Hidden inside every one of us is a structure essential to life, yet when glimpsed it can
fill us with deep fear, the skeleton.
As varied in shape and size as all the creatures across the face of the earth, fish, birds,
amphibians and reptiles, and mammals, all have what we commonly think of as a skeleton,
an internal frame of bones on which the soft body hangs, the endoskeleton.
The skeleton supports the body, anchors the muscles, and forms a hard shield for the vital
organs.
It permits movement, feeding, procreation, life itself.
An elephant's thigh bone is a hundred times bigger than a vole's, yet both, like mole
and monkey, hedgehog and horse share the same design of bones.
The spine, rigid yet able to bend dramatically, supports the entire body, from the limbs,
which give thrust for movement, to the cage of ribs protecting the heart and lung, to
the skull, casing for the brain and the vital senses.
It's a design which includes what is to us the most interesting skeleton of all, our
own.
The human skeleton begins life with over 300 bones, which slowly fuse into the 206 bones
of the adult man or woman, a body that can grow to almost 9 feet, so tall that an ordinary
table is at knee height, or remain so stunted it could ride a spaniel as a horse, and with
a skull which guards the only brain capable of studying itself.
The skeleton, foundation of the living body, and image of its death.
It's a cause for mockery.
As Winston Churchill said of a rather gaunt rival, I've seen better looking faces on
a pirate flag.
The skull and crossbones emblem of danger from pirate flags to poison bottles.
But occasionally this set of rattling bones is an invitation to the carnival to come and
laugh at death, a symbol of freedom from earthly cares.
And birds enjoy the freedom of disguise precisely because of the way their bones are made.
They're almost hollow.
Some even contain air sacs as extensions of the lungs.
Light as a feather, almost.
Every creature on earth reveals its style of movement in its skeleton.
The enormous thrust needed to help a bird take off and fly comes from its chest, a breast
bone with a huge keel to anchor the powerful wing muscles.
In land animals, movement comes from the rear.
The hips and pelvis connected to the spine transmit the thrust from the hind legs through
the entire body.
This is true whether the action is running at great speed, leaping across rivers, bounding
over long distances, or just dealing with an inconvenience.
Yet what about fish, which have no legs or wings?
Here a flick of the tail pushes the water back, driving the fish forward.
And since in water they carry no weight, fish bones are light, and sometimes they're not
bones at all.
Sharks, rays, and dogfish have cartilage instead, flexible but hard.
For animals which do have hind legs, the tools on the end of them can have a multitude of
uses.
They can kick out as weapons, or kick water like paddles.
They can grip like pincers.
Hook a fish clean out of water.
Or in the case of the ibex, find footholds on almost vertical rock.
They can be flat shoes that will carry the animal at great speed.
Or as with the caribou, divide into two halves that splay out and spread the weight like
snowshoes.
Some animals can stand on their hind limbs, if only for a few moments.
For humans this posture is a way of life.
We have a spine originally designed for an animal that traveled on all fours.
By standing upright, our spine has modified to an S shape, so the body is balanced over
the legs and feet, and the weight carried on the thigh and the shin, the largest and
strongest bones in the body.
Powerful and resilient.
Moving on the hind legs alone requires a highly tuned sense of balance, and makes possible
a whole new range of movement.
Movement begins at the hip, a classic ball and socket joint combining strength and mobility.
Further down, the knee acts as a hinge, allowing the lower part of the leg to move forwards
and backwards.
And at the bottom, the ankle and the heel tilt the foot downwards for thrust against
the ground.
Hips, knees, ankles work in perfect harmony, moved by muscles and controlled by the brain.
Though at times it does help to have someone pulling the strings.
The skeleton has taught us almost everything we know of the evolution of life on earth.
For the skeleton is the body's most enduring element and its permanent record.
Moving after death to the bottom of river, lake, sea or swamp to be transformed over
millions of years into rock.
Fossils, the only clues we have of our early ancestors.
From ammonite to dinosaur, from fish to mammoth.
To the primitive humanoids, and so to ourselves.
In all air breathing animals, the lungs need strong protection, yet enough freedom to expand.
The ribs, a flexible cage with joints on the front at the breastbone and at the back anchored
on the body's central pillar, the spine.
A column made up of a row of linked bones, the vertebrae, from nine in a frog to four
hundred in some snakes.
The spine runs from the tip of the tail, if an animal has one, right up to the twisting
and turning joints at the base of the skull.
Though from shoulders to head can be some distance.
Each vertebra can move only a small amount in relation to the next one, but over the
whole length the movements add up to great flexibility.
Far more common than a long neck is the extension of the spine in the other direction, the tail.
Used by many creatures for balance, support, an extra limb, or to just flick away flies.
And in evolving from a horizontal support to a vertical column on two legs, the human spine has lost none of its flexibility, at least not in the young and very fit.
Bone itself can be pliable.
Tail bone has been used for centuries, most notably in corsets, tightening women's waists
into tiny circles, sometimes no bigger than a saucer.
Light, certainly, but its lack of elasticity caused circulation problems, fainting fits,
even fractures, and occasionally it wasn't just the wearer who collapsed from exhaustion.
Bone is a remarkable material, active living tissue with nerves and blood vessels, and
a center honeycombed with holes that reduce weight.
Some bones have marrow which produces blood cells, and all bones store minerals for the
body.
Indeed, without minerals, bones can bend like rubber.
And when a bone is broken, it has the extraordinary ability to mend itself, although sometimes
it does need a little help.
But there is another kind of skeleton, not made of bone and not on the inside of the
body.
The vast majority of animals have an external suit of armor which surrounds and protects
the soft, boneless body, the exoskeleton.
Some exoskeletons have even changed the very shape of the land.
Coral reefs and islands are created by billions of tiny marine polyps living together in communities.
Each animal makes its own chalky exoskeleton, and as it dies, the skeleton remains, fusing
with others to form a growing mass of coral.
But the most common form of underwater skeleton is also the most effective.
The shell, the simplest shield, and a powerful protector.
The limpet sticks to a surface with the strength of superglue and hides itself in a shell almost
as tough as the rock itself.
The giant clam's three foot wide shell is the largest in the sea and can close like
an impenetrable door.
People have always been fascinated by the beauty of the shell and have used this simple
skeleton for an extraordinary variety of ornament and decoration.
The crab, like lobsters, shrimp, and other crustaceans, has a softer shell and joints
covered in tough skin.
And those with shells not strong enough to protect them have to hedge their bets.
Hermit crabs haul themselves into any abandoned shell they can find for double protection.
As they outgrow their adopted home, they must find a larger one to move into.
Occasionally, the new shell is already occupied and the crab must fight to evict the sitting
tenant.
Water reduces shell weight so that these creatures can grow larger than those on land, but their
shells are rigid and cannot expand.
In order to grow, they have to shed the old skeleton.
The crab finds a safe place to hide, sometimes literally under the protection of its mate,
until the new skin hardens, it will be highly vulnerable.
The old skeleton splits down the abdomen and the crab crawls out backwards, leaving the
shell behind.
It is this sense of regeneration and growth which has made the shell into a symbol of
birth and renewal.
Renaissance art expressed this in Venus, a rising newborn from the shell of a scallop.
For deep within the shell there is a sense of power and eternity, and always the sound
of the scene.
Land animals with exoskeletons also need to shed their casing to grow.
Here the building material is chitin, hard, flexible and highly adaptable.
Some creatures can bend enough to perform surprising feats of self-protection, curling
and uncurling by stretching their dorsal segments.
The most heavily armored mammal of all, the armadillo, can do the same, although its armor
isn't an exoskeleton, but toughened hide.
Other animals have even more external protection, turtles have endoskeletons, but with a bony
outer shell.
They enjoy the best of both worlds, plus enormous strength.
The giant tortoise has two bone sections, top and bottom, with the spine fused to the
inside of the top dome.
As much as six feet long, it's an almost perfect fortress.
All skeletons cover the most vital body parts, and survival depends on the strength of the
covering.
Yet however strong the shell may be, survival isn't guaranteed.
The thrush beats a snail against the stone anvil until the shell breaks.
It is not only the shell which needs to be strong, the bird's skull has to withstand
these jarring impacts.
The woodpecker has taken this to extremes.
With a tremendously strong skull and beak, it hammers through the bark of a tree to find
insects, and it can be heard three miles away.
Yet there are skulls which take far more powerful blows without flinching.
The skull of a musk ox is reinforced by shock-absorbent bone, which is fortunate since each of these
animals weighs nearly half a ton and could smash straight through the brick wall of a
house.
The skull reveals more about an animal than any other part.
Weight, size, shape, and position of the organs tell us how well the creature sees and hears,
what it hunts, and how it survives.
The skull is a blueprint of lifestyle.
It is perhaps because the skull is essential for survival that people have put it to so
many uses, cultural, practical, and superstitious.
Ceremonial drums have been made from the skulls of the vanquished warriors of rival tribes,
just as the Northman's custom of drinking from their enemy's skulls has led to the
Scandinavian drinker's greeting, skull.
The skull traditionally harbors the soul, so the holy Tibetan lamas drink from ceremonial
skull cups, a symbol of consuming another's mind.
Many 19th century doctors believed in phrenology, the so-called science which taught that a
person's character could be read from the shape of their skull, each area governing
a part of the personality.
Queen Victoria had the skull shapes of all the royal children analyzed.
Even today, people may respond to odd behavior by exclaiming, you need your head examined.
And some do need their heads examined.
Despite its many attributes, the skull is not invincible.
A sudden blow to the jaw can shake the brain in its casing, resulting in a knockout.
No part of the skull reveals as much about lifestyle as the jaws and teeth.
From vegetation-eating animals with jaws that move up and down and sideways, to the rodent's
large sharp front teeth for gnawing, and the strong thick jaws of the lion with a huge
muscle that runs from the front to the back of the skull, giving it the most powerful
bite of all the animals.
But the strength of some birds' beaks is just as awesome.
The scarlet macaw can crack open rocks to get at vital mineral salts.
But the most unusual jaws belong to the snake, with joints that unhinge and spread to an
opening up to eight times the size of the snake's head.
That's equivalent to a man swallowing a German shepherd dog whole.
The snake's muscles are powerful enough to crush the skull of its prey.
The skull is the body's strongest bone structure, protecting the organs of sight, smell, taste,
and hearing, guarding the vital entry of food and oxygen, and encasing the most complex
control center ever known.
The eyeballs and the air channel are both well-shielded by the bones of the face, while
the highly adaptable jawbone helps the thirty-two teeth chew their way through half a ton of
meat and plants each year.
But to the human mind, the sight of a skull does represent a threat.
No part of the body is so full of mystery.
Our instant repulsion when coming upon such a clear vision of death is linked to the instinctive
urge for survival.
Only the elephant is likewise fascinated by and afraid of its own bones, perhaps not surprising
since these creatures have been systematically slaughtered and their skulls desecrated for
one special part, the tusk.
Made of ivory, these highly modified teeth serve both as tools and weapons, and not only
in elephants.
The walrus uses its tusks to dig out food and pull itself along, to spear the hull of
a boat in anger, or to drag itself on board by hooking its tusks over the sides.
The narwhal has only two teeth.
In the male, one of them grows into a fearsome nine-foot tusk, almost as long as the animal
itself.
The male Barbarossa pig has four tusks, two of which actually grow up through the roof
of its mouth.
Ivory is the most widely used skeleton material, adapted to every imaginable ornament and artifact.
And other specialized bones have caught the imagination of humans, antlers, emblems of
aggression, power, and supremacy.
Antlers have another, more subtle purpose.
They help to control body temperature, radiating excess heat to keep the animal cool.
Antlers in their many forms are all around us, yet they still terrify us.
Like the skeleton in the closet, placed there by an evil husband who forced his unfaithful
wife to kiss the skull of her former lover every night.
In many cultures, the human skeleton has become a powerful symbol, an omen.
The mere sight of a skeleton is a vivid reminder of our own mortality.
In the fortune-telling tarot deck, the most feared card is death.
The skeleton is the monster conjured up to frighten enemies.
The leader of the dance of death, the grim reaper, the dreaded hunter of souls.
Yet these images in art have themselves been created by a skeletal part.
The hand, or forelimb, is more elaborate and refined in humans than in any other animal.
From the front fin of the earliest fish, it has evolved into the widest possible range
of implements, from flippers, grippers, and paddles, to paws, pincers, and hooks.
And even to the thirteen-foot wingspan of the albatross that carries it all around the
world in three months.
The closely related moles and bats have forelimbs, which have taken opposite paths, one digging
into the earth as the other lifts it skyward.
That first fin has developed into the human arm and hand, the most versatile and sophisticated
instrument on earth.
A series of multipurpose connected joints, ending in a set of fingers, enabling us to
perform a greater range of tasks than any mechanical tool.
The hand that has passed down to us knowledge, a record and understanding of ourselves, that
has painted, molded, and celebrated life and death.
Every year the Mexican people shrug off the traditional fear of death and its image.
They rejoice, mock, and embrace it as a part of life itself.
The Day of the Dead, tribute to the departed, to the past, and to life.
And this joyous celebration transmits to the world the skeleton's ultimate message, that
death comes all too soon, so drink deeply of the cup of life while it is still full.
The Day of the Dead, tribute to the departed, to the past, and to life.
The Eyewitness 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 Eyewitness.
The distinct style of the eyewitness books is the basis for each of the programs.
Each half hour episode is based on a book title. The eyewitness book's visual style
gives the program makers a starting point and a challenge.
The challenge of transferring the clarity and super realism into moving images and sound.
Now let's take a look behind the scenes at the making of skeleton.
To bring the human skeleton to life, we needed an exceptional opening shot.
We were inspired by a Victorian illustration, a pastoral scene which on closer inspection
reveals itself to form the shape of a skull. We decided to create this optical illusion
in three dimensions.
In order for the illusion to work, great attention had to be paid to the details of the set.
A vital element was the model who sat for hours while objects around her were moved
millimeter by millimeter.
After 12 hours of building, we were ready to shoot.
The final shot had to match exactly the computer generated skull that had been on monitors
in the studio during the build.
After this amount of preparation, everyone was nervous as we prepared the camera track.
During the take, we knew we had the shot. It had worked perfectly.
The actual filming took less than five minutes. A perfect introduction to our hero, Smedley
the skeleton.
Smedley was created using computer generated graphics. Within the computer, he could walk
and react.
But he needed some real settings to bring him to life.
In the eyewitness studio, we created a skeleton room with everything Smedley could want, including
a strong hook, which would prove useful during the course of the program.
Smedley was placed carefully against created backgrounds using computer graphics.
Sometimes he had to do more than just be placed in a set. The production manager, Pete, opened
the door for Smedley to escape from his skeletal room.
With help from the computer operator, Smedley could experience the true wonder of the Eyewitness
Museum.
This is the End of the Tour.