Nova (1974–…): Season 46, Episode 23 - Animal Espionage - full transcript

Camera traps and drones offer an up-close look at animals without disturbing them, providing insight into the secret world of animals such as whales, tigers, and giant armadillos.

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From frigid oceans...

Okay, there he is.

...to distant jungles...

You can keep going
a little bit more.

...there's a hidden world

of exotic creatures

just out of view.

Finding the animal is
like looking

for a needle in a haystack.

It's really difficult.

Around the world,



researchers are tracking
the most vulnerable animals,

trying to save them
before they vanish forever.

This powerful-looking animal
is so fragile.

The pieces of knowledge
that are needed

to make it survive

are critical.

Now, new technology

is revealing their secret lives.

They're really
silent little spies

that make no noise,

that can capture
intimate moments of the animals.

You get millions and millions
of photographs,

and you suddenly see things
for the first time.

Frame by frame,



the invisible world of animals
is coming to life.

I could not believe
this species existed,

that it was right here,
around us.

I had no idea they did that.

Their habits, fears,
and most intimate moments.

It has completely revolutionized

our ability
to understand behaviors.

Rare footage
from the animal kingdom

is offering up new clues.

Can we uncover the secrets
to these animals' survival

before it's too late?

"Animal Espionage,"

right now, on "NOVA."

Major funding for "NOVA"
is provided by the following:

Our planet is teeming
with millions of species,

yet we've only been able to
study a small fraction of them.

In this hidden world,
much goes unseen...

until now.

Advances in camera technology

are opening our eyes
to the world around us.

The invaluable information
that people will get

from a simple,
wee, little camera

that anybody can buy
off the shelf,

it's unbelievable.

What can researchers learn
by spying on animals?

Why are they doing that?

And why did they do that?

And what are they going
to do next?

Can a new wave
of animal surveillance

turn the tide

and help preserve our planet's
most vulnerable species

before they disappear?

Cumberland Sound, Canada,

about 300 miles west
of Greenland.

Beneath these frigid waters
dwells a mysterious giant...

the bowhead whale.

Little footage of
these 100-ton creatures exists.

They are the longest-living
mammal on the planet.

Some have reached
the ripe old age of 200.

But their survival
isn't guaranteed.

The species could be in trouble.

They're living in the Arctic,
and this is a place

where climate change could be
threatening their, their future.

Marine biologist Sarah Fortune
studies bowheads

in Cumberland Sound,

where the whales come to feed
for months at a time.

But rising temperatures
and melting sea ice

are affecting
their primary food source...

tiny animals called zooplankton.

Bowheads favor
a nutrient-rich variety,

and their numbers are dropping.

This could be catastrophic
for the whales:

one bowhead needs to eat about
100 tons of food each year.

I need know what the whales
are feeding on today

and how energy-rich
their current food resource is.

Monitoring their size
and weight over time

will tell Sarah if these whales
are getting enough to eat.

But tracking them
is no simple task.

Bowheads are
a little bit elusive.

They dive for half an hour,
an hour.

You spend a lot of time waiting
for them to come up again.

And then it's also,
can be really difficult

to track where that whale
has gone.

Okay, there he is.

Even when they find a whale,

it's hard to see
its entire body.

We see what everyone else sees...

the top of the whale's head,
their flukes,

sort of, a really small
proportion of the whale's body.

And so that means that a lot of
their behavior goes unknown.

Fortune and
her colleague Bill Koski

are monitoring a group
of about 80 bowheads

in Cumberland Sound.

A bowhead expert, Bill is eager
to get a new perspective

on an animal
he's been studying for decades.

Most of the studies I've done,

I've been flying in an airplane,

and we're circling whales
at a thousand feet or so,

so that we won't affect
their behavior.

Any closer, and a noisy plane
spooks the whales,

who will dive and disappear.

Is he up now?

So Sarah is trying
a new approach.

She's going spy on the whales

with a-state-of-the-art
high-definition drone.

All right, full power.
Okay.

Awesome.

The drone quietly hovers
just above the whales.

They seem oblivious to the
flying camera following them.

It's exactly analogous
to a bird.

The same level of reaction

that you would get from
a bowhead having birds overhead

is what you get
with a drone being overhead.

Finally, they can see the whale
in its entirety.

Its body tells a story about
day-to-day life in the Arctic.

They often need to break
thick ice with their heads.

And so, we'll see
that they have white scars.

The scars are like fingerprints,

allowing scientists to identify
and track individual whales.

The drone helps
the team measure the whale

by comparing its body
to the length of the boat.

That gives us an idea of how fat
or how skinny an individual is.

And that's a way that we can
assess their overall health.

So, are these whales getting
enough food to eat?

Over time,
we can monitor these animals

to see how healthy they are

in the face
of a changing environment.

When the whale dives
below the surface to feed,

the drone keeps an eye on it.

Because the water is
so clear here,

it provides this really
wonderful opportunity

to observe their behaviors
over long periods of time.

Otherwise, we would just be
sitting on the boat

wondering
where the whale had gone.

Now, clear water
and a bird's-eye view

reveal new insights
into bowhead behavior.

Biologists used to think that
bowheads were solitary creatures

that sometimes swam in pods,
but rarely interacted.

The whales were constantly
touching each other.

And before, there was no way

that we could have seen that,
right?

It was illuminating
to see how these animals

are more social
than we could appreciate

just by observing them
at the surface.

We're able to see how that whale
is engaging with other animals,

how it's engaging
with the environment.

So I think it has completely
revolutionized our ability

to understand
bowhead whale behaviors.

For scientists like Sarah,
the drone is a window

into the lives of these
mysterious creatures

and a way to gauge their
survival in a changing climate.

When the Inuit's ancestors
first settled Baffin Island

thousands of years ago,

the surrounding waters
were teeming with whales.

By the late 19th century,

the commercial whaling industry
had nearly wiped them out.

Today, the Inuit are among the
few communities in the world

permitted to sustainably hunt
bowhead whales.

The Inuit in this region take
up to five whales per year.

A single bowhead will feed
hundreds of people.

Sarah is sharing her research
with the board

of the Hunters and Trappers
Association,

which manages hunting.

They're concerned about the fate
of the 6,500 bowheads

in this area of the Arctic.

If anyone has any
suggestions or questions

that you think we could answer

with this technology,

that would be really helpful
to know.

The images yield new insights

that intrigue even the locals,

who have lived with these whales
for decades.

What part do you study
in order to get the age?

Based, based on our experience
with the photographs,

the amount of white
just in front of the tail,

it gets more and more white
as they get older.

So when you see one

with lots of white on it,
you know it's a very old whale,

probably 150 years or so.

Knowing the size and age
of the whales around here

helps locals plan for hunts

that leave enough whales in the
ocean for future generations.

There's one question

that fascinates both locals
and scientists.

Year after year, the bowheads
gravitate toward the shore

and hang around
the big rocks there.

No one knows why.

Sarah is hoping the drone
will explain a mystery

first recorded
more than 170 years ago.

Ricky Killabuck,
an Inuit fisherman,

brings them to the site.

So have you seen any whales
in this bay this year?

- Oh, yeah, yeah.
- Yeah? Okay.

If you go back to the whaling
records dating back to 1845,

whalers had made note

that these whales
would go near shore,

and they'd rest their heads,
or their chins,

upon these large rocks.

Going along this coast,

we've been seeing whales
along the rocks

in this area.
Okay.

Some people thought
that they might be feeding.

Others thought
that they're resting.

Without a clear view,
it was impossible to know.

Around our 11:00.

So we have a whale up ahead.

We're heading towards it now.

Set that camera out to the aft.

Full power, go.

So then, I think you're going
to want to bring it

to our 11:00 here,
maybe to the bow.

It's starting to come shallow.

Mm-hmm, it's coming.

This whale seems to be
scratching his back

against the rocks.

Now we know that the whales
aren't just coming here

for feeding purposes.

They're also coming here
for molting purposes,

rubbing on these large boulders
as exfoliation,

so to help expedite
the molting process.

The best guess is they're trying
to keep their skin healthy

and free of parasites.

The drone reveals
Cumberland Sound,

with its shallow rocks
and plentiful zooplankton,

to be a critical
bowhead habitat.

Yet it's also a place
destined to change.

These are whales
that will be impacted

in one way or another
by environmental change.

We don't know
if it's going to be detrimental,

we don't know if these whales
will be very adaptable,

but we know that things are
going to change,

just like they're going
to change

for the people in the North

that are living
in these communities.

For now, keeping a close eye
on these giants of the Arctic

is critical.

The really big win about drones

is that we're able to collect
a lot of data about the whales

with zero impact to them.

And so, I think this is
a very positive step forwards.

Great, awesome.

Thanks so much, guys.

For more than 100 years,

we've used cameras to try
to capture the natural world

as it truly is,
away from human eyes.

In the late 19th century,

an ambitious young photographer
named George Shiras III

pioneered the field
of spying on animals.

Using crude trip wires
and flashbulbs,

he was the first
to photograph a hidden world.

He roamed North America,

photographing predator
and prey alike.

Published in
"National Geographic" in 1906,

his images were
the first of their kind

ever printed in that magazine.

The experience turned Shiras
from a hunter and fisherman

into a conservationist.

He pushed for the creation
of parks and policies

to protect the wildlife
he photographed.

Years later,
scientists like Arnaud Desbiez

are perfecting Shiras's
camera-trap system,

trying to capture images
of creatures

that few people
have ever laid eyes on.

The animals Arnaud seeks

live in the Pantanal region
of Brazil,

far south of the Amazon River.

At nearly 75,000 square miles,

it is the world's
largest wetland

and home to
some fascinating creatures.

You could also say that the
Pantanal is the land of giants.

Here we have giant otters,

giant anteaters,

the largest jaguars.

And of course,
the giant armadillo.

The giant armadillo,
which practically no one...

not even among
the local population...

has ever seen.

The giant armadillo is almost
like a ghost species,

the Holy Grail of, of animals.

They occur
at very, very low density,

and they're very, very hard
to find.

They are a nocturnal species,

so to follow them at night
is almost impossible.

There are more than 20
different species of armadillo

all across the Americas,
some as far north as Nebraska.

Like their anteater cousins,

armadillos dine mostly
on insects and grubs,

which they dig for
with powerful claws

and lap up
with sticky, long tongues.

A shell of overlapping
bony plates

protects them from predators.

The smallest of the species

could fit in the palm
of your hand,

while giant armadillos
can grow to be as big

as a Labrador retriever.

But so little is known
about them.

How many offspring do they have?

How do they communicate?

Are they thriving
or doomed to extinction?

Arnaud is hoping to find out
by setting up cameras

right outside their homes.

Finding a giant armadillo burrow

is like looking for a needle
in a haystack.

It's really, really difficult.

Individual giant armadillos are
thinly scattered

across the Pantanal,

sometimes as few as seven
in a 40-square-mile area.

So Arnaud has placed thousands
of camera traps like this one

all over the wetlands.

A camera trap is essentially

a device that you can place
anywhere.

And when something passes
in front of it,

it will take a series
of pictures and videos.

This is the part
I really want to get.

So, I'm going to get
the motion sensor to work.

Then, he waits.

So, the camera traps are,
for a field biologist,

what a microscope is
to a microbiologist.

It helps us see things that
we can't see with our own eyes.

The camera traps are basically
our eyes in the field.

Weeks later, Arnaud and
his team review the footage.

Frame by frame,

the hidden world of the Pantanal
comes to life.

But no sign
of the giant armadillo.

After sifting
through hours' worth of footage,

the star finally appears.

Do you remember
when you were a child

and you saw your first image
of a dinosaur?

That's how I felt the first time
I saw an image

of a giant armadillo
from a camera trap.

I could not believe
that this species existed,

that it was right here,
around us.

Arnaud's fleet of camera traps

has revealed much
about this prehistoric creature.

We were able to document
the role of giant armadillos

as ecosystem engineers.

Giant-armadillo burrows
are used by other species

as a refuge against predators,

as a refuge
against extreme temperatures,

as a place to forage.

We suddenly were able
to register

a whole community of animals
using giant-armadillo burrows.

And that giant sand mound
outside their door?

It's like their inbox,
where they leave messages,

because when they dig,
they defecate and urinate.

The giant armadillos,
which are solitary creatures,

will communicate
and learn about each other

in, from the sand mound.

Leaving a camera trap
in front of the sand mound,

we can find out
who's coming to visit.

And the camera traps caught
something

never before recorded on camera.

A baby giant armadillo.

It was an incredible experience

to be able to see
this tiny little white shape.

They have no coloring.

You can tell
that the shell is soft,

and they're a little bit clumsy
the way they move.

The scientists nicknamed
the baby

Alex.

All of us got extremely attached
to this little giant armadillo,

with whom we actually had
no physical contact.

Our whole relationship
was through these images.

Every time we came to the field,
it was an exciting moment.

"What is Alex going
to be doing now?

How has he progressed?"

Thanks to Alex,

scientists estimate
that giant armadillos

have just one offspring
every three years.

The babies nurse for a year

and live with their mothers
for 18 months.

Parental care
is much, much longer

than we could ever
have imagined.

And so, we were able
to follow that...

time spent inside the burrow,

time spent outside the burrow.

And so those measures of time,
now, today,

help us to estimate the age
of a baby giant armadillo,

because we related those
to the age of Alex.

Arnaud shared Alex's story
with the public.

Soon, everyone was hooked
on the day-to-day life

of this vulnerable
baby armadillo.

I remember telling them

when he predated
his first termite mound.

I remember when he dug
his first burrows.

We were almost like
you'd celebrate

a child's first achievements;

we were doing that with Alex.

After a few months living
on his own,

Alex's story took a sad turn.

One day, we saw

that he had entered one
of his mother's old burrows.

So we set a camera trap
in front of the burrow,

but he didn't come out
that night.

And he didn't come out
the night after.

We saw a vulture land
in front of the camera trap.

I went and put my face
against the burrow,

and I smelled a rotting,
nasty smell from the burrow.

A necropsy revealed
a mortal wound in his shoulder.

Only one animal in this area
could inflict such damage:

the puma.

News of Alex's death hit hard.

There was an outpouring
of public sympathy.

This little armadillo had
actually become

quite the ambassador
for, for his species.

People were able to understand
how vulnerable this species is,

and how easy it is
to locally extinct

a population
of giant armadillos,

because any threat...
whether it's habitat loss

or hunting or roadkill...

will have a huge impact
on the species.

That impact is already evident.

In the past 25 years,
the giant armadillo population

has likely declined
by at least 30%.

In eight years,
Arnaud's camera traps

have captured
just 50 giant armadillos.

Each one needs monitoring.

So now we just applied
the anesthetic.

We're going to wait
a few minutes

for the animal to fall asleep,

and then we'll take him out for,
to start the procedure.

Arnaud and his team
will tag, track,

and spy on this young armadillo,
like they did with Alex.

It's a highlight of our project.

This is a moment
we get to interact

and get to meet the species
we hardly spend any time with.

We're actually like paparazzi,

we're spying on the animal
the whole time.

So, for us, yes,
it's like meeting a celebrity.

It's a, this is a highlight
for us.

It's very, very exciting.

Today, state authorities
in Brazil

use the giant armadillo
as a guide

when planning new parks
and protected areas.

The goal is to keep
this species' habitat intact.

Arnaud's camera trap data
is a key piece of those efforts.

We will try
to estimate densities

and find out
how many are still left,

so that we can find out,

are there enough
giant armadillos for the future,

or are these populations
already ecologically extinct?

And so we want to inform
conservation measures,

such as habitat protection,
creation of corridors,

so that we can protect
giant armadillos

for generations to come.

Remote cameras introduce us

to species rarely seen
by the human eye,

and invite us to see the world
from a different point of view.

Location's coming up
just over this next ridgeline.

Research scientist Art Rodgers
is headed

into Canada's boreal forest,

a large swath of mostly
coniferous trees and bogs

stretching across the country.

It's home to rare
and endangered animals,

including a subspecies
of reindeer,

the boreal woodland caribou.

Caribou roam across Europe,
Siberia, and North America.

Where's the antenna?

It's in my pack.

Here, in Ontario's
boreal forest,

there are just 5,000
boreal woodland caribou left...

and they are hard to find.

These caribou generally
don't occur in large numbers.

They're fairly solitary animals,

moving in relatively
small groups

of maybe five to ten.

Industrial development poses

a serious threat
to these caribou.

They need vast areas
of intact forest to survive,

and that land is disappearing.

Art wants to figure out
which habitats need protecting

to ensure the caribou
don't go extinct.

One of the key things we,
we need to know about caribou

is their food habits.

We know that caribou are eating
lichen through the wintertime.

So, we wanted to find out

what caribou were eating
during the summertime.

What kinds of habitats have
the food that they really need?

These caribou roam across
100 square miles or more,

and are hard to track.

Camera traps are not an option.

So, one of Art's colleagues
came up with an idea:

why not hitch a ride
with the caribou

and watch them eat?

Huh, oh, there it is.

We were close.

Ah, good place for it.

This lightweight collar

contains a small camera and GPS.

The leather, the belting
isn't chewed too much.

Six months ago,
researchers placed it

around the neck
of a captured caribou.

The camera is programmed

to take a ten-second clip
every ten minutes

for two hours in the morning and
two hours towards the evening,

during the times of day

when we know that caribou are
likely to be feeding.

Yeah, we got the collar.

Art is hoping the footage
on this camera will reveal

everything he wants to know

about where and what
this caribou ate.

Oh, here we go, look at this.

Not Oscar-winning
cinematography,

but to Art,
the footage is simply amazing.

Wow, look.

We can see this.

We can actually see
what they're doing.

We can see what they're eating.

It allows you
to accompany the animal

on its journey through life.

Finally, Art and his team can
see what caribou are munching on

during the summer.

The result is surprising:

more lichen.

We thought, well, once,
you know, the world turns green,

and all the other plants
and leafy vegetation comes up,

that they would switch on
to the, the easy stuff,

relatively speaking.

And relatively more nutritious.

But the way they eat it
in the summer is unique.

They graze along the top
of the lichen mat,

and maybe just take
the top centimeter or two,

a couple of centimeters, sort of
the newest growth on the lichen.

And in a sense, you can call
that sort of farming the lichen.

They're leaving some behind
to grow back for another time.

And the cameras turn up
more surprises.

Caribou like mushrooms.

It's quite amusing to watch

a caribou walking
through a forest,

feeding on these large mushrooms

and basically just
picking them off.

Oh, there goes another mushroom.

And another one.

There's just no other way

we would have known that
or seen that,

and no one ever has,
till we got these videos.

With fresh water scarce
in the winter months,

caribou wash their food down

by mushing up snow and ice
with their hooves,

a behavior Art calls slushing.

The cameras create caribou
home movies of entire herds,

including its newest members.

One of the most
exciting moments was

the first time we saw a newborn
calf in one of our video clips

trying to stand up
for the first time,

and mom drying it off.

It gave me the impression
right away that,

"Gosh, we're going to see
all kinds of wonderful things

"that we would never, ever,
ever see any other way

than without having these
video cameras on the collars."

One key discovery:

certain habitats
are especially important

for calf-bearing and -rearing.

New mothers stick close
to the forest's lakes and bogs,

with nearby islands.

If mom senses a predator,
she can swim her calf to safety.

Over the course of eight years,

scientists have mounted cameras
on dozens of caribou here.

They can see the boreal forest
as a caribou would

and understand which areas
it needs

to survive.

And when we know
what those habitat types are,

we can start planning for those,

in terms of, of land-use
planning and forest management

and other industrial
developments,

and make sure
that there is enough of that

to conserve caribou
on the landscape.

Camera technology
is opening our eyes

to the hidden lives of animals.

But what can it tell us
about not just one species,

but an entire ecosystem?

We need hundreds of cameras
in this area if we can get it.

Biologist Craig Packer has
traveled all over Africa,

studying wildlife in the
continent's parks and reserves.

And it's clear to him
the animals are in trouble.

A lot of the research all points
to the same thing:

that wildlife populations
are declining quite rapidly.

In Africa, elephants,

lions,

wild dogs,

and the black rhino

are just a few of the species

whose numbers have plummeted
in the past 50 years.

Habitat loss and poaching

are the biggest threats
to their existence.

Different countries are tackling
these problems

with a variety of methods,

in the hopes
of saving their wildlife.

But how can anyone know

which conservation methods
are actually working?

What I know as a scientist is
that we have to measure things.

So we want to make it possible

for people to have
readily available to them

reliable information
on the abundance and the trends

in all of the species
within their reserves.

So Craig had an idea.

What if you took a census

of all the wildlife parks
and reserves in Africa

to get a clear picture

of animal populations
and conservation methods?

I'm aiming for this program
to include camera grids

from 50 different sites.

This will be able
to provide data

that we can use to assess
how things are going

in terms of the conservation.

We've got literally
thousands of these cameras

being set up all over Africa.

Just have to make sure
we know where we are and when.

So we're in
the Klaserie Reserve,

this is camera K013,

and this is the 22nd of July,
I hope.

This is the 23rd of July.

So we'll have camera-trap grids
in Kruger Park,

Mountain Zebra National Park,

Maasai Mara in Kenya.

There's cameras in Ruaha
in Tanzania.

There are cameras
in Niassa Reserve in Mozambique.

Thousands
of motion-sensor cameras,

powered on 24/7
for weeks at a time,

watching everything.

They will show
that what may look

like a tranquil
savanna landscape

is actually an ecosystem
teeming with life.

The cameras reveal
where zebras gather...

The gentle intimacy
of elephants...

And an antelope's
curious nature.

But the cameras were snapping
photos nonstop.

The practicalities
were daunting.

We were generating millions
of photographs.

How do you make scientific sense
out of so many images?

Then, Craig's graduate students
came up with a solution:

the internet.

They would upload
all their photos

and ask the world for help.

And you could have volunteers
from all over the world

look at your data
and then help classify it.

More than 140,000 people
from all across the globe

have participated
in Craig's project

as citizen scientists.

There is a real community

around the camera-trap process

that involves
a broader segment of society

than we ever could have
otherwise.

So far, millions of pictures
and over 50 species

have been IDed and catalogued.

The citizen scientists have
helped discover behaviors

that had been mysteries
to biologists,

like relationships
between major predators.

After a very large number
of observations of lions

at these cameras,

we never saw a cheetah show up
at the same spot

less than 12 hours afterwards.

So they waited
a good, safe time.

And then they might come

and actually sleep
under the same tree,

so they're,
it's kind of a timeshare.

And they're safe enough apart
in time

that there's no risk
of an encounter.

The cameras capture
some surprising moments.

With the cameras, we know
where everything goes at night.

Birds that ordinarily roost
in trees

we've discovered like to roost

in the crotch of a giraffe,
for example.

These are oxpeckers

who've decided
that that's a nice, warm place

to spend the night, and
I had no idea they did that.

There's also interactions
between other species

that sometimes seem
really amusing,

like a warthog that looks like
it's talking to a gazelle.

So those kinds of things can
just suddenly make you laugh.

And while some images might
bring a smile,

all are part
of a long-term study

trying to answer tough questions
about wildlife management

in one of the wildest places
on Earth.

Can you save prey animals
without destroying predators?

Do fences help or hurt?

What investments are
most effective

when you're managing
a wildlife reserve?

An ideal outcome
ten to 15 years from now is,

we have a really good view
of what's going on.

I think the ultimate power
of these cameras is

that you've got hundreds of eyes
out in the field

that are collecting information.

And you have literally hundreds
of thousands of eyes

looking at those photographs

that are all part
of the scientific program

to say,
"This is what's happening.

This is how well this area
is being conserved."

Sometimes,
conventional camera traps

can't capture all the data
that scientists need.

So this is...

All right, we're at Den Four,
this is ABR 15.

Right.

Like Craig,

biologists Liana Zanette
and Mike Clinchy are spying

on animals in South Africa.

But their camera traps are
very different.

It's playing hoopoes.

This camera setup plays back
sounds of predators

in order to trigger
a fear response.

So lions at 11:42
on the 23rd of July.

Make the terrible noise,
there we are.

When the animal walks by,

the system will activate
the speaker.

It'll get that ten seconds
of sound,

so we can see
what the animal was doing

just before it heard the sound,

what it does
when it's hearing the sound,

and also what it does
after the sound stops.

This may sound like
a mean practical joke.

But Liana and Mike are trying

to understand the role
that fear plays in an ecosystem.

What happens when animals
aren't killed

but just scared?

We are basically counting fear.

So we're figuring out the degree

to which fear affects
everything.

Their work addresses
a serious problem

in ecosystems
all over the world:

the dwindling number of scary,
but natural, predators.

Wherever large carnivores
have been exterminated,

there's often
massive ecosystem problems.

The prey have nothing to fear.

And because
they have nothing to fear,

they can overgraze everything
down to the ground.

That's happened repeatedly
all over the world,

it continues to happen,

and it's a real
ecological problem.

Decades ago,

Yellowstone National Park
faced a crisis.

With the native gray wolf
locally extinct,

the elk population exploded,

gorging on plants
and decimating the landscape.

In 1995, the park service

reintroduced the gray wolf
to Yellowstone,

and the elk population dropped.

Soon, parts of the ecosystem
began to change.

Vegetation flourished.

Willow trees thrived,

helping to stabilize
the once-eroding river banks.

Scavengers such
as fox, black bear,

and even birds

benefited from the elk carcasses

left by wolves.

Exactly how the wolves changed
Yellowstone's landscape

is still being debated.

But Liana and Mike say
it's not just

about the number of kills
that predators make,

it's how many prey they scare.

Predators will kill
way fewer prey

than they scare.

Predators scare
all of their prey,

they kill a few of them.

To better understand

how fear affects animals,

Liana and Mike have spent days
setting up dozens of cameras

that record video
and play sounds

from three different predators
here:

lions, cheetahs, and wild dogs.

The cameras give us the ability

to do a manipulation
of this sort,

which is very difficult.

I mean, working out here is
very difficult, right?

These animals, we don't know
where they're going to be.

They're not radio-tagged
or anything like that.

I don't want to be out here
at night,

when all the lions
and the cheetahs

and the leopards are out.

Thankfully, we have the cameras
that can be out here.

A week later, they return.

Grab the laptop.

Okay, just double-check.

Looking through hours
of footage,

Liana and Mike analyze
fear responses

to the three predators.

This is... ooh!

Ooh, didn't like the wild dogs.

Cheetahs startle some animals...

But not others.

Wild dogs are scary...

Unless you're a rhino.

And lions make just about
everybody run for the hills.

Camera 13.

Camera 13.

The next phase will be to see

how fear affects these animals'
reproduction rates

and feeding times.

Liana and Mike have conducted
similar studies

elsewhere in the world,

and the results are startling.

What we've discovered
over the years

is that this has
massive repercussions

on a long timescale in terms
of the number of offspring

that animals are able
to produce.

In British Columbia,
sparrows subjected

to the sounds of a hawk

produced 40% fewer offspring.

Raccoons frightened
by hearing large carnivores...

...spent 66% less time feeding,

leaving more crabs and fish
in the oceans.

And when cougars heard the sound
of their predator... humans...

their feeding times went down
by half.

Just because they think
that there's predators around,

there's fewer offspring
that are produced.

The predators aren't killing
the offspring.

It's just thinking
that there's predators around

that is causing this
massive reduction in population.

Their research is sounding
an alarm to conservationists:

Big, scary predators
affect landscapes

in ways that aren't
always obvious.

Failing to protect them

could cause entire ecosystems
to collapse.

By incorporating fear
into the equation,

we have a much better
understanding

of management plans
that, that may work,

management plans
that will not work.

It's just the beginning
of a whole new understanding

of how the fear of predators
can shape everything.

It's unbelievable.

On another continent,

a predator at the apex
of the food chain

is struggling to survive:

the wild tiger.

The largest member
of the cat family,

tigers can weigh
500 pounds or more.

They roam solo, and hunt often;

an adult tiger needs one large
prey animal per week

to survive.

You can keep going
a little bit more.

Ullas Karanth is a tiger expert
and conservationist

working in Karnataka state
in India,

where most of the world's tigers
live.

He has dedicated his life

to preserving
these elusive predators.

I grew up in a small village.

The local culture had tiger
deeply infused in it.

People used to wear tiger masks
and dance during festivals.

Yet ironically,

last of the wild tigers
were being hunted out

by people around me.

100 years ago,

there were close
to 100,000 tigers in Asia.

Today, only about 3,500 remain.

Most of them are in India,

where conservation campaigns
and a hunting ban

saved the species
from local extinction.

But even here,

this iconic predator is
far from safe.

Poaching is still a problem.

And as India develops
at a rapid clip,

tiger habitats get carved up.

In some areas,
tigers are running out of prey,

such as deer and wild cattle.

Often tigers disappear

not because
they have been hunted,

but because their food
has been taken away,

their prey have been hunted out
by local people.

How do you protect

one of the world's
most vulnerable predators

in one of the
fastest-growing countries?

Conservation is
a difficult enterprise.

That's where the role
of counting tigers accurately,

monitoring their populations,

monitoring their distributions,
comes.

It's an audit
of whether tiger conservation

is succeeding or failing.

An audit that requires accuracy

if we are to know
how many tigers are left

and where they are thriving...

not easy when counting
one of the world's

most dangerous and elusive
predators.

For years, conservationists
kept a safe distance

by counting tiger pawprints.

But when a young Ullas Karanth
began studying tigers in 1986,

he spotted a serious flaw.

It's almost impossible to
identify each tiger individually

from its track shape,

because the speed
at which the animal is walking,

the soil on which it's walking...

all these make
massive differences

and distort the shape.

It is impossible to wander

across hundreds of square
kilometers of tiger habitat

in a couple of weeks,

and find the tracks
of every tiger,

so it simply didn't work.

Ullas had a better idea.

Tiger stripes
are like fingerprints...

no two are alike.

Why not count tigers
by photographing them?

What camera trapping
allows you to do

is to photographically capture
a very large number of tigers

over very vast landscapes,

which you cannot do
with any other technique.

The stripes on two sides
are very different,

so you need two cameras

so that you get both sides
of the animal

and identify it permanently.

Once you have
a permanent identification,

any single-flank picture

also can be pinned down
to that tiger.

As the database grew,
Ullas faced a new challenge.

How do you compare
each new tiger image

to thousands of others?

See, you have to compare
the same side.

So, Ullas turned to scientists,

who pioneered a new way
to identify individual animals.

This program examines
each tiger-stripe pattern

as a series of squares.

In minutes, its algorithm
compares this series

to thousands of others,
until it hits a match.

Once the model is matched,

then it's very easy to identify.

Ullas ran decades' worth
of tiger photos

through the software.

What emerged were
hundreds of matches

for individual tigers.

It adds up to a lot of knowledge
about tigers,

how they are spread
across the land.

And using that data, we can know

not only how many tigers
there are,

we can estimate
how those numbers are changing.

We can get to know

what proportion of tigers
are surviving,

how many new tigers are getting
to the population.

All this adds up to knowledge

that is critical
for saving tigers.

The pictures have revealed
how far a tiger can range

from its birthplace...
up to 100 miles.

In some instances,

Ullas's data has been used
to convict poachers.

Camera traps are now widely used
for tracking tigers in India.

In Karnataka state alone,

Ullas has generated
25 years' worth of data,

information that could give
conservationists a clearer idea

of where to focus their efforts,
now and in the future.

This powerful-looking animal is
so fragile ecologically.

It can disappear so fast.

The pieces of knowledge that are
needed to make it survive

are critical.

Today,

cameras are revealing more
about our planet's wildlife

than we could ever see
with the naked eye.

In the Pacific,
off Vancouver Island,

unmanned cameras
are 7,000 feet down,

filming fantastic creatures
few people have ever heard of,

let alone seen.

At this bat cave,

high-speed thermal cameras
shed light

on an otherwise
pitch-black world.

Slowed down, the images allow
scientists to track individuals,

count wing beats...

even watch the bats interact.

This 36-hour time lapse
in the savanna

shows us just how many animals
are fed by a single kill.

Remote cameras can be
left behind

in the coldest places on Earth,

like in Antarctica,

where Penguin Watch uses
a network

of 75 weatherproof,
solar-powered cameras

to record the secret lives
of penguins

and the impact of climate change
on their world.

Frame by frame,

cameras document
a changing planet

and the risks facing
its most vulnerable creatures.

Someone whose daily life
isn't really affected

by environmental change,

to be able to see
imagery of the animals

that are reliant
on their natural environment

is really powerful,

and I think that's one of the,
the benefits of this technology.

Cameras are playing a major role
in conservation,

from the Arctic Circle
to deepest Africa.

Their data could help save
species from extinction.

Unless we can really say

that there are growing
populations of wildebeests,

zebra, impala, et cetera,

we can't really be sure

whether these places
are truly succeeding.

You could spend all the time
in the world

trying to track these animals
on foot through the bush,

and never get close enough
to, to observe these things.

When so much is invested
in tiger conservation...

people even sacrificing
their lives for tigers...

we need to know accurately

whether what we are doing
is working.

And with each new image,
cameras give us another chance

to connect with
the natural world.

These images help us

reach people's minds
through their hearts.

We can show people, "Look,

"here is this
incredible species,

"and it's right here, right now,

and if we don't do something,
we will lose it."

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