The most fearsome predator of the Jurassic
is watching his prey.
Peering through the water,
the carnivore fixes on his unwary victim,
waiting for the perfect moment to strike.
Under these azure waters,
lies the future continent of Europe,
but now in the late Jurassic period,
all that exists here are a few scattered islands.
The breakup of the old continents has pushed up
the ocean floor and raised sea levels,
flooding the lowlands, and creating vast,
shallow seas.
Here dinosaurs do not rule.
Instead, giant marine reptiles have evolved.
Perfectly adapted to the life in these beautiful waters.
All of them are air breathers
like this eight ton cryptoclidus.
On the land they are cumbersome hulks,
but in the water, they are transformed.
All sea reptiles once lived on land,
but 75 million years ago, the ancestors of these creatures
took to the water, and their legs became graceful flippers.
They share this shallow sea with
other strange Jurassic creatures.
Like the ammonites that ride the currents,
snaring small prey with their tentacles.
These rich sunlit waters are on the northern edge
of the ancient Tethys ocean.
The sea that separates the Earth's two continents,
one in the north and one in the south.
Once a year, the are the stage for a remarkable
natural drama.
It starts with a single pregnant ophthalmosaurus.
Followed by hundreds more of her kind.
All are gathering here from deeper water to give birth.
These are the oldest of marine reptiles,
and most completely adapted to aquatic life,
with streamlined, fish like bodies.
Most other marine reptiles like cryptoclidus
use all four flippers to chase the blizzards of fish
through the water.
Flapping like underwater wings,
these flippers can be used separately
to give the enormous maneuverability,
altogether for sudden bursts of speed.
This unique method of locomotion is destined to disappear
from the ocean at the end of the age of the dinosaurs.
The animals on the small islands above
also depend on the sea's bounty for their survival.
Among the jagged rocks live a colony of flying reptiles,
these sea terrasaurs are called ramforinkus.
They have evolved a unique way of catching fish
without getting their wing membranes wet.
Their streamline beaks skim through the water,
grabbing anything in their path.
The teeth of these flying reptiles may look bizarre,
but they are ideal for snatching slippery fish
from the water.
However, swallowing their catch is a different matter.
The ophthalmosaurus are starting to give birth.
Most sea reptiles return to the land to lay eggs,
but not ophthalmosaurus.
They give birth to live young.
This frees the adults from the need to crawl out
of the water and has allowed them to evolve
their fish like shapes.
A single female has between two and five pups.
But since they are air breathers, the young must be born
tail first, otherwise they would drown in the time
it takes them to escape from the mother.
The newborn pups have just a few seconds to reach
the surface and take their first breath.
From the moment they are born,
the little pups are vulnerable.
These waters are full of predators,
even adult ophthalmosaurus will eat the offspring
of others to increase the chance of survival
for their own pups.
The only real safety is amongst the crags of coral.
Birth is a dangerous time for the mothers too.
This female is trying desperately to expel
her unborn offspring, fighting for air,
she stays near the surface.
Her struggles are a lure to sharks.
These predators have acute hearing.
And the sound of splashing portrays an animal in distress.
As perfectly evolved killing machines,
sharks were patrolling the oceans long before
marine reptiles appeared.
After 20 minutes, her exertions are exhausting her.
She is having to breathe more frequently.
The sharks start to move in closer.
Suddenly something lurking in the gloom scatters the sharks.
Liopleurodon, at 150 tons, it is the largest
and most powerful carnivore ever to live on the planet.
This make measures a colossal 25 meters,
and is big even for his kind.
His size means he is probably over 100 years old.
He too detected the mother's distress from a distance.
Liopleurodon has a directional sense of smell.
Two separate chambers is his nose work in the same way
as a pair of ears, pinpointing exactly where
the smell is coming from.
A sophisticated tracking device,
steering the largest carnivorous jaws ever known.
Each one of liopleurodon's four flippers is over
three meters long, giving him enough power
to guide his huge bulk effortlessly through the water.
By now, the coral reefs around the islands are full
of baby ophthalmosaurus.
This intricate network of caves is their refuge.
A safe haven from which they can start to learn
about their world.
Unlike the adults, the baby ophthalmosaurus
have prominent teeth.
This allows them to cope with the variety of tough prey
they find in among the coral.
But this little male has yet to learn that ammonite
shells are too tough for him.
Above the sea, food is less plentiful.
A lonely dinosaur has been forced to swim
between the islands in search of a meal.
With huge marine predators in the water,
this is a dangerous journey.
Large dinosaurs are rare here,
at five meters from nose to tail, eustreptospondylus
is the biggest.
They are primarily scavengers,
combing the beaches for dead animals.
But on such small islands, they are always under pressure
to find more carrion.
But another scavenger has got here first.
This eustreptospondylus is picking the last rotten strips
of flesh off a dead turtle.
But even these decaying remains are enough
to trigger a confrontation.
Neither will risk an injury, and in the end
it is the loudest roar that wins.
The only food supply on these islands
that does not come from the sea are the insects.
Bark beetles infest the trees here.
They represent a tantalizing feast of protein,
just under the surface.
This tempts the young ramforinkus
to probe for insect larva.
This is not really a job his beak is evolved to cope with.
Now two weeks old, the young ophthalmosaurus
are growing fast on a seafood diet.
But they are still at risk, especially from shark attack.
A head of coral provides a temporary refuge for this pup.
His pursuer has a deadly advantage.
He does not need to return to the surface to breathe
and has only to wait until the pup needs air.
But the little reptile has one thing on his side.
Speed.
Safe.
Until he needs to breathe again.
Having a lung full of air presents all marine reptiles
with a buoyancy problem.
Cryptoclidus has found one solution.
He is not searching for food in the sand,
he is in fact after pebbles and grit.
Sieving off the fine grains, he retains the larger stones
in his stomach, for ballast, which weighs him down
and counteracts the air in his lungs.
The land represents safety for the cryptoclidus.
With the high tide the have come up on the rock ledges
to rest, and also to be out of reach of liopleurodon.
Darkness does not bring peace in the restless sea.
Billions of microscopic creatures rise up from the depths
as the light fails, and shows a fish surge
into life to pursue them.
Ophthalmosaurus adults are masters of hunting at night,
and although most have left for deeper waters,
a few remain to take advantage of the plenty here.
With their enormous light-sensitive eyes,
they pick out squid in the gloom.
Their long toothless snouts are streamlined weapons
making it easy for them to snap up fast moving prey.
With the approaching full moon,
strange looking visitors gather on the shore line
in their 1000's.
These are horseshoe crabs.
Ancient creatures whose origins lie 150 million years
before the Jurassic.
On a high tide, the females struggle up the beach,
and each lay as many as 18,000 eggs,
which the males compete eagerly to fertilize.
It is a reproductive strategy that has served them well
since before the dinosaurs appeared,
and will do so for at least another 150 million years
to come.
Early morning and the arrival of the horseshoe crabs
has caused a feeding frenzy.
Every year, the ramforinkus come swarming to this beach,
to gather up the eggs laid in the night.
While the last few crabs struggle back into the water.
The nutritious eggs are an easy meal for these reptiles.
But nature seldom offers anything free of risk.
A month later, tiny horseshoe crabs start to work
their way out of the eggs.
The high tide that brought the females up the beach
now sweeps their offspring back into the sea.
For the pups, their secure life around the reef
is coming to an end.
In a few weeks, they will be big enough for life
in the open oceans.
The first signs are when like adults,
they show the skills to hunt fish in open waters.
This is not without risk.
The sharks are still a danger.
One day these would be the most feared predators in the sea.
But in these Jurassic waters, they themselves are prey.
The liopleurodon is an expert at ambush.
He takes one giant gulp of air, then descends to hide
in the depths.
There he can hold his breath for over an hour,
and liopleurodon is a shark eater.
Unexpectedly a female liopleuradon arrives on the scene.
This, the bull will not tolerate.
Liopleurodon are fiercely territorial
about their hunting areas, and confrontations
almost always end in violence.
The female is forced to leave the area.
Her flipper has been badly ripped by the male's
tusk like teeth attracting sharks that follow
her trail of blood.
It is four months since the pups were born,
and they're ready to leave, but they're about to face
one of the greatest hazards of this cruel Jurassic sea.
These islands are regularly ravaged by violent
topical storms from the east
that are strong enough to tear up the shallow sea beds,
smash corals, and kill 1000's of marine animals.
The storm has had it's victims.
It was not just these delicate boned ramforinkus
that were broken in the 100 mile an hour winds,
the old liopleurodon disorientated in the murky waters
has ended up stranded on an island beach.
As the beachcombers start the gather, they are wary.
While the giant is still alive, his enormous jaws
are lethal.
But they can afford to bide their time.
The carnivore's own 150 ton body is slowly suffocating him.
The liopleurodon's life has now ebbed away.
The mightiest carnivore the world has ever seen
is no more but a banquet for a group of lucky scavengers.
The Jurassic is a golden period for giant marine reptiles.
It will be another 90 million years before they disappear
from the oceans, along with the extinction
of the dinosaurs on land.
Most of the ophthalmosaurus pups have survived the storm,
and now face life in the open sea.
One day the females will return,
and when they do, they will be carrying the next generation.
Marine reptiles were one of the glories
of this ancient time.
Even though turtles are the only one's left today,
there was another major group of reptiles
that shared the dinosaur's world,
the flying terrasaurs, and as we shall see
in the next episode, they were just as spectacular.