:31:02,700 --> 00:31:05,200
It's an essential
mid-ocean nursery

421
00:31:05,233 --> 00:31:07,233
for half a million seabirds.

422
00:31:11,133 --> 00:31:14,033
Once they become one
with their wings,

423
00:31:14,066 --> 00:31:16,700
the chicks' maiden voyage
will be all the way

424
00:31:16,733 --> 00:31:18,400
to the Bering Sea.

425
00:31:18,433 --> 00:31:21,600
♪♪

426
00:31:21,633 --> 00:31:25,266
But, first, they must
make a successful flight.

427
00:31:25,300 --> 00:31:30,900
♪♪

428
00:31:30,933 --> 00:31:34,300
It's harder for them to succeed
than for most birds

429
00:31:34,333 --> 00:31:36,633
because of the strength
they must build

430
00:31:36,666 --> 00:31:38,466
to power such long wings.

431
00:31:38,500 --> 00:31:46,900
♪♪

432
00:31:46,933 --> 00:31:56,900
♪♪

433
00:31:56,933 --> 00:31:58,966
♪♪

434
00:32:02,000 --> 00:32:06,800
The small group of tiger sharks
around Tern Island knows when --

435
00:32:06,833 --> 00:32:09,933
and where --
chicks practice takeoffs.

436
00:32:09,966 --> 00:32:13,733
♪♪

437
00:32:13,766 --> 00:32:16,800
And the chicks,
focused on flight,

438
00:32:16,833 --> 00:32:20,300
have no idea of what lurks
beneath the waves.

439
00:32:22,566 --> 00:32:30,200
♪♪

440
00:32:30,233 --> 00:32:33,633
Most fledglings become airborne
after a few attempts.

441
00:32:33,666 --> 00:32:37,366
♪♪

442
00:32:37,400 --> 00:32:39,400
But not all.

443
00:32:39,433 --> 00:32:48,100
♪♪

444
00:32:48,133 --> 00:32:49,566
In other places,

445
00:32:49,600 --> 00:32:53,000
a water landing would just be
part of the learning process,

446
00:32:53,033 --> 00:32:55,500
a gentle respite
for the beginner attempting

447
00:32:55,533 --> 00:32:57,133
to get the hang of takeoff.

448
00:32:57,166 --> 00:33:00,666
♪♪

449
00:33:00,700 --> 00:33:05,566
But here, soggy and exhausted,
the chick's a sitting duck.

450
00:33:05,600 --> 00:33:14,966
♪♪

451
00:33:15,000 --> 00:33:21,900
♪♪

452
00:33:21,933 --> 00:33:24,566
In order to escape
the predator's jaws,

453
00:33:24,600 --> 00:33:26,866
the chick attempts
to walk on water.

454
00:33:26,900 --> 00:33:32,100
♪♪

455
00:33:32,133 --> 00:33:35,000
But, there's no miracle today.

456
00:33:35,033 --> 00:33:44,900
♪♪

457
00:33:44,933 --> 00:33:54,900
♪♪

458
00:33:54,933 --> 00:34:02,966
♪♪

459
00:34:03,000 --> 00:34:05,600
♪♪

460
00:34:05,633 --> 00:34:09,600
This chick's first flight
was also its last.

461
00:34:09,633 --> 00:34:13,566
♪♪

462
00:34:13,600 --> 00:34:16,933
It's impossible to know
if the other young birds realize

463
00:34:16,966 --> 00:34:18,433
what they've just seen.

464
00:34:18,466 --> 00:34:24,433
♪♪

465
00:34:33,266 --> 00:34:35,933
Once they leave the rookery
on Tern Island,

466
00:34:35,966 --> 00:34:39,100
they won't be back
for three years.

467
00:34:39,133 --> 00:34:41,200
Then, they'll choose
their mate for life

468
00:34:41,233 --> 00:34:42,900
and hatch chicks of their own.

469
00:34:45,700 --> 00:34:50,400
The tiger sharks
will be waiting.

470
00:34:50,433 --> 00:34:52,900
It's a strange twist
in the story,

471
00:34:52,933 --> 00:34:55,433
for the chicks
that escape the sharks

472
00:34:55,466 --> 00:34:58,066
will prey on fish in return.

473
00:35:02,633 --> 00:35:06,000
♪♪

474
00:35:06,033 --> 00:35:10,900
The Hawaiian Sun sinks swiftly
below the horizon.

475
00:35:10,933 --> 00:35:12,433
Here, in the tropics,

476
00:35:12,466 --> 00:35:16,366
twilight is brief,
a mere moment of magic.

477
00:35:16,400 --> 00:35:24,966
♪♪

478
00:35:25,000 --> 00:35:27,200
♪♪

479
00:35:27,233 --> 00:35:30,200
On the reef,
creatures are already preparing

480
00:35:30,233 --> 00:35:31,600
for their nightly business.

481
00:35:31,633 --> 00:35:33,733
♪♪

482
00:35:33,766 --> 00:35:36,766
It's dinnertime
and miniature lanterns are

483
00:35:36,800 --> 00:35:39,900
about to appear
as guides to a feast.

484
00:35:39,933 --> 00:35:46,900
♪♪

485
00:35:46,933 --> 00:35:51,033
Tiny fish and tasty zooplankton
rise from the deep,

486
00:35:51,066 --> 00:35:53,266
flaunting their bioluminescence.

487
00:35:53,300 --> 00:35:58,233
♪♪

488
00:35:58,266 --> 00:36:00,566
These animals use
chemical reactions

489
00:36:00,600 --> 00:36:04,533
within their own bodies
to make light.

490
00:36:04,566 --> 00:36:06,700
They might become instant prey,

491
00:36:06,733 --> 00:36:10,200
serving as the first course
in a complex food chain.

492
00:36:10,233 --> 00:36:13,833
♪♪

493
00:36:13,866 --> 00:36:17,800
Some use their inner glow
to draw even tinier prey closer.

494
00:36:17,833 --> 00:36:19,600
♪♪

495
00:36:19,633 --> 00:36:22,533
Still others shine
to attract mates.

496
00:36:22,566 --> 00:36:28,966
♪♪

497
00:36:29,000 --> 00:36:33,166
♪♪

498
00:36:33,200 --> 00:36:37,433
Box jellyfish aren't impressed
by the displays.

499
00:36:37,466 --> 00:36:41,666
To them, the radiant organisms
are simply...food.

500
00:36:41,700 --> 00:36:45,166
♪♪

501
00:36:45,200 --> 00:36:48,733
The light show attracts
more plankton

502
00:36:48,766 --> 00:36:52,166
and, ultimately,
giants from the deep.

503
00:36:52,200 --> 00:36:56,800
♪♪

504
00:36:56,833 --> 00:36:59,900
Giant manta rays
are shark cousins,

505
00:36:59,933 --> 00:37:01,766
but they are filter feeders,

506
00:37:01,800 --> 00:37:04,733
with wingspans
that can reach 29 feet.

507
00:37:04,766 --> 00:37:09,700
♪♪

508
00:37:09,733 --> 00:37:13,433
At birth, mantas are rolled up
like burritos

509
00:37:13,466 --> 00:37:16,733
and then unfurl
to an astonishing six feet.

510
00:37:16,766 --> 00:37:23,766
♪♪

511
00:37:23,800 --> 00:37:26,466
But no two are alike.

512
00:37:26,500 --> 00:37:28,200
Blotches on their underbellies

513
00:37:28,233 --> 00:37:31,300
are equivalent
to human fingerprints.

514
00:37:31,333 --> 00:37:34,866
They're thought to have
individual personalities, too --

515
00:37:34,900 --> 00:37:38,100
some curious, others shy --

516
00:37:38,133 --> 00:37:41,166
which researchers consider
a sign of intelligence.

517
00:37:41,200 --> 00:37:42,666
♪♪

518
00:37:42,700 --> 00:37:44,666
They're all voracious.

519
00:37:44,700 --> 00:37:51,666
♪♪

520
00:37:51,700 --> 00:37:55,100
Sophisticated fins,
called devil horns,

521
00:37:55,133 --> 00:37:57,900
whisk plankton
into their cavernous mouths.

522
00:37:57,933 --> 00:38:04,766
♪♪

523
00:38:04,800 --> 00:38:06,733
But, it's recently
been discovered

524
00:38:06,766 --> 00:38:09,633
that those gaping mouths
are also swallowing

525
00:38:09,666 --> 00:38:12,466
great mouthfuls of small fish,

526
00:38:12,500 --> 00:38:13,533
whole.

527
00:38:13,566 --> 00:38:22,966
♪♪

528
00:38:23,000 --> 00:38:28,300
♪♪

529
00:38:28,333 --> 00:38:30,833
They sweep the night ocean
until dawn,

530
00:38:30,866 --> 00:38:32,666
near Kona on the Big Island.

531
00:38:32,700 --> 00:38:36,533
♪♪

532
00:38:36,566 --> 00:38:38,833
Graceful, gentle giants,

533
00:38:38,866 --> 00:38:42,633
these marine marvels have
only large sharks to fear.

534
00:38:42,666 --> 00:38:51,900
♪♪

535
00:38:51,933 --> 00:38:56,500
Ironically, the largest shark
of all is also benign.

536
00:38:56,533 --> 00:39:03,900
♪♪

537
00:39:03,933 --> 00:39:07,466
Whale sharks are the largest
sharks on Earth

538
00:39:07,500 --> 00:39:11,066
and sometimes they pass
through the Hawaiian Islands.

539
00:39:11,100 --> 00:39:12,233
Slowly.

540
00:39:12,266 --> 00:39:15,633
♪♪

541
00:39:15,666 --> 00:39:18,066
They swim extreme distances

542
00:39:18,100 --> 00:39:20,200
because they need
enormous amounts

543
00:39:20,233 --> 00:39:24,000
of plankton and coral spawn
to power their bulk --

544
00:39:24,033 --> 00:39:26,366
up to 90 pounds per day.

545
00:39:26,400 --> 00:39:34,966
♪♪

546
00:39:35,000 --> 00:39:38,433
♪♪

547
00:39:38,466 --> 00:39:40,566
Forty feet long,

548
00:39:40,600 --> 00:39:43,500
their mouths stretch
four feet wide.

549
00:39:43,533 --> 00:39:46,100
But plankton is strained
and swallowed

550
00:39:46,133 --> 00:39:50,133
by a throat so small,
it's just the size of a coin.

551
00:39:50,166 --> 00:39:56,566
♪♪

552
00:39:56,600 --> 00:39:58,966
Thick, rubbery skin
acts like armor

553
00:39:59,000 --> 00:40:02,600
to deter would-be
shark predators,

554
00:40:02,633 --> 00:40:05,200
but not a bevy of freeloaders.

555
00:40:05,233 --> 00:40:08,266
♪♪

556
00:40:08,300 --> 00:40:12,233
Remoras accompany whale sharks
everywhere they go

557
00:40:12,266 --> 00:40:13,600
and position themselves

558
00:40:13,633 --> 00:40:16,400
to ensure they don't
miss any scraps.

559
00:40:16,433 --> 00:40:24,966
♪♪

560
00:40:25,000 --> 00:40:32,900
♪♪

561
00:40:32,933 --> 00:40:35,600
♪♪

562
00:40:35,633 --> 00:40:37,866
There are more giants here.

563
00:40:37,900 --> 00:40:41,333
Nine thousand pilot whales
are Hawaiian residents.

564
00:40:41,366 --> 00:40:44,900
[ Squeaking ]

565
00:40:44,933 --> 00:40:47,866
They're actually
supersized dolphins,

566
00:40:47,900 --> 00:40:50,733
cruising the deep channels
between islands,

567
00:40:50,766 --> 00:40:55,133
capable of diving 3,000 feet
down in search of squid.

568
00:41:04,533 --> 00:41:07,166
Large, fatty melons
on their foreheads

569
00:41:07,200 --> 00:41:11,533
magnify the sounds
that they use to communicate

570
00:41:11,566 --> 00:41:14,633
and to find prey
through echolocation.

571
00:41:20,733 --> 00:41:22,233
[ Clicking ]

572
00:41:22,266 --> 00:41:26,100
They travel in large groups,
made up of several families.

573
00:41:39,600 --> 00:41:41,166
Sharks don't target

574
00:41:41,200 --> 00:41:44,800
these intelligent,
20-foot-long mammals,

575
00:41:44,833 --> 00:41:46,633
but some follow them.

576
00:41:59,333 --> 00:42:02,366
Oceanic whitetips rely
on the whales' sonar

577
00:42:02,400 --> 00:42:05,066
to lead them to food
in the open ocean

578
00:42:05,100 --> 00:42:07,866
and the pod
doesn't seem to mind.

579
00:42:12,066 --> 00:42:13,933
The sharks grab fish scraps

580
00:42:13,966 --> 00:42:16,233
when the pilot whales
pillage a school.

581
00:42:21,200 --> 00:42:23,866
In this realm of endless blue,

582
00:42:23,900 --> 00:42:26,500
it's a challenge for them
to get enough to eat.

583
00:42:33,266 --> 00:42:36,700
So, every meal counts,

584
00:42:36,733 --> 00:42:40,200
including ones the whales
have already digested.

585
00:42:47,500 --> 00:42:49,500
In other places
around the world,

586
00:42:49,533 --> 00:42:53,133
sandbar sharks
migrate long distances,

587
00:42:53,166 --> 00:42:56,100
but Hawaii has everything
they need,

588
00:42:56,133 --> 00:42:58,200
so they live here year-round.

589
00:43:07,800 --> 00:43:10,033
They prefer to stay deep.

590
00:43:10,066 --> 00:43:13,066
It's unusual to see them
so close to the surface.

591
00:43:15,233 --> 00:43:18,500
They're just finishing a meal
of tasty mackerel,

592
00:43:18,533 --> 00:43:20,900
known in Hawaii as
opelu.

593
00:43:24,266 --> 00:43:27,166
The sandbars have formed a gang,

594
00:43:27,200 --> 00:43:31,066
probably all males,
because females travel alone.

595
00:43:44,500 --> 00:43:46,966
They've had the school
of opelu to themselves

596
00:43:47,000 --> 00:43:48,400
for quite some time.

597
00:43:52,100 --> 00:43:55,466
Then, a massive
bronze whaler decides

598
00:43:55,500 --> 00:43:57,133
to make an appearance
to the party.

599
00:43:57,166 --> 00:44:01,766
♪♪

600
00:44:01,800 --> 00:44:04,166
Little is known
about these sharks,

601
00:44:04,200 --> 00:44:07,866
but they tend to return
to the same locations over time.

602
00:44:07,900 --> 00:44:10,366
♪♪

603
00:44:10,400 --> 00:44:13,800
Today, there's not much left
for the latecomer.

604
00:44:13,833 --> 00:44:22,966
♪♪

605
00:44:23,000 --> 00:44:32,900
♪♪

606
00:44:32,933 --> 00:44:35,400
♪♪

607
00:44:38,300 --> 00:44:41,300
Meanwhile,
off the coast of Maui,

608
00:44:41,333 --> 00:44:43,633
a tiger shark is on patrol.

609
00:44:43,666 --> 00:44:47,666
♪♪

610
00:44:47,700 --> 00:44:51,000
Tigers in Hawaii have been
waiting for this season.

611
00:44:51,033 --> 00:44:52,666
♪♪

612
00:44:52,700 --> 00:44:57,033
By now, many humpback calves
have been born.

613
00:44:57,066 --> 00:44:59,833
♪♪

614
00:44:59,866 --> 00:45:02,233
They'll nurse
for at least a year,

615
00:45:02,266 --> 00:45:04,033
growing a foot every month

616
00:45:04,066 --> 00:45:08,600
by drinking 100 gallons
of rich milk every day.

617
00:45:08,633 --> 00:45:16,633
♪♪

618
00:45:16,666 --> 00:45:20,533
Mother whales will try
to keep their newborns close,

619
00:45:20,566 --> 00:45:23,766
but tigers are clever
and stealthy.

620
00:45:23,800 --> 00:45:30,433
♪♪

621
00:45:30,466 --> 00:45:34,866
And, while adult whales can
submerge for close to an hour...

622
00:45:34,900 --> 00:45:37,166
♪♪

623
00:45:37,200 --> 00:45:39,000
...little calves must surface

624
00:45:39,033 --> 00:45:41,166
every few minutes to breathe.

625
00:45:41,200 --> 00:45:49,066
♪♪

626
00:45:49,100 --> 00:45:51,833
This is when they are
most in danger.

627
00:45:51,866 --> 00:45:59,233
♪♪

628
00:45:59,266 --> 00:46:03,200
Many survivors show terrible
scars from shark attacks.

629
00:46:03,233 --> 00:46:05,966
♪♪

630
00:46:06,000 --> 00:46:07,800
In just a few months,

631
00:46:07,833 --> 00:46:10,800
they'll be too large for the
sharks to even consider.

632
00:46:10,833 --> 00:46:20,400
♪♪

633
00:46:20,433 --> 00:46:24,533
But, until then, the tigers
will actively hunt them.

634
00:46:24,566 --> 00:46:32,900
♪♪

635
00:46:32,933 --> 00:46:35,000
♪♪

636
00:46:35,033 --> 00:46:38,366
When the predator
sees an opportunity,

637
00:46:38,400 --> 00:46:40,166
it moves in for the kill.

638
00:46:40,200 --> 00:46:49,600
♪♪

639
00:46:49,633 --> 00:46:51,866
Still, even newborn calves

640
00:46:51,900 --> 00:46:54,800
are roughly the same size
as tiger sharks,

641
00:46:54,833 --> 00:46:55,933
and a challenge.

642
00:46:55,966 --> 00:47:03,266
♪♪

643
00:47:03,300 --> 00:47:06,833
Today, this one escapes
a gruesome fate.

644
00:47:06,866 --> 00:47:12,466
♪♪

645
00:47:12,500 --> 00:47:16,633
Hundreds of humpback calves
are born in Hawaii every winter

646
00:47:16,666 --> 00:47:18,700
and not all will be so lucky.

647
00:47:18,733 --> 00:47:22,066
♪♪

648
00:47:22,100 --> 00:47:24,400
Those that escape
the fearsome jaws

649
00:47:24,433 --> 00:47:26,733
will migrate north
with their pod.

650
00:47:26,766 --> 00:47:34,900
♪♪

651
00:47:34,933 --> 00:47:40,166
♪♪

652
00:47:40,200 --> 00:47:43,866
Foiled for now,
the tiger shark smells

653
00:47:43,900 --> 00:47:46,966
the equivalent
of an underwater dinner bell.

654
00:47:47,000 --> 00:47:50,066
♪♪

655
00:47:52,500 --> 00:47:54,566
It's ringing 80 miles away,

656
00:47:54,600 --> 00:47:57,066
along the coast
of the Big Island,

657
00:47:57,100 --> 00:48:01,133
announcing a dead sperm whale
still afloat offshore.

658
00:48:04,166 --> 00:48:09,533
♪♪

659
00:48:09,566 --> 00:48:12,900
One hundred thousand pounds
of nutritious flesh

660
00:48:12,933 --> 00:48:14,333
won't go to waste.

661
00:48:14,366 --> 00:48:16,633
♪♪

662
00:48:16,666 --> 00:48:20,100
We don't know how,
or why, it died,

663
00:48:20,133 --> 00:48:22,433
but internal gases
have kept the carcass

664
00:48:22,466 --> 00:48:24,333
from sinking into the abyss.

665
00:48:24,366 --> 00:48:26,333
♪♪

666
00:48:26,366 --> 00:48:28,800
Blubber is a calorie bomb

667
00:48:28,833 --> 00:48:32,433
and nature has dropped it
into shark-filled waters.

668
00:48:32,466 --> 00:48:38,900
♪♪

669
00:48:38,933 --> 00:48:44,200
♪♪

670
00:48:44,233 --> 00:48:47,200
Resident tigers
will continue to gather

671
00:48:47,233 --> 00:48:49,866
because there is plenty
to go around,

672
00:48:49,900 --> 00:48:50,966
for days.

673
00:48:51,000 --> 00:48:55,633
♪♪

674
00:48:55,666 --> 00:48:59,300
It's a leisurely feast,
rare in the ocean realm.

675
00:48:59,333 --> 00:49:08,966
♪♪

676
00:49:09,000 --> 00:49:18,966
♪♪

677
00:49:19,000 --> 00:49:22,033
♪♪

678
00:49:22,066 --> 00:49:26,400
The 50-foot leviathan
is slowly devoured

679
00:49:26,433 --> 00:49:30,733
as the tigers search for the
softest places to feed on first.

680
00:49:30,766 --> 00:49:38,966
♪♪

681
00:49:39,000 --> 00:49:48,966
♪♪

682
00:49:49,000 --> 00:49:58,966
♪♪

683
00:49:59,000 --> 00:50:08,966
♪♪

684
00:50:09,000 --> 00:50:16,100
♪♪

685
00:50:16,133 --> 00:50:19,100
Then, an out-of-towner arrives.

686
00:50:19,133 --> 00:50:22,266
♪♪

687
00:50:22,300 --> 00:50:25,500
She's not a frequent flier
to Hawaii,

688
00:50:25,533 --> 00:50:27,633
but she's not a stranger,
either.

689
00:50:27,666 --> 00:50:30,233
♪♪

690
00:50:30,266 --> 00:50:33,300
She's a well-known
great white female

691
00:50:33,333 --> 00:50:35,766
that goes by the name Deep Blue.

692
00:50:35,800 --> 00:50:40,133
♪♪

693
00:50:40,166 --> 00:50:43,966
She's one of the largest
white sharks ever seen,

694
00:50:44,000 --> 00:50:46,766
weighing at least 2.5 tons,

695
00:50:46,800 --> 00:50:48,800
over 8 feet tall

696
00:50:48,833 --> 00:50:50,366
and 20 feet long.

697
00:50:50,400 --> 00:50:52,633
♪♪

698
00:50:52,666 --> 00:50:55,166
She often hangs
around Guadalupe Island,

699
00:50:55,200 --> 00:50:56,766
in Mexico,

700
00:50:56,800 --> 00:50:59,766
but this is the first time
she's been seen here.

701
00:50:59,800 --> 00:51:07,600
♪♪

702
00:51:07,633 --> 00:51:11,200
And, now,
she is so intimidating,

703
00:51:11,233 --> 00:51:14,100
she gets the whale carcass
to herself.

704
00:51:14,133 --> 00:51:22,966
♪♪

705
00:51:23,000 --> 00:51:30,966
♪♪

706
00:51:31,000 --> 00:51:33,733
♪♪

707
00:51:33,766 --> 00:51:38,200
No one knows why she's traveled
all the way to Hawaii,

708
00:51:38,233 --> 00:51:40,900
but she appears to be pregnant.

709
00:51:40,933 --> 00:51:43,433
Perhaps she, too, is searching

710
00:51:43,466 --> 00:51:45,766
for the perfect place
to give birth.

711
00:51:45,800 --> 00:51:53,966
♪♪

712
00:51:54,000 --> 00:51:58,833
In this place of battle

713
00:51:58,866 --> 00:52:01,100
and beauty,

714
00:52:01,133 --> 00:52:05,200
among the violent volcanoes

715
00:52:05,233 --> 00:52:09,066
and vibrant coral reefs,

716
00:52:09,100 --> 00:52:12,166
so many sharks have made
Hawaii their home.

717
00:52:12,200 --> 00:52:15,533
♪♪

718
00:52:15,566 --> 00:52:18,700
Perhaps the most
formidable of all,

719
00:52:18,733 --> 00:52:20,266
the great white,

720
00:52:20,300 --> 00:52:22,633
will find paradise here, too.

721
00:52:22,666 --> 00:52:25,233
♪♪

722
00:52:27,633 --> 00:52:30,000
To order this "Nature"
program on DVD,

723
00:52:30,033 --> 00:52:34,900
visit shopPBS
or call 1-800-PLAY-PBS.

724
00:52:34,933 --> 00:52:38,833
This program is also available
on Amazon Prime Video.

725
00:52:38,866 --> 00:52:43,833
♪♪

726
00:52:43,866 --> 00:52:53,833
♪♪

727
00:52:53,866 --> 00:53:03,900
♪♪

728
00:53:03,933 --> 00:53:11,166
♪♪

729
00:53:11,200 --> 00:53:14,766
To learn more about what you've
seen on this "Nature" program,

730
00:53:14,800 --> 00:53:16,833
visit pbs.org.

731
00:53:16,866 --> 00:53:26,266
♪♪