Original subtitles

NARRATOR: From frigid oceans...

Okay, there he is.

NARRATOR: ...to distant jungles...

ULLAS KARANTH: You can keep going a little bit more.

NARRATOR: ...there's a hidden world

of exotic creatures

just out of view.

ARNAUD DESBIEZ: Finding the animal is like looking

for a needle in a haystack.

It's really difficult.

NARRATOR: Around the world,

researchers are tracking the most vulnerable animals,

trying to save them before they vanish forever.

KARANTH: This powerful-looking animal is so fragile.

The pieces of knowledge that are needed

to make it survive

are critical.

NARRATOR: Now, new technology

is revealing their secret lives.

DESBIEZ: They're really silent little spies

that make no noise,

that can capture intimate moments of the animals.

CRAIG PACKER: You get millions and millions of photographs,

and you suddenly see things for the first time.

NARRATOR: Frame by frame,

the invisible world of animals is coming to life.

DESBIEZ: I could not believe this species existed,

that it was right here, around us.

I had no idea they did that.

NARRATOR: Their habits, fears, and most intimate moments.

SARAH FORTUNE: It has completely revolutionized

our ability to understand behaviors.

NARRATOR: 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:

♪

NARRATOR: 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.

LIANA ZANETTE: The invaluable information that people will get

from a simple, wee, little camera

that anybody can buy off the shelf,

it's unbelievable.

NARRATOR: What can researchers learn by spying on animals?

ART RODGERS: Why are they doing that?

And why did they do that?

And what are they going to do next?

NARRATOR: 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.

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.

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

where climate change could be threatening their, their future.

NARRATOR: 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.

FORTUNE: I need know what the whales are feeding on today

and how energy-rich their current food resource is.

NARRATOR: 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.

FORTUNE: 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.

NARRATOR: Even when they find a whale,

it's hard to see its entire body.

FORTUNE: 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.

NARRATOR: 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.

KOSKI: 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.

NARRATOR: Any closer, and a noisy plane spooks the whales,

who will dive and disappear.

Is he up now?

NARRATOR: 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.

All right, full power. Okay.

FORTUNE: Awesome.

♪

(water sprays out blowhole)

NARRATOR: The drone quietly hovers just above the whales.

(buzzing softly)

They seem oblivious to the flying camera following them.

♪

FORTUNE: 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.

NARRATOR: Finally, they can see the whale in its entirety.

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

FORTUNE: They often need to break thick ice with their heads.

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

NARRATOR: 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.

FORTUNE: 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.

NARRATOR: When the whale dives below the surface to feed,

the drone keeps an eye on it.

FORTUNE: 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.

♪

NARRATOR: 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.

FORTUNE: 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.

NARRATOR: For scientists like Sarah, the drone is a window

into the lives of these mysterious creatures

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.

FORTUNE: If anyone has any suggestions or questions

that you think we could answer

with this technology,

that would be really helpful to know.

NARRATOR: The images yield new insights

that intrigue even the locals,

who have lived with these whales for decades.

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

KOSKI: 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.

NARRATOR: 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.

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

KILLABUCK: Oh, yeah, yeah. Yeah? Okay.

FORTUNE: 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.

NARRATOR: 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.

TOMMY: 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.

TOMMY: It's starting to come shallow.

TOMMY: It's starting to come shallow.

FORTUNE: Mm-hmm, it's coming.

♪

NARRATOR: This whale seems to be scratching his back

against the rocks.

FORTUNE: 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.

NARRATOR: 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.

FORTUNE: 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.

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

is critical.

FORTUNE: 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.

NARRATOR: 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.

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.

NARRATOR: The giant armadillo, which practically no one--

not even among the local population--

has ever seen.

DESBIEZ: 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.

NARRATOR: 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.

DESBIEZ: Finding a giant armadillo burrow

is like looking for a needle in a haystack.

It's really, really difficult.

NARRATOR: 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.

DESBIEZ: 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.

NARRATOR: Then, he waits.

DESBIEZ: 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.

The camera traps are basically our eyes in the field.

NARRATOR: Weeks later, Arnaud and his team review the footage.

Frame by frame,

the hidden world of the Pantanal comes to life.

(scientists talking in background)

♪

NARRATOR: But no sign of the giant armadillo.

After sifting through hours' worth of footage,

the star finally appears.

(scientists murmuring excitedly)

(exclaims)

(gasps)

DESBIEZ: 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.

NARRATOR: Arnaud's fleet of camera traps

has revealed much about this prehistoric creature.

DESBIEZ: 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.

NARRATOR: And that giant sand mound outside their door?

DESBIEZ: 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.

NARRATOR: And the camera traps caught something

never before recorded on camera.

(exclaiming softly)

(scientists chuckling)

NARRATOR: A baby giant armadillo.

(yelps)

(speaking foreign language)

DESBIEZ: 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.

NARRATOR: The scientists nicknamed the baby

Alex.

DESBIEZ: 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?"

NARRATOR: 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.

DESBIEZ: 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 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.

(speaking Portuguese)

(speaking Portuguese)

NARRATOR: Arnaud shared Alex's story with the public.

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

of this vulnerable baby armadillo.

DESBIEZ: 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.

NARRATOR: After a few months living on his own,

Alex's story took a sad turn.

DESBIEZ: 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.

(vulture squawking)

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.

NARRATOR: 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.

DESBIEZ: 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.

NARRATOR: 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.

DESBIEZ (whispering): 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.

NARRATOR: Arnaud and his team will tag, track,

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

DESBIEZ: 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.

NARRATOR: 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.

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

DESBIEZ: 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.

♪

NARRATOR: 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.

♪

MAN (on radio): Location's coming up just over this next ridgeline.

NARRATOR: 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.

RODGERS: Where's the antenna?

BLAKE: It's in my pack.

NARRATOR: Here, in Ontario's boreal forest,

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

and they are hard to find.

RODGERS: These caribou generally don't occur in large numbers.

They're fairly solitary animals,

moving in relatively small groups

of maybe five to ten.

NARRATOR: 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.

RODGERS: 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?

NARRATOR: 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?

RODGERS: Huh, oh, there it is.

BLAKE: We were close.

RODGERS: Ah, good place for it.

NARRATOR: This lightweight collar

contains a small camera and GPS.

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

NARRATOR: Six months ago, researchers placed it

around the neck of a captured caribou.

RODGERS: 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.

when we know that caribou are likely to be feeding.

Yeah, we got the collar.

NARRATOR: 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.

♪

NARRATOR: Not Oscar-winning cinematography,

but to Art, the footage is simply amazing.

RODGERS: 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.

NARRATOR: 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.

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

RODGERS: 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.

NARRATOR: And the cameras turn up more surprises.

Caribou like mushrooms.

RODGERS: 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.

RODGERS: There's just no other way

we would have known that or seen that,

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

NARRATOR: 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.

RODGERS: 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."

NARRATOR: 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.

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.

RODGERS: 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.

NARRATOR: 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.

NARRATOR: 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.

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

that wildlife populations are declining quite rapidly.

NARRATOR: 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.

♪

NARRATOR: 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?

PACKER: 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.

NARRATOR: Thousands of motion-sensor cameras,

powered on 24/7 for weeks at a time,

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.

PACKER: The practicalities were daunting.

We were generating millions of photographs.

NARRATOR: 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.

PACKER: And you could have volunteers from all over the world

look at your data and then help classify it.

NARRATOR: More than 140,000 people from all across the globe

have participated in Craig's project

as citizen scientists.

PACKER: There is a real community

around the camera-trap process

that involves a broader segment of society

than we ever could have otherwise.

♪

NARRATOR: 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.

PACKER: 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.

NARRATOR: 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.

NARRATOR: And while some images might bring a smile,

all are part of a long-term study

trying to answer tough questions about wildlife management

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?

PACKER: 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."

♪

NARRATOR: Sometimes, conventional camera traps

can't capture all the data that scientists need.

MIKE CLINCHY: So this is...

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

Right.

NARRATOR: 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.

NARRATOR: 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.

(lions growling on recording)

ZANETTE: 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.

NARRATOR: 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?

ZANETTE: We are basically counting fear.

So we're figuring out the degree

to which fear affects everything.

NARRATOR: Their work addresses a serious problem

in ecosystems all over the world:

the dwindling number of scary, but natural, predators.

ZANETTE: 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.

NARRATOR: 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,

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.

ZANETTE: Predators will kill way fewer prey

than they scare.

Predators scare all of their prey,

they kill a few of them.

NARRATOR: 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.

ZANETTE: 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.

♪

NARRATOR: A week later, they return.

Grab the laptop.

Okay, just double-check.

NARRATOR: Looking through hours of footage,

Liana and Mike analyze fear responses

to the three predators.

(recorded wild dogs barking)

ZANETTE: This is... ooh!

Ooh, didn't like the wild dogs.

(chuckles)

NARRATOR: Cheetahs startle some animals...

(recorded cheetah moaning)

But not others.

Wild dogs are scary...

(recorded wild dogs barking)

♪

Unless you're a rhino.

(recorded lion growling)

And lions make just about everybody run for the hills.

(recorded lion roars)

(recorded lion growling)

ZANETTE: Camera 13.

CLINCHY: Camera 13.

NARRATOR: 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.

ZANETTE: 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.

(chirping)

NARRATOR: In British Columbia, sparrows subjected

to the sounds of a hawk

produced 40% fewer offspring.

Raccoons frightened by hearing large carnivores...

Raccoons frightened by hearing large carnivores...

(recorded animal growling)

...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.

ZANETTE: 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.

NARRATOR: 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.

ZANETTE: 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.

♪

NARRATOR: 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.

KARANTH: You can keep going a little bit more.

NARRATOR: 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.

NARRATOR: 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.

(rifle fires)

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.

such as deer and wild cattle.

KARANTH: 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.

NARRATOR: How do you protect

one of the world's most vulnerable predators

in one of the fastest-growing countries?

KARANTH: 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.

NARRATOR: 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.

NARRATOR: Ullas had a better idea.

Tiger stripes are like fingerprints--

no two are alike.

Why not count tigers by photographing them?

KARANTH: 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.

NARRATOR: As the database grew, Ullas faced a new challenge.

How do you compare each new tiger image

to thousands of others?

KARANTH: See, you have to compare the same side.

NARRATOR: 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.

KARANTH: Once the model is matched,

then it's very easy to identify.

NARRATOR: Ullas ran decades' worth of tiger photos

through the software.

What emerged were hundreds of matches

for individual tigers.

KARANTH: It adds up to a lot of knowledge about tigers,

how they are spread across the land.

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.

NARRATOR: 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.

KARANTH: 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.

NARRATOR: 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.

(bats squeaking)

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.

FORTUNE: 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.

♪

NARRATOR: Cameras are playing a major role in conservation,

from the Arctic Circle to deepest Africa.

Their data could help save species from extinction.

PACKER: Unless we can really say

that there are growing populations of wildebeests,

that there are growing populations of wildebeests,

zebra, impala, et cetera,

we can't really be sure

whether these places are truly succeeding.

RODGERS: 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.

(caribou grunting)

KARANTH: 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.

♪

NARRATOR: And with each new image, cameras give us another chance

to connect with the natural world.

DESBIEZ: 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."

♪

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

♪

To order this program on DVD,

visit ShopPBS or call 1-800-PLAY-PBS.

Episodes of "NOVA" are available with Passport.

"NOVA" is also available on Amazon Prime Video.

♪