David Attenborough's Natural Curiosities (2013) s02e02 Episode Script
Armored Animals
ATTENBOROUGH: The natural world is full of extraordinary animals with amazing life histories.
Yet, certain stories are more intriguing than most.
The mysteries of a butterfly's life-cycle or the strange biology of the emperor penguin.
some of these creatures were surrounded by myths and misunderstandings for a very long time.
And some have only recently revealed their secrets.
These are the animals that stand out from the crowd.
The curiosities 1 find most fascinating of all.
some animals appear to protect themselves with formidable suits of armour.
The rhino carries plates of thick hide on its flanks while the hedgehog is covered in prickly spines.
Both, in previous centuries, inspired far-fetched and outlandish ideas.
But what is the true nature of their strange coats? Rhinoceroses are strange-looking creatures.
There are five kinds.
The Indian, this one, has a single horn, squat legs, tiny eyes Whoa! And thick, folded skin.
For many centuries before any had reached Europe, they were surrounded by myth as much as the unicorn.
Few people had ever seen a live rhino.
But, in 1 741 , a young Indian rhinoceros called Clara came to Europe and she transformed our image and understanding of the rhinoceros.
Thank you.
Before Clara arrived, little was known in Europe about the rhinoceros.
A few animals arrived here in Roman times, but they didn't last long, many being slaughtered during the brutal Roman games.
1t wasn't until the 1 6th century that they first made a real mark on Western society.
1n 1 5 1 5, a woodcut of a rhino was created by an artist called Durer.
1t was a beautiful image of an elaborately-armoured creature, but it was inaccurate.
1t's doubtful whether Durer ever saw a live rhinoceros.
It's little wonder that the rhinoceros was thought of as a magical, mythical creature, if Durer's woodcut of 1 51 5 was to be believed.
He shows an armour-plated beast with a large horn and a strange little spike on his back.
But in the 1 8th century, the perception of the rhinoceros was to change, when Clara came to Europe on an extraordinary 1 7-year tour.
Clara was captured in Assam at just a few months of age when hunters killed her mother.
A director of the Dutch East 1ndia Company raised her in his household as a pet.
she wandered indoors amongst the elegant furniture, ate from a plate and was a popular attraction at his dinner parties.
But, inevitably, Clara got too big and a little-known Dutch sea captain called van der Meer seized the chance to own possibly the only tame rhino in the world.
He saw the opportunity of making a lifetime's income with an ambitious rhinoceros tour.
Clara became an orphan while she was still dependant on her mother.
Rhino calves usually stay with their mothers for up to two years, sustained by the milk.
Only after that, are they able to feed independently on soft, green grass.
Keeping a young rhino healthy was certainly a challenge.
But van der Meer was smart and took good care of his new charge.
He travelled with her all the way from 1ndia, around the Cape of Good Hope, up the coast of Africa to the Netherlands, and his home town of Leiden.
He discovered very soon that Clara had a huge appetite.
And he made sure that she always had plenty to eat.
Rhinoceros spend a great deal of time feeding.
They eat plant matter but they don't have multiple stomachs to digest and absorb nutrients.
So they need to eat large quantities of food to survive, up to 1 00 kilos a day.
1t takes a lot to fuel such an enormous body.
An adult rhino weighs over a tonne.
And the 1ndian rhino has a special mobile lip to help it grasp and rip up the vegetation.
After reaching Europe, Clara lived quietly in Leiden for two years, feeding and growing, while van der Meer made plans for his European tour.
At the time, a live rhino was a wondrous thing, as van der Meer well appreciated.
He was a clever businessman and he knew that publicity was needed if his grand tour was to be a success.
van der Meer made an unusual alliance with an ambitious Dutch anatomist B.
S.
Albinus, who was hoping to produce a definitive medical textbook.
Both men were looking for publicity.
And together, they commissioned jan Wanderlaar, an accomplished artist, to make prints that would serve to advertise both the book and Clara.
They were strange but compelling pictures that combined precisely-drawn human skeletons and detailed images of Clara.
They were the most accurate drawings yet of the rhinoceros.
Wanderlaar sketched Clara from life.
He was fascinated by the texture of her skin and he depicted the rhino more realistically than Durer did.
so, at last, the myths surrounding the animal's appearance came to an end.
As the news of Clara's tour spread, everyone was eager to see this wonderful new creature.
And Clara's first trip to Vienna was for a royal appointment.
The Empress Maria Theresa was so eager to see Clara and so impressed by her appearance and good temperament, that she brought her children back for another private showing.
Clara became the talk of the town and European heads of state were eager to meet her.
she travelled through Europe like a celebrity and met both royalty and crowds of curious onlookers.
Her horn in particular attracted much attention.
1n Paris, she started a rhino mania, with fashionable women styling their hair a la rhinoceros.
some regarded rhinos as living unicorns.
The scientific name for the 1ndian rhino is, in fact, Rhinoceros unicornis.
And, at the time, it was believed that the horn was made of bone.
But this, in fact, is not the case.
Rhinoceros horn grows from a spongy base positioned here on the skull.
The horn has no bony core.
It's made of keratin, the same substance as fingernails, and can grow again if it's lost.
Well, in june, 1 750, Clara's horn fell off, probably due to her rubbing it on the travel crate.
To van der Meer, this seemed to be a disaster, since he had no idea that it would regrow.
But ingeniously, he used the event as a publicity stunt and the crowds flocked all the more to see Clara, fearing that she might be dying.
Even without a horn, Clara was still a fascinating creature, and her strange, armoured skin was another talking point.
Why would such a gentle creature have such thick and elaborate folds? The rhinoceros' skin in some parts is almost five centimetres thick, nearly three times thicker than you would expect for an animal that size.
We now know that in the wild, rhinoceros are not always as gentle as Clara.
They can be very aggressive, particularly during the mating season.
And the tough skin provides them with some protection.
But it also has other benefits.
Thick skin is a good barrier against sun, flies and other parasites.
But why the skin of an Indian rhino grows in plate-like structures with deep grooves, has only recently been explained.
We know that the thicker-skinned areas are good physical protection, but something deeper is going on.
1t seems that the large folds increase the surface area of the skin and help the rhino regulate its body temperature.
The tissues around the grooves are particularly rich in blood vessels and transmit heat to the enlarged skin plates which act like cooling radiators.
1ndian rhinoceros bathe regularly and the folds in their skin not only trap water but hold it even after they come back onto land.
so it turns out that the 1ndian rhinoceros' skin is a far more specialised structure than anyone could've imagined.
For 1 7 years, Clara travelled across Europe stopping off in all the main towns and cities.
Everywhere she went, the crowds queued up to see her.
she visited England three times, but her third visit proved to be her last.
In 1 758, at the age of little more than 20, Clara unexpectedly died in London.
van der Meer was deeply shocked, as he thought she might live to be 1 00.
Life on the road was over, but Clara's 1 7-year tour had changed the image of the rhinoceros forever.
Durer's classic engraving of the fierce armoured beast was now a part of history.
And new accurate images were produced.
The true Indian rhinoceros, like Clara, looked just like this wonderful animal painted by the great 1 8th century artist George Stubbs.
van der Meer made his fortune with her, on the grand tour, but Clara, more importantly, also enabled people to get a first realistic view of what a rhinoceros looks like and put to rest the idea of a heavily-armoured mythical creature.
There is a more familiar animal whose body armour also perplexed us for a surprisingly long time.
The hedgehog.
This delightful little creature is one of our most familiar garden animals, and yet it's got a surprisingly unusual appearance.
Instead of fur, like most mammals, it's got a thick coat of spines.
The only parts of its body not covered by them are its face and its underside.
The hedgehog's coat may appear to be painfully prickly, but when the hedgehog's relaxed, it can lay its spines down flat.
When it senses danger, of course, it rolls itself into a ball and is completely hidden and protected.
It's a formidable suit of armour, these spines, nothing much can get past them.
1t seems obvious that spines must serve as protection.
But their function was, in fact, misunderstood for a long time.
Early books claim the spines were used for collecting food.
The hedgehogs were said to climb apple trees, knock down the fruit and roll on it, impaling the apples on their spines, and carrying them off to their burrows.
Today, we know that hedgehogs are better at climbing than you might think but they still haven't been seen to climb trees.
And there were other myths.
1n medieval times, farmers believed that hedgehogs would steal milk from their cows at night.
so the Elizabethan Parliament put a three pence bounty on the head of every hedgehog and thousands were slaughtered as a result.
Our attitude to the hedgehog is now very different.
Today, many of us get great pleasure from seeing this appealing little creature in our gardens.
We know that they are a gardener's friend, feeding mostly on insects and slugs and helping to rid our plants of pests.
Some of us even put out special food to attract them.
We now also understand more about the hedgehog's spines.
They are, in fact, modified hairs, hollow inside, but reinforced with keratin, the same material that forms a rhinoceros' horn.
That makes them strong, while keeping weight down to a minimum.
A hedgehog has over 5,000 spines.
And their main purpose is indeed protection.
But hedgehogs don't start life with a coat of armour.
1t'd be painful for a hedgehog mother to give birth to spiny babies.
But nature has dealt with that problem.
Tiny hoglets are born with their spines covered by a layer of skin.
Within a few hours, the thin quills break through.
The baby hedgehog's first spines are soft and white.
But these soon fall out and are replaced by darker and harder ones.
Hedgehog spines are shed and regrown at various stages in their lives, just like the hair of mammals.
surprisingly, a spiny armour is not common in the animal kingdom.
1n Europe, the hedgehog is the only one of its kind.
But in other parts of the world, there are creatures that have evolved a similar spiky coat.
This is an African crested porcupine.
It's got a formidable coat of spines, but it's no relative of the hedgehog.
And the spines are, in fact, very different.
For one thing, they're very much longer.
Normally, they lie flat against the body, but if the animal is irritated, it erects them to give a very spectacular warning.
Even the most ferocious predator will take care when approaching a porcupine.
The quills will break off easily and become lodged in the skin.
The lions' only chance is to attack from the front.
As they circle their quarry, the porcupine twists and turns to keep its armoured back to them.
This time, the lion got too close.
1t has no way of removing the spike and may be unable to feed.
1t could prove fatal for the predator.
Although the porcupine's quills may appear thin, even flimsy, once they get stuck in your flesh, they're remarkably difficult and painful to remove.
Why this should be was not known until recently.
But when looked at under an electron microscope, you can see that each quill is coated with tiny backwards-facing barbs.
The barbs act like the teeth on a serrated knife making it easier to penetrate the skin.
But when it comes to removing the quills, the barbs have the opposite effect and act as anchors, preventing the spine from sliding out of the wound.
The porcupine's spiky coat seems more formidable than the hedgehog's.
But the hedgehog has a very effective way of protecting its vulnerable underbelly.
1t rolls itself into a ball so that it is completely encased in spines.
Foxes do attack hedgehogs, but a fox must wait until the animal is on the move if it's to get at its unprotected underside.
1f the hedgehog stays rolled in a defensive ball, the fox can't harm it.
All the hedgehog has to do is to sit it out until the fox loses interest.
But if spines are such an effective defence, why don't many other animals adopt them? The answer seems to be connected with the difficulties of life with spines.
spines may be something of a hindrance when it comes to mating.
1ndeed, early naturalists thought that the hedgehogs must mate belly to belly to avoid being impaled on each other's spines.
We now know that that's not the case.
The spines seem to do nothing to hinder the ardour of a male hedgehog.
1f she's willing, he tries to oblige but it still looks like a tricky and uncomfortable operation.
Despite the limitations of a spiny coat, hedgehogs have remained largely unchanged for almost 1 5 million years.
And new evidence suggests that the spines may play another rather surprising role in their lives.
Hedgehogs, when encountering an unfamiliar or toxic object, sometimes behave in a very strange way.
They will lick and bite it until they start to foam at the mouth.
The froth is then transferred to their spines.
We still don't fully understand this strange behaviour.
1t may help to camouflage the hedgehog's smell or make the spiny coat more distasteful to predators.
Or maybe it helps hedgehogs communicate with each other.
Or make them more attractive to the opposite sex.
We might one day discover its true purpose, but we haven't yet.
Our familiar British hedgehog has provoked some very strange and far-fetched ideas.
But for many of us, it remains one of the most engaging animals in the British countryside and its prickly coat makes it that much more attractive.
so it turns out that some of the early ideas about the purpose of the rhino's armour and the hedgehog's spines were only partly correct.
Their true functions are far more complex than we yet realise.
Yet, certain stories are more intriguing than most.
The mysteries of a butterfly's life-cycle or the strange biology of the emperor penguin.
some of these creatures were surrounded by myths and misunderstandings for a very long time.
And some have only recently revealed their secrets.
These are the animals that stand out from the crowd.
The curiosities 1 find most fascinating of all.
some animals appear to protect themselves with formidable suits of armour.
The rhino carries plates of thick hide on its flanks while the hedgehog is covered in prickly spines.
Both, in previous centuries, inspired far-fetched and outlandish ideas.
But what is the true nature of their strange coats? Rhinoceroses are strange-looking creatures.
There are five kinds.
The Indian, this one, has a single horn, squat legs, tiny eyes Whoa! And thick, folded skin.
For many centuries before any had reached Europe, they were surrounded by myth as much as the unicorn.
Few people had ever seen a live rhino.
But, in 1 741 , a young Indian rhinoceros called Clara came to Europe and she transformed our image and understanding of the rhinoceros.
Thank you.
Before Clara arrived, little was known in Europe about the rhinoceros.
A few animals arrived here in Roman times, but they didn't last long, many being slaughtered during the brutal Roman games.
1t wasn't until the 1 6th century that they first made a real mark on Western society.
1n 1 5 1 5, a woodcut of a rhino was created by an artist called Durer.
1t was a beautiful image of an elaborately-armoured creature, but it was inaccurate.
1t's doubtful whether Durer ever saw a live rhinoceros.
It's little wonder that the rhinoceros was thought of as a magical, mythical creature, if Durer's woodcut of 1 51 5 was to be believed.
He shows an armour-plated beast with a large horn and a strange little spike on his back.
But in the 1 8th century, the perception of the rhinoceros was to change, when Clara came to Europe on an extraordinary 1 7-year tour.
Clara was captured in Assam at just a few months of age when hunters killed her mother.
A director of the Dutch East 1ndia Company raised her in his household as a pet.
she wandered indoors amongst the elegant furniture, ate from a plate and was a popular attraction at his dinner parties.
But, inevitably, Clara got too big and a little-known Dutch sea captain called van der Meer seized the chance to own possibly the only tame rhino in the world.
He saw the opportunity of making a lifetime's income with an ambitious rhinoceros tour.
Clara became an orphan while she was still dependant on her mother.
Rhino calves usually stay with their mothers for up to two years, sustained by the milk.
Only after that, are they able to feed independently on soft, green grass.
Keeping a young rhino healthy was certainly a challenge.
But van der Meer was smart and took good care of his new charge.
He travelled with her all the way from 1ndia, around the Cape of Good Hope, up the coast of Africa to the Netherlands, and his home town of Leiden.
He discovered very soon that Clara had a huge appetite.
And he made sure that she always had plenty to eat.
Rhinoceros spend a great deal of time feeding.
They eat plant matter but they don't have multiple stomachs to digest and absorb nutrients.
So they need to eat large quantities of food to survive, up to 1 00 kilos a day.
1t takes a lot to fuel such an enormous body.
An adult rhino weighs over a tonne.
And the 1ndian rhino has a special mobile lip to help it grasp and rip up the vegetation.
After reaching Europe, Clara lived quietly in Leiden for two years, feeding and growing, while van der Meer made plans for his European tour.
At the time, a live rhino was a wondrous thing, as van der Meer well appreciated.
He was a clever businessman and he knew that publicity was needed if his grand tour was to be a success.
van der Meer made an unusual alliance with an ambitious Dutch anatomist B.
S.
Albinus, who was hoping to produce a definitive medical textbook.
Both men were looking for publicity.
And together, they commissioned jan Wanderlaar, an accomplished artist, to make prints that would serve to advertise both the book and Clara.
They were strange but compelling pictures that combined precisely-drawn human skeletons and detailed images of Clara.
They were the most accurate drawings yet of the rhinoceros.
Wanderlaar sketched Clara from life.
He was fascinated by the texture of her skin and he depicted the rhino more realistically than Durer did.
so, at last, the myths surrounding the animal's appearance came to an end.
As the news of Clara's tour spread, everyone was eager to see this wonderful new creature.
And Clara's first trip to Vienna was for a royal appointment.
The Empress Maria Theresa was so eager to see Clara and so impressed by her appearance and good temperament, that she brought her children back for another private showing.
Clara became the talk of the town and European heads of state were eager to meet her.
she travelled through Europe like a celebrity and met both royalty and crowds of curious onlookers.
Her horn in particular attracted much attention.
1n Paris, she started a rhino mania, with fashionable women styling their hair a la rhinoceros.
some regarded rhinos as living unicorns.
The scientific name for the 1ndian rhino is, in fact, Rhinoceros unicornis.
And, at the time, it was believed that the horn was made of bone.
But this, in fact, is not the case.
Rhinoceros horn grows from a spongy base positioned here on the skull.
The horn has no bony core.
It's made of keratin, the same substance as fingernails, and can grow again if it's lost.
Well, in june, 1 750, Clara's horn fell off, probably due to her rubbing it on the travel crate.
To van der Meer, this seemed to be a disaster, since he had no idea that it would regrow.
But ingeniously, he used the event as a publicity stunt and the crowds flocked all the more to see Clara, fearing that she might be dying.
Even without a horn, Clara was still a fascinating creature, and her strange, armoured skin was another talking point.
Why would such a gentle creature have such thick and elaborate folds? The rhinoceros' skin in some parts is almost five centimetres thick, nearly three times thicker than you would expect for an animal that size.
We now know that in the wild, rhinoceros are not always as gentle as Clara.
They can be very aggressive, particularly during the mating season.
And the tough skin provides them with some protection.
But it also has other benefits.
Thick skin is a good barrier against sun, flies and other parasites.
But why the skin of an Indian rhino grows in plate-like structures with deep grooves, has only recently been explained.
We know that the thicker-skinned areas are good physical protection, but something deeper is going on.
1t seems that the large folds increase the surface area of the skin and help the rhino regulate its body temperature.
The tissues around the grooves are particularly rich in blood vessels and transmit heat to the enlarged skin plates which act like cooling radiators.
1ndian rhinoceros bathe regularly and the folds in their skin not only trap water but hold it even after they come back onto land.
so it turns out that the 1ndian rhinoceros' skin is a far more specialised structure than anyone could've imagined.
For 1 7 years, Clara travelled across Europe stopping off in all the main towns and cities.
Everywhere she went, the crowds queued up to see her.
she visited England three times, but her third visit proved to be her last.
In 1 758, at the age of little more than 20, Clara unexpectedly died in London.
van der Meer was deeply shocked, as he thought she might live to be 1 00.
Life on the road was over, but Clara's 1 7-year tour had changed the image of the rhinoceros forever.
Durer's classic engraving of the fierce armoured beast was now a part of history.
And new accurate images were produced.
The true Indian rhinoceros, like Clara, looked just like this wonderful animal painted by the great 1 8th century artist George Stubbs.
van der Meer made his fortune with her, on the grand tour, but Clara, more importantly, also enabled people to get a first realistic view of what a rhinoceros looks like and put to rest the idea of a heavily-armoured mythical creature.
There is a more familiar animal whose body armour also perplexed us for a surprisingly long time.
The hedgehog.
This delightful little creature is one of our most familiar garden animals, and yet it's got a surprisingly unusual appearance.
Instead of fur, like most mammals, it's got a thick coat of spines.
The only parts of its body not covered by them are its face and its underside.
The hedgehog's coat may appear to be painfully prickly, but when the hedgehog's relaxed, it can lay its spines down flat.
When it senses danger, of course, it rolls itself into a ball and is completely hidden and protected.
It's a formidable suit of armour, these spines, nothing much can get past them.
1t seems obvious that spines must serve as protection.
But their function was, in fact, misunderstood for a long time.
Early books claim the spines were used for collecting food.
The hedgehogs were said to climb apple trees, knock down the fruit and roll on it, impaling the apples on their spines, and carrying them off to their burrows.
Today, we know that hedgehogs are better at climbing than you might think but they still haven't been seen to climb trees.
And there were other myths.
1n medieval times, farmers believed that hedgehogs would steal milk from their cows at night.
so the Elizabethan Parliament put a three pence bounty on the head of every hedgehog and thousands were slaughtered as a result.
Our attitude to the hedgehog is now very different.
Today, many of us get great pleasure from seeing this appealing little creature in our gardens.
We know that they are a gardener's friend, feeding mostly on insects and slugs and helping to rid our plants of pests.
Some of us even put out special food to attract them.
We now also understand more about the hedgehog's spines.
They are, in fact, modified hairs, hollow inside, but reinforced with keratin, the same material that forms a rhinoceros' horn.
That makes them strong, while keeping weight down to a minimum.
A hedgehog has over 5,000 spines.
And their main purpose is indeed protection.
But hedgehogs don't start life with a coat of armour.
1t'd be painful for a hedgehog mother to give birth to spiny babies.
But nature has dealt with that problem.
Tiny hoglets are born with their spines covered by a layer of skin.
Within a few hours, the thin quills break through.
The baby hedgehog's first spines are soft and white.
But these soon fall out and are replaced by darker and harder ones.
Hedgehog spines are shed and regrown at various stages in their lives, just like the hair of mammals.
surprisingly, a spiny armour is not common in the animal kingdom.
1n Europe, the hedgehog is the only one of its kind.
But in other parts of the world, there are creatures that have evolved a similar spiky coat.
This is an African crested porcupine.
It's got a formidable coat of spines, but it's no relative of the hedgehog.
And the spines are, in fact, very different.
For one thing, they're very much longer.
Normally, they lie flat against the body, but if the animal is irritated, it erects them to give a very spectacular warning.
Even the most ferocious predator will take care when approaching a porcupine.
The quills will break off easily and become lodged in the skin.
The lions' only chance is to attack from the front.
As they circle their quarry, the porcupine twists and turns to keep its armoured back to them.
This time, the lion got too close.
1t has no way of removing the spike and may be unable to feed.
1t could prove fatal for the predator.
Although the porcupine's quills may appear thin, even flimsy, once they get stuck in your flesh, they're remarkably difficult and painful to remove.
Why this should be was not known until recently.
But when looked at under an electron microscope, you can see that each quill is coated with tiny backwards-facing barbs.
The barbs act like the teeth on a serrated knife making it easier to penetrate the skin.
But when it comes to removing the quills, the barbs have the opposite effect and act as anchors, preventing the spine from sliding out of the wound.
The porcupine's spiky coat seems more formidable than the hedgehog's.
But the hedgehog has a very effective way of protecting its vulnerable underbelly.
1t rolls itself into a ball so that it is completely encased in spines.
Foxes do attack hedgehogs, but a fox must wait until the animal is on the move if it's to get at its unprotected underside.
1f the hedgehog stays rolled in a defensive ball, the fox can't harm it.
All the hedgehog has to do is to sit it out until the fox loses interest.
But if spines are such an effective defence, why don't many other animals adopt them? The answer seems to be connected with the difficulties of life with spines.
spines may be something of a hindrance when it comes to mating.
1ndeed, early naturalists thought that the hedgehogs must mate belly to belly to avoid being impaled on each other's spines.
We now know that that's not the case.
The spines seem to do nothing to hinder the ardour of a male hedgehog.
1f she's willing, he tries to oblige but it still looks like a tricky and uncomfortable operation.
Despite the limitations of a spiny coat, hedgehogs have remained largely unchanged for almost 1 5 million years.
And new evidence suggests that the spines may play another rather surprising role in their lives.
Hedgehogs, when encountering an unfamiliar or toxic object, sometimes behave in a very strange way.
They will lick and bite it until they start to foam at the mouth.
The froth is then transferred to their spines.
We still don't fully understand this strange behaviour.
1t may help to camouflage the hedgehog's smell or make the spiny coat more distasteful to predators.
Or maybe it helps hedgehogs communicate with each other.
Or make them more attractive to the opposite sex.
We might one day discover its true purpose, but we haven't yet.
Our familiar British hedgehog has provoked some very strange and far-fetched ideas.
But for many of us, it remains one of the most engaging animals in the British countryside and its prickly coat makes it that much more attractive.
so it turns out that some of the early ideas about the purpose of the rhino's armour and the hedgehog's spines were only partly correct.
Their true functions are far more complex than we yet realise.