Dinosaurs ruled the planet
for over 150 million years.
They occupied almost every corner of the globe
and came in almost every shape and size imaginable.
Some were truly extraordinary.
[grunts]
We now know that T. rex was a powerful swimmer,
Velociraptors were cunning, feathered hunters,
and that some dinosaurs had the most bizarre behavior.
But new discoveries are being made almost every day
that tell us more about life on this planet 66 million years ago.
[bellowing, rumbling]
[David Attenborough] This time on Prehistoric Planet,
- we reveal new animals... - [roars]
...and new insight into their quest to find a partner...
[chirps]
...the challenges faced by raising a family...
[bellows]
...and their titanic battles.
[rumbling]
[bellows]
[roars]
- [roars] - [squawking]
Journey to a time when nature put on its greatest show.
This is Prehistoric Planet 2.
[animal grunting]
The coast of the vast inland sea
that almost splits North America in half.
Here in the south, as the tide falls,
- giants are drawn to the shoreline. - [animal bellowing]
[grunts]
[rumbling]
These Alamosaurs are a hundred feet long
and weigh some 80 tons.
They are the largest dinosaurs on the continent.
So huge that no predator can tackle them.
Some live to a great age.
This male is around 70 years old.
[rumbling]
Many in the herd are likely to be his offspring.
But his long life is now coming to an end.
His immense body is beginning to fail him.
[groans]
[breathing heavily]
He may not survive the night.
[bellowing]
[animal grunting]
Dawn.
And these troodontids have picked up a scent.
[sniffing]
They're quick to investigate anything new...
- [grunting] - ...especially if it might be worth eating.
But biting through a three-inch-thick hide is beyond their power.
- [grunts] - [Attenborough] Very frustrating.
[animal rumbling]
[shrieks]
Tyrannosaurus rex...
[grunts, growls]
...North America's top predator.
[tyrannosaur grunts, bites]
With his six-inch-long teeth,
tearing through an Alamosaur's tough skin is not a problem.
[tyrannosaur rumbles]
[grunts]
[snarls]
[grunting]
[roars]
T. rex might be able to bully troodontids,
but a carcass as big as this soon attracts more formidable competition.
[rumbles]
[roars]
[hisses, snarls]
Quetzalcoatlus, a giant pterosaur.
[grunts, roaring]
One of the few creatures that will challenge an adult tyrannosaur.
[snarls]
[grunting]
One strike from its six-foot-long beak
could easily cost T. rex an eye.
[grunts]
[growls]
Even so, it seems that he's not going to back down.
- [rumbling] - [pterosaur 2 growls]
[grunts]
But the arrival of a second Quetzalcoatlus...
[growls]
...changes the odds.
[rumbling]
- [pterosaur growls] - [snarls]
After all, two beaks are deadlier than one.
[all snarling]
For T. rex, this is now too dangerous.
[tyrannosaur rumbles]
[growling]
Some fights just aren't worth the risk.
For now, the flying giants have won.
They quickly eat all they can.
But T. rex will almost certainly be back to claim his share
once his flying rivals leave.
In the waters that surround North America, there are other giant predators.
But they have no rivals.
Mosasaurs.
They may look like huge sharks,
but they are in fact a kind of aquatic lizard.
Size, speed and powerful jaws mean
that very few creatures in the ocean are safe from these hunters.
In the Gulf of Mexico, this Globidens mosasaur is searching
for one particular kind of prey.
Tiger ammonites, Sphenodiscus.
Every year, huge shoals of females come up
from deep water and travel towards the coast.
They have all recently mated and each is now carrying hundreds of fertilized eggs.
The eggs must be laid in the shallows.
And that is where the mosasaur is waiting.
Tiger ammonites are themselves hunters.
The combination of a streamlined profile and a powerful siphon enables them
to shoot through the water at great speed.
But so can the mosasaur.
Globidens has broad, rounded teeth that easily crack the ammonites' shell,
releasing the air that keeps them buoyant.
Without it, they sink helplessly to the seabed.
Before the ammonites can escape, the mosasaur disables as many as it can.
Finally, time to tuck in.
Globidens may have killed dozens...
but even this makes only a small impact on the overall numbers of ammonites.
Most of the shoal have survived
and continue on their journey to their spawning grounds.
The rocky seabed here has many cracks and crevices,
ideal places for attaching the ammonites' precious egg sacs.
The females then abandon them.
But safe in this coastal nursery,
these eggs will produce the next generation.
These coastal seas are full of life.
Yet on land, and only a few hundred miles away,
there is desolation.
Here, powerful movements deep in the earth's crust are beginning
to raise the Rocky Mountains.
The immense changes in the landscape have cut off this lake from nearby rivers.
Its waters evaporate in the strong winds and intense summer sun.
And the minerals that are dissolved in it are beginning to reach toxic levels.
For most, this water is simply too poisonous to drink.
Even so, every year this place is visited by all kinds of animals.
[birds squawking]
Flocks of Styginetta,
a primitive relative of ducks, stop here on their travels.
[squawking]
And they're not alone.
Dinosaurs are here too.
[grunting]
A family of Pectinodon. They're feathered but flightless.
[growls, grunting]
And they're led by their father.
[grunting]
These dinosaurs and the Styginetta are both drawn here
by a strange seasonal bonanza.
[buzzing]
Flies.
The larvae of these insects are able to filter out the lake's toxic salts,
and, as a consequence, they thrive in immense numbers.
Now they're hatching into adults...
in their millions.
They are a rich and abundant source of protein for all the lake's visitors.
[grunting]
Pectinodon are particularly intelligent dinosaurs.
It doesn't take them long to work out the best way to collect flies.
[buzzing]
[grunting]
[whistling]
[both grunt]
But their father has his eyes on a bigger prize.
- [troodontid growls] - [squawks]
Pectinodon are not only intelligent,
they're also very skillful hunters.
[squawking]
The Styginetta are unaware of his approach.
[groaning]
- Success. - [grunting]
A rather more substantial meal for the family,
and just as well.
The flies will only be here for so long.
And the dinosaur family will be forced to find food elsewhere.
[animals growling]
Further north,
the Rocky Mountains are still slowly rising.
And as they do, they create higher, cooler landscapes
where vast pine forests flourish.
[distant bellowing]
As spring arrives, strange calls echo through the trees.
[bellowing continues]
The mating season has arrived
for one of North America's most heavily armed dinosaurs.
[dinosaur bellowing]
Triceratops.
Every year, large numbers of these giants gather in clearings.
The females have come to choose a mate.
[bellowing]
The six-ton males fight and display their strength.
[bellows]
This young male looks to be in prime condition.
Showing off his spectacular meter-long horns...
and his colorful head-frill.
His horns appear perfect.
Not yet damaged by battle.
To a female, however,
the absence of any wear and tear might suggest a potentially critical weakness.
A lack of experience.
These gatherings are crucial events in the lives of Triceratops.
They provide the best chance in the whole year for the adults to become parents.
And young hopefuls are not the only ones here.
[grunting, rumbling]
[bellows]
A 30-year-old male weighing more than ten tons.
If there's one thing that he has in spades,
it's decades of wear and tear.
[bellowing]
He may be old,
but he's still strong enough to challenge a young rival, however fit.
[grunting]
[bellowing]
[huffs]
The stakes are high,
and neither is willing to back down.
[bellowing]
[grunting]
The veteran has a four-ton weight advantage...
[bellowing]
...and the skill to make it count.
[huffs]
The youngster's horns are no longer perfect.
[bellows]
[bellowing]
The old bull's fighting prowess
certainly seems to have impressed this female.
For the loser, the mating season is over.
However, his newly won battle scars might be just enough to attract a female
next time the herds gather here to mate.
For plant-eating dinosaurs like Triceratops,
the vast forests that cover much of North America offer plenty to eat
all year round.
But for those that live in the cold far north of the Americas,
food is much harder to come by.
Here within the Arctic Circle,
for three months of the year, the sun barely rises.
When its warmth finally returns after the long winter...
feathered Ornithomimus are quick to take advantage.
These fleet-footed travelers are among the fastest runners of all dinosaurs.
Capable of covering vast distances in search of fresh vegetation.
They're so fast that they're very difficult for predators to catch.
[huffs]
After a tough winter,
this female Nanuqsaur needs to make a kill soon.
A smaller relative of T. rex, but more agile and, critically, faster.
There is nowhere to hide, so a surprise attack is impossible.
Instead, she resorts to creating panic.
She needs to pick out a single target...
and stick with it.
The Ornithomimus' bursts of speed just give them the edge.
[bellows]
Each failed hunt uses up more precious energy...
bringing her ever closer to starvation.
It may be spring,
but this far north, freezing winds can quickly cause temperatures to fall.
Flurries of snow and a rocky outcrop could give the Nanuqsaur a second chance.
Now she's harder to spot.
Every inch forward brings her closer to success.
[muffled footsteps approaching]
[Ornithomimus screeches]
She selects her target.
This prize is not only for her.
[chittering]
She is a mother.
Fresh meat for her youngsters.
Perhaps the first for many weeks.
If her babies are to thrive,
she will have to repeat today's success over and over again.
Until her young are old enough to join her in the hunt
and eventually fend for themselves.
Here, in this remote and perhaps most challenging frontier
of the North American continent,
66 million years ago.
This is one of the most dramatic skulls from our prehistoric planet.
It belonged to a plant-eating dinosaur called Triceratops.
[rumbling, bellowing]
This dinosaur is instantly recognizable
from the massive frill at the back of its head.
But 140 years after the first fossil was found,
scientists are still asking,
"What was the frill for?"
[professor] These were enormous structures,
so it's an enormous investment in bone and in tissue
and also in the muscular effort to hold these structures up.
All of this investment must mean that these features are very important
to the animal's way of life.
[Attenborough] But how?
[grunts]
Evidence of injury on Triceratops fossils suggests
that the frills were important in defense and combat.
We can see, um, lesions on the skull
which are areas where the skull has been damaged and healed.
We can also see where a predator has taken a chunk out of a frill.
That might indicate that we're looking at some sort of defensive structure.
But the story doesn't end there.
Another possibility is that the frill was used to attract prospective mates.
We see this in living animals
where structures like horns show off how healthy they are
and who's a good prospect for producing lots of young.
[bellowing]
[Attenborough] For a moose,
having large antlers makes the male more attractive.
Vital when it reaches sexual maturity.
Could the same apply to the Triceratops' frill?
[Maidment] If it was only for defense,
then we would expect to see them develop
to the same degree in juveniles as in adults, but we don't.
We see them being much smaller in the juveniles
and not really developing into the very, very large structures
of the adults until much later.
[Attenborough] This isn't the only evidence
that they were used in sexual display.
The surfaces of the frills are very heavily grooved.
These grooves probably carried nerves and blood vessels
that would have supplied the skin growing over those frills.
This may have been very brightly colored,
a big surface area for the animal to show off to potential mates.
[Attenborough] Scientists now believe that
the Triceratops' best-known feature was truly multipurpose.
Very useful for attack and defense...
but also ideal for attracting a mate.
[bellows]
It would have been an awe-inspiring sight to friend or foe.
[grunting, rumbling]
[bellows]