19x12 - Triumph of Life: The Survivors

[bunniefuu]

On a restless and violent planet

life has fought for survival
for billions of years.

Only winners leave descendants
in a ruthless and costly battle.

On the tree of life
are many dead branches.

Whole armies are now extinct,
known only by their fossils.

Today's animals are
the few survivors

of a four-billion-year w*r.

Against incredible odds,
many have dodged disaster

again and again.

Can the secrets
of these ultimate survivors

help to predict
the future winners

in the triumph of life?

This could be a scene from today

but it's the Cretaceous period,


In this distant age,
many animals look familiar.

Some creatures are
very different.

But evolution is shaping life
in exactly the same way.

Animals are exploiting each
other, trying to get ahead.

In this survival game,
the rules are always the same.

Only the players change.

But long-term success depends
on the ability

to cope with the unexpected.

A catastrophe like this
could happen again.

But whenever life stumbles

other life steps in and seizes
the chance to triumph.

After the dinosaurs' extinction

small, furry survivors
would inherit the earth

and give rise
to every mammal we know today

including ourselves.

A mass extinction

has always been followed
by a time

of enormous opportunity
for the survivors.

Dinosaur bones had hardly
started gathering moss

when mammals began building
a new dynasty.

many where small
insect-eating animals

rather like the tree shrews
of today.

For millions of years

they had lived in the shadow
of the dinosaurs

hiding under the cover
of night.

With the giant reptiles extinct

they emerged into the day
and flourished.

Usually, evolution works
at a snail's pace

but after a mass extinction,
the process goes into overdrive

filling the vacuum left by all
the animals that disappeared.

The resourceful mammals were
quick to take advantage

of new opportunities.

By coincidence, flowering plants
were also on the rise.

The mammals soon discovered

novel foods, like nectar,
pollinating insects

and fruit.

The furry pioneers began
to specialize

as they carved up
the new world between them.

Today, the mammals fill
all the roles once held

by the giant reptiles.

Giraffes specialize
in reaching the treetops

just as sauropods once did.

And big cats tear up large prey

following in the footsteps
of tyrannosaurs.

The dinosaur extinction
should be dear to our hearts.

It gave the mammals a chance
to take centerstage

and that made
our own evolution possible.

The history of life is
like a tree in early spring.

At the tips of the branches
are green shoots

representing species
alive today.

But these are a tiny fraction
of the tree's history.

A journey back in time
travels down the branches

that led to today's creatures.

Below are the boughs
and sturdy trunk

that represent
animals long gone.

Mass extinctions are like storms

stripping most of the leaves
from the tree.

The story of life is also
the story of extinction.

Some places look as though
they've been lifeless

for an eternity.

But the rocks tell
a different story.

Here and there,
the forces of erosion

open windows onto the past.

Today, only fossils tell us
that dinosaurs ever existed.

Most of life's secrets are
still hidden in the rocks.

Each step down the strata
is a step back in time.

Here and there we see snapshots
of past worlds now long gone.

The conditions needed
for a fossil to form are rare

so only occasionally
do these rocks hold

a glimpse
of our planet's life story.

Some chapters
are missing altogether

but where fossils are abundant

we can piece together
the world of that time.


the rocks preserved rare insight

into the story
of one large extinction.

This was the time of the clams.

Their watery homes buffered them

from the fires
that raged on land

and their shells protected them
from early predators.

For millions of years,
their world changed little

so neither did they.

The clam's simple design
had been a huge success

yet they were heading
for disaster.

A new generation of predators
with superior weaponry

invaded the clams' world.

The crustacean claw had arrived.

The claw was a huge advance
in shell-smashing technology.

Until then, thin shells
had provided ample protection

but predation
had just shifted gear.

The crustaceans caused carnage
on the sea floor

but their claws were
just the first blow.

For the clams, the next deadly
innovation was closer to home.

Carnivorous snails--

relatives of the clams--

evolved a tongue like a drill.

This rasping tool could grind
through the toughest shells.

Once the clams' defenses
were breached

the k*ller snails sucked out
their prey's innards

through the drill hole.

Now the clams were under siege.

A third blow came from fish.

Sharks had been around
for millions of years

and were no threat to the clams.

But from sharks
came a new generation

of specialist shell busters--

the skates and rays.

These clam K*llers had
bodies flattened

for life on the seabed

and powerful jaws
that could easily crunch

through fragile shell.

Before this predatory as*ault

clams had covered
the sea floor around the world

but now their numbers collapsed.

This was the end of an era.

Clams either shaped up
or faced extinction.

Clams hadn't changed
in millions of years

but a few kinds were able
to adapt quickly

and avoided extinction.

Some escaped by burrowing
out of reach.

Others, like the mussels,
fled to the edge of the sea

taking advantage of the tides

to leave
their old enemies behind.

Some clams
have removed themselves

from the fray completely.

Coquinas stay in shallow water.

They move up and down the beach,
tracking the surf line.

By living at the very edge
of the sea

coquinas dodge predators
from both ocean and land.

It's a marginal existence

but this adaptation saved them
from extinction.

If adaptability is
the secret of success

why have some ancient creatures
never changed?

The aardvark is
a design classic.

It has outlived
most of the early mammals

but is virtually identical to those
first aardvarks

preserved in the fossil record.

Aardvarks eat ants and termites

and for 70 million years,
they've hunted nothing else.

Valves in the nose
keep out soil.

Powerful claws make
light work of digging

and upside-down eyelashes
deflect upward flying dirt.

Aardvarks are
totally specialized

for eating termites.

tiny termites seem
a strange choice of food

for a large mammal

but they are
the aardvark's survival secret.

These insects have been
reliably numerous

for hundreds
of millions of years

giving termite eaters
the ultimate in job security.

Aardvarks can even break
into termite mounds.

Their huge claws smash
through rock-hard mud with ease.

Termites do fight back

squirting caustic chemicals
at the intruder.

But the aardvark
is rarely deterred.

And the longer
the predator stays

the more termites rise
from the depths

and swarm over the intruder.

But to no effect.

The aardvark
is now so specialized

that it couldn't eat
anything else.

Because it laps up termites
through a tubular snout

the aardvark has lost
its front teeth.

This would prevent it changing
diet if termites ever vanished.

The aardvark needs
enormous claws and sturdy limbs

but these would be too clumsy
for chasing larger prey.

This specialist will never be
a flexible creature

and yet its future looks secure.

The long-term survival
of any predator

is usually linked to its prey

and there will likely be plenty
of termites for aardvarks.

Other specialists
are more vulnerable.

But the cat's extreme speed
comes at a cost:

reduced bulk and strength.

It can no longer k*ll
with brute force.

It can trip a gazelle

but this tactic works
with few other animals.

Its jaws fit perfectly
around a gazelle's windpipe

but don't have the power
to choke other prey.

The cheetah's genes
for swift hunting

will pass to its young

giving them an edge
during their lifetime.

But specializations
that help an individual cheetah

are handicapping the long-term
survival of the cheetah line.

The African plains seem
full of prey for big cats

but a cheetah is now
very short of options.

Having sacrificed brawn
for speed to catch gazelles

most of the other wildlife
is now beyond its reach.

The cheetah is
not even strong enough

to guarantee protection
for its cubs.

Every year,
large numbers are lost

to slower
but more powerful lions.

This spirited attempt
to distract the lion has worked

but it will be many months

before the cubs
are out of danger.

The unspecialized hyena,
often a scavenger

is easily strong enough
to steal a cheetah's k*ll.

Hyenas are opportunists and
will steal prey from anything.

Their teeth can crush
the toughest bone.

Both fresh kills and rotting
carrion can be digested

by their huge stomachs.

Their behavior is
very flexible...

and they can hunt together

tackling animals a single hyena
could never manage.

Hyenas are versatile animals
with a bright future...

unlike cheetahs.

These elegant cats are
so reliant on gazelles

that if their prey
ever went extinct

or evolved a way
of outrunning them

cheetahs would soon disappear.

As the fastest land animal

the cheetah may be
a pinnacle of evolution

but ironically,
its success may be short-lived

like many specialists before it.

Nowhere is the triumph
of flexible behavior

more dramatically seen

than on the barren island
of Espanola, in the Galapagos.

Mockingbirds share this harsh
shoreline with seabird colonies.

They live by opening seeds
with a sharp, powerful beak.

The first mockingbirds to arrive
would have faced difficulties.

Seeds can be scarce

but the biggest challenge was
to find enough fresh water.

Seabirds get water
from their fish diet

but the mockingbirds had to find
other ways to get liquid.

Their flexible behavior led them
to investigate abandoned eggs.

But the supply of eggs
is highly seasonal

and there aren't enough
to go around.

Marine iguanas are common
on this island

and mockingbirds often clean
parasites from their skin.

Removing ticks can spill
small amounts of blood

and this perhaps led these birds
to discover a new fluid.

The mockingbirds of Espanola
have become vampires.

A beak evolved for seed eating

seems ready-made
for this new role.

With no freshwater pools

this island should support
very few mockingbirds

but their opportunistic approach
to finding fluid

has solved their biggest problem
in this difficult environment.

Today, they only enlarge
existing wounds

but they may be just a step away
from attacking undamaged flesh

and opening up new opportunities
for bloodsucking.

These mockingbirds may be
the founders

of a new dynasty
of avian vampires.

Mockingbirds have used
their resourceful behavior

to conquer
a challenging environment.

They share this ability

with an ancient survivor.

Crocodiles were successful
long before the dinosaurs.

Since they first appeared

millions of other animals
have come and gone.

So why have these prehistoric
reptiles hardly changed?

To start with, crocodiles
are not picky eaters

and will take
anything they can catch

regardless of size.

Crocodiles are also widespread.

If they die out
in one corner of the globe

they can recolonize
from another.

Their ability to live in water
gave them a retreat

which has buffered them from
fires and storms to this day.

Protection from the elements
has ensured the survival

of many animals on a planet
that's always changing.

For over four billion years,
the earth has been reshaped

by the extreme physical forces
battering its surface.

During this vast stretch of time

the same violent forces
have taken their toll on life.

At times, conditions on earth
became so severe

that life was virtually
snuffed out altogether.

Five mass extinctions
have struck

in the planet's long history

but the greatest die-off of all
was 250 million years ago

in an age known as the Permian.

This was a time of great
upheaval in the earth's crust.

The planet was shaken
to its core.

Poisonous gases filled
the atmosphere

trapping the suns rays and
sending temperatures soaring.

Seas and lakes stagnated
and began to dry out.

Many creatures
from that early time

such as brachiopods and clams,
were left high and dry

as seas and lakes gave way
to salt pans and scorched earth.

The scale of the loss
is hard to imagine

and many of life's branches
died forever.

But somehow,
survivors pulled through.

Among them
were two lines of reptiles.

One line gave rise
to the dinosaurs

the other to an animal
still alive today

on an island near New Zealand.

The tuatara outlived
the dinosaurs

but was driven
nearly to extinction

by the rise of the mammals.

Remarkably, no mammals
have ever reached this island

and the tuatara continues
its outdated way of life today.

They'd never be able to compete

with modern animals
from the mainland.

Theirs is life
lived in the slow lane.

Occasionally, they intimidate
their neighbors

and settle disputes
with short bursts of aggression.

But these quickly
leave them exhausted.

The outmoded tuatara will
never be abundant again.

And if mainland predators
ever breached

this island's natural defenses

Three million years ago,
such an invasion happened

on the once separate continents
of North and South America.

The earth's crust
was on the move

and the two islands drifted
towards each other

on a lake of molten rock.

As the gap closed,
the sea floor folded

pushing up
the isthmus of Panama.

Animals that had evolved apart
now came face to face

in an epic battle for survival.

Armadillos, anteaters
and possums moved north.

Pushing south went bears,
wild dogs and cats.

Moving into the jungles
of South America

these deadly cats gave rise

to many variations
still found today.

From spotted cats

to jaguars and jaguarundis

cats changed the face
of predation in South America.

Before long,
animals like ocelots

were hunting the jungles.

Unlike the native
marsupial predators

these cats
could tackle anything.

Their speed,
power and flexibility

were light-years ahead
of their rivals.

And much of the South American
fauna was hunted to extinction.

The south's native predators

would have looked
much like this quoll.

They were less efficient
hunters than the cats

but this was
only part of their problem.

Their forests were invaded
by new prey they couldn't catch.

The new wave of North American
rodents were tricky customers.

In the end, animals from
the north proved too strong

for their southern counterparts.

Although there were casualties
on both sides

the animals from the south
took the greater beating.

Three million years later

a huge bird would be
the first victim

in a new wave
of island extinctions.

This time, drifting continents
were not to blame;

the culprit would be man.

The dodo was flightless.

Mauritius had
no natural predators

and the bird's ancestors
lost the ability to fly

as they became specialized
to live and hunt on the ground.

The bird was ill-prepared
to defend itself

against new arrivals.

Dutch sailors began
visiting Mauritius

to stock their larders
for long voyages.

They also brought monkeys
and pigs with them...

animals that would play a big
part in the dodo's downfall.

When the sailors first arrived,
the dodos were sitting ducks.

Even when they learned to run

they were no match
for human hunters.

Although sailors ate many dodos

and stocked their ships
with large numbers

they didn't drive
the dodo to extinction.

It was the monkeys and pigs
they brought with them.

The dodo only laid a single egg,
and grew slowly.

Against these
introduced predators

they were indeed
"as dead as dodos."

Alien invaders have been driving
native animals to extinction

at an ever-increasing rate

and island creatures are
still the most at risk.

This is Guam, a remote island
in the mid-Pacific.

Its rocky coastline
and tall cliffs

once made a protective fortress
for its native wildlife.

But the arrival
of modern transportation

shattered Guam's isolation.

Animals can now cross the globe
in a single day;

journeys that once took millions
of years can be made in hours.

In the 1940s,
some animals made a journey

that would change
the island of Guam forever.

A ship from New Guinea carried
some dangerous stowaways...

brown tree snakes.

These predators were efficient
K*llers in their homeland

but on Guam they would
prove even deadlier.

The snakes' nocturnal habits

allowed them
to go unnoticed for a while.

But every morning revealed their
deadly toll on Guam's wildlife.

Birds, like this rail,
began to disappear.

They had evolved on a island
free from predators

and the invaders sent
their numbers tumbling.

While people searched
for a culprit

the predators were holed up...

waiting for nightfall.

Under cover of darkness

the snakes spread across Guam
like a wave of death

leaving a trail of destruction
in their wake.

The demands of hunting wary prey
at home in New Guinea

had left the brown tree snake a
highly accomplished bird hunter.

For this snake

even Guam's tree-nesting birds
were easy targets.

The ground-dwelling rail
had no chance.

Like the dodo on Mauritius,
the rail is flightless

and often leaves its eggs
unattended on the ground.

Today, the rail has become
another island bird

threatened with extinction.

As the snakes' numbers climbed,
bird populations collapsed.

For Guam's wildlife

the snake's calling card
was a symbol of disaster.

Insect numbers boomed

their populations no longer
held in check by birds.

Spiders also benefited

and Guam's forests
are often choked with webs.

Now the balance of nature
has changed.

Island animals have always been
vulnerable to extinction

but today, islands
aren't only found at sea.

The Amazon rain forest
in Brazil--

still home to more species
than anywhere else on earth.

But each year, its area
is reduced by logging

and perhaps more significantly

the forest is being fragmented
into a series of islands.

But are animals living
on these islands

more likely to become extinct?

loggers were asked
to spare patches of rain forest

for an experiment.

Scientists catalogued the plants
and animals living in them

then waited to see
what would happen

to the islands'
diversity of life.

Out in the open, the earth soon
became eroded and scorched

trapping animals
in their islands.

But how were
these animals surviving?

Signs of decay were everywhere.

Trees near the edge
of plots were dying

k*lled by the light and dry
winds that could now penetrate.

Many insects were gone, along
with the birds that ate them.

Without monkeys,
the canopy fell silent.

Spider monkeys needed plenty
of forest to find enough fruit.

Being tree dwellers,
they could not cross

the scorched open ground
to the next patch of forest

and starved.

Without the monkeys

uneaten fruits rotted,
leaving their seeds undispersed.

No young seedlings would replace
older trees as they died.

Many of these extinctions
were predictable

but some resulted
from a domino effect

as the loss of one animal
knocked down others.

It isn't obvious that a pig
would be responsible

for the fate of a frog.

Yet peccaries make wallows

by scouring out puddles
in wet areas

and many creatures rely
on these ponds to breed.

This is a striped monkey frog.

The most vulnerable
early stages are spent

developing in the relative
safety of the canopy.

When the time comes to hatch,
they all leave together

cascading on a mucus slide
into the wallow

ready for their big change
into froglets.

But peccaries are
large, social animals.

To find enough food
to support a whole group

they range great distances.

Confined to a small island
of forest, they starve.

Without the action of peccaries
to keep them full of water

wallows dry out
and fill with leaves.

With the wallows gone

many frogs have
nowhere to breed

and another domino is knocked down.

The frogs dissappear.

Most of these
extinctions happened

because smaller areas of forest
held smaller populations

less able to bounce back
from disaster.

At the start
of the new millennium

earth's forests
have been reduced

to one-tenth
of their former area.

Results from
this experiment suggest

that half of the species
they once held

have already been lost.

This is extinction
on the same scale

and at a similar rate

as the one which
wiped out the dinosaurs.

It is the beginning of our
planet's sixth mass extinction.

As before,
when faced with disaster

specialists will be more
vounerable than other animals.

In China

pandas are incredibly picky
about their food.

Eating bamboo is
about the only thing they do

but curiously,
they aren't very good at it.

The panda can harvest
they arbamboo quickly at it.

thanks to a specialized thumb
for gripping leaves.

But its intestines are not
good at digesting plant matter

and most of it passes
straight through.

With their
inefficient digestion

pandas need
huge quantities of bamboo.

This has become
their biggest problem.

Stands of bamboo go
through natural cycles

of death and regeneration.

When one stand dies off,
the panda migrates to a new one.

Now that pandas are trapped
in small islands of forest

when their local bamboo dies,
they have nowhere to go.

They starve.

If only the panda could leave
its bamboo island

or find new food
on this rapidly changing planet.

But the panda is not
that kind of animal.

The black bear in North America
is a close relative of the panda

and has a similar digestion

but unlike
its bamboo-fixated cousin

this bear eats almost anything.

Black bears are
amazingly resourceful

in their relentless quest
for worms, grubs and ants.

Although black bears evolved

from the same
ancestral stock as pandas

their flexible behavior
gives them

an enormous edge
in the survival game.

Most of the bear's
original forest

has been cut down
or fragmented into islands

yet there are
as many black bears now

as there were when the first
white settlers arrived.

Similar changes that spell
disaster for the panda in China

spell opportunity
for the resourceful black bear.

Many modern bears have
almost given up on wild foods

and hang out at dumps,
waiting for fresh deliveries.

With this constant supply
of high-energy junk food

they put on weight, which
allows them to have more young.

It is the black bears'
flexibility at food finding

that has inevitably brought them
out of the forest to scavenge.

Bears are showing the
flexibility of true survivors

but their long-term success
is not guaranteed.

Their future will depend on us
tolerating their habits.

If we continue to do so

the black bear should survive
this sixth extinction.

Our world is rapidly changing.

Yet again, a storm
is threatening the tree of life

this time a storm
of our own creation

and many leaves will fall
into extinction.

History suggests life recovers.

Life's future will depend
on which branches survive

and which of these flourish
in the new conditions.

In the past,
a spectacular spring

has always followed winter.

But which creatures will survive
current extinction?

Human technology, moving
more quickly than evolution

might protect us
from the rapid changes ahead.

But what will become
of the rest of life on earth?

For all our technology,
we just don't know.

The web of life is complex.

We can't predict

what will happen
as we cut its intricate threads.

We could ignore wildlife

and only preserve creatures
vital to our survival.

But our past has always
been tightly bound

to the natural world.

Without it, the future
could be lonely and uncertain.

We now have the knowledge
to save much of what remains.

The choice is ours.

Given the slightest chance,
life can bounce back.

Nature has amazing powers
of renewal

which emerge from
the very process of evolution.

Today's fabulous diversity

is the result of a four-billion-
year w*r for survival.

Out of this battle

has come not only the horror,
spectacle and beauty

we perceive in the world

but also life's
extraordinary ability

to recover from disaster.

It's impossible to know

what the future may hold
for our planet.

Life's greatest triumphs
may be yet to come.