Planet Dinosaur (2011): Season 1, Episode 6 - The Great Survivors - full transcript

We are living through THE golden age
of dinosaur discoveries.

From all over the world, a whole new
generation of dinosaurs has been revealed.

From the biggest giants...

and the deadliest killers,

to the weird and wonderful.

From the Arctic,

to Africa.

From South America, to Asia.

Using the latest evidence,
for the first time

we have a truly global view
of these incredible animals.

In this episode,



we explore the dinosaur's
extraordinary ability to survive.

And witness how they have
transformed over millions of years

into some of the most alien-looking
animals the world has ever seen.

This astonishing capacity
to evolve

into ever more diverse
and bizarre forms

meant that it helped them not only
spread throughout the world,

but also dominate life upon it.

Dinosaurs lived for on Earth
for more than 160 million years,

most famously throughout
the Jurassic period.

But it was during the later
Cretaceous period that the biggest,

baddest and most bizarre
dinosaurs lived.

By the end of the Cretaceous,

dinosaurs were flourishing
on every continent.

Even dinosaurs that had been around
for over 100 million years,



like the giant, plant-eating
sauropods, were still thriving.

Back then, Europe was
a series of large islands.

On one of these, Hateg Island,

a giant dinosaur showed a most
surprising adjustment to island life.

Cut off from everywhere else,

Hateg Island has its own unique
collection of animals.

Bradycneme
is one of the predators here.

Magyarosaurus, a plant-eater,

is the potential prey.

And it's the youngest which are
in greatest danger from predators.

Hateg is a island where much
is not as it first appears.

This is a world turned upside down.

They may look like giants

but the Magyarosaurus
from Hateg Island

actually stood no taller
than a pony.

Weighing around one tonne,

they are fraction of the size
of their mainland relatives.

And weigh at least 70 times less
than their cousin Argentinosaurus.

On the island of Hateg,

there simply wasn't enough food
to support a plant-eating giant.

So, over many tens of thousands
of years, they adapted,

creating a world were many of the
dinosaurs were pocket-size versions

of their relatives.

But some animals are still huge.

This is the largest flying
vertebrate ever known.

A pterosaur
with a ten-metre wingspan.

It's as tall as a giraffe,

standing over
five-and-a-half metres.

Discovered in 2002...

its skull alone
is three metres long.

This is Hatzegopteryx.

A giant that we assumed
hunted from the skies.

That was until the discovery
of a series of fossil footprints,

unlike any found before.

The footprints
were those of a giant pterosaur,

and they showed that
these creatures did not just fly,

but could comfortably walk
on all fours.

It seems these monsters
actually hunt on the ground.

Hunting with impunity,
Hatzegopteryx are the top predators.

Able to fly from island to island,
this is their kingdom.

Hateg island is one example of the
strange paths evolution can take.

But all over the world,
bizarre-shaped dinosaurs

continually evolved
throughout their long reign.

Perhaps the strangest
of all dinosaurs

is one particularly weird group,
Therizinosaurs.

And the best example
of these peculiar animals

was announced in 2009.

The skeleton revealed the secrets
of this strange creature

that lived in New Mexico
92 million years ago.

These swamps
are home to zuni-tyrannus,

a mid-sized tyrannosaur.

And they're also home to this
weird creature, Nothronychus.

It's actually
a close relative of the tyrannosaur,

but with one major difference.

Nothronychus has given up
eating meat.

Here, the tyrannosaur
is the top predator.

Therizinosaurs had been a mystery
for decades,

known only from
tantalising fragments.

That all changed
with the discovery of Nothronychus.

It gave us our clearest look
at this strange group of dinosaurs.

It walked upright
on short, stocky legs.

It had wide hips,
and a long neck.

Its teeth showed that
these weren't the teeth of a killer.

Far from its ferocious
tyrannosaur cousins,

this pot-bellied dinosaur had
evolved into a strict vegetarian.

But armed with viciously long claws
on its forearms,

it was by no means defenceless.

By becoming a plant eater,

Nothronychus has easy access
to food.

And because it walks on two legs,

it can use its claws to pull down
branches to reach leaves.

Nothronychus thrives here

because it doesn't compete
with the tyrannosaurs for food.

But just because
you're not competing for food

doesn't mean
you're not seen AS food.

These are dangerous places to be
at the bottom of the food chain.

Unable to run, Nothronychus
relies on brute strength.

Tyrannosaurs are predators
that will eat anything,

even one of their own,
whether they've killed it or not.

And a discovery found in Montana
of a number of meat-eating dinosaurs

appeared to show that
being such an unfussy eater

could have dramatic consequences.

It seems scavenging
can hold hidden dangers.

This tyrannosaur
wasn't killed by Nothronychus.

There's a more deadly killer
at work here.

All the predator's bones
were found alongside

the edge
of an ancient stagnant lake.

And all of them died
at the same time.

Similar mass killings
have been found today among birds.

And the killer - a fast-acting,
naturally occurring deadly disease.

Botulism.

Botulism is caused by bacteria that
can thrive in rotting carcasses.

We think that the dinosaurs too

might have been victims
of this lethal and invisible killer.

Once a carcass is poisoned,

it is quickly passed on
to any animal that eats it.

With lethal results.

But plant-eaters, like Nothronychus,

are usually safe
from such deadly killers.

By completely changing its diet,

Nothronychus shows
the extraordinary adaptability

of the group known as
the theropod dinosaurs.

These two-legged dinosaurs

were the most diverse
of all the dinosaur groups.

From predators like Mapusaurus
and Majungasaurus

to the bizarre Therizinosaurs...

the extraordinary
tree-living Microraptor,

to the weird Gigantoraptor.

They evolved into an incredible
range of shapes and sizes.

The tyrannosaurs
were the most successful

of the theropod predators.

And once tyrannosaurs
dominated in an area,

many other meat-eating dinosaurs
simply disappeared.

But those that had
changed their diets flourished.

Mongolia, 85 millions years ago.

One group of dinosaurs thrives here

despite the fact that they live in
the shadow of a deadly tyrannosaur.

These are Oviraptorids, omnivores
that eat animals and plants,

and so don't compete directly for
food with the biggest of killers.

And the benefits are clear,

because some of these creatures
become huge,

like the eight-metre Gigantoraptor.

But this group have another trick
to help them survive,

the way they nest.

In Mongolia in 1994,

a nest of very large dinosaur eggs
was discovered.

An array of more than 20 eggs

arranged in pairs
around the edge of a shallow pit.

They were the biggest dinosaur eggs
ever found.

When an embryo was found preserved
within an egg,

it proved that the nest,
eggs and embryo

were almost certainly those
of Gigantoraptor.

But nesting
makes an animal vulnerable.

Alectrosaurus.

But against
a pair of Gigantoraptors,

a five-metre tyrannosaur
has little chance of success.

As Mongolia has given up it secrets,

we have learnt more and more
about these extraordinary creatures.

In 2005, one particular fossil
was found to contain two eggs

within its body cavity,
ready to be laid.

Even more amazing
were a number of other finds

that revealed the nesting behaviour
of these dinosaurs.

Three dinosaurs were discovered, all
sitting on top of nests of eggs...

the dinosaurs sitting in the centre
of the nest with their long arms

spread out to protect the pairs
of eggs arranged around them.

These dinosaurs were brooding.

Looking after their eggs increases
the chance of them hatching.

And having large eggs means
the hatchling is more developed,

making it less vulnerable
to predators.

But it takes longer to hatch -
up to 80 days for Gigantoraptor.

A time when both egg
and the brooding parent

are permanently at risk.

Smaller Oviraptors
are no more than a nuisance.

Larger predators
are a different story.

Unwilling to leave the nest,
the adult protects its offspring,

first, by hiding...

and if that fails,
it goes on the offensive.

Protecting the nest

means Gigantoraptors' young
are more likely to survive.

It now seems clear
that the instinct to nurture

and care for a nest of eggs
had its origins with the dinosaurs.

It's a behaviour
that was so successful,

it's still widespread today
with birds.

But the fossils show something else.

These animals all died
sitting on their nests.

It seems that the threats
don't always come from predators.

Sometimes the real danger
comes from the most unlikely places.

These dinosaurs
were all buried alive.

Planet Dinosaur was an incredibly
diverse and varied place,

with these creatures able to
colonise every continent on Earth.

Continually evolving and changing,

their dominance of life on Earth
was absolute.

Yet, they were doomed.

Their downfall was caused by
an asteroid smashing into the Earth.

Travelling 20 times faster than
a speeding bullet,

15 kilometres across,

it slammed into The Gulf of Mexico.

The impact released more energy
than a billion atomic bombs.

The initial impact
triggered wild fires,

massive earthquakes and tsunamis.

But most devastating was the debris
blasted high into the atmosphere.

This shrouded the planet in a cloak
of darkness that lasted for months,

cutting off sunlight.

The Earth was thrown into
almost permanent night.

Animals that survived the blast

were now faced with
their greatest ordeal,

as a devastating chain of events
was set in motion.

Deprived of light, many plants died.

Plant-eaters like this Magyarosaurus
are the first to be affected.

With no food,
the biggest succumb first.

Fresh growth of plants
offers a glimmer of hope,

allowing smaller plant-eaters
to scratch out a living.

But these aren't enough
to sustain anything for long.

Scavengers initially
have an easier time of it.

As the plant-eaters
succumb to starvation,

there is a glut of food.

But this surplus is an illusion.

Once gone,
scavengers will starve, too.

The impact resulted in the collapse
of whole food chains,

and the extinction
didn't just affect dinosaurs.

Virtually all life
on Earth was affected.

More than 60% of all species
were wiped out.

Yet the extinction wasn't a lottery.

One factor more than any other
determined the dinosaur's fate.

Size.

On land, no animal weighing
more than 25 kilograms survived.

There just isn't enough food
to sustain large animals.

Ironically, it's the very thing
that make dinosaurs so iconic

that condemns them to extinction.

The finds and discoveries
of recent years

have painted a staggering picture.

Dinosaurs were incredibly adaptable,

with an astonishing capacity
for survival.

Enduring the break-up of continents,
sea-level rises

and countless changes in climate,

they continued to diversify
and thrive.

On land, in water,

among the trees
and even in the skies.

They conquered every continent,

dominating life on Earth
for more than 150 million years.

The most successful animals
the world has ever known.

It was only with an unprecedented
extraterrestrial impact

that finally
saw the end of Planet Dinosaur.