Original subtitles

NARRATOR: The Ethiopian highlands.

Lost world.

Home to creatures found nowhere else.

A monkey like no other.

Sole survivor of a vanished tribe

that once ruled the continent.

And one of Africa's rarest predators,

a high altitude rat-catching wolf.

How do these extraordinary animals survive

in this land of extremes?

And how did they get here?

To find out, we must travel to one of the most geologically

violent places on earth.

Where awesome forces create and destroy

and ferocious rivals battle for dominance,

changing the course of evolution on the roof of Africa.

Hello.

I'm David Schwimmer, and I play a paleontologist on television,

but in real life, I'm a pretend naturalist.

Behind me is a rat, one of the delightful creatures

eaten in this episode of "Mysterious

Planet, Roof of Africa."

[eerie music]

Dawn in the highlands of Ethiopia,

a group of very unusual animals huddle together

on the edge of the abyss.

Gelada, not Italian ice cream but

just as tasty, a species of monkey unlike any other

found only here, an environment few can survive.

After spending the night sleeping on a sheer cliff,

their day begins by warming up in the sun.

Upon inspection, they look to be hot air balloons.

This is a family unit, a mature male

with a magnificent cape of fur, several females,

and their offspring.

And these are young males, who hang out together until they

get their own family.

But all geladas share the same distinctive feature,

an hourglass shaped patch of red skin on their chests,

which gives them their unofficial name,

the Bleeding Heart Baboon.

Even in the highlands, political branding occurs.

But geladas are not actually baboons.

They are something unique.

They are the sole survivor of an ancient group of monkeys

that once dominated African.

So how did they end up all alone in this high altitude realm?

The Ethiopian highlands are one of the most dramatic landscapes

in Africa, a vast, high altitude plateau spiked

with dramatic peaks and split in half

by a great shear-sided valley.

At 2 miles above sea level, the air is thin

and UV radiation fierce.

And not a dermatologist available anywhere.

The temperature can change over 70 degrees in a day

from below freezing to almost 80.

On the roof of Africa, it's summer every day

and winter every night.

So spring is around noonish.

Once the gelada family has warmed up,

it's time to begin their daily commute.

Sometimes over 1,000 geladas join up and travel together.

One of the largest gatherings of primates on Earth.

And they're all after the same thing, a very

unusual food for a monkey.

Pancakes?

Nope, grass.

Geladas are the only monkey on Earth to feed

almost entirely on grass.

With nimble fingers, they carefully

select the juiciest blades.

But grass is low in nutrients, so geladas

have to search for the richest meadows

and spend up to 10 hours a day sitting, plucking, and chewing.

A monkey with the diet of a cow, a conky.

There were once many more like them spread across Africa,

but now the gelada is the last of the grass-eating monkeys

isolated on the roof of Africa.

Geladas are not the only unique animals living up here.

At their heart, the highlands are

a great high altitude grassland, a savanna in the African sky.

But there are no wildebeest or zebras here.

It's too cold, and the air is too thin for Africa's

large grazers.

There is life, you just have to look a little closer.

Rodents.

In the Ethiopian highlands, 14 unique species of rat and mouse

have evolved to take the place of more familiar herds.

Not sure it's something to brag about, but how do

they thrive where others can't?

Ask the ones that live in my wall.

Ah, by living underground.

Their burrows protect them from the harsh climate

and the vast grasslands sustain huge populations,

up to 15,000 rodents per square mile, like the East Village.

The largest rodent in the highlands

is the giant mole rat, and he can talk.

Not really, but they can weigh over 2 pounds

and spend most of their time in their network of burrows.

They only emerge to quickly grab a mouthful of food

before disappearing again, similar to the North

American teenager.

It's wise for the rodents of the highlands to be careful though.

Uh-oh.

Where there are rodents, there are rodent eaters.

The Ethiopian wolf, lean and lethal,

perfectly adapted to the high altitude and harsh climate,

and a specialist rodent hunter.

But it's not always this easy.

Wolves must be patient and cunning.

The rats lairs can have multiple entrances,

so the wolf must listen carefully to pinpoint its prey.

It's a game of hide and squeak.

It's long thin muzzle is perfect for poking into rodent burrows.

And for blowing to flush its victims out.

Fortunately, the rat doesn't have a brick house.

Of all the rodents in the highlands,

there is one the wolf loves best.

A giant mole rat is a juicy feast, if you can catch one.

Though the mole rat has poor eyesight,

it has highly sensitive hearing and no toothbrush.

The slightest movement, cue wolf, and it's gone.

Damn it.

But this ruthless hunter will not be denied.

OK, that's-- we don't need to watch this.

Yep, that's-- OK.

Ethiopian wolves often hunt in the geladas meadows,

but the wolves are such specialists rodent hunters

they completely ignore the monkeys.

Rude.

And the geladas have no fear of the wolves.

Two unique species living side by side on the roof of Africa.

So how did they get here?

To find out, we need to descend deep

into the belly of the Earth where awesome forces

are tearing Africa apart.

Suspenseful beat.

Right through the heart of the Ethiopian highlands

is a great rift, sheer cliffs drop two

miles down into a vast valley.

And at its northern end is a sunken tortured landscape,

the Afar Depression, gateway to hell.

Here, we get a glimpse of the forces that have shaped

life in this part of Africa.

This is Erta Ale, one of the most remarkable

volcanoes in the world.

A bubbling cauldron of molten lava

over 1,800 degrees, a window into what

is going on right beneath Ethiopia and into my psyche.

It all begins 40 million years ago

when a massive column of magma starts

melting its way towards the Earth's surface, a super plume.

It pushes up the ground in a huge dome like a blister.

Prom flashback.

Lava oozes through cracks in the dome covering most of Ethiopia

in a layer over a mile thick.

And as the land continues to rise, huge volcanoes erupt.

Today's highland's are the weathered remains

of this volcanic dome.

Over time, life takes hold, and in isolation

evolves to become unique.

Derek?

Yes?

Why the long face?

The super plume lurking beneath Ethiopia

pushes up these highlands, but it doesn't stop there.

Next, it begins to tear the whole continent of Africa

apart.

Pushy plume.

The colossal heat from below opens up a great rift

in the Earth's crust spreading from the Afar Depression

splitting the Ethiopian highlands in half

and creating a dramatic Valley 300 miles long.

At the bottom of this rift lives another monkey,

which has played a leading role in the mystery of the gelada.

A group of them is on the move across the hot,

arid Rift Valley.

At first glance, they look like geladas,

but they are very different.

These are Hamadryas baboons.

The ancient Egyptians once worshipped them as gods.

I mean, did you see their red butt?

But those days are long gone.

They must struggle to survive at the foot of the highlands.

If geladas live on the roof of Africa,

hamadryas live in the basement, like the average college

graduate.

There are no lush pastures here, water and food are scarce.

Hamadryas are true baboons, and like all baboons,

they are omnivores and will eat almost anything.

This environment is too harsh to be fussy.

Is he eating what I think he's eating?

Ugh.

They are constantly on the move foraging for any scraps

of food or poop they can find.

The alpha male keeps a careful eye on his family,

especially the females.

It's dangerous to be so spread out in the open,

yet they have to move to survive.

But he knows where he is going, and he leads his family

to a special place with deep pools of clear water and palm

trees laden with fruit.

Where did this oasis come from?

Is this a baboon mirage?

These are the Dollol hot springs,

say that fast three times.

The water is 113 degrees, a baboon day spa,

heated by the same fury beneath the earth that created

the highlands, and a reminder of the powerful forces

that have shaped all life here.

The super plume that lurks below Ethiopia

has created two very different habitats

for two very different monkeys.

Although they live separate lives today, millions of years

ago, their ancestors clashed in a desperate struggle

for survival on Africa's grasslands.

One tribe dominated, while the other was

almost wiped from the earth.

High on the roof of Africa, a troupe of geladas

are doing what they spend almost all their time doing,

eating grass, and calculus.

It's a smart evolutionary strategy,

though grass is nutrient poor, there is so much of it they

don't need to fight for food, so their society

is stable and peaceful.

Huge groups mixed together happily and violence is rare.

But there are exceptions.

As the females of the family graze, the alpha male

is keeping a close eye out for trouble.

And here it comes.

A gang of young bachelor males, troublemakers on the edge

of society, especially if they've been drinking,

waiting and watching for an opportunity.

It starts with the stare down now.

Oh, I have been here before.

The alpha male warns the intruders

first with an eyebrow raise.

You talking to me?

Then by rolling back his top lip and exposing

his huge canine teeth.

I would have opened with that one.

The largest in proportion to body

size of any mammal on Earth, but his challengers

are not scared off that easily.

The bachelors charge the alpha and appear

to have him on the run.

But it's a trick, he's leading them away from his family.

Smart monkey.

Not that they seem very concerned.

Why?

Because it's mostly all for show.

The bachelor males are challenging the alpha,

but not in a battle to the death.

It's more about showing off.

All of the females in each family group are related,

and they call the shots.

If this alpha male can't demonstrate

he's fit enough to defend the family,

they will choose another.

This combination of abundant food and a stable social system

was a winning formula for the geladas ancestors

when they first evolved.

And their rise was a direct result

of the violent geological forces that lurk

below this part of the world.

4 million years ago, Africa's climate is much wetter

and lush forest is widespread, but again,

the mantle plume is stirring.

As the Rift Valley continues to unzip East Africa,

mountains rise along its edge and the climate

of the whole continent changes.

The high terrain creates a rainshadow and East Africa

begins to dry out.

Rainforests shrink and grasslands grow.

A group of monkeys called therapithicus

take advantage of this change.

They evolve to become specialist grass eaters

and spread across Africa.

Some grow as big as gorillas.

One species even colonizes the remote Ethiopian highlands

and becomes today's geladas.

The peaceful, grass eating monkeys

dominate Africa's savanna for over a million years.

Yet, geladas are now the last of them

confined to their harsh sanctuary in the clouds.

What brought the reign of the therapithicus monkeys

to an end?

One of the key suspects lives two miles below, a rival monkey

tribe that has forsaken living peacefully

and chosen the path of war.

The violent volcanic forces beneath Ethiopia

have forged a unique and dramatic landscape.

These vertical cliffs are ancient fault lines

along the floor of the Rift Valley, an ideal sanctuary

for hamadryas baboons.

Their family structure is the opposite

of the female dominated geladas in the highlands above.

The alpha male is firmly in control,

and he employs a carrot and stick

approach to ruling the family.

He can be kind and helps look after the young,

but any females that dare to wander from his sight

are ruthlessly dealt with.

See, that's the definition of harassment.

Luckily for this family there's little need to stray.

The geothermal oasis provides plenty of food and water.

They can stay close to each other and the alpha male

is less concerned about wayward females.

But like Ethiopia itself, violent forces

bubble just below the surface always threatening to erupt.

Lookouts sound the alarm.

War is on its way.

A rival clan wants what they have.

The alpha males hurl themselves into battle, apes of wrath.

Ordered society turns to chaos, like Twitter.

The family leader is cornered by snarling rivals,

like peer reviews gone horribly wrong.

But there is method to the madness.

The raiders have a clear strategic goal.

They're not after food or water.

They're after females.

This is a mass kidnapping, and when

they have what they came for, they retreat,

leaving the hot springs clan licking their wounds

and minus several young females.

Such violence couldn't be more different from gelada society,

but is typical of baboons, and is a key part of their success.

It was baboons that out competed the geladas ancestors in all

but the highlands of Ethiopia to become the dominant monkey

of Africa's grasslands, so at least they've

got that going for them.

But again, it was geology that provided the catalyst.

Baboons evolved in the far South of Africa at a time

when impenetrable rain forest stretched right

across the continent's center.

But as the Great Rift spreads South creating new grasslands

for the ancestors of the gelada, it also

opens up a route North for the baboons, a corridor 3 and 1/2

thousand miles long, an invasion route.

The aggressive, adaptable baboons rapidly

move up the Rift Valley and enter the realm

of the peaceful grass-eating monkeys,

like a high school bully in the hall,

and soon begin to outcompete them.

And there are more arrivals on the way.

An evolutionary explosion of grazing mammals

also spreads North along the Rift corridor

and soon dominates the savanna.

Even the climate turns against the therapithicus

against monkeys.

Et tu, climate?

Africa dries out so much that lush, green pastures

become arid scrub lands.

Adaptable baboons can still find food,

but one by one, the grass-eating monkeys become extinct.

I guess that's the law of the savanna.

Leaving just a single species isolated

in a mountain fortress.

The geladas high altitude kingdom is too harsh

for baboons or large grazer's to endure,

so the Ethiopian highlands become the last stand

of the grass-eating monkeys.

Passive aggressive victory.

Another day in the Ethiopian highlands, the rising sun

bringing relief from the frozen night,

but Ethiopian wolves are used to the cold.

They may hunt alone, but like all wolves,

they rely on the pack to survive.

Their day always begins with social bonding.

Oh, yeah, can you get that?

Thank you.

Thank you.

And the newest members of the pack

emerge from their den to greet the sun.

Yeah, that's a lot of cuteness.

While the babysitter guards the pups, the rest of the pack

goes out on patrol.

Hey, pups, you'll be kings of all that you survey.

The bad news, all you eat are rats.

DNA analysis has revealed the Ethiopian wolf's

closest ancestor is the greywolf of Europe and Asia.

How did they end up in the highlands of Ethiopia?

Teleport?

Simple, just like this.

They traveled across frozen grasslands.

After being torn apart by volcanic fire,

Ethiopia goes through one more dramatic change.

This time because of ice.

100,000 years ago the Earth is in the grip

of its last major Ice Age.

Frozen grasslands stretch from the Arctic

to Northern Africa allowing the Ethiopian wolf's

ancestor to simply walk its way onto a whole new continent.

After another successful hunting trip,

the pack returns to the den with bellies full of rodents,

hopefully dead, which they regurgitate for their young.

Oh, who's picking these clips?

Ugh.

In just a few months, the pups will

be hunting rats for themselves.

Yeah.

But for now, they're still enjoying

the best of both worlds, fresh rats

and fresh milk, rat milkshakes.

Awesome.

It's good they're well-fed because every Ethiopian wolf

pup is precious.

There are less than 500 of their species left on the planet.

20,000 years ago, the world begins

to thaw as the Ice Age recedes.

The wolf's habitat disappears everywhere

except in the Ethiopian highlands,

a frozen island in a warm sea.

Today, Ethiopian wolves have become such specialist rodent

hunters, they can't survive on anything else,

like me and ramen.

And since their prey lives nowhere else,

the wolves are stranded here.

The better they get at hunting rodents,

the more they lock themselves deeper into a desperate battle

for survival.

One of the rarest carnivores on Earth,

too specialized for its own good, which ironically might

be a play by Virginia Woolf.

At the foot of the Ethiopian highlands,

the hamadryas family is once again on the move.

As they walk, they send visual signals to one another.

A red swollen behind signals that a male is a mature adult,

or that a female is ready to mate.

Well, hello.

Since they're always on the move,

having these signals on their rear makes them easy to see.

No kidding.

It's a feature shared by all baboons

and a couple of guys I know.

This Rift Valley helped their ancestors become

the dominant monkey of Africa's grasslands

by invading the realm of the grass-eating therapithicus

monkeys and driving them from the earth,

except for one species.

Two miles above, the geladas are safe in their high altitude

sanctuary, but one mystery remains.

Why do they have that distinctive red patch

on their chests, the bleeding heart?

Geladas are not baboons.

They are the last of the grass-eating monkeys,

and since they spend their days sitting down,

it's no use having their sexual signals on their behinds.

Oh, I get it now.

So they wear them on their chests,

where everyone can see them.

Right.

Their highland home was created by a super plume of magma

beneath Ethiopia, which uplifted a vast volcanic dome

and created a refuge for a small group

of tough and unique animals.

Free of competitors and wet enough

to nourish lush pastures, the Ethiopian highlands became

a sanctuary in the African sky.

The last place these magnificent monkeys can call home.

Their ancestors were driven from the lowlands

by hordes of baboons, but there is another primate

that helped wipe them out.

What?

Who?

Us.

Oh, OK, sorry.

At the same time that baboons were expanding

into the African grasslands, the ancestors of our own species

came down from the trees and migrated up the Rift Valley.

Fossil evidence shows they preyed on the geladas ancestors

along the way.

The decline of their kind coincided

with the rise of ours.

And today, the grass-eating monkeys face a new invasion.

Ethiopia is one of the fastest growing countries in the world,

home to over 100 million people, and

the highlands contains some of the most

fertile land in Africa.

Now, the most remote reaches of the geladas kingdom

are being colonized by humans, and

the grass-eating monkeys are once again being

driven from their pastures.

I have opposable thumbs, why are you messing with me?

Ah, I'm out of here.

As the day draws to an end, the temperature

quickly begins to drop.

Winter is coming, as it does every night up here.

The geladas return to their sleeping cliffs.

The last of their kind, alone with their bleeding

hearts on the roof of Africa.