♪♪ [ Suspenseful music plays ] ♪♪ THOMPSON: Horses.

[ Snorts ] No other animal has done more for us.

They're bigger, stronger, and faster than we are.

[ Poignant tune plays ] And, not so long ago, all horses were wild.

[ Neighing ] So how did this huge animal end up as our companion?

[ Grumbling ] My name is Niobe Thompson.

I'm an anthropologist [chuckling] and I just love horses.

[ Whinnying ] I've discovered that's something I share with people all over the world.

[ Triumphant music climbs ] So I wonder: What makes horses and humans so perfect for each other?

Come with me on a journey around the world and back in time to the origins of this magnificent creature.

♪♪ [ Theme plays ] ♪♪ ♪♪ [ Portentous chorale plays ] THOMPSON: A horse in motion [ Neighing ] is poetry.

We call them the aristocrat of animals for a reason.

Their beauty is hypnotizing.

[ Suspenseful music plays ] But there's more to a horse than meets the eye.

Like their unparalleled speed.

A horse can gallop twice the speed of humans, with a rider on its back.

[ Suspenseful chord strikes ] ♪♪ No horse is bigger than this.

A Belgian draft horse can pull 4 tons.

♪♪ But that isn't all.

[ Suspenseful music climbs ] [ Performer vocalizing tender tune ] The body of a horse works in some very strange ways.

♪♪ Horses have enormous eyes... [ Neighs ] ...the biggest eyes of any animal on land.

[ Huffs ] In daylight, horses see almost as well as humans.

But, at night, they see better.

♪♪ They have almost 360° vision.

They have only two blind spots: just behind and directly in front.

♪♪ But, even here, [ Neighs ] horses have a kind of second sight.

Like a human hand, their lips are loaded with nerve endings.

[ Grumbling ] Their whiskers are so sensitive, they can detect what their eyes can't see.

[ Grumbling ] ♪♪ Like beavers, their teeth never stop growing.

♪♪ [ Ominous chord strikes ] And, at the end of their long, thin legs, horses have shock absorbers.

[chuckling] They're called hooves.

♪♪ These natural gifts add up to an incredible animal.

[ Triumphant music plays ] But the most amazing thing of all is they give those gifts to us.

♪♪ When I ride my horse, I forget how much bigger he is than me.

♪♪ He's just so eager to please.

♪♪ So how did Nature create such a perfect partner?

♪♪ What are the origins of the horse?

[ Suspenseful music plays ] It's a story that began 45 million years back in time.

The Eocene.

Dinosaurs had gone extinct.

[ Birds twittering ] Tiny primates, our ancestors, had emerged.

And so had the earliest horse.

[ Whimsical sting plays ] Few traces remain of that ancient world.

The best place to find them is this abandoned mine in Germany, called Grube Messel.

Evolutionary biologist Martin Fischer began his career digging for fossils here.

It was a good choice.

This is the world's richest source of Eocene fossils.

FISCHER: It's beautiful.

-THOMPSON: Is that a alligator or a...?

-FISCHER: It's a fish.

THOMPSON: It's a fish?

-FISCHER: It's a fish.

THOMPSON: Nearby is a museum, built to hold the discoveries from below.

♪♪ FISCHER: These are all original fossils.

100% original.

THOMPSON: This is the treasure room.

It holds some of the most perfectly preserved fossils ever discovered.

Crocodiles.

Birds.

Even bats, with their wing tissues still visible.

And the crown jewel: a 40-million-year-old fossil of Dawn Horse.

A creature like this led to all horses today.

Amazing!

I've never seen such a well-preserved fossil from this era.

FISCHER: Yeah.

It's just wonderful.

But, we have special permission to take it up, to see it some very close, and I can explain the anatomy.

THOMPSON: Oh, it's heavy!

-FISCHER: It's heavy.

Okay.

THOMPSON: The fossil is so complete, we can even see its last meal: grapes.

Dawn Horse was a fruit eater.

FISCHER: It's perfectly preserved in here and we have the four toes in the front.

You see these huge canines here.

It looks like a dog.

-THOMPSON: It really does.

I mean, this looks like a meat eater to me.

FISCHER: [laughs] If you ask yourself why today's stallions have a canine, the answer is here.

THOMPSON: But, still, Martin, I look at this animal.

I mean, it's tiny.

It has these big, padded feet.

I just don't see anything of the horse in this fossil.

FISCHER: I totally agree.

And, actually, this horse never thought of becoming a horse.

Like always in my life, I wanted to see things moving and I would love to see this horse moving.

THOMPSON: Martin made his name by showing us how animals really move from the inside out.

Dogs.

Cats.

♪♪ Even lizards.

♪♪ But with Dawn Horse, he's tackling something much more difficult.

Using what he's learned about living animals, Martin is going to rebuild Dawn Horse, bone by bone, and, then, bring her to life.

It's the very definition of an educated guess.

FISCHER: We can show you a first attempt.

THOMPSON: You've got some of the bones in movement now?

FISCHER: Yeah.

THOMPSON: Yeah, I'd love to see that.

Wow.

Okay, so, there's a sense of life there.

Those legs seem to be moving realistically to me.

FISCHER: That's the point.

-THOMPSON: Even though there's nothing attached to those legs, -FISCHER: [Laughing] THOMPSON: there's no animal above them, the legs are moving.

How long is it going to take you to get to the full, moving animal?

FISCHER: I would guess that -- What you would say, another three months?

MAN: [Laughing] FISCHER: Two to four months?

Simply difficult.

THOMPSON: Okay, Martin, well, I'm gonna come back in three months and we'll see how far you've gotten.

How 'bout that?

-FISCHER: Okay.

Sirs, no more weekend, [ Laughter ] no holidays, no nothing.

Doing all this work, it is fun.

That's science.

It's sailing to an unknown island and our island, in the moment, is Dawn Horse.

This is what an explorer or a scientist does and it's great fun.

♪♪ THOMPSON: All Martin's hard work finally pays off.

[ Whimsical tune plays ] He can now reveal how Dawn Horse's bones fit together.

[ Clacking ] ♪♪ And how this creature moved.

♪♪ Unlike a horse, sh e had a flexible spine.

♪♪ She could turn and corner.

♪♪ Dawn Horse didn't gallop.

She scampered.

♪♪ [ Snort ] Compared to horses today, she was tiny, a vulnerable animal.

♪♪ Desperate for cover.

♪♪ [ Insects chirping ] It's true this creature was nothing like the horse we know.

[ Suspenseful music plays ] But she was a perfect reflection of her own tropical world.

There were dangerous predators.

[ Neighs ] But also places to hide.

♪♪ Dawn Horse was built to survive in dense forests.

[ Ethereal vocals play ] But I wonder: How did this evolve into this?

[ Ominous music climbs ] What on Earth happened to horses?

[ Suspenseful music plays ] Well, the answer is: Earth happened.

[ Portentous chorale plays ] Early horses were perfectly suited to their world, full of dense, lush forests, full of cover from predators.

I'm only a few feet away from you, but look how easy it is for me to hide.

And look at all the succulent leaves: a herbivore's feast!

This was a greenhouse world.

It stayed hot for millions of years and, in all that time, Dawn Horse hardly changed at all.

And then, about 18 million years ago, the Earth began to cool.

♪♪ With the cooling climate, tropical forests began to disappear.

[ Birds chirping ] A cooler world was also a drier world and, now, early horses were challenged to adapt.

As new kinds of horse emerged, to survive the cooling climate, new plants also appeared and the result was that large parts of the planet were covered by an entirely new habitat: grasslands!

[ Triumphant chorale climbs ] ♪♪ Grasses were Nature's answer to this cooler, drier world.

♪♪ Pound for pound, grass isn't nearly as nutritious as the fruits and nuts of the Eocene forest, but this was now the habitat horses chose and it's amazing, just how much this plant shaped the horse.

[ Snuffling ] Blades of grass are like sandpaper on teeth.

♪♪ So horses' heads became longer, to make room for rows of molars that never stop growing.

[ Snorting ] Their enormous eyes moved up their long heads, perfect for spotting danger while eating.

♪♪ Horses even developed a special kind of stomach, able to quickly digest grasses and immediately run.

♪♪ No cow can do that.

♪♪ Horses now lived in a world without cover.

Keeping a distance from predators was critical, so horses had to get faster.

♪♪ As horses grew, their legs became longer and thinner, the legs of a runner.

[ Neighing ] ♪♪ But the most amazing change of all was in their toes.

♪♪ They lost them all.

Except one.

[ Crackling ] Martin Fisher helps me understand.

FISCHER: Remember the Dawn Horse?

Four in the front THOMPSON: Yeah.

-FISCHER: and three in the back.

THOMPSON: That's right.

The phalanges, the finger bones.

FISCHER: This is the upper arm and this is the lower arm.

That's the wrist joint.

These are the bones here.

-THOMPSON: Mm-hmm.

FISCHER: And this is the finger.

THOMPSON: The finger.

Amazing.

And they stand on the end of that finger and run on it.

I mean, that's incredible.

-FISCHER: That's the point.

THOMPSON: And you say running.

How does this structure make running more efficient or faster?

FISCHER: The lesser surface you have, the lesser friction you have.

The lesser friction you have, the faster you can go.

THOMPSON: Right.

Stands to reason.

So it makes sense that you would go up on one toe and have a delicate connection to the Earth.

FISCHER: This is really an extreme adaptation.

THOMPSON: The epitome of a runner.

♪♪ Standing on a single toe, the horse sits far out on the end of its evolutionary branch: an animal built to run, specialized for speed.

♪♪ Millions of years after it evolved, that extraordinary ability has us bewitched.

♪♪ In the modern world, machines do the work horses once did, but our fascination with the running horse hasn't ebbed at all.

♪♪ For good reason.

There's no other animal on Earth that can carry a human this fast.

♪♪ It just shouldn't be possible.

How does this huge mammal practically fly?

[ Birds chirping ] If you want to understand just why horses are so fast, Kentucky is a good place to start.

David Lambert has spent a lifetime studying the thoroughbred, breaking down the physics and chemistry of a running horse.

I've pulled David away from his work to help me understand, with the help of a special, slow-motion camera.

There we go.

So we'll be able to see the footage on this monitor as the horse runs by.

LAMBERT: Perfect.

Yeah.

Let's do it.

[ Hooves thudding ] THOMPSON: Hoh!

-LAMBERT: [Laughing] THOMPSON: Honestly, all I see is a blur LAMBERT: Yes.

Yes.

-THOMPSON: of moving parts as he goes past.

If we take that run-past and slow it down a little bit, tell me what you're seeing there in the body.

LAMBERT: So let's look as he puts his foot onto the ground, right there, and, now, he's loading that tendon and that ligament, and it's bouncing and throwing the leg forward.

That leg's being thrown by elastic, stored energy, not by muscle.

And it's like a catapult.

The size of the forces just throw those bones out there and back again and onto the next stride.

THOMPSON: So that's very efficient, when those elastics give the energy back to the horse.

-LAMBERT: Yes.

Yes, without that elastic energy, he'd have to have legs which were 100 pounds in weight, just in muscle, to move his big body.

[ Suspenseful music plays ] We're dealing here with a very heavy animal.

1,000 pounds, 1,100, 1,200 pounds.

[ Snorts ] As that weight descends, it loads up all the soft tissues in that limb.

The load is suddenly released and, then, the leg is simply propelled out into space, driven by stored, elastic energy.

It's happening all over the horse's body: along his back, on his hind legs.

When he gets going, he's going so fast and there is so much stored energy, it reaches a point where it's beyond control.

♪♪ ♪♪ When you compare him to all the other mammalian species, he kind of stands alone, in terms of his size and his speed.

He's out there on a little pinnacle all on his own.

♪♪ THOMPSON: You know, I've noticed one thing: When we're listening to the training horses as they go past, you hear this enormous breath, every stride.

It sounds like they're struggling for breath.

LAMBERT: Their stride is linked, one-to-one, to their breathing.

When the horse runs, he must breathe out when his front legs hit the ground and he can only breathe in when he's up in the air.

[ Suspenseful chord strikes ] ♪♪ When we run and breathe, we're using our ribs.

He's not doing that.

His ribs are locked closed and when he puts his weight on his front legs like that, the weight and the momentum of his viscera is pushing against the diaphragm and creating like a big piston inside his body, so it pushes the air out -THOMPSON: I see.

LAMBERT: and then, when he comes up in the air, the viscera drop back and it sucks the air in.

So he's a big piston, doing this.

THOMPSON: Front legs down, breathe out.

Up in the air, breathe in.

♪♪ LAMBERT: And that creates certain limitations.

The faster he goes, the less time he's got to breathe.

THOMPSON: It sounds to me like it's not -- It's not like breath holding, but it is like suffocation.

LAMBERT: It would be suffocation for you and I, but, again, the horse is different.

His body has adapted to tolerate this unique situation that allows him to keep going far longer than you or I could keep going.

♪♪ We don't think of racing, the first step of a race, as being the first event in asphyxiation.

If you or I were to run, we can't drop our oxygen level.

It's too painful.

A horse, however, doesn't seem to have those same restraints.

He'll take all the last, little drop of oxygen and drain it all out, right to the very, very last drop.

♪♪ He's at a point, at the end of a race, which would render you or I unconscious.

For some people, it would almost kill them.

It's extraordinarily severe.

♪♪ THOMPSON: Severe for us, but not for a horse.

♪♪ That ability, to run on very little oxygen, is a gift of evolution and in the past, it kept wild horses alive as they outran their predators.

[ Whinnying ] All horses can do it.

But some can do it better.

♪♪ Tapeta Farm, in Maryland.

A kind of exclusive, private school for thoroughbreds and the home of legendary trainer Michael Dickinson.

Owners send Michael their most promising horses and he tells them how promising they really are.

[ Static crackles ] DICKINSON: That's nearly perfect.

THOMPSON: He works closely with David, who's spent a lifetime building a system to predict how fast a horse will run.

[ Neighing in distance ] [ Whinnying ] SPEAKER: Easy, girl.

THOMPSON: Today, David and Michael are taking three horses out for testing.

He needs these horses to sustain 45 miles an hour for a full mile.

That's twice as fast as humans have ever gone.

DICKINSON: Perfect.

[ Crackle ] Well done, Alex.

Thank you.

My one-acre road.

So they all went all right, didn't they?

[ Grumbling ] Did nothing wrong, did he?

THOMPSON: A hard gallop is punishing.

But it turns out, the cost is even higher than I thought.

[ Neighing ] LAMBERT: When a horse tries to run flat out, he's so big and he's going so fast, so there's a price to pay for that.

The blood gets more and more acidic all the time.

The carbon dioxide in his blood builds up and up and up and up and gets really high.

THOMPSON: These are all things that, when we're running or we're swimming, feel really painful, and tell us to stop, -LAMBERT: Yes, yes, exactly.

-THOMPSON: like a brake on our effort.

-LAMBERT: Yes, yes, exactly.

And horses switch those brakes off.

[ Neighs, snorts ] It's not altogether surprising that horses should be able to do this because there are other animals.

Seals, when they dive.

He can go down into the water and swim around for a long time without having to breathe.

Essentially, it's the same process.

[ Huffing ] THOMPSON: So when we get a pain signal that tells us to stop running, something different happens in a horse.

It begins to metabolize energy without oxygen.

Human can do this, but not as well as horses.

LAMBERT: Some of the byproducts of this process are euphoric.

He's feeling positive; he's feeling energized.

Basically, he's high.

So the typical picture that a person would have of a thoroughbred racehorse is that bouncing, lively, snorting animal.

All of that is coming from this euphoria they're feeling, having gone to a level of fatigue that we couldn't even tolerate.

THOMPSON: The physiology of the horse is set up to sacrifice everything for a run.

-LAMBERT: Mm-hmm, absolutely.

THOMPSON: Can you think of another animal that would do that for us?

-LAMBERT: No, no, it's amazing.

[ Suspenseful music plays ] [ Ethereal vocals join ] ♪♪ All those things that we feel when we're around a racehorse: courage, admiration.

♪♪ There's something special about these animals because they've endured.

♪♪ [ Snuffling ] ♪♪ And there's something unbelievably trusting about the way they will respond to the care of the humans and come around and do it again.

♪♪ THOMPSON: Horses take us to speeds we could never reach on our own two feet.

[ Triumphant chorale plays ] Yet, without a human in sight, horses still love to run.

It's just their nature.

♪♪ [ Neighs ] So I wonder, in the horse's past, was their amazing speed how they survived?

♪♪ Only one animal can answer that question.

[ Neighs ] ♪♪ Deep in Mongolia's Gobi Desert, there's a cousin of the modern horse, very different than the animal we know.

We call them Przewalski horses.

Incredible.

It's gorgeous!

Right down there is a green valley running right along the sands of the Gobi Desert and, somewhere in that valley is the closest living relative of the horse.

This species went extinct in the wild, but, now, it's back.

[ Suspenseful music plays ] ♪♪ [ Birds tweeting ] [ Tender tune plays ] ♪♪ [ Snorts, grumbles ] ♪♪ [ Snorts ] A stallion group.

[ Whinnying ] No mares in sight.

For now, this is play-fighting.

Rehearsal.

[ Snorts ] ♪♪ The Przewalski horse is so rare, I've only ever seen them in pictures.

At one point, there were only 12 animals left, all of them in captivity.

[ Whinnies ] Few people believed these horses would ever return to the wild.

[ Whinnying ] They're here today because of this woman: conservation biologist Claudia Feh.

For decades, Claudia fought to bring a handful out of captivity and, eventually, back to their native habitat.

Now, there are 67 in her reserve.

Most of them were born here, in the wild.

[ Whinnying, snorting ] Claudia's project is a fragile success.

♪♪ Because the Przewalski lives in the closest thing there is to the original home of horses, I think they can tell me how horses survived before we tamed them.

♪♪ At dawn, Claudia takes me out to find the biggest herd.

To survive, wild horses need a big territory, but that means they can be very hard to find, even for Claudia.

Yep.

I don't see a thing.

FEH: I see many things, but no horse.

[ Laughter ] -[Speaking local language] [ Clicking ] -They're in the sandy part.

Very strange.

Usually, when they are in unusual places, something happened in the night.

Either there were stallion problems, stallion fights, or wolf attacks.

[ Birds chirping ] THOMPSON: Just a generation ago, all Przewalskis lived in zoos.

But out here, nothing is protecting them from predators.

The Mongolian wolf is a constant threat.

[ Snorting ] So is it speed that keeps these horses alive?

Or is it something else?

FEH: I choose the animals in such a way that they would be compatible because I really hoped that they would form a herd again.

The big herds are much more efficient against predators.

[ Whinnying ] Horses' typical predators are wolves.

They hunt in packs.

I've seen wolf attacks.

The whole herd gathered together and the stallions attacked.

THOMPSON: The stallions attacked?

FEH: Attacked.

They attacked; tried to bite and tried to kick them with their forelegs.

So you have cooperative predators and cooperative prey.

THOMPSON: So the fact that they're being predated by groups of wolves has forced ho rses to be cooperative.

FEH: They do have a sort of real cooperation.

They know what task sharing is in the highly complex social herds.

[ Snorting ] [ Poignant tune plays ] THOMPSON: But not all herds are the same.

There are bachelor groups, a collection of stallions without mates; and there are family groups, mares and foals, with a single stallion.

♪♪ The bonding behavior is constant.

Mutual grooming.

Subtle hierarchy displays.

And, sometimes, not so subtle.

[ Whinnying ] ♪♪ The horses are constantly negotiating for a rung on the ladder.

Each horse has its place.

Hierarchy gives the herd strength and ensures only the fittest stallions get to mate.

♪♪ But I'm surprised to learn it isn't just the toughest stallions who rise to the top.

FEH: The dominance hierarchy in horses is not based on size.

It's not based on physical strength.

It's mental strength.

It's personality.

THOMPSON: It's recognizing character.

You recognize the character of the leader.

FEH: Yeah.

And I think that translates to the horse-human relationship because, obviously, if you ride a horse, I mean, the horses are, what, about ten times heavier or five times heavier?

So how can we ride a horse, being so much smaller, and dominate the horse?

It's mental.

[ Snorts ] ♪♪ THOMPSON: These wild horses can fight and run.

But, according to Claudia, that isn't really why they're still here.

♪♪ For them, survival is about working together, about social life.

Perhaps that's why they accept Claudia almost like one of the herd.

♪♪ Left to themselves, horses build a community.

And, just like for us, it's the community that protects them.

FEH: I try to help them have a more natural life.

Horses do not need to be ridden, you know?

[laughs] They don't need us.

They are independent, happy to be independent.

♪♪ THOMPSON: This amazing spectacle, truly wild horses living without humans, it's like a vision from the past with a message about horses today.

It turns out, speed and power aren't so important as the quality they share with us: a social mind.

[ Grumbling ] And, everywhere we see horses today, we see that social mind at work.

What the Przewalski horses do in the wild, our own horses do in our fields, if we only let them be themselves.

It's amazing how eager horses are to please.

Without a language in common, that's like mind-reading, an incredible ability that English animal psychologist Karen McComb is trying to understand.

At a riding stable, Karen's researchers are preparing for a day of horse testing.

For Karen, this is science.

But, for the horses, [chuckling] it's play.

McCOMB: I mean, anyone who's worked with horses, they sense this enormous personality that differs from individual to individual.

No one has looked at that it an animal.

We're used to the way humans express emotion, but, actually, horses are making these very subtle facial movements and have an incredibly mobile face and they are expressing emotions as well.

What we really want to do is work out what the emotional life of horses really is, what their emotional world is really like.

THOMPSON: To build her library of horse emotions, Karen has designed a set of experiments to trigger them.

[ Whimsical tune plays ] She plays recorded horse talk and observes the response.

[ Rumbling nearby ] Startled and afraid.

[ Cheeping ] Or curious.

♪♪ She shows them photographs of horses and of humans.

[ Neighing nearby ] ♪♪ Toffee likes this one.

[ Neighing nearby ] [ Snorting ] This one isn't so popular.

♪♪ Karen's team has made the surprising discovery that horses have 17 different facial expressions.

That's three more than chimpanzees and one more than dogs.

[ Neighing nearby ] They're subtle.

But, by playing the images back, Karen can show me what the untrained eye might miss.

McCOMB: He's sniffing the ground, ostensibly, and you'd think, "Ooh, he's just sniffing the ground.

Another horse was in here."

But stop.

Actually, that sniffing the ground again occurs consistently in response to something that's a bit more negative, so that he's unsure about this.

Humans do that as well, you know.

When we're a bit uncomfortable, we might scratch ourselves or we glance away from something.

Just gives us a little bit of time to adjust.

[ Birds chirping ] [ Hooves thudding ] [ Snorting ] So, now, this'll be interesting.

Look at what part of the face he's gonna go to.

Look, he's going towards the -- -THOMPSON: Right to the mouth.

McCOMB: The mouth, yeah.

And sometimes they go right up to the eyes.

Yeah.

It's interesting, that sweep between the mouth and the eyes.

It's almost as if they understand that the mouth and the eyes are the most significant bit of the human face.

They have enough understanding to interpret, not only emotion in the faces of their own species, but emotion in our faces.

[ Birds chirping ] [ Hooves thudding ] THOMPSON: It makes sense that horses use emotions [ Neighing nearby ] to communicate with each other.

But what fascinates me is they can read our emotions as well.

[ Huffing ] McCOMB: They're capable of putting together the sort of representation of the person with the emotion.

To me, that shows a very acute emotional awareness.

I mean, that means, really, horses are eavesdropping on the human world all the time.

[ Neighing nearby ] [ Snorts ] THOMPSON: Horses are mind-readers.

But that's not all.

Karen is also interested in another quality: curiosity.

[ Neighing ] So this is interesting.

Leanne is going to do what she calls a novel-object test, which means walking into a paddock full of horses with a great, big beach ball and leaving it there and observing what the horses do.

Will they run away from it or will they come and investigate it?

-[Neighing] -[Snorts] McCOMB: Horses are naturally very inquisitive.

[ Neighing nearby ] We're also trying to see where personality fits into the whole thing.

For example, how bold an individual is, versus shy.

It's these differences, which we also see in humans, that are going to be the stuff of their emotional lives, too.

[ Grumbling ] THOMPSON: With these tests, Karen is able to identify outgoing horses and introverts, just like we see in humans.

Popular horses like to spend time with other horses.

But the horse standing at the edge of the field might prefer human company.

-[Neighing] -[Snorts] McCOMB: Children who don't fit in will turn to their pets, but it's quite interesting [chuckling] that horses that don't quite fit in will also turn to humans.

[ Neighing nearby ] [ Snorting ] And our tests are actually showing that.

[ Tender tune plays ] [ Rumbling ] THOMPSON: These experiments paint a picture of an intensely social, curious, emotionally alive creature.

If we pay attention, we can read a horse's mind and they can read ours.

[ Neigh nearby ] ♪♪ And, wherever we bring horses to work, mind-reading is just part of the job.

[ Lowing ] On the eastern slopes of the Rocky Mountains, horsepower still means just what it always has.

Working cattle is one of the most demanding jobs a human can ask a horse to do, and that's why cowboys created the quarter horse... [ Snorts ] ...a remarkable breed, combining endurance, agility, power... ANDERSON: Whoa.

-THOMPSON: ...and smarts.

ANDERSON: [Whistles] [ Birds chirping ] [ Smooching ] THOMPSON: In horse country, Jimmy Anderson is a bit of a legend.

They say he can read a horse's mind.

But maybe it's the other way around.

[ Snorting ] Either way, he seems to have a secret language with his horse, a gelding called Maverick.

-ANDERSON: Up.

[cluck] Up.

[cluck] He likes sittin'.

[ Laughing ] Whoa.

[ Birds chirping ] THOMPSON: People who are not working with horses the way you work with horses, they're just seeing the tip of the iceberg.

There's a whole animal they haven't discovered.

ANDERSON: The person really doesn't see and look at that horse.

They just kind a treat it like a motorbike.

THOMPSON: And a motorbike is not a smart animal.

[ Laughter ] Not compared to a horse.

ANDERSON: Not compared to a horse.

That is so true.

[ Lowing ] THOMPSON: Cutting calves is standard ranch work.

But, it fascinates me.

In nature, wild horses were chased by predators.

So how does Jimmy get Maverick to do this?

It's the behavior of a sheepdog, not a horse.

When you're cutting, are you giving Maverick directions to go right and left?

ANDERSON: It's happenin' too fast.

If you're trying to give them directions to go right and left, most times, you're late.

When I drop my hand, that's signaling to him, "Okay, now it's your turn, your responsibility.

Take over."

-THOMPSON: Takes over.

ANDERSON: Yeah.

-THOMPSON: Knows what to do.

ANDERSON: Knows what to do.

They just look after that.

Yeah.

-THOMPSON: That's incredible.

ANDERSON: That's kind of the exciting part, is how smart these horses are.

You can really train a horse to do anything.

We could train it to fetch, if we wanted.

THOMPSON: Horses are so smart, they can learn to do things that go completely against their nature.

But it takes training.

We used to call it breaking a horse.

But that isn't it at all.

♪♪ ANDERSON: In the past, when we've talked about colt starting and colt breaking, that's what it was.

They wanted to get a job done, kinda just force everything onto this horse.

They expected the horse to jump; they expected the horse to rear, they expected 'im to buck, because there was no relationship.

Talk about breaking the spirit.

And, now, it's almost the opposite of what we're wanting now.

We want that spirit; we want that heart; we want that desire.

THOMPSON: I'm here to see Jimmy start a two-year-old colt called Shiver.

Until now, Shiver's only seen humans from a distance.

He's never been ridden.

[ Neighing ] [ Huffs ] [ Neighing ] ANDERSON: Now, what I'm gonna do is start workin' myself a little bit closer to 'im.

THOMPSON: I've come for the week, but Jimmy figures he'll get a saddle on sooner than that.

[ Neighing ] That seems a little optimistic to me.

[ Neighing ] ANDERSON: And so... he's tryin'... [ Snorts, huffing ] There.

The-e-re we go.

You'll hear me talk about two eyes.

THOMPSON: Mm-hmm.

-ANDERSON: When that horse can start to give me them two eyes, he also gives me his focus.

[ Huffs ] [ Snorts ] Ni-i-i-ce.

He really needs to get used to this.

THOMPSON: If he can't take that touch, he won't take a saddle.

ANDERSON: [chuckling] No.

We're getting him used to an external pressure.

Tap this hind end and have him yield that hind end.

Nice.

Tap this hind end... [ Huffing ] The-e-re.

Nice.

I'm gonna come up here, see if I can't get some pettin' in there.

[ Huffing ] [ Grumbles ] THOMPSON: Jimmy knows horses are prey animals.

Dogs are always looking for supper, but horses are looking for safety.

And that need is Jimmy's magic key.

[ Grumbling ] ANDERSON: When I look at horses that are spooky, if he's away from the herd, he doesn't have a leader.

When you get that trust and that confidence and that relationship with a horse, I mean, really, sky is the limit of what you can do.

[ Huffing ] When I start a colt, it's never a competition.

It's more of a partnership and a relationship that we can start to get workin' together.

I'm gonna come up here and, now, with the rope, I'm gonna move them hindquarters.

Move those hindquarters.

Move those hindquarters.

Nice.

[ Snorts ] [ Grumbling ] THOMPSON: How do you know how far to take it and when to stop?

ANDERSON: You know, we're lookin' at the expression in his face, lookin' at that tightness through his neck.

He's tellin' me, "Jim, you can do more," or "Jim, I'm gettin' too worried.

I can't take this."

So that's where I'm just readin' him and lettin' him tell me how much.

And so, when I can go through this with him not gettin' worried and just no big deal, that's when it's gonna tell me he's ready to saddle.

[ Neighing ] [ Grumbling ] Now, he's gettin' good with the tarp.

Ni-i-i-ce.

Good boy.

THOMPSON: So what are you doin' now, Jim?

ANDERSON: I'm just bringin' Maverick in.

Maverick's gonna give him a little bit of confidence as I put the saddle on.

THOMPSON: And that's the first time?

ANDERSON: That's the first time, right there, yeah.

[ Neighing ] [ Grumbling ] [ Whinnying ] [ Grumbles ] And that is totally okay with me.

He kinda got worried.

He had to deal with it that way a little bit.

That's totally okay.

Yeah.

There, he moved his feet, kinda tightened up, but come back.

And so, the next thing that I'm workin' here -- see, every time he stops, I want him to start to look for me.

The-e-e-re we go.

Ni-i-i-ce.

[ Birds squawking ] That's what I wanna see.

That focus, that lookin' to me for that answer.

THOMPSON: [chuckling] He's come a long way since morning.

ANDERSON: He's come a long ways, yeah.

[ Snuffling ] [ Birds chirping ] I need to get him used to me jumpin' up and down here 'cause, if I wanna get on him... [ Grumbling ] [ Grumbling ] Really, really good changes here.

[ Clucking ] [ Grumbles ] [ Poignant tune plays ] ♪♪ ♪♪ THOMPSON: Just amazing.

Completely calm.

♪♪ ANDERSON: [Clucking] ♪♪ My partner's helpin' me.

THOMPSON: [Laughing] ANDERSON: [ Smooching ] Yeah.

[ Smooching ] ♪♪ [ Clucking ] -[Snorts] [ Smooching ] ♪♪ [ Smooching ] -[Whinnies] [ Smooching ] ♪♪ Nice.

THOMPSON: That was just superb.

That was incredible to watch.

ANDERSON: Good boy.

You know, couldn't have asked for a better first day.

Good boy.

And here he is.

For the first time.

THOMPSON: He's your best friend now, isn't he?

ANDERSON: Yeah.

When I take the halter off, what I want to see is him not leavin' me.

[ Birds chirping ] [ Whistles ] His focus isn't there.

[ Grumbling ] Ni-i-i-ce.

Perfect.

See?

And I wanna be hooked up to these, not through a rope -THOMPSON: Yeah.

ANDERSON: or through manhandlin' or forcin', through their mind.

♪♪ THOMPSON: In a single morning, Jimmy and Shiver have found a common language.

♪♪ It's truly incredible, what we can do together when a horse agrees to trust in us.

♪♪ After all, we sit on a horse's back exactly where a wolf would've leapt up to attack.

It shows us: horses judge humans and some of us pass the test.

ANDERSON: Horses are really amazing, [ Lowing ] how much they will be a partner and they try a crazy amount and I wanna try that same amount back for them.

[ Lowing ] When they give me that much trust, I can never let anythin' bad happen to 'em.

When I lay Maverick down in the arena, he has given me his trust.

Maverick knows I won't let somethin' happen to him.

♪♪ THOMPSON: The more time I spend with horses, the more I understand what a gift they are.

A body loaded with the most amazing physical attributes, yet, also, a mind that connects with our own.

That's what makes our partnership unique.

But I wonder: How did it all begin?

[ Suspenseful music plays ] In the final episode, travel back in time and discover how horses sparked the beginning of art.

FLOSS: These guys had a spiritual connection with these animals.

Join me on a journey into the incredible world of horses today and be amazed at their diversity.

♪♪ [ Neighing ] From the coldest place on Earth to the hottest, and even to an uninhabited island where horses rely for survival on seals.

[ Poignant tune plays ] And learn why, no matter what, horses are here to stay.

RED CROW: We are still on our horses, just like our forefathers.

It's our way of life.

[ Music climbs ] THOMPSON: From their incredible power and speed to their intelligent and social nature, it's no surprise we built our world with horsepower.

ANDERSON: When you get that trust with a horse, sky is the limit of what you can do.

THOMPSON: But how did we shape this remarkable creature into the 350 breeds that exist today?

Let's take a global tour of the most fascinating members of the modern horse club.

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

♪♪