All language subtitles for Great.Migrations.S01E05.Science.of.Great.Migrations.720p.BluRay.x264-Pahe.in

NARRATOR: Migrations.

Mysterious feats of navigation...

endurance...

and courage.

Now, technology allows scientists
to go along for the ride...

MAN: Really diving down...

MAN: Yook, snap!

NARRATOR: ...like never before.

MAN: lt's an incredible thrill.

Stuff happens that you wouldn't
believe in your wildest dreams.

NARRATOR: ...learning
where the animals go...

MAN: Cool! Wow.

That's perfect.
Look at that!

NARRATOR: ...why...

and how they survive.

MAN: This is really
cutting-edge stuff.

MAN: We are the first to find out
what they're really doing.

NARRATOR: This is the inside story

of the science behind
the great migrations.

On this October morning,

elephant seals are nearing
the end of breeding season.

From here in Patagonia,
they will soon embark

on an odyssey
through the southern oceans.

That's why a team of biologists
led by Flavio Quintana is here.

To deploy a state-of-the-art tag
in hopes of tracking their every move.

For ten months out of the year,
the seals migrate thousands of miles...

disappearing into the sea to feed,

where their behavior
is largely unknown.

lt is a question vexing Quintana
for much of his 20-year career.

QUlNTANA: We are always surprised
to study this kind of animal,

because they are incredible, incredible.

They are diving machines;
l'm really impressed with that.

Because they need to come
back to shore to breed and to molt,

but they spend 80 percent
of their life at sea.

And nobody knows
what they are doing at sea.

This is what we
are trying to discover.

NARRATOR: lf the high-tech tag works,

scientists will finally solve the mystery
of the elephant seals' migration.

Quintana's special weapon
is called the Daily Diary,

invented by this man, Rory Wilson.

WlLSON: There are
temperature sensors in there,

there are speed sensors in there,
there are light sensors in there,

all packaged in this resin.

This part here,
all this big clunky bit here,

these are two batteries.

The batteries are
inside stainless steel,

and that's in order to protect

against the ridiculous
amounts of pressures

to which the animals
expose themselves routinely.

NARRATOR: lt's the result
of ten years of trial and error.

No other tag records
such a wide array of data.

Wilson got the idea for his Daily Diary
while studying penguins.

WlLSON: lt's terribly depressing.

You go out on your island,

you're going to do your whole Ph.D.,

your doctorate on penguins,

on what they do at sea,

and they're all standing
around the edge

looking at you saying,
"Yes, we're the penguins."

Then they all jump in the water
and disappear.

So in a grumpy
and foul-mouthed mood,

l went back and thought,
"lf l can't see them,

then l'll find something else
that's just going to record for me."

Rather makeshift.

NARRATOR: He tested the prototype
on an animal that follows direction...

WlLSON: Stay!

NARRATOR: ...his dog, Moon.

Moon's Daily Diary recorded
her speed, her temperature,

every breath, step and wag.

WlLSON: Here's where l tell her
to run, throw the stick.

Look at this activity here,
tearing towards the stick.

Picks it up and then
this very regular canter back.

NARRATOR: But it also revealed
things Wilson didn't expect.

WlLSON: Her panting.

She'll breathe up to six times a second
when she's panting...

[panting]

...when she's been running around.

And when l'm about
to give her a command,

l put my hand up, and
l discovered looking at the trace,

she actually holds her breath
when my hand goes up.

NARRATOR: This intrigued Wilson.

He wanted to know more

about the importance of breathing
in animal behavior.

He returned to his penguins.

The results were astonishing.

WlLSON: Each one of these
is a flipper beating.

lt's swimming
the whole time underwater,

and relaxing a bit as it comes
back to the surface here.

You can see as it comes back
for the first breath,

it's using the buoyancy
to help it go up.

So what the penguin's doing
is it's gone down,

slight curve on the way down,

it's come up,
it's spotted a prey,

it's come up really rapidly
and it's gone yook, snap...

and then drifted up to the surface.

NARRATOR: The penguin takes in
the exact amount of air it needs

in advance of a dive.

WlLSON: You know, the penguin
before it goes down is saying:

"How deep am l going to go
on the next dive,

how many fish do l think
l'm going to catch?"

They're inhaling
already at the surface

the right amount of air volume
to give them neutral buoyancy

at the depth at which
they're going to forage.

So the implication is they know:

"Ha, 30 meters, l need 600 milliliters
to be neutrally buoyant at that,

so, 600, l'm going down."

That's quite complicated stuff
for a small bird.

NARRATOR: Their buoyant bodies
can then rise like balloons through the water,

effortlessly catching fish
along the way.

By doing this, the animal
conserves what it needs most

for its migratory journey:

energy.

With this discovery,
Wilson joins Quintana

to study the migration
of the elephant seals.

ln two months, these behemoths
will return here to molt‒

a perfect time to retrieve
the Daily Diaries

because the batteries
won't last much longer.

WlLSON: We've never
done this before

in animals that are
going to go this deep,

and it can just go horribly wrong.

NARRATOR: Elephant seals
dive thousands of feet.

lf the Daily Diary works
under such high pressure,

we will witness a new era
of biological discovery.

Quintana identifies females to tag‒

at 2,000 pounds,

they're easier to deal with
than the 8,000-pound males.

Male or female, it's risky business.

And the colony is restless.

lt's up to Marcela Uhart
to anesthetize the giants.

UHART: Elephant seals
are so big and so powerful, you know,

they have very few predators.

They don't really fear us that much.

They actually challenge you.

[groaning]

[seal barking]

UHART: Tomorrow he's going to be
on his own, l think...

[growling]

WlLSON: l don't like this
being protective of your friend stuff.

l'd rather they just deserted them
and left them to it.

NARRATOR: They name the tagged seals
after submarines and space stations.

ln all, five females are successfully
rigged with Daily Diaries.

WlLSON: We have five.

lf we're lucky,
l think we'll get four back.

l sort of tip somewhere
between three and four.

And l'll just hope and pray
that they all are working okay.

NARRATOR: lf it goes well,

Wilson will be the first to tell
the story of this hidden journey.

These seals' ocean pathways
are nearly boundless.

But that is not the case
with many migratory routes on land.

As human populations grow
and habitats diminish,

the great migrating animals
are increasingly in peril...

particularly the monarch butterfly.

The monarchs' migration
spans generations of individuals

and is an astounding
4,000 miles long,

from Mexico to as far as Canada
and back again each year.

CHlP TAYLOR: This is one of the world's
most magnificent natural phenomena.

l mean, here you have
an insect that migrates

to the same general location
every year,

and then returns to breed
in the northern part of North America.

NARRATOR: Chip Taylor
has dedicated his life's work

to the ceaseless habits
of the monarch.

For 18 years, he's been
tracking the migration

with the same device:
a plastic tag.

And he's learned a surprising
amount from this simple tool.

ln one study, Taylor released
a monarch born in captivity

2,000 miles from its birthplace.

The butterfly still migrated
southwest to Mexico.

TAYLOR: These butterflies
have to navigate across a continent.

They have to navigate.

How does a butterfly
coming out of Maine

know how to get to Mexico?

NARRATOR: ln 2009, scientists
discovered the monarch's internal GPS,

a network of not one
but two internal clocks.

A clock in the brain
tracks the location of the sun.

And a second clock,
in the antennae,

keeps track of time.

TAYLOR: What they
are programmed to do

is follow and respond
to certain physical cues,

and these physical cues
have a default sort of mechanism

of getting them to the right place.

Now the trick for us is to try
to figure out what are those cues?

NARRATOR: Understanding these cues
has never been more important.

The monarch population is down
by halfjust from last year.

lts ancient flyway
is unrecognizable

as development
overwhelms the landscape.

And the milkweed plant
the monarch needs to lay its eggs

is vanishing.

TAYLOR: We're losing 6,000 acres a day
in this country due to development.

That's 2.2 million acres a year.

That's just an astounding amount
of habitat to turn into concrete.

And you just can't
keep on doing that

without having a really significant
impact on wildlife out there.

NARRATOR: Knowing how far
the monarchs fly each day

and where they stop
could save them.

An electronic tag that records
precise data could help.

But this creature is light as smoke,
and a tag is a heavy load.

Enter Martin Wikelski.

He's a migration ecologist,

leading the charge
to miniaturize tag technology.

WlKELSKl: The smaller
you can get the tag,

the more power you can output,
the better the study we can do.

And that's going to be
a total breakthrough

in our understanding
of the natural environment.

We need to understand
small animals

to understand life on Earth,

and that's what we still
have no clue about.

NARRATOR: With radio tags,

Wikelski followed the route
of a one-ounce thrush,

discovering how it
navigates at night.

Then he went smaller,
switching to insects.

His team designed
a tiny hearing aid battery

attached to an antenna
made of a guitar string.

The smaller the device,
the simpler the data.

This radio tag only tracked
location and direction.

But it was a start.

Wikelski tried it on bees.

They flew.

He tried it on dragonflies

and discovered that one migrated
a hundred miles in a single day.

But the monarch is
half the weight of a dragonfly.

TAYLOR: l first learned
about Martin's work a few years ago

when l heard of his studies

where he was putting radio tags
on dragonflies,

and l thought that was
pretty fascinating.

l thought, "Aw, man you'll never
get them small enough

to put them on monarchs."

NARRATOR:
Martin Wikelski's Kitty Hawk

is the butterfly house
in Constance, Germany.

WlKELSKl: Nice.

NARRATOR: The tag is the smallest yet,
half the weight of this butterfly.

WlKELSKl: Available radio tag,

and they just barely got it
in the size range

that the butterfly
might fly with it.

And now we just try it.

NARRATOR: Trial one: no go.

A slight antenna adjustment,
then trial two.

And liftoff.

WlKELSKl: Wow!

[laughing]

Oh, there it is.

lt's working.

lt's totally amazing, l mean,
the first flight of a butterfly with a tag!

So it's working, l mean, you see
it's just flying all over the place.

So l think it's going to work
in the field as well.

This is flying beautifully.

lt's amazing.

NARRATOR: Wikelski and Taylor
will now team up

to see if they are on the brink
of a new age of monarch science.

[rooster crows]

The migration ecologist
Martin Wikelski

finally meets
the monarch sage Chip Taylor.

Together, they'll conduct
the first test ever

of an electronic tag
on a monarch butterfly.

lt's a meeting of like minds...

but not when it comes
to catching butterflies.

TAYLOR: Come up behind the butterfly
while it's sitting on a flower.

What you don't want to do
is swing at them in the air.

WlKELSKl: Okay.

TAYLOR: Get it! Whoa!

l mean, he's like a little kid;
it's wonderful.

At my age, l don't do that anymore.

l prefer the sneaky method!

Looks like we got one here.

NARRATOR: The scientists
catch six in all.

Success will be determined

if the tags do not disrupt
the monarchs' migration.

And if the insects
can be found after takeoff.

WlKELSKl: l'll just get the transmitter.

NARRATOR: But Taylor has his doubts.

TAYLOR: One of the things
about these kinds of tests

is that you do them indoors,
you do them under ideal conditions,

and then we bring them
out here in the field,

and we're dealing
with 20-mile-an-hour winds,

and it's going to be
quite challenging for the butterfly

to figure out how to handle
all of this mass

that you're attaching
to the abdomen.

WlKELSKl: Now it's up to the butterfly.

TAYLOR: Well, we're not going
to name it lcarus, right?

WlKELSKl: Let's call it lcarus
and see if lcarus can fly.

WlKELSKl: Wow.

TAYLOR: Wow. lt's flying pretty well,
look at that.

WlKELSKl: That's amazing.

TAYLOR: lt's staying close
to the ground, though.

WlKELSKl: Wow, it's flying!

TAYLOR: All right, let's start
with liftoff here.

WlKELSKl: Wow!

TAYLOR: There she goes.

That's cool.

That's terrific, look at that!

WlKELSKl: Wow, it's really taking off.

TAYLOR: lt's really catching the wind.

WlKELSKl: lt's coming over to your side.

TAYLOR: Big Boy.

WlKELSKl: Wow, that's a big one.

TAYLOR: That's the biggest
butterfly we've got.

There it goes.

WlKELSKl: There she goes.

l think he still wants to feed.

[laughing]

NARRATOR: Taylor and Wikelski
take to the air, too,

in pursuit of the tagged monarchs.

With radio receivers in tow,
they listen for a telltale click.

WlKELSKl: We are looking
for liftoff right now.

NARRATOR: Each butterfly
is on its own frequency.

[click]

WlKELSKl: There it is, do you hear it?

We've got a signal.

NARRATOR: An auspicious start—
some signals come in loud and clear.

WlKELSKl: So liftoff is still
probably at the field down there.

NARRATOR: But the test is incomplete
until a butterfly has flown

more than a few miles
in a northeasterly direction.

TAYLOR: Martin, any sign of lcarus?

WlKELSKl: Nope, we will go
a little lower

and search closer to the ground.

TAYLOR: Let's hope it works.

[buzzing]

WlKELSKl: Yep, yep, there it is.

l do hear lcarus.

TAYLOR: Good old lcarus.

WlKELSKl: lcarus is down there, yes.

NARRATOR: All but one
are accounted for.

Big Boy is still missing.

TAYLOR: Martin, do you hear anything?

WlKELSKl: Nope.

NARRATOR: Perhaps he's
a long distance flyer...

or the weight weighed him down,
plummeting him to Earth.

Taylor and Wikelski
continue northeast.

Five miles out.

Nothing.

Ten miles out.

[buzzing]

And they get it.

WlKELSKl: That's the signal!

TAYLOR: That's fantastic!

[cheering]

[laughing]

TAYLOR: lt was incredible!
lt was unbelievable!

We got Big Boy
out there about 15 miles!

NARRATOR: There's one last step.

They need to find Big Boy
on the ground

to identify his stopover point

and find out if he's
still in good condition.

WlKELSKl: That's three miles out there.

TAYLOR: Yeah.

NARRATOR: They follow
Big Boy's radio signal.

Weaker.

Stronger.

WlKELSKl: ln a few hundred meters,
l think we should take a right.

[static]

NARRATOR: Weaker again.

WlKELSKl: No, that's not good.

Maybe we should have gone left
and then go north, l don't know.

TAYLOR: Big Boy's moved
out of town.

WlKELSKl: There it is,
l've got a signal.

Yes!

Okay, now we get it.

WlKELSKl: On this side
or the other side?

TAYLOR: lt's not appropriate for him
to say, "Come to me, Big Boy."

WlKELSKl: Hey! Here he is!

That's it!

[laughing]

TAYLOR: Fantastic!

WlKELSKl: Yes!

TAYLOR: Fantastic!
All right!

Good for you!

NARRATOR: A scientific breakthrough,
the first test of its kind.

Big Boy is found
in perfect condition.

WlKELSKl: lt's really perfect.

TAYLOR: Yeah, this antenna
is not an impediment at all.

WlKELSKl: No, no.

TAYLOR: Hot damn...

[laughing]

hot damn!

NARRATOR: The technology works,

and the future for these insects
as well as countless other animals

may soon be the better for it.

TAYLOR: Big Boy is ready to go,
go to Wisconsin,

find a girlfriend,
there he goes.

WlKELSKl: Yeah.

TAYLOR: There he goes, all right!

And look it, he's going northeast,
he headed out that way.

Right along the tree line, northeast.

WlKELSKl: A lot of people complain
that it's hard to discover things these days

because everything's known.

Absolutely not!

Everything's new.

Every time we look at it,
we see something new here.

NARRATOR: Taylor now has a new tool
in which to continue his life's work.

TAYLOR: l watch this population go up,
and l watch it go down.

l watch its life and death struggles
all of the time.

l'm so intimately attached
and involved with this butterfly.

And l don't know how
to explain it any other way.

lt's just what l am,

and that's about all
l can say about it.

NARRATOR: Migration is
seldom attempted alone.

But there's more than safety
in numbers.

For mathematical ecologist John Fryxell,
migration is math in motion.

Where we see animals,
he sees mathematical patterns.

And he's using these patterns
to unlock the key

to wildebeest survival
and migration.

FRYXELL: l think migration
is kind of a theme in my life.

There's just something about mobility
that fascinates me.

The urge to try and predict
patterns of movement

to me is just really intriguing.

NARRATOR: ln the Serengeti
grasslands of Tanzania,

wildebeest are on
their 300-mile journey.

This annual event is among
the great natural spectacles on the planet,

as herds of zebra, gazelle
and wildebeest

chase the rain
and the grass it nurtures.

But the wildebeest
pay a hefty toll...

five out of six young
don't make it.

And yet the herd
is a million strong.

Fryxell is determined
to figure out how‒

despite these odds‒
the herd thrives.

He begins by observing
the wildebeest behavior from the air.

From up here, he can see
the patterns of the herds.

FRYXELL: We can see a hyena
over there heading over to the track.

Certainly there's some complex dynamics
within the whole herd of wildebeest.

Well, the interesting thing
during the migration

is it's a series of individuals,
one after the other,

following blindly behind
the movement of a key individual.

l mean, this is, you know,
really interesting,

this kind of streaming behavior
of the wildebeest,

you know, going forward.

Clearly there are some individuals
that are at the front of the line.

The behavior of some leaders

gets translated to the rest
of the group,

and then the group behaves
like a super organism.

NARRATOR: Wildebeest
as super organism‒

individuals affecting
the behavior of the whole.

Fryxell then looks at what forces

shape the migratory path
of this super organism.

He suspects the key to why they survive
in such great numbers is here‒

starting with an insect.

The dung beetle thrives
on wildebeest manure,

which it collects into balls
and stores underground,

fertilizing the soil...

allowing more wildebeest
to graze.

Millions of mouths
mow the grass,

keeping trees in check,
but allowing brush to grow.

Forming the perfect cover
for predators that eat wildebeest.

lt all leads, in the end,
to the predators.

Fryxell believes predators‒
more than anything‒

shape the herd's patterns.

And his team takes
a closer look at the lioness.

MAN: Okay.

[fires rifle]

FRYXELL: Nine, so now we move
to the upper right canine.

NARRATOR: The GPS on the collar
will allow the team to track its movement.

An accelerometer records
her every start, stop and speed,

which tells when the hunter rests,
prowls or takes to the chase.

FRYXELL: Five, six,
seven wildebeest...

NARRATOR: Using
on-site observations...

FRYXELL: ...21 wildebeest.

NARRATOR: ...data from collared predators
and collared wildebeests,

Fryxell can build
mathematical models

that predict the behavior
of predator and prey.

lt reads like a video game

where he can create different scenarios
between lions and wildebeest.

First, Fryxell conjures up
wildebeests that do not herd.

He spreads them out
like marbles over the landscape.

Then he lets a simulated lion loose.

FRYXELL: There's a kill,
and another kill.

And the net result is that it's very easy
for the lion to encounter fresh prey,

so with that very high
density of prey,

you see the lion doesn't even
have to go very far

before it finds a new meal.

NARRATOR: ln this model,
the wildebeest do not stand a chance.

The next simulation more closely
models a typical herd's behavior.

FRYXELL: Grouping together
creates great big vacant areas

that aren't very efficient
for the lion to search in.

NARRATOR: Here, the wildebeest
evade predators

by grouping together and forming
what he calls holes in the landscape,

vast areas where a lion
can't see a wildebeest.

The super organism
then goes a step further:

the holes in the landscape move.

FRYXELL: Well, when you're
the best meal on four hooves,

the best thing you can do
is be unpredictable.

The last thing you want to be

is a meal where the lions
expect you to be.

NARRATOR: Lions know
when seasonal herds

pass through their territory,

but they won't know
exactly where to find them.

FRYXELL: So we can see this
on this map of the Serengeti ecosystem,

where the bright colors signify
really high densities of animals,

large herds that are shifting
without any kind of predictable pattern

across the landscape
from month to month.

Now imagine that you're
a lion or hyena

trying to make a living
in that kind of landscape.

lt's virtually impossible
for you to know

what would be the best place
for you to set up a territory.

NARRATOR: The herd
as super organism,

and the surprisingly random
nature of its movement,

keep a predator guessing,

keeping the wildebeest
a million strong.

But this ingenious
survival mechanism

could never work
without a large habitat.

And large habitats
are increasingly rare

as humans encroach
on wild spaces.

For many of the world's
migratory animals,

this is the main threat
to their survival.

ln Mali, West Africa,
the desert elephant

once roamed vast distances
unimpeded.

Now the last animals
of their kind are under threat.

Tracker El Mehdi Doumbia
and biologist Jake Wall

from the organization
Save the Elephants

have collared nine
of the 350 elephants here.

The more they can learn
about the herd's habits...

WALL: Good, fresh tracks.

NARRATOR: ...the better they will be able
to protect their migratory routes.

WALL: These elephants
don't give us a moment to rest,

they keep moving,

we keep having to work
really, really hard

to try and find them,

and, even with the tracking data,
it's not an easy job.

NARRATOR: The only way
the Mali elephants can survive

is to move.

They walk endlessly over a home range
of over 12,000 square miles

in the harsh heat of the Sahel.

No other elephants travel farther
in search of food and water.

During the dry season,
they end up here.

Lake Banzena is one of the few places
to find water year round.

The herds linger
until distant rains begin.

Elephants can hear rain fall
vast distances away

because of its low
infrasonic signal.

Then, within 24 hours,
they go to where the rain is.

And this year,
water is most critical.

lt is the worst drought in 26 years.

The herd must move fast,

because between the lake
and the next stopover point

lies 60 miles of desert...

and a big obstacle:
the Gandamia Plateau.

There's just one way through:

la portes des elephants,
the elephants' door—

a cut in the mountain the herds
have been using for centuries.

lt's also a place with
increasing human settlement...

and where elephants compete

with herders and their animals
for water.

These images capture
a dramatic scene

as villagers and
a Save the Elephants team

desperately try to rescue
a teenage female and three juveniles.

They fell, one after another,
into a man-made well searching for water.

The older elephant crushed
and killed a younger one

during the three-day ordeal.

These tragedies happen as humans
settle on ancient elephant paths.

But 3,000 miles to the east,
in the grasslands of Kenya...

lAlN DOUGLAS-HAMlLTON:
l am just going to put a little bit of water

on the back without splashing.

DABALLEN: Don't step
on the ears, please.

NARRATOR: ...a solution
is being tested.

Biologist lain Douglas-Hamilton
has gained near legendary status

for being the African elephant's
custodian.

DOUGLAS-HAMlLTON: You don't think
that's too loose?

We're collaring elephants

because we believe
that by understanding their movements,

we can understand
their decisions.

And if we understand their decisions,
we understand what they need.

Elephants are at a tough time now,
and we have to plan for their future.

NARRATOR: Over the years,
Douglas-Hamilton has witnessed first hand

the disastrous consequences
of human-elephant conflict.

Poaching for ivory tusks was once
the chief killer of elephants.

Today, it's farmers
who protect their crops.

Douglas-Hamilton
with his wife Oria

founded Save the Elephants
40 years ago

to study and protect this
severely endangered species.

This rustic outpost
is the repository

of the organization's studies
on elephants

from all over the African continent...

information that scientists
throughout the world

have come to rely on.

DOUGLAS-HAMlLTON: lt's actually
a kilometer wide.

lt's working well.

NARRATOR: Today, the team
is collaring an elephant

with a state-of-the-art device
that might save its life‒

a tag that sends an alert
when the animal nears a farm.

DOUGLAS-HAMlLTON: Many elephants
across Africa get shot

because they cause damage
to human property,

to crops, to livelihoods,
and indeed they kill people.

And you want every high-tech option
that you can deploy.

NARRATOR: lain Douglas-Hamilton
searches for a herd,

scanning the landscape by air

while researcher David Daballen's
team is on the ground.

DOUGLAS-HAMlLTON:
David, David!

DABALLEN: Sorry, lain?

DOUGLAS-HAMlLTON:
Where l am circling

there are two groups of elephants
tightly under the trees.

DABALLEN: He has found them
in a perfect place.

We don't want to lose them,

because they are not quite often
at the moment around.

We want to take the opportunity
to dart them, put a collar,

because we know that
from our past experience

they will defend so much.

And if we have four cars

we can position ourselves
in different positions

to make sure that the females

will not see the female
that has gone down.

NARRATOR: They identify
the female to be collared.

DABALLEN: Dart in.

She's down, she's down!

Let's get a good position.

Drive.

Drive, drive!

NARRATOR:
Once she's unconscious,

Daballen has only 20 minutes
to attach the collar.

The anesthesia makes
the trunk muscles go slack‒

a stick will keep her airway open.

This particular collar will do

what Douglas-Hamilton
once only dreamed of:

lt will allow an elephant
to communicate with him.

The collar sends its alert
to a cell phone via text message.

This high-tech innovation
is called geofencing.

When an elephant crosses
a virtual fence line,

the GPS unit in the collar
sends an SMS or text message

to a server in Nairobi.

The server then sends text alerts
to a list of recipients

who can quickly intercept the herd

before it reaches a farm
or human settlement.

DABALLEN: Get in the car!

NARRATOR: The female awakes
groggy but unharmed‒

the collar fits perfectly.

She will blow out the stick
in her trunk,

but for now it assures her
an open airway.

DOUGLAS-HAMlLTON: Sometimes
when you have dense agriculture,

the best thing you can do

is to separate the people
from the elephants.

When an elephant crosses
a certain boundary,

we get an alarm to be set off,

and it gets sent to us
on a mobile telephone,

which allows us to plan much better
how to cope with the crop raiding.

This is really cutting-edge stuff.

NARRATOR: Geofencing is still
in the testing phase,

but Douglas-Hamilton
believes this is the future.

But there is a terrible setback.

A torrential storm causes the banks
of the Ewaso Ng'iro River to crest,

creating the worst flood in memory.

Save the Elephants' research center
is all but gone.

Most of the buildings and much
of the decade's long research

DOUGLAS-HAMlLTON: Well, this flood
has had a terrible effect on our work.

First of all, it's caused

hundreds of thousands of dollars
worth of damage.

l don't know how we're gonna
get the money to rebuild,

but we've also lost some data,
which is particularly precious to us.

NARRATOR: But Douglas-Hamilton
and his team are determined

to dig themselves out
and start over again.

DOUGLAS-HAMlLTON:
We've got to carry on.

Our mission is to secure
a future for elephants.

l've been working
on elephants for 43 years,

and it's all to save
the elephants.

So we're not going
to give up on that.

NARRATOR:
As Save the Elephants recovers,

the Mali elephants
survive the drought.

And Douglas-Hamilton with his team
will continue tracking elephants,

working to preserve
their ancient paths.

DOUGLAS-HAMlLTON: l think
the worst-case scenario

would be a cutting
of the migration routes,

completely cut off
from their water supplies.

lt would then only be
a matter of time

before the elephants
had nothing to live with.

That would be my
worst-case scenario for Mali.

But it's not going to happen.
We've got to prevent it.

NARRATOR: Working in the natural world
is always a gamble.

Science needs data,
and if nature doesn't cooperate,

data will get destroyed, eaten
or swept out to sea.

ln Patagonia, the scientists return,
hoping their gamble pays off.

The elephant seals have returned
to molt after two months at sea.

With good fortune,
the five Daily Diaries will return, too.

Flavio Quintana's team use GPS

to find out when
the tagged seals arrive...

and where they settle
on the beach.

Over the course of a week,

the team retrieves
four out of the five tags.

Each Daily Diary
is perfectly intact.

7,300 miles away, Rory Wilson
at his lab in Swansea, Wales,

begins to read
the much anticipated story‒

the secrets of the seal migration.

WlLSON: You know, you're opening
the book on it for the first time,

it's an incredible thrill.

Stuff happens that you wouldn't
believe in your wildest dreams.

NARRATOR: First, Wilson reconstructs
the movement of the seal named Mir.

WlLSON: This is the moment

where Mir comes off
the continental shelf, the platform

and goes down
into the deep water,

and you can actually see this
in her depth traces...

and they get deeper and deeper.

NARRATOR: Mir's deepest dive
was nearly half a mile,

an acrobatic feeding frenzy.

WlLSON: The animal was in free fall,

the body was in all these
extraordinary ballet-like postures.

And you think, whoa, l never
thought elephant seals did that!

NARRATOR: Then Wilson looks
at how the seal swam

as it traveled great distances.

He compares its sway—
side-to-side movement...

WlLSON: So these are the tail beats,
and the glide,

and the tail beat
and the glide...

NARRATOR: ...to the surge‒
vertical and horizontal position.

WlLSON: And as the tail beats occur,
the animal's pointing up,

and when she glides,
she points down.

So up and down.

NARRATOR:
Then calculates pressure

to determine the depth
and length of her dips.

WlLSON: And the interesting thing
is she's doing exactly the same thing

as sparrows do when they fly
or some of these small birds.

NARRATOR: To his surprise,
elephant seals are behaving like birds:

they fly underwater.

This is how they
conserve energy.

Small birds flap their wings
to gain momentum when flying up,

and hitch a ride
on the current going down.

WlLSON: You see small birds
flap, flap, flap, flap and glide down,

flap, flap, flap and glide down,

and that's a way of saving energy.

An animal as big
as an elephant seal does it,

and an animal as small
as a sparrow does it as well.

NARRATOR: Both the small bird
and the enormous elephant seal

evolved to conserve energy
in similar ways.

WlLSON: Energy is critical for animals,
for their survival...

but they spend it in going out
to get stuff to feed.

So this balance of energy expenditure
against energy gain

on migrations or off them

is something that's
really critical to animals.

And as we go gleefully
through the planet

and change everything,

we really need to be
considering that.

NARRATOR: For the first time,
we are able to witness the elephant seal

as it journeys through the ocean.

WlLSON: Lovely data, aren't they?

Really beautiful, beautiful stuff
that comes out of this tag.

NARRATOR: With inventions
like the Daily Diary,

the invisible is becoming visible.

lt is in these details

where the true secrets
of the elephant seal reside...

revealing how this great wanderer

can survive its long trek
through the southern seas.

Wilson and his colleagues
won't stop here.

They will continue to test.

WlKELSKl: Wow, it's really taking off.

TAYLOR: lt's really catching the wind.

NARRATOR: lnvent...

DOUGLAS-HAMlLTON:
We get an alarm to be set off.

NARRATOR: ...break new ground.

And with each technological advance,
the science of the great migrations

gives us a larger understanding
of our world.

WlLSON: lt's a little bit frustrating
that the Daily Diary is still as big as it is.

l still want it to be smaller,
l want it on swifts,

but there's no limit to that.

When are you going to stop?
Ants, you know?