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 break-up 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 life in these beautiful waters
All of them are air-breathers, like this eight-tonne Cryptoclidus
On the land, they are cumbersome hulks,
but in water, they are transformed
All sea reptiles once lived on land,
but 75 million years ago,
their ancestors took to the water
and their legs became flippers
They share this shallow sea
with other strange Jurassic creatures, like the ammonites,
that snare 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, they 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, the flippers can be used separately
to give them huge manoeuvrability,
or together, 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 pterosaurs are called Rhamphorhynchus
They have evolved a way of catching fish
without getting their wings wet
Their 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
(Harsh squawking)
(Low growling)
The Ophthalmosaurus are starting to give birth
Most sea reptiles lay eggs on land, but not Ophthalmosaurus
They give birth to live young
This frees them from the need to crawl out of the water,
and has allowed them to evolve their fish-like shapes
A female has two to five pups,
but since they are air-breathers,
the young must be born tail first,
or they would drown before they escaped from the mother
The newborn pups have just a few seconds
to reach the surface and take their first breath
As soon as they are born, the 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 betrays an animal in distress
As perfectly evolved killing machines,
sharks patrolled 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 tonnes,
it is the largest and most powerful carnivore
ever to live on the planet
This male measures a colossal 25 metres,
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 chambers in his nose
work in the same way as a pair of ears -
pinpointing the source of a smell-
a sophisticated tracking device,
steering the largest carnivorous jaws ever known
Each one of Liopleurodon's four flippers is over three metres 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
Baby Ophthalmosaurus have prominent teeth,
allowing them to cope with the tough prey
they find 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,
and at five metres 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
(Growling)
Neither will risk an injury
and in the end, it is the loudest roar that wins
(Fierce roar)
The only food supply here that is not from the sea is the insects
Bark beetles infest the trees here
They represent a tantalising feast of protein
just under the surface
This tempts a young Rhamphorhynchus to probe for insect larvae,
but 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 have 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 lungful of air
presents marine reptiles with a buoyancy problem
Cryptoclidus has found one solution
He is not searching for food in the sand
He is 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 -
they have come up onto 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 shoals of fish surge into life to pursue them
Ophthalmosaurus adults are masters of hunting at night
Most have left for deeper waters,
but 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 shoreline in their thousands
These are horseshoe crabs - ancient creatures
who originated 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 to fertilise
This strategy 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 horseshoe crabs cause a feeding frenzy
Every year, the Rhamphorhynchus come to this beach
to gather up the eggs,
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
(Low growling)
(Squawking)
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'll 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 will 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 Liopleurodon arrives on the scene
This, the bull will not tolerate
Liopleurodon are fiercely territorial
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 are facing one of the greatest hazards
of this cruel sea
These islands are regularly ravaged
by violent tropical storms that are strong enough
to tear up the shallow sea beds, smash corals
and kill thousands of marine animals
The storm has had its victims
It was not just these delicate-boned Rhamphorhynchus
that were broken in the 100-mph winds
the old Liopleurodon, disorientated in the murky waters,
has ended up stranded on an island beach
As the beachcombers start to 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-tonne body
is slowly suffocating him
The Liopleurodon's life has now ebbed away
The mightiest carnivore the world has ever seen
is no more than 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 vanish 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 ones left today
Another group of reptiles shared the dinosaurs' world - the pterosaurs
As we shall see in the next episode, they were just as spectacular