Older than the mountains, exquisite in form, a masterpiece of engineering and design, a
sacred symbol of protection and strength.
The shell is one of nature's most successful creations.
From the driest desert to the deepest ocean, shells have been adopted by hundreds of thousands
of species.
All creatures have some strategy for survival.
It could be camouflage, safety in numbers.
Most just make a run for it, leaving trouble behind.
At first sight, a shell seems more of a liability than an asset.
Heavy and inflexible, it certainly slows a creature down.
But in Aesop's fable of the hare and the tortoise, the tortoise turns out to be the winner.
In evolutionary terms, too, the shell strategy has proved a winning one, hardly altered over
millions of years.
There may be flashier lifestyles, but why change a winning formula?
They've proved over and over again the moral of Aesop's fable.
Slow and steady wins the race.
Shells set off on the evolutionary race millions of years ago.
Long before there were mammals, even before the dinosaurs, there were shelled animals
living in prehistoric oceans.
Preserved as fossils, many extinct species are found embedded in rock far inland, evidence
of how the geography of Earth has changed over millions of years.
Today we understand the origin of these fossils, but in the past, they gave rise to some improbable
explanations.
In 15th century Whitby, England, ammonites were thought to be the remains of coiled serpents
beheaded by the Saxon abbess St. Hilda and turned to stone.
Local people perpetuated the myth by carving snake's heads onto the fossils and selling
them to pilgrims.
In many places, the landscape itself is made of shells, the remains of marine creatures
who died out millions of years ago.
Their shells were crushed into rock and then raised by geological upheavals into mountains
and gorges, limestone landscapes and chalk cliffs.
The shells we find today on the beach are usually the abandoned homes of sea snails.
At birth, the mollusk has a tiny shell already in place, a minute core of calcium.
As the snail inside grows, it extends its home, building around a central shaft like
a spiral staircase.
The calcium is broken down into a sort of liquid cement, secreted from a sheet of soft
tissue called the mantle.
Adding arc to craft, the mantle can work like an inkjet printer, squirting out dots and
dashes of pigment to create an infinite variety of patterns.
Most shells spiral to the right as they grow, but some go the other way.
Just like people, nature can be left or right handed.
In the Hindu religion, the chank shell, a kind of conch, is sacred to the god Vishnu,
symbolizing the origin of existence.
A spiral growth pattern is shared by a whole host of single-shelled creatures, collectively
known as gastropods.
Their name means belly foot.
Like Napoleon's army, a snail marches on its stomach.
The sea snail, the land snail spiral shell, is often decorated with elegant patterns and
colors.
A beautiful home, but not exactly mobile, it's a dilemma faced by all shelled creatures.
The shell that offers protection limits mobility.
Dragging its house on its back, the land snail lubricates its journey with mucus to help
it slide on its way.
The snail's trail shows just how far a snail can go in search of food.
A sprightly snail can cover 10 yards in an hour.
Even bivalves, the name for snails and other animals with two shells, don't even try to
get around.
They let the food come to them.
Oysters, mussels, and clams all feed by filtering nutrients from the sea around them.
With a constant food supply, there's no problem until the consumer becomes the consumed.
The final defense is just to clam up.
Bivalves have developed a powerful hinge muscle which slams shut at the first hint of trouble.
Once they've decided they're not coming out, it's almost impossible to make them.
Brute force is the only answer, but the succulent contents make it well worth the effort.
The empty shells we find on the shore are often the remains of lost battles.
For in the race for survival, no sooner does one creature develop an effective means of
defense than another finds a way around it.
Despite the benefits of mobility, shellfish have stuck with their steady success story.
But they've never been short of determined predators.
Ancient human settlements reveal the remains of thousands of prehistoric shellfish dinners.
A shell-bound life poses few problems than a little ingenuity can't solve.
The poisonous Portuguese man of war is just a floating dinner for a resourceful shellfish.
This mollusk produces bubbles which support the weight of its shell, allowing it to bob
alongside the jellyfish.
It dines on the poison-filled tentacles, to which it is completely immune.
Shellfish can be poisoners, too.
One of the deadliest shell shocks comes from the beautiful cone shell.
It paralyzes its prey, then swallows it whole.
Although collectors value its extraordinary beauty, collecting the prize can be fatal.
The Japanese carrier shell prefers to merge with its surroundings.
It's a master of decorative disguise.
A sticky coating provides the glue for any bits and pieces it can find.
All stones, glass, even other shells are piled on to fool the predatory eye.
A heavy shell can be made to move surprisingly fast.
The cockle can put on quite a turn of speed, while scallops seem to defy gravity with their
energetic dance.
A scallop's multiple eyes help it spot an approaching predator, but just how many does
it see?
The mobility of the scallop was put to use by Venus, the Roman goddess of love and beauty.
Born of the sea, she's often represented being carried on the waves in a scallop shell, like
a divine surfer.
In medieval Europe, pilgrims on their way to the shrine at Santiago de Compostela in
Spain followed scallop shell signs, the symbol of St. James.
One story tells of a horseman saved by St. James from the sea.
When the rider reached dry land, both he and his horse were miraculously covered with scallop
shells.
As well as protection from predators, a shell offers a permanent shelter.
Few other animals can boast such all-weather protection.
There are shelled homes to suit all habitats.
When wave power is the challenge, there are ingenious solutions.
Piddocks dig themselves into the rocks by pile driving with their shells, as much as
three feet deep.
While the edible date mussel secretes a chemical so powerful, it actually softens the rock,
allowing the mollusk to dig deep and stay put in safety.
Staying put is what some shells do best.
They cling to rocks by shielding mussel power.
This is thread strong as steel cable binds the mussels to their rocky home.
The force of the waves erodes the rocks, yet fails to shift the mussels.
Beneath the waves, the same fine thread anchors the noble pen shell to the seabed.
With the strength of steel comes the softness of silk.
In Toronto, Italy, pen shell business was woven into the finest gold cloth.
For generations, the crowned heads of Europe wore lace woven from this rare and naturally
golden thread.
On dry land, some shelled creatures stay in the race using a different engineering strategy
altogether.
The shell of the tortoise is an extension of its backbone.
A shell on the outside and a skeleton on the inside provide double protection.
Although the tortoise can walk, albeit awkwardly, on land, the turtle takes to the water with
astonishing grace and agility.
The scorpion, though it has no internal skeleton, has joints in its shell made of tough and
flexible chitin.
Nimble and dangerous, it scours the desert looking for prey, licensed to kill with its
own lethal weapon.
A brush with a scorpion has a real sting in its tail.
A woodlouse with its articulated armor plating can really move.
When danger threatens, the links in its armor allow it to curl up into an impregnable ball.
Though the family resemblance might not be obvious, it's a relative of the lobster and
the crab.
The lobster's articulated armor, its exoskeleton, works exactly like that of a medieval knight.
A suit of armor provides protection, but its sheer weight makes any kind of movement ponderous
and exhausting.
Supported by water, the lobster's shell poses no such problems.
Each year, spiny lobsters off the coast of Florida gather and migrate huge distances
across the seabed, looking like knights of old bearing lances mounted on their chargers.
The lobsters form huge corrals to intimidate their predators.
When group defense is no option, a shell on your back can prove to be the difference between
life and death.
There's one problem with homegrown suits of armor.
The suit doesn't grow with the animal.
From time to time, most crustacea, the family that includes lobsters, crabs, and woodlice,
have to shed their shells and grow a new one.
It's a dangerous time.
Without a shell, these animals are defenseless.
Nature's armor plating comes in many sizes and shapes and offers a degree of protection
that the speedy but vulnerable hare might envy.
But there are shellfish, which do without this protection altogether.
Surprisingly, cuttlefish and squid are shellfish too, but their shell is severely reduced.
Now they only have a small internal shell, which gives rudimentary support to their mass
of flesh and muscle.
The giant squid is the largest of all the invertebrates, growing up to 20 yards from
end to end.
There are tales of such giants of the deep dragging whole ships to a watery grave.
Humans have been linked to shellfish since the earliest times.
The Romans were particularly fond of oysters.
And they loved the color purple.
They obtained it from the humble murex, a sea snail, which was ground up to make a dye
called Tyrian purple.
It took 8,000 shells to make just a pinch or two of this dye.
Few Romans could afford the luxury, and under Nero, only the emperor himself was permitted
to wear this most royal of colors.
Cleopatra's lover, Mark Antony, tried to overwhelm his enemies with envy.
After the Battle of Actium, he had the sails of his battleship dyed with Tyrian purple.
Above all, it's their natural iridescent beauty which has always drawn us to shells.
Once shells were used as hard cash.
In the East Coast of the United States, wampum, disks cut from the purple rim of the cohog
clam shell, was common currency for some Native Americans.
In New York of the 1700s, you could still pay your fare on the Brooklyn Ferry with wampum.
But eventually the dollar became king, and wampum went back to being shellfish.
Two hundred years ago, throughout Africa and the South Seas, the shell of the cowry was
legal tender.
The going rate for a cow was 2,500 calories, a goat could be bought for 500, and a chicken
a sniff at just 25.
A hard shell protects the riches of life to come.
The coconut, fruit of the coconut palm, protects its seed within a hairy outer shell.
Travelers of tropical seas, coconuts may drift thousands of miles before they wash
up on dry land, split, and germinate, unless the robber crab gets to them first.
For the land-based robber crab has developed a taste for coconuts, and with it, the tree
climbing skills to collect them.
Humans appreciate the coconut too.
In Kerala, India, it provides food, fuel, and livelihood to the local people, and its
shell is the focus of religious ceremonies.
Climbers may be great travelers, but barnacles can outdo them.
Clinging to ships' hulls, they sail the seven seas.
A tinier mollusk gives ships much bigger problems.
The voracious shipworm burrows deep inside the hulls of wooden ships.
It builds a rock-like lining to each tunnel, drilling and protecting at the same time.
This devastating pest inspired two British engineers to develop a new tunneling technique
using this very principle.
Mark Brunel and his son Isambard called their system the Great Shield, and used it to build
a tunnel under the River Thames in London, the first ever to be dug beneath the river.
More inventive inspiration came from the nautilus, a relative of the squid and descendant of
the ammonite.
Though not much of a horizontal swimmer, it is a master of the vertical.
Committing to great depths, it uses regulating chambers within its shell.
Flood the chambers with water, and down it goes.
Push the water out with gas, and up she rises, precisely the technique that inspired the
first submarine, named the nautilus.
Wherever we look, we can find shells shaping our landscape.
Even beneath the seas, coral reefs are made up of the exoskeletons of countless tiny creatures,
billions of coral polyps, each secreting its own minute limestone shell.
Some of the smallest shells of all are found swimming with the plankton, a perpetual snow
storm of microscopic creatures, drifting in the currents, creating a rich and nutritious
soup for thousands of other species.
Whales and basking sharks, though big, eat small, consuming tons of these tiny-shelled
creatures each day.
But the largest seashell, the giant clam, can grow up to three feet across and weigh
as much as a baby elephant.
Legend has it that the vice-like shell can trap the unwary diver if he puts his foot
in it.
Whether true or not, divers are willing to face other real perils in search of the treasure
provided by another underwater mollusk.
That mollusk is the oyster.
That treasure is the pearl.
A treasure so valuable that pearlfishers will risk their lives for it.
But while humans prize pearls for their beauty, the pearl starts out as no more than a source
of irritation for the oyster.
A foreign body like a grain of sand finds its way into the oyster's shell.
To ease the itch, the shellfish coats it with layer upon layer of nacre, mother of pearl.
If the original source of irritation is a tiny fish, that too can be coated in nacre,
a fish-shaped pearl.
Over 700 years ago, there was a Chinese fashion for putting tiny clay figures of Buddha into
freshwater mussels.
The little figurines were soon coated in glistening mother of pearl.
Shellfishes come in different colors, white, pink, even black, according to the species
that produces them.
The largest pearl ever found is the pearl of ala, produced by what must have been a
very irritated clam.
It weighs more than a sack of potatoes.
Shellfish deal with invaders more directly, with sharp, poisonous spines.
Sea urchins are good to eat, but only if you're careful.
Shear size can be an effective way to discourage interference.
The tortoise family includes some formidable shell giants.
The Galapagos tortoise can weigh in at 600 pounds, and often lives 100 years or more.
Some turtles grow a mass of seven feet long, with the weight of 10 men.
The leatherback spends most of its life in the sea, but it must return to the shore to
breed.
Clumsy and vulnerable on land, the young turtles face a dangerous journey on their way back
to the sea.
The opposite is true of land crabs.
Though well adapted to land life, their evolution from sea crabs means they must lay their eggs
in the ocean, or as near as they can manage.
Every year on Christmas Island, millions of red land crabs hurry to the surf for an orgy
of egg laying.
While the eggs need the sea to survive, for their parents it's a huge risk.
These crabs left the sea behind so long ago, they can no longer survive beneath the waves.
They've forgotten how to sail.
Of all the shells, a bird's egg shell is perhaps the most perfectly designed.
Fragile enough for a hatchling to peck its way out, the shape of an egg allows it to
resist enormous pressure.
Shells of all forms featured strongly in ancient mythology.
The Egyptians believed the universe itself had formed from a cosmic egg.
According to the Mayan religion, Quetzalcoatl, the feathered serpent god, emerged full grown
from a snail shell, and his palace in heaven was built entirely of shells.
On land, in the sea, in the depths of the human imagination, shells have kept and earned
their place.
The tortoise, the oyster, the lobster and the scorpion, the seashell and the land snail
all started the race early and have survived unchanged.
Later on to a winner, an evolutionary design that has stood the test of time.
The
eye witness museum, created by combining traditional filmmaking techniques with state of the art
graphics, stripping away the mysteries of nature and science to reveal the essence of
each subject, bringing the world into sharp focus.
The making of eye witness.
The distinct style of the eye witness books is the basis for each of the programmes.
Each half hour episode is based on a book title.
The eye witness book's visual style gives the programme makers a starting point and
a challenge, the challenge of transferring clarity and super realism into moving images
and sound.
Now let's take a look behind the scenes at the making of Shell.
Like all the programmes in the series, Shell is dominated by the white backgrounds that
have become the eye witness hallmark.
The super clarity helps the programme makers bring out the best in their subjects and the
addition of movement gives a new dimension to the books, bringing their pages to life.
But the eye witness studio is extremely large and in order to keep it white, it's constantly
repainted.
To cover the entire studio, we used over 20 gallons of paint and several pairs of shoes.
Some people find ways of avoiding spillage on their shoes and some people, well they
don't bother wearing any at all.
In the studio, everyone has their own important role to play to help bring the programme together.
From the art department who are responsible for props and special effects, to the make
up artist, to the cameraman and his assistant.
Each individual member of the crew that makes up the eye witness team is an expert in their
own field, but occasionally in the line of duty, they are called upon to do something
outside their normal activity.
In Shell, it was the turn of the studio's spark or electrician to lay down his lights
for the production.
He was the only one who could fit into the suit of armour.
While some members of the crew lent a hand, for others it was a photo opportunity.
Once we'd worked out how the armour fitted, it was time to lay our knight under the camera.
He was put in exactly the same position as a previously filmed lobster.
Everything went smoothly until, out of frame, the armour seized up, which just goes to prove
the point we were making.
Shells can be heavy and inflexible.
I'll see you next time.