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00:00:16,517 --> 00:00:21,563
Surely, one of the most remarkable animals
that has ever existed,

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00:00:22,105 --> 00:00:26,318
and certainly one of the most famous,
is a dinosaur.

3
00:00:27,361 --> 00:00:29,613
Tyrannosaurus rex.

4
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An animal to spark the imagination
for all of us.

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What kind of an animal was it?

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00:00:38,330 --> 00:00:41,542
What did it look like? How did it live?

7
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Now, scientific research has answered
such questions.

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00:00:45,671 --> 00:00:47,923
And not just about T. rex,

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00:00:48,006 --> 00:00:51,343
but the other species
that lived alongside it.

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00:00:51,426 --> 00:00:58,016
And the latest imaging technology
enables us to bring them all to life.

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[grunting]

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[David Attenborough]
Planet Earth, 66 million years ago.

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[roars]

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[roars]

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The skies are filled with flying giants.

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In the seas,
monstrous reptiles patrol the depths.

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And on land, dinosaurs of every kind,

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all facing the struggle to survive.

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[leaves rustling]

20
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[groaning]

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We now know so much about a world
that was ruled by the dinosaurs.

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[roars]

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[shrieks]

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This is their story.

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[Attenborough] For millions of years,
the lands of planet Earth

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have been carved by water.

27
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And the rivers that flow here
are still shaping these great canyons.

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Such places are the home
of flying reptiles.

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Pterosaurs.

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Their wings of skin stretch
from finger to ankle.

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And they can fly
for hundreds of miles in a day.

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[pterosaurs chirping]

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[chirping]

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Each evening,

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they come to this canyon in huge numbers
to roost on its narrow ledges.

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There is safety in numbers.

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And anyway,
few land-living hunters venture here.

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But one does.

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A type of dinosaur. Velociraptor.

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Their bodies are kept warm by feathers,
but they can't fly.

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They are, however, exceptionally agile.

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[chirps]

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And just as well.

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One false step here could bring disaster.

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[dinosaur squawks]

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The pterosaurs are skittish.

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They will take to the air
at the first sign of danger.

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If the Velociraptors are to get a meal,
the element of surprise will be crucial.

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Lightweight bodies
and feathered arms help them

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to control their descent.

51
00:05:31,623 --> 00:05:36,044
And their broad tails assist them
in keeping their balance.

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[squawking]

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Those pterosaurs
that are resting on the margins

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of the colony will be the easiest targets.

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[squawking]

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[rocks crashing]

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[pterosaurs chirping]

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The roar of the waterfall drowns the sound
of slipping rocks.

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The female goes high.

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The two males stay low.

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A few pterosaurs are almost
within striking distance.

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-[rocks crashing]
-[pterosaurs shrieking]

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She has one,
but now the whole colony is alarmed.

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[shrieking continues]

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In the chaos,
her victim slips from the ledge.

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The female puts the effectiveness
of her feathered tail to the test.

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[rocks sliding]

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And, in the end, she gets her meal.

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The males are left to face the pterosaurs.

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The power of fresh water
is at work all around the planet.

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[thunder rumbles]

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Global temperatures are high.

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There are violent storms
and torrential rains.

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[dinosaur groans]

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Much of North America is covered
by thick, lush forest.

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[groaning continues]

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[thumping]

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Here live some of the most gigantic
plant-eaters that have ever existed.

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[dinosaur roaring]

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And they, in turn, are prey
for the most ferocious of hunters.

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[flies buzzing]

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[dinosaur grunting]

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Tyrannosaurus rex.

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00:10:14,823 --> 00:10:19,077
This old male has just brought down
a Triceratops.

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[roars]

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But in doing so, he's been injured.

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[groans]

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T. rex are built
for hunting large herbivores…

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though many of those have evolved
heavy defensive weapons.

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Decades of battling armored prey
has scarred his body.

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One battle even cost him
the tip of his tail.

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These new injuries are more serious.

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At his great age,
infection is a real risk.

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[birds warbling]

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River water could help
to clean his wounds.

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He stands a good chance of living
to fight another day.

97
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But that day could come sooner
than expected.

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[leaves rustling]

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Another T. rex.

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[roars]

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A stranger.

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[roars]

103
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But this newcomer has a different smell.

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It's a female.

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She's younger and smaller.

106
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But nonetheless,
she might also be a rival.

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[throat vibrating]

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He, however, makes it clear
that he's not interested in fighting.

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[vibrating continues]

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He would prefer to mate.

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She seems to approve.

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The facial area of a tyrannosaur
is very sensitive to touch,

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and they nuzzle.

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His great size and his battle scars
are evidence that he is a survivor.

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And that perhaps, in her eyes,
makes him an attractive partner.

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[groaning]

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So, they stay together.

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And in the coming weeks,
they mate frequently.

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Eventually, she'll lay up to 15 eggs.

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And with them comes the promise
of the next generation.

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Habitats that depend on fresh water
can change rapidly and radically.

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In parts of central Asia,

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heavy seasonal rains
fill the rivers until, eventually,

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they overflow their banks.

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The surrounding plains are flooded.

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And through the water wades one
of the most bizarre of all dinosaurs.

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[dinosaur grunting]

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Deinocheirus.

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It's even taller than T. rex.

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And its massive duck-bill snout
is very effective

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in gathering water plants.

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This male feeds voraciously,

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having eaten very little
during the long dry season.

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[grunting continues]

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00:16:46,131 --> 00:16:48,926
Water plants are rich in nutrients.

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And his huge, curved claws,
eight inches long,

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enable him to dredge them up
from deep beneath the surface.

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[flies buzzing]

139
00:17:08,904 --> 00:17:12,741
He himself is a source of food
for smaller creatures.

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Bloodsucking flies, which infest his coat.

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00:17:29,216 --> 00:17:31,969
They're irritating and even painful.

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00:17:32,928 --> 00:17:36,682
And while his huge claws enable him
to have a good scratch…

143
00:17:39,643 --> 00:17:43,981
there are always some spots
that are just out of reach.

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[grunting continues]

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00:17:51,029 --> 00:17:54,074
To get to them, he needs assistance.

146
00:17:58,078 --> 00:18:01,999
A dead tree. That could be the answer.

147
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[bird shrieks]

148
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[wood cracking]

149
00:18:23,520 --> 00:18:25,105
That's much better.

150
00:18:35,741 --> 00:18:36,742
[grunts]

151
00:18:40,037 --> 00:18:42,497
And now he can get back to feeding.

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[grumbling]

153
00:18:48,086 --> 00:18:52,299
But a diet that consists almost entirely
of wet vegetation

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does have one inevitable consequence.

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[grunts]

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[splash]

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00:19:09,691 --> 00:19:15,739
What was food for one becomes fertilizer
for many others.

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And a giant as big
as Deinocheirus can produce

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00:19:24,957 --> 00:19:28,126
over 20 tons of dung every year.

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00:19:34,716 --> 00:19:36,718
[birds chirping]

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00:19:39,805 --> 00:19:41,265
Southern Africa.

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00:19:43,976 --> 00:19:47,187
Here, too, the annual rains create floods.

163
00:19:50,065 --> 00:19:53,819
And the land
turns into a maze of narrow channels

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running between countless small islands.

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[insects chirping]

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00:20:03,370 --> 00:20:06,373
This is now a swamp forest.

167
00:20:13,672 --> 00:20:18,760
And it attracts one of the largest
flying animals that has ever lived

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00:20:18,844 --> 00:20:20,179
on planet Earth.

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00:20:31,690 --> 00:20:36,069
A giant pterosaur. Quetzalcoatlus.

170
00:20:49,416 --> 00:20:50,751
This is a female.

171
00:20:51,418 --> 00:20:54,254
Her wings are over 30 feet across.

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00:20:57,090 --> 00:21:00,260
And she's come here
for one particular reason.

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00:21:28,914 --> 00:21:31,792
The small islands
created by the rising waters

174
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are just the place
for her to lay her eggs.

175
00:21:50,561 --> 00:21:53,814
Quetzalcoatlus are certainly masters
of flight.

176
00:21:53,897 --> 00:21:58,235
But they're also, perhaps surprisingly,
very competent on the ground.

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00:22:00,779 --> 00:22:05,659
Each wing is supported by the single
greatly elongated bone

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00:22:05,742 --> 00:22:07,286
of her fourth finger.

179
00:22:08,245 --> 00:22:10,247
By turning her wings upwards,

180
00:22:10,330 --> 00:22:13,667
she can walk very effectively
on all fours.

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00:22:16,837 --> 00:22:19,256
[grumbling]

182
00:22:25,387 --> 00:22:28,223
She's come here to make a nest.

183
00:22:35,689 --> 00:22:39,526
She chooses to do so on damp, swampy soil

184
00:22:39,610 --> 00:22:43,197
that will prevent her soft-shelled eggs
from drying out.

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00:23:10,849 --> 00:23:13,560
These first two are just the start.

186
00:23:25,864 --> 00:23:29,910
For the next three weeks,
she will guard the open nest…

187
00:23:37,000 --> 00:23:40,796
and add two more eggs every few days.

188
00:23:50,764 --> 00:23:54,434
Producing eggs takes a lot
of effort and energy.

189
00:23:55,269 --> 00:23:58,939
Each one is huge, weighing around a kilo.

190
00:24:12,578 --> 00:24:16,331
Eventually, she produces a clutch
of a dozen or so.

191
00:24:19,501 --> 00:24:22,754
She covers them with vegetation
to conceal them.

192
00:24:34,725 --> 00:24:37,102
Now, she needs to eat.

193
00:24:39,563 --> 00:24:44,651
There should be enough food on this island
to sustain her youngsters when they hatch.

194
00:24:46,236 --> 00:24:51,366
But there's nothing substantial
enough here to satisfy her own hunger.

195
00:24:56,455 --> 00:25:00,083
She must leave to hunt for prey elsewhere…

196
00:25:02,127 --> 00:25:07,674
and trust that the isolation of her nest
will keep her unhatched young safe

197
00:25:07,758 --> 00:25:09,176
while she's away.

198
00:25:12,596 --> 00:25:15,682
-[leaves rustling]
-[birds cawing]

199
00:25:29,363 --> 00:25:32,741
Another, much older Quetzalcoatlus female.

200
00:25:45,963 --> 00:25:49,675
She, too, is looking for a safe place
to lay her eggs.

201
00:25:52,010 --> 00:25:57,516
And there may not be enough food here
for two sets of giant nestlings.

202
00:25:58,851 --> 00:26:01,228
But there is a way to solve that problem.

203
00:26:12,281 --> 00:26:15,492
And eggs, after all, are very nutritious.

204
00:26:38,557 --> 00:26:40,058
[young female groans]

205
00:26:43,145 --> 00:26:45,480
The owner of the nest is back.

206
00:26:47,357 --> 00:26:50,861
[groaning continues]

207
00:27:10,422 --> 00:27:14,218
[hissing, grunting]

208
00:27:18,722 --> 00:27:20,140
[groans]

209
00:27:24,728 --> 00:27:27,231
The older female is driven off.

210
00:27:35,155 --> 00:27:37,866
But the younger female's nest is wrecked.

211
00:28:01,932 --> 00:28:06,603
Out of the dozen eggs that she laid,
only three have survived.

212
00:28:12,860 --> 00:28:18,615
The success of her breeding season
now rests on these three fragile eggs.

213
00:28:23,579 --> 00:28:28,750
She will protect them as best she can
until they hatch in a few months' time.

214
00:28:31,795 --> 00:28:35,966
But after that, her young will have
to fend for themselves.

215
00:28:42,723 --> 00:28:44,975
As river water flows downstream,

216
00:28:45,058 --> 00:28:51,273
it scours out billions of tons of sand
and gravel and even shifts great boulders.

217
00:28:54,443 --> 00:28:58,197
The finer sediments may be transported
for hundreds of miles,

218
00:28:58,280 --> 00:29:01,283
but as the river broadens, it slows.

219
00:29:02,868 --> 00:29:07,122
And as a consequence,
it begins to drop some of its load.

220
00:29:13,629 --> 00:29:18,425
And animals whose ancestors lived
in the sea begin to appear.

221
00:29:24,264 --> 00:29:25,265
Crabs.

222
00:29:30,020 --> 00:29:33,273
In some places,
there may be dozens per square meter.

223
00:29:48,080 --> 00:29:50,832
This is Masiakasaurus.

224
00:29:51,667 --> 00:29:53,919
A female, six feet long.

225
00:29:54,002 --> 00:29:56,839
And she has a mouthful
of needle-sharp teeth.

226
00:29:59,383 --> 00:30:03,679
Just what you need
to deal with awkward, multi-legged prey.

227
00:30:10,477 --> 00:30:13,021
[chittering]

228
00:30:23,073 --> 00:30:28,370
Crabs may have hard shells,
but they're full of protein.

229
00:30:31,748 --> 00:30:34,209
Too good an opportunity to miss.

230
00:30:44,845 --> 00:30:46,430
And not only for her.

231
00:30:47,181 --> 00:30:50,475
[offspring chittering]

232
00:30:51,852 --> 00:30:53,562
She has three young.

233
00:30:57,024 --> 00:30:59,359
Only four inches tall.

234
00:31:03,197 --> 00:31:07,117
And not quite ready
to take on large crabs.

235
00:31:07,201 --> 00:31:08,827
[chittering continues]

236
00:31:15,167 --> 00:31:18,003
They still rely
on their mother's leftovers.

237
00:31:23,759 --> 00:31:27,346
But some youngsters
develop hunting instincts early.

238
00:31:37,397 --> 00:31:38,565
Very tempting.

239
00:31:45,489 --> 00:31:48,242
The smallest crabs can be swallowed whole.

240
00:31:54,456 --> 00:32:00,087
Unfortunately, what they lack in size,
they make up for in speed.

241
00:32:15,686 --> 00:32:18,021
-[offspring chitters]
-[squawks]

242
00:32:18,105 --> 00:32:21,775
It's best for the young
not to stray too far.

243
00:32:32,786 --> 00:32:34,162
[offspring shrieks]

244
00:32:36,582 --> 00:32:38,834
[shrieking continues, stops]

245
00:32:45,299 --> 00:32:48,886
Beelzebufo, the devil toad.

246
00:32:50,721 --> 00:32:54,183
One of the largest frogs
that has ever existed.

247
00:32:58,979 --> 00:33:00,981
[chittering]

248
00:33:05,861 --> 00:33:09,323
He won't need to feed again for a month.

249
00:33:19,208 --> 00:33:22,252
These sandbars may be
a rich feeding ground,

250
00:33:22,336 --> 00:33:25,923
but there can be a high price
to pay for living here.

251
00:33:29,760 --> 00:33:32,179
[dinosaurs groaning]

252
00:33:35,140 --> 00:33:38,477
The river water
is now approaching the sea.

253
00:33:42,022 --> 00:33:45,859
A taste of salt
in its waters is already detectable.

254
00:33:49,279 --> 00:33:50,822
[wildlife grunting]

255
00:33:53,700 --> 00:33:54,868
At high tide,

256
00:33:54,952 --> 00:33:59,289
visitors come in from the open sea
to explore these channels.

257
00:34:35,909 --> 00:34:37,661
Elasmosaurs.

258
00:34:39,830 --> 00:34:43,333
These are true oceangoing reptiles.

259
00:34:45,793 --> 00:34:50,215
But some come to estuaries
to explore the brackish waters.

260
00:34:56,429 --> 00:35:00,809
[dinosaurs groaning]

261
00:35:29,296 --> 00:35:32,007
Now, the millions of tons
of sediment carried here

262
00:35:32,090 --> 00:35:35,636
by rivers is finally delivered
into the sea.

263
00:35:41,391 --> 00:35:45,604
The river water takes time to mix
with the ocean, and, for a while,

264
00:35:45,687 --> 00:35:48,607
the two waters flow side by side.

265
00:35:51,485 --> 00:35:52,486
Nonetheless,

266
00:35:52,569 --> 00:35:57,533
great shoals of fish find plenty
on which to feed in these waters.

267
00:36:01,662 --> 00:36:06,625
The clouds of sediment conceal the fish,
if they're any distance away.

268
00:36:09,670 --> 00:36:14,550
But the Elasmosaurs don't hesitate
to swim into the murkiest of waters

269
00:36:14,633 --> 00:36:16,218
to pursue their prey.

270
00:36:35,779 --> 00:36:37,990
There is no escape for the fish…

271
00:36:45,706 --> 00:36:47,791
even above the water.

272
00:37:07,936 --> 00:37:12,441
These Elasmosaurs
collect the last of the river's gifts

273
00:37:12,524 --> 00:37:19,198
before its traces are finally lost
in the oceans of the prehistoric planet.

274
00:37:31,543 --> 00:37:33,587
Next on Prehistoric Planet,

275
00:37:33,670 --> 00:37:38,008
the bond between mother and young
is tested to the limit

276
00:37:38,091 --> 00:37:40,093
as they struggle to survive.

277
00:37:40,802 --> 00:37:44,932
Ancient foes battle each other
and freezing blizzards.

278
00:37:45,015 --> 00:37:46,058
[roars]

279
00:37:46,141 --> 00:37:49,978
And feathered dinosaurs
rule the ice worlds.

280
00:37:50,646 --> 00:37:53,649
To discover the science
behind the stories,

281
00:37:53,732 --> 00:37:58,070
go now to the Prehistoric Planet
show page.