♪♪ ABRAHAM: Big or small, cats have conquered the planet.

But as adaptable as they are, we're encroaching on their space.

Around the world cat numbers are decreasing.

KARANTH: If we get complacent we could see tigers go extinct.

I couldn't imagine a world without tigers.

♪♪ ABRAHAM: It's a critical time for new research and cat conservation.

ELBROCH: Holy mackerel.

He's a loose cannon.

ABRAHAM: But there are success stories to be told.

This is an age of discovery that's revolutionizing how we view this amazing, super family.

[ Theme music playing ] ♪♪ ♪♪ ABRAHAM: Cheetahs are the world's fastest land animal.

♪♪ It's said they can accelerate faster than a Ferrari.

♪♪ ♪♪ But no one knows for sure what they're really capable of.

♪♪ Professor Alan Wilson has spent the last five years trying to find out.

WILSON: Cheetahs are amazing, they're so much faster than anything else.

We've got an animal that has got four times the acceleration of Usain Bolt and more than twice the top speed, how can they not be fascinating to study.

ABRAHAM: Alan wants to find the cheetah's top speed when it really counts... during a hunt.

He's developed high tech collars to record the cheetah's speed, position, and G force while they're hunting.

♪♪ The cheetahs soon disappear.

They cover hundreds of miles in search of their prey.

That makes getting any information back from the collars a real challenge.

Alan's solution?

He's built his own plane -- from scratch, learned how to fly it, and then filled it to the brim with the latest technology.

WILSON: We have a tracking antenna on the wing.

We have a three-dimensional laser scanner.

We have a video camera on a gimbal.

That's a missile guidance system.

Okay, let's go find some cheetah.

♪♪ ♪♪ ♪♪ Coming into the air is just such a revolution for wildlife research.

♪♪ Okay, cheetahs on the left wingtip.

♪♪ ABRAHAM: The cheetahs' collars record details of their movements 300 times a second.

As the plane flies over, it locks on to each collar and downloads the data.

WILSON: There we go, we're downloading collar 7-5-0.

Each of those files represents one hunt.

ABRAHAM: After recording more than 500 hunts, Alan clocked a cheetah's top speed of 58 miles an hour.

♪♪ Impressive.

But what surprised him was that most hunts were much slower, only half their potential top speed.

It turns out, for a cheetah, hunting is not all about the sprint.

♪♪ So, what are they relying on to catch their dinner?

♪♪ To investigate, Alan has enlisted three volunteers... [ Cheetah purring ] And a rag on a string.

These hand-reared cheetahs love chasing a moving lure... Replicating how cheetahs behave when hunting.

♪♪ Prey animals don't run in a straight line for long.

To follow their prey, cheetahs must also weave and change direction.

This maneuvering inevitably slows them down, but it's also where their real strength lies.

♪♪ WILSON: The accelerations and decelerations, the G forces they're pulling in the turns are very high.

ABRAHAM: The force going through their legs would be enough to break a human leg bone.

♪♪ WILSON: The lure's just taken the corner and the cheetah's banking and see how it's using its tail here, which is helping control the roll of its body and helping stabilize it and it slowed down to turn then it's accelerating again out of shot towards the lure.

♪♪ ABRAHAM: Rather than speed, the key to the cheetahs' hunting success is their agility.

♪♪ WILSON: We started believing that cheetahs are the elite sprinter and that was their main attribute.

What we've seen is that they're gymnasts, they can accelerate, they can maneuver, they can turn, and that is what they're good at, almost the speed is a by-product of all that athleticism.

So they are remarkable athletes, but we shouldn't think of them as just a speed merchant, there's much more to their repertoire than that.

♪♪ ABRAHAM: Even with the most familiar cats there's still so much to discover.

♪♪ ♪♪ [ Roars ] Lions.

Supreme hunters.

The strongest cat.

Could they also be the smartest big cat?

♪♪ Dr. Natalia Borrego certainly thinks so, and is on a mission to prove it...

Though it's not the easiest thing to test in any cat, let alone a lion.

Her theory is based on the fact that lions live together in prides.

[ Starts engine ] BORREGO: So cats are all solitary and effectively live on their own, except for lions, they live in prides and are very social and when we think of other social species -- elephants, dolphins, spotted hyenas, chimpanzees -- they're all very intelligent.

So in theory lions should be the smartest of the cats.

ABRAHAM: The idea that social animals are more intelligent is well established, but has never been proved for lions.

[ Low roar ] Cats are notoriously uncooperative.

What possible IQ test could you give a lion?

Natalia's traveled to South Africa for the chance to test a slightly unusual pride.

♪♪ ♪♪ ♪♪ Kevin Richardson has an unconventional approach to working with lions.

♪♪ For 10 years he's lived alongside these rescued animals, becoming part of the pride.

♪♪ Kevin can act as a go-between to the lions, giving Natalia a unique opportunity to run her experiments.

BORREGO: So, here looks good.

ABRAHAM: Natalia has designed a puzzle for the cats to solve.

RICHARDSON: Mind your fingers.

BORREGO: Yeah.

ABRAHAM: The lion must work out how to open a door, then reach her head inside to get to a reward.

BORREGO: Good.

ABRAHAM: There's nothing like this in nature, so to Ginny the lion, it's a Rubik's cube.

RICHARDSON: And if the lions come, you just pop it down.

BORREGO: I just pop it back down.

RICHARDSON: Ginny.

[ Whistles ] Here.

Look here.

ABRAHAM: First, she must figure out how to pull the door with her paw.

♪♪ BORREGO: Clever!

RICHARDSON: Aw, you're so clever.

You are so clever my sweetie, oh, but it slams, eh?

BORREGO: What did it do?

I think she's more interested in the box now than the food.

RICHARDSON: Here.

Here.

ABRAHAM: Next she needs to learn to stand back and allow the door to swing open.

RICHARDSON: Get your head out the way.

Get your head out the way.

There we go.

ABRAHAM: Before, finally, she can reach her head inside.

RICHARDSON: That's not bad.

BORREGO: No that's good.

Clever.

RICHARDSON: One more time?

BORREGO: Yeah.

RICHARDSON: Two more times?

BORREGO: I think a couple more times.

RICHARDSON: Couple more times.

BORREGO: There, see, she got it.

ABRAHAM: It's taken Ginny 20 minutes to figure it out.

But now she's cracked it.

RICHARDSON: There we go.

BORREGO: Yeah, she's getting her head out of the way now.

RICHARDSON: There we go.

One more time.

Okay, okay, cool.

BORREGO: Yeah, there you go.

RICHARDSON: Easy now she's got it.

BORREGO: Well done.

RICHARDSON: That deserves a round of applause.

ABRAHAM: Next comes the crucial part of the test.

Kevin has brought the lions into an enclosure to allow pride mate, Libby, to watch Ginny's efforts.

The ability to learn by watching others is considered a real sign of intelligence.

It would put lions in the company of the brightest minds in the natural world.

RICHARDSON: Good.

Yeah you slam that door.

That's it, stay open.

Good girl.

BORREGO: No there she goes.

RICHARDSON: She can see what she's doing.

Yeah.

BORREGO: Yeah, I think she's got it and it's time to let Libby out.

ABRAHAM: If lions can learn from each other, Libby should solve the puzzle in seconds.

If not... BORREGO: See what she does ABRAHAM: It's going to take her another 20 minutes.

BORREGO: Now she goes to the right side.

[ Both laugh ] There, I think, I don't think you can get any clearer than that, that was amazing.

RICHARDSON: Yeah, here we go my girl, here here, here here.

BORREGO: Good job, Libby.

ABRAHAM: It's the very first time anyone has shown that lions learn from each other.

RICHARDSON: She knows that that's the one.

ABRAHAM: Natalia has tested leopards and tigers -- lions outperform them both.

It looks like Natalia is right... RICHARDSON: Now she doesn't even bother.

ABRAHAM: Lions are the smartest big cat.

BORREGO: So the experiments went really well, much better than expected, and it really did show that lions can learn socially from each other.

♪♪ ABRAHAM: Their intelligence and ability to learn from each other allows lions to hunt like no other cat.

♪♪ ♪♪ ♪♪ ♪♪ No cat is easy to study, though at least lions are relatively easy to find.

[ Mews ] ♪♪ But most cats are so elusive... secretive... and well camouflaged... that they're rarely seen, let alone studied.

Learning more about these cats takes people whose dedication knows no bounds.

♪♪ Someone like Dr. Andrew Hearn.

♪♪ Deep in the forests of Borneo, a chance encounter set him off on his life's mission.

HEARN: I was part of an expedition team to an uncharted area of Indonesian Borneo.

One morning I went along a trail just to go and sit down and relax and see what wildlife I could see.

And I was sat there quietly, and a small little red cat walked out of the side of the forest, walked across the trail, paused about 20 meters in front of me.

I grabbed my notebook, started to sketch it, but I had no idea what it was.

It was only when I returned back to the camp later that day, spoke to some of the Indonesian staff and said, "Do you know this -- do you know this cat?"

So it was only then that I learned that this was this, um, the Borneo Bay cat, and it quickly became apparent that nothing was known about this animal.

ABRAHAM: The bay cat is one of the world's least known cats... And Andrew has devoted every year since to finding out anything about them.

But the chance of him seeing another one would be like winning the lottery twice.

♪♪ ♪♪ So, how do you study something you can't see?

Camera traps.

Combining a sensitive motion sensor with a high resolution camera, Andrew and his team deploy dozens of these through the forest... and spend months trekking through the jungle checking them.

♪♪ Back at base there are thousands of hours of footage to plow through.

Most contain no cats whatsoever.

[ Squealing ] But eventually, Andrew struck gold.

♪♪ Almost.

HEARN: So this is the first-ever video of the bay cat in the world.

It's not the finest video, it's not the most exciting, but to us that was just spectacular.

We were absolutely blown away when this thing appeared on the camera traps in front of us.

ABRAHAM: This is the fruit of 12 years' labor.

Yet to this day, only two videos of wild bay cats exist: Andrew's and this one, more recently captured.

♪♪ No wonder we know so little about these cats, and now, it's a race against time.

Borneo has one of the highest rates of deforestation in the world.

To protect some space for the bay cat, Andrew wants to find out what kind of forest they need.

He has managed to capture photographs which help shed some light.

♪♪ HEARN: In, what is it, 12 odd years we've only got something like 60 photos.

They're so rare, they're so hard come by.

Each photograph of the bay cat is worth its weight in gold.

It helps to piece together the ecology and the conservation needs of these cats.

ABRAHAM: Much of the deforestation in Borneo is to make space for palm oil.

While some cats can make it in these plantations, bay cats disappear.

For the bay cat to survive, some natural forest must be protected.

Andrew's determined to uncover whatever else he can about the mysterious bay cat, even if it takes another 12 years.

♪♪ Camera traps are revolutionizing our understanding of the entire cat family.

Deploying them in the remotest corners of the planet for months at a time is yielding unique insights into these very private lives.

♪♪ In China, two cats that wouldn't normally cross paths, a leopard and a snow leopard, are filmed by the same camera just days apart.

♪♪ In Costa Rica, a margay argues with an angry possum.

♪♪ ♪♪ And in the dunes of the Western Sahara, camera traps record the first ever shots of wild sand cat kittens.

♪♪ [ Sniffing ] ♪♪ One pioneering study has taken the use of camera traps to another level.

♪♪ Mountain lions, also known as cougars or pumas.

♪♪ Camera traps are now challenging what we know about this American icon.

♪♪ ELBROCH: She's here.

ABRAHAM: It all started with Dr. Mark Elbroch's passion for these charismatic cats.

ELBROCH: Here she is, running across.

Look at the size of the footprint.

I live mountain lions.

I track them, I watch videos of them, I go to sleep at night and I dream about mountain lions.

This guy's a, he's a loose cannon.

This is the part where you try not to get bit.

ABRAHAM: In the Teton Mountains of Wyoming, Mark and his team want to learn more about mountain lion hunting and feeding behavior.

Using GPS collars to track the animals, they identify cat hotspots.

ELBROCH: ...quite a bit, which is good.

No, so we should get in there and set some cameras -Sounds good.

♪♪ ♪♪ ABRAHAM: Mark expected an insight into the solitary life of lone cats...

But the more he watched, the more he began to realize something else was going on.

♪♪ ELBROCH: Here comes the nine year old resident female, and she comes round and she turns and here comes a six year old female.

She's doing mild hissing and in the beginning we thought, gosh, all that hissing, it's the pre-runner to violence, it's super aggressive.

No, hissing seems pretty normal now that we've seen it over and over and over again.

So what happened next?

They spent two days together and this is what they did.

They shared a meal.

It blew me away.

ABRAHAM: That wasn't his only surprising discovery.

♪♪ It's thought that males are normally aggressive towards females, even capable of killing them.

But the cameras show that's not true either.

ELBROCH: Every time we've seen a male approach a female outside courtship this is exactly what they do, they slink in.

Notice how low he's holding his body to the ground, his ears are to the side and almost sagging, they minimize their profile, they try to look smaller, it is completely non-aggressive, he clearly just wants to share a meal.

And you can see as he comes in there's no hissing, there's nothing, she just watches.

And it's the kitten that does all the hissing.

[ Hissing ] There they are, massive resident adult male feeding on the carcass, three month old kitten and mother falling asleep in the background.

ABRAHAM: Rather than always being aggressive, males become positively meek when they want to share a meal.

After analyzing 13 years of data and thousands of videos, Mark has discovered these social interactions follow a pattern.

Mountain lions remember each other, and they're much more likely to share their dinner with a cat that has been generous with them in the past.

ELBROCH: We're beginning to describe a species that has some sort of social system, that is interacting with a frequency that challenges this idea that they are solitary animals and it's just opening our eyes and completely turning everything on its head on what we thought were the social lives of mountain lions.

[ Hissing ] ABRAHAM: Cats never fail to surprise us.

♪♪ ♪♪ Covering more than 30 square miles and employing 20,000 people... Secunda CTL is the biggest industrial complex in Africa.

♪♪ An unlikely place for a cat...

But ecologist Daan Loock made an amazing discovery here.

It all started with reports of strange creatures prowling the site after dark.

♪♪ I just can't make out what it is.

Hopefully it crosses here but I don't think so, there's a lot of thickets just to our left hand side, I think it will, there it is just in front of us!

There it is!

Oh, that's very special.

ABRAHAM: The strange creature is a serval.

There it goes.

I'm very excited, I must say.

ABRAHAM: Daan covered the site in camera traps, and to his surprise, there were servals everywhere.

He worked out that the population density is six times higher than in the most pristine wilderness.

Servals are not merely surviving here...

This is the densest population known.

ABRAHAM: Servals are found across Africa and specialize in hunting rodents and small birds.

♪♪ They have the biggest ears of any cat, to help pinpoint their prey.

[ Rustling ] ♪♪ And with spring-like legs, they pounce over ten feet.

♪♪ By fitting servals with GPS radio collars, Daan was able to answer why there were so many on site.

ABRAHAM: Most importantly, Daan's map reveals the servals are concentrated in particular areas -- around water.

Ponds and streams used to cool the heavy industry create the perfect habitat for rodents... abundant food for the servals.

♪♪ With no other big predators, there's no competition.

Servals have become the apex predators... and run riot.

Now, this site has the highest concentration of servals anywhere in the world.

All across the planet, cats are adapting to urban habitats.

♪♪ In response, people often need to learn how to live alongside cats.

[ Kitten mewing ] ♪♪ Mumbai, India.

One of the world's largest cities, home to over 20 million people.

♪♪ ♪♪ Mumbai is also home to the world's highest known density of leopards.

In the dead of night, they creep into the city from the surrounding forests.

♪♪ Krishna Tiwari grew up in Mumbai.

[ Conversing in Hindi ] He's now dedicated his life to studying the city's urban leopards.

[ Conversing in Hindi ] TIWARI: He saw a leopard the day before yesterday and when the leopard saw him he just ran away to the other side of the wall.

ABRAHAM: The story is the same all across the city.

[ Conversing in Hindi ] People encounter leopards on a regular basis.

TIWARI: She came out at around 8:30 to wash clothes here and when she put up a torch she saw a leopard sitting on the rocks and as soon as, you know, there was light on the leopard he just got up, and she was so afraid that you know she came back to the house and called her husband.

ABRAHAM: The outcome of these encounters isn't always so peaceful... [ Goats bleating ] After all, the leopards are coming into the city to hunt.

[ Grunting ] ♪♪ Livestock are abundant and unprotected.

♪♪ ♪♪ ♪♪ Stealth is the leopard's most effective weapon.

♪♪ ♪♪ Dogs often provide an early warning... [ Dogs barking ] But drawing attention from a leopard isn't a good idea.

[ Snorting, grunting ] Dogs are also on the menu.

[ Dog barking ] [ Squealing ] ♪♪ [ Squealing ] [ Grunting ] ♪♪ ♪♪ And sadly, it doesn't stop there.

♪♪ In the 23 years from 1990 to 2013, 176 people were attacked by leopards in Mumbai.

♪♪ But in just one month during 2004, 10 people were killed.

♪♪ Something had to be done.

Krishna and the authorities took a bold approach.

Pioneering an education program, Krishna wanted to teach people how to live safely alongside leopards.

[ Speaking Hindi ] Simple measures like staying in groups at night, locking up livestock, and not running from leopards has made a huge difference.

20,000 people have attended the meetings.

TIWARI: The awareness program has been a great success as the last four years have seen no leopard attacks and I think it's a good and long-term solution to reduce the human/leopard conflicts in Mumbai.

♪♪ ABRAHAM: Unfortunately, educating the local dogs has proven trickier.

They provide a vital early warning, but are still being taken.

♪♪ Raj has lost 3 dogs to leopard attacks.

He then hit on an idea which might help protect his current pet.

♪♪ TIWARI: He thinks that the dog, the leopard will think that it is also a leopard.

Even you know it's being protected by other dogs so I think it's a good idea.

ABRAHAM: The jury's still out on whether this even works, and anyway, what self-respecting dog wants to be dressed up as a cat?

♪♪ He's certainly not convinced.

Krishna's mission to spread tolerance is working.

♪♪ And Mumbai's leopard population is thriving.

It's a rare example of people accepting their presence and making space for cats.

♪♪ Elsewhere, it's a very different story.

Nearly half of all wild cats are threatened with extinction.

As top predators they need a lot of food and space... And with an ever-growing human population, competition for that space is rising.

In the last 20 years, leopards have been wiped out from 40% of their range.

♪♪ ♪♪ Cheetahs have become extinct in 25 countries.

♪♪ Not even lions are spared.

Numbers have fallen by nearly half in two decades.

The King of Beasts could go extinct in the wild.

♪♪ ♪♪ The driving passion people feel for cats is now their greatest hope for survival.

ELBROCH: Holy mackerel.

♪♪ ABRAHAM: Especially for the animal that's long been the face of cat conservation.

♪♪ ♪♪ Dr. Krithi Karanth's love of tigers started at a very young age.

KARANTH: I first saw a tiger when I was two years old with my father and my grandfather in Nagarhole National Park.

I was amazed and in awe.

There is nothing like seeing a tiger in the wild.

ABRAHAM: Years later, and now a world-renowned tiger conservationist, Krithi remains enthralled.

♪♪ KARANTH: There are no words that can really capture the emotion of seeing a tiger.

Every single time I've seen a tiger in the wild I've been either left speechless or giggling silly or crying, I mean it's a range of emotions, but you never forget.

To me, tigers are truly one of the most spectacular cats on the planet.

ABRAHAM: But like so many of the cats, survival of the tiger is on a knife edge.

KARANTH: We see images and stories about tigers all the time, could give us the impression that they're not endangered but they absolutely are.

They're one of the most threatened big cats in the world today.

ABRAHAM: Over the last century, 95% of wild tigers have vanished.

There are now more tigers in captivity in the United States alone than in all the wild.

♪♪ ♪♪ KARANTH: It is impossible for me to imagine a world without wild tigers.

But if we get complacent we could see tigers go extinct.

♪♪ ♪♪ Sorry.

I -- I couldn't, I couldn't imagine a world without tigers.

♪♪ ♪♪ ABRAHAM: Krithi has spent her life raising awareness and funding to save the tiger.

♪♪ She's set up a project that helps villagers get compensation when tigers attack their livestock.

It's helping ease some of the conflict with local people.

♪♪ Here in India, the greatest challenge is giving tigers the space they so desperately need.

One solution is to help villagers who currently live within the National Parks to relocate.

♪♪ Krithi is part of a team that assists those who choose to make a new home beyond the park boundaries.

KARANTH: Once you move people out, the vegetation comes back, the prey numbers rebound, and then tiger numbers come back.

So, ecological recovery takes time, but I think nature knows how to heal itself.

ABRAHAM: There's been a lot of time, money, and effort spent -- and the tide may be turning.

KARANTH: After a long time we're seeing wild tigers come back, population stabilize and recover in many tiger reserves.

ABRAHAM: It shows that we can change the future for cats if there is the will to protect them.

[ Growling ] ♪♪ One pioneering project is even attempting to rescue a cat from the very edge of extinction.

♪♪ Just a century ago, thousands of Iberian lynx roamed the ancient woodlands of Spain and Portugal.

♪♪ But a combination of habitat loss, hunting, and lack of prey caused their numbers to collapse.

♪♪ By 2002, fewer than a hundred were left.

The Iberian lynx was declared the rarest cat on the planet.

[ Buzzing ] Today, an international team of scientists and conservationists are working to bring these cats back from the brink.

[ Static ] ♪♪ The team has undertaken an intensive breeding program on a scale never attempted before.

Vicky Ascensio is a vet dedicated to the project.

She works at the newest of the breeding centers.

Spread across Spain and Portugal, these multi-million dollar facilities are built to meet a lynx's every need.

To ensure they can produce as many cubs as possible for release back into the wild.

♪♪ It's also designed so Vicky can keep a close eye on each and every precious cub.

ASCENSIO: In total we have 116 cameras.

[ Motor whirring ] We try to see the animals 24 hours.

ABRAHAM: This hands-off approach is vital so the cubs never meet a human.

ASCENSIO: They are all day very quiet, very calm, and they don't see that we are always looking them.

It's very important for us specially when we have cubs.

ABRAHAM: The Iberian lynx has become a species in intensive care.

♪♪ The breeding centers are just one piece of the puzzle.

The team is also working hard to improve the natural habitat so young lynx can be released into ideal conditions.

♪♪ Today Vicky is running some crucial health checks.

One-year-old cubs Navio and Noa are scheduled for release.

♪♪ ASCENSIO: We are checking that all the animal is healthy and also we take some samples to see that he has not any infections or diseases or something like that.

Our goal always is to release the animals.

It's our most important goal.

[ Speaking Spanish ] ABRAHAM: The cubs are ready.

A release is big news around here.

Crowds gather to catch a glimpse of this iconic Spanish cat.

♪♪ ASCENSIO: This is a very special moment for me because it's an animal that was born in the center and now you are giving him the freedom.

It's very emotional for us.

♪♪ ABRAHAM: Navio and Noa are given their freedom, running wild for the first time.

♪♪ ♪♪ ♪♪ ♪♪ ♪♪ ♪♪ This ambitious project has become one of the most successful reintroductions on the planet.

Nearly 500 cats once again roam these ancient woodlands.

♪♪ ♪♪ The more we learn about cats, the more they surprise and amaze us.

♪♪ Only by understanding their needs can we help safeguard their future.

[ Calling ] There's a lot of work still to do, but across the globe people are putting heart and soul into finding answers... and making sure the future always has a place for cats -- big and small.

♪♪ -This is an animal you should never underestimate.

-Squirrels are one of the most agile animals on Earth.

-From outwitting rattlesnakes to surviving sub-zero temperatures, squirrels are anything but ordinary.

[ Squeak ] Now, one orphaned red squirrel and a cast of ch eeky characters are going to reveal the secret to squirrel success.

♪♪ ♪♪ ♪♪ ♪♪ ♪♪ ♪♪ To learn more about what you've seen on this "Nature" program, visit pbs.org.

♪♪ ♪♪