0:00:02 > 0:00:06The natural world is full of extraordinary animals
0:00:06 > 0:00:09with amazing life histories.
0:00:09 > 0:00:13Yet certain stories are more intriguing than most.
0:00:16 > 0:00:19The mysteries of a butterfly's life cycle
0:00:19 > 0:00:23or the strange biology of the Emperor penguin.
0:00:23 > 0:00:26Some of these creatures were surrounded by myth
0:00:26 > 0:00:30and misunderstandings for a very long time
0:00:30 > 0:00:33and some have only recently revealed their secrets.
0:00:35 > 0:00:39These are the animals that stand out from the crowd.
0:00:39 > 0:00:42The curiosities I find most fascinating of all.
0:00:51 > 0:00:54Some animals appear to protect themselves
0:00:54 > 0:00:57with formidable suits of armour.
0:00:57 > 0:01:00The rhino carries plates of thick hide on its flanks.
0:01:02 > 0:01:06While the hedgehog is covered in prickly spines.
0:01:07 > 0:01:09Both, in previous centuries,
0:01:09 > 0:01:14inspired far-fetched and outlandish ideas,
0:01:14 > 0:01:18but what is the true nature of their strange coats?
0:01:25 > 0:01:29Rhinoceroses are strange-looking creatures.
0:01:29 > 0:01:30There are five kinds.
0:01:30 > 0:01:36The Indian, this one, has a single horn, squat legs, tiny eyes...
0:01:36 > 0:01:38Whoa!
0:01:38 > 0:01:41..and thick folded skin.
0:01:41 > 0:01:43For many centuries, before any had reached Europe,
0:01:43 > 0:01:48they were surrounded by myth as much as the unicorn.
0:01:48 > 0:01:53Few people had ever seen a live rhino, but, in 1741,
0:01:53 > 0:01:57a young Indian rhinoceros called Clara came to Europe
0:01:57 > 0:02:01and she transformed our image and understanding of the rhinoceros.
0:02:02 > 0:02:03Thank you.
0:02:05 > 0:02:07Before Clara arrived,
0:02:07 > 0:02:10little was known in Europe about the rhinoceros.
0:02:10 > 0:02:14A few animals arrived here in Roman times, but they didn't last long,
0:02:14 > 0:02:18many being slaughtered during the brutal Roman Games.
0:02:19 > 0:02:21It wasn't until the 16th century
0:02:21 > 0:02:24that they first made a real mark on western society.
0:02:26 > 0:02:31In 1515, a woodcut of a rhino was created by an artist called Durer.
0:02:33 > 0:02:37It was a beautiful image of an elaborately armoured creature,
0:02:37 > 0:02:39but it was inaccurate.
0:02:39 > 0:02:44It's doubtful whether Durer ever saw a live rhinoceros.
0:02:46 > 0:02:50It's little wonder that the rhinoceros was thought of
0:02:50 > 0:02:52as a magical mythical creature
0:02:52 > 0:02:56if Durer's woodcut of 1515 was to be believed.
0:02:56 > 0:03:00He shows an armour-plated beast with a large horn
0:03:00 > 0:03:03and a strange little spike on its back.
0:03:03 > 0:03:06But in the 18th century, the perception of the rhinoceros was
0:03:06 > 0:03:12to change when Clara came to Europe on an extraordinary 17-year tour.
0:03:14 > 0:03:17Clara was captured in Assam at just a few months of age
0:03:17 > 0:03:19when hunters killed her mother.
0:03:19 > 0:03:22A director of the Dutch East India Company
0:03:22 > 0:03:24raised her in his household as a pet.
0:03:24 > 0:03:27She wandered indoors amongst the elegant furniture,
0:03:27 > 0:03:31ate from a plate and was a popular attraction at his dinner parties.
0:03:31 > 0:03:34But, inevitably, Clara got too big
0:03:34 > 0:03:37and a little-known Dutch sea captain called Van der Meer
0:03:37 > 0:03:42seized the chance to own possibly the only tame rhino in the world.
0:03:42 > 0:03:45He saw the opportunity of making a lifetime's income
0:03:45 > 0:03:48with an ambitious rhinoceros tour.
0:03:51 > 0:03:55Clara became an orphan while she was still dependent on her mother.
0:03:55 > 0:04:00Rhino calves usually stay with their mothers for up to two years,
0:04:00 > 0:04:02sustained by the milk.
0:04:02 > 0:04:05Only after that are they able to feed independently
0:04:05 > 0:04:07on soft green grass.
0:04:09 > 0:04:12Keeping a young rhino healthy was certainly a challenge,
0:04:12 > 0:04:17but Van der Meer was smart and took good care of his new charge.
0:04:19 > 0:04:21He travelled with her all the way from India
0:04:21 > 0:04:25around the Cape of Good Hope, up the coast of Africa to the Netherlands
0:04:25 > 0:04:28and his home town of Leiden.
0:04:28 > 0:04:32He discovered very soon that Clara had a huge appetite
0:04:32 > 0:04:35and he made sure that she always had plenty to eat.
0:04:36 > 0:04:41Rhinoceros spend a great deal of time feeding.
0:04:41 > 0:04:44They eat plant matter, but they don't have multiple stomachs
0:04:44 > 0:04:46to digest and absorb nutrients,
0:04:46 > 0:04:49so they need to eat large quantities of food to survive,
0:04:49 > 0:04:51up to 100 kilos a day.
0:04:54 > 0:04:58It takes a lot to fuel such an enormous body.
0:04:58 > 0:05:00An adult rhino weighs over a tonne.
0:05:02 > 0:05:04And the Indian rhino has a special mobile lip
0:05:04 > 0:05:08to help it grasp and rip up the vegetation.
0:05:13 > 0:05:17After reaching Europe, Clara lived quietly in Leiden for two years,
0:05:17 > 0:05:19feeding and growing,
0:05:19 > 0:05:23while Van der Meer made plans for his European tour.
0:05:24 > 0:05:28At the time, a live rhino was a wondrous thing,
0:05:28 > 0:05:31as Van der Meer well appreciated.
0:05:31 > 0:05:35He was a clever businessman and he knew that publicity was needed
0:05:35 > 0:05:38if his grand tour was to be a success.
0:05:40 > 0:05:43Van der Meer made an unusual alliance with an ambitious
0:05:43 > 0:05:46Dutch anatomist, BS Albinus,
0:05:46 > 0:05:50who was hoping to produce a definitive medical textbook.
0:05:50 > 0:05:52Both men were looking for publicity
0:05:52 > 0:05:55and together they commissioned Jan Wandelaar,
0:05:55 > 0:05:57an accomplished artist,
0:05:57 > 0:06:01to make prints that would serve to advertise both the book and Clara.
0:06:01 > 0:06:04They were strange but compelling pictures that combined
0:06:04 > 0:06:10precisely drawn human skeletons and detailed images of Clara.
0:06:10 > 0:06:14They were the most accurate drawings yet of the rhinoceros.
0:06:15 > 0:06:17Wandelaar sketched Clara from life.
0:06:17 > 0:06:21He was fascinated by the texture of her skin
0:06:21 > 0:06:25and he depicted a rhino more realistically than Durer did,
0:06:25 > 0:06:26so, at last,
0:06:26 > 0:06:29the myths surrounding the animal's appearance came to an end.
0:06:32 > 0:06:34As the news of Clara's tour spread,
0:06:34 > 0:06:37everyone was eager to see this wonderful new creature
0:06:37 > 0:06:41and Clara's first trip to Vienna was for a royal appointment.
0:06:43 > 0:06:46The Empress Maria-Theresa was so eager to see Clara
0:06:46 > 0:06:49and so impressed by her appearance and good temperament,
0:06:49 > 0:06:53that she brought her children back for another private showing.
0:06:53 > 0:06:56Clara became the talk of the town
0:06:56 > 0:06:59and European heads of state were eager to meet her.
0:07:02 > 0:07:05She travelled through Europe like a celebrity
0:07:05 > 0:07:09and met both royalty and crowds of curious onlookers.
0:07:10 > 0:07:14Her horn in particular attracted much attention.
0:07:14 > 0:07:17In Paris she started a rhino-mania
0:07:17 > 0:07:22with fashionable women styling their hair 'a la rhinoceros!'
0:07:28 > 0:07:31Some regarded rhinos as living unicorns.
0:07:31 > 0:07:34The scientific name for the Indian rhino is, in fact,
0:07:34 > 0:07:37Rhinoceros Unicornis,
0:07:37 > 0:07:42and, at the time, it was believed that the horn was made of bone.
0:07:42 > 0:07:45But this in fact is not the case.
0:07:48 > 0:07:54Rhinoceros horn grows from a spongy base positioned here on the skull.
0:07:54 > 0:07:57The horn has no bony core.
0:07:57 > 0:08:00It's made of keratin, the same substance as fingernails
0:08:00 > 0:08:03and can grow again if it's lost.
0:08:03 > 0:08:07Well, in June 1750, Clara's horn fell off,
0:08:07 > 0:08:10probably due to her rubbing it on the travel crate.
0:08:10 > 0:08:13To Van der Meer, this seemed to be a disaster
0:08:13 > 0:08:16since he had no idea that it would regrow.
0:08:16 > 0:08:20But, ingenuously, he used the event as a publicity stunt and the crowds
0:08:20 > 0:08:23flocked all the more to see Clara fearing that she might be dying.
0:08:27 > 0:08:30Even without a horn, Clara was still a fascinating creature
0:08:30 > 0:08:34and her strange armoured skin was another talking point.
0:08:34 > 0:08:39Why would such a gentle creature have such thick and elaborate folds?
0:08:41 > 0:08:46The rhinoceros's skin in some parts is almost five centimetres thick,
0:08:46 > 0:08:49nearly three times thicker than you would expect
0:08:49 > 0:08:51for an animal that size.
0:08:54 > 0:08:56We now know that, in the wild,
0:08:56 > 0:08:59rhinoceros are not always as gentle as Clara.
0:08:59 > 0:09:01They can be very aggressive,
0:09:01 > 0:09:03particularly during the mating season,
0:09:03 > 0:09:07and the tough skin provides them with some protection.
0:09:07 > 0:09:11But it also has other benefits.
0:09:11 > 0:09:16Thick skin is a good barrier against sun, flies and other parasites,
0:09:16 > 0:09:21but why the skin of an Indian rhino grows in plate-like structures
0:09:21 > 0:09:25with deep grooves has only recently been explained.
0:09:25 > 0:09:28We know that the thicker skin areas are good physical protection,
0:09:28 > 0:09:30but something deeper is going on.
0:09:32 > 0:09:36It seems that the large folds increase the surface area
0:09:36 > 0:09:41of the skin and help the rhino regulate its body temperature.
0:09:41 > 0:09:45The tissues around the grooves are particularly rich in blood vessels
0:09:45 > 0:09:48and transmit heat to the enlarged skin plates
0:09:48 > 0:09:51which act like cooling radiators.
0:09:53 > 0:09:57Indian rhinoceros bathe regularly and the folds in their skin
0:09:57 > 0:10:02not only trap water but hold it even after they come back onto land.
0:10:04 > 0:10:07So it turns out that the Indian rhinoceros's skin
0:10:07 > 0:10:11is a far more specialised structure than anyone could have imagined.
0:10:14 > 0:10:18For 17 years, Clara travelled across Europe,
0:10:18 > 0:10:21stopping off in all the main towns and cities.
0:10:21 > 0:10:24Everywhere she went, the crowds queued up to see her.
0:10:26 > 0:10:29She visited England three times,
0:10:29 > 0:10:32but her third visit proved to be her last.
0:10:34 > 0:10:38In 1758, at the age of little more than 20,
0:10:38 > 0:10:42Clara unexpectedly died in London.
0:10:42 > 0:10:46Van der Meer was deeply shocked as he thought she might live to be 100.
0:10:46 > 0:10:51Life on the road was over, but Clara's 17-year tour
0:10:51 > 0:10:55had changed the image of the rhinoceros forever.
0:10:55 > 0:10:58Durer's classic engraving of the fierce armoured beast was now
0:10:58 > 0:11:03a part of history and new accurate images were produced.
0:11:03 > 0:11:06The true Indian rhinoceros, like Clara,
0:11:06 > 0:11:08looked just like this wonderful animal
0:11:08 > 0:11:12painted by the great 18th-century artist George Stubbs.
0:11:15 > 0:11:18Van der Meer made his fortune with her on the grand tour,
0:11:18 > 0:11:21but Clara, more importantly, also enabled people
0:11:21 > 0:11:25to get a first realistic view of what a rhinoceros looks like
0:11:25 > 0:11:30and put to rest the idea of a heavily armoured mythical creature.
0:11:35 > 0:11:39There is a more familiar animal whose body armour
0:11:39 > 0:11:42also perplexed us for a surprisingly long time.
0:11:42 > 0:11:45The hedgehog.
0:11:45 > 0:11:49This delightful little creature is one of our most familiar
0:11:49 > 0:11:54garden animals and yet it's got a surprisingly unusual appearance.
0:11:54 > 0:11:59Instead of fur, like most mammals, it's got a thick coat of spines.
0:11:59 > 0:12:02The only part of its body not covered by them
0:12:02 > 0:12:04are its face and its underside.
0:12:04 > 0:12:08The hedgehog's coat may appear to be painfully prickly,
0:12:08 > 0:12:12but when the hedgehog is relaxed, it can lay its spines down flat.
0:12:12 > 0:12:16When it senses danger, of course, it rolls itself up into a ball
0:12:16 > 0:12:19and is completely hidden and protected.
0:12:19 > 0:12:21It's a formidable suit of armour, these spines.
0:12:21 > 0:12:24Nothing much can get past them.
0:12:24 > 0:12:29It seems obvious that spines must serve as a protection
0:12:29 > 0:12:33but their function was, in fact, misunderstood for a long time.
0:12:35 > 0:12:39Early books claimed the spines were used for collecting food.
0:12:39 > 0:12:42The hedgehogs were said to climb apple trees,
0:12:42 > 0:12:46knock down the fruit and roll on it, impaling the apples on their spines
0:12:46 > 0:12:49and carrying them off to their burrows.
0:12:53 > 0:12:56Today we know that hedgehogs are better at climbing
0:12:56 > 0:13:00than you might think, but they still haven't been seen to climb trees.
0:13:05 > 0:13:07And there were other myths.
0:13:07 > 0:13:11In medieval times, farmers believed that hedgehogs would steal milk
0:13:11 > 0:13:13from their cows at night.
0:13:13 > 0:13:18So the Elizabethan Parliament put a three-pence bounty on the head
0:13:18 > 0:13:22of every hedgehog and thousands were slaughtered as a result.
0:13:25 > 0:13:28Our attitude to the hedgehog is now very different.
0:13:32 > 0:13:34Today, many of us get great pleasure
0:13:34 > 0:13:39from seeing this appealing little creature in our gardens.
0:13:39 > 0:13:41We know that they are a gardener's friend,
0:13:41 > 0:13:43feeding mostly on insects and slugs
0:13:43 > 0:13:46and helping to rid our plants of pests.
0:13:46 > 0:13:49Some of us even put out special food to attract them.
0:13:51 > 0:13:56We now also understand more about the hedgehog's spines.
0:13:56 > 0:13:59They are, in fact, modified hairs,
0:13:59 > 0:14:02hollow inside but reinforced with keratin,
0:14:02 > 0:14:05the same material that forms a rhinoceros's horn.
0:14:07 > 0:14:11That makes them strong while keeping weight down to a minimum.
0:14:12 > 0:14:16A hedgehog has over 5,000 spines
0:14:16 > 0:14:20and their main purpose is indeed protection.
0:14:22 > 0:14:26But hedgehogs don't start life with a coat of armour.
0:14:32 > 0:14:35It would be painful for a hedgehog mother
0:14:35 > 0:14:37to give birth to spiny babies.
0:14:37 > 0:14:40But nature has dealt with that problem.
0:14:40 > 0:14:45Tiny hoglets are born with their spines covered by a layer of skin.
0:14:48 > 0:14:51Within a few hours, the thin quills break through.
0:14:54 > 0:14:58A baby hedgehog's first spines are soft and white
0:14:58 > 0:15:02but these soon fall out and are replaced by darker and harder ones.
0:15:11 > 0:15:15Hedgehog spines are shed and regrown at various stages in their lives,
0:15:15 > 0:15:17just like the hair of mammals.
0:15:22 > 0:15:26Surprisingly, a spiny armour is not common in the animal kingdom.
0:15:28 > 0:15:32In Europe, the hedgehog is the only one of its kind.
0:15:34 > 0:15:37But in other parts of the world, there are creatures that have
0:15:37 > 0:15:39evolved a similar spiky coat.
0:15:46 > 0:15:48This is an African crested porcupine.
0:15:49 > 0:15:53It's got a formidable coat of spines but it's no relative
0:15:53 > 0:15:57of the hedgehog and the spines are in fact very different.
0:15:57 > 0:16:01For one thing, they are very much longer.
0:16:01 > 0:16:05Normally, they lie flat against the body but if the animal is irritated,
0:16:05 > 0:16:08it directs them to give a very spectacular warning.
0:16:10 > 0:16:13Even the most ferocious predator will take care
0:16:13 > 0:16:15when approaching a porcupine.
0:16:17 > 0:16:20The quills will break off easily and become lodged in the skin.
0:16:23 > 0:16:26The lion's only chance is to attack from the front.
0:16:29 > 0:16:32As they circle, the porcupine twists and turns
0:16:32 > 0:16:34to keep its armoured back to them.
0:16:38 > 0:16:41This time, the lion got too close.
0:16:43 > 0:16:47It has no way of removing the spike and may be unable to feed.
0:16:48 > 0:16:50It could prove fatal for the predator.
0:16:55 > 0:16:59Although the porcupine's quills may appear thin, even flimsy,
0:16:59 > 0:17:03once they get stuck in your flesh, they are remarkably difficult
0:17:03 > 0:17:05and painful to remove.
0:17:05 > 0:17:08Why this should be was not known until recently.
0:17:08 > 0:17:12But when looked at under an electron microscope, you can see
0:17:12 > 0:17:16that each quill is coated with tiny backwards facing barbs.
0:17:17 > 0:17:20The barbs act like the teeth on a serrated knife,
0:17:20 > 0:17:22making it easier to penetrate the skin,
0:17:22 > 0:17:25but when it comes to removing the quills,
0:17:25 > 0:17:29the barbs have the opposite effect and act as anchors,
0:17:29 > 0:17:31preventing the spine from sliding out of the wound.
0:17:34 > 0:17:40The porcupine's spiky coat seems more formidable than the hedgehog's.
0:17:40 > 0:17:44But the hedgehog has a very effective way of protecting
0:17:44 > 0:17:47its vulnerable underbelly.
0:17:47 > 0:17:53It rolls itself into a ball, so that it is completely encased in spines.
0:17:57 > 0:18:01Foxes do attack hedgehogs but a fox must wait until the animal
0:18:01 > 0:18:05is on the move if it is to get at its unprotected underside.
0:18:08 > 0:18:11If the hedgehog stays rolled in a defensive ball,
0:18:11 > 0:18:13the fox can't harm it.
0:18:16 > 0:18:22All the hedgehog has to do is to sit it out until the fox loses interest.
0:18:30 > 0:18:33But if spines are such an effective defence,
0:18:33 > 0:18:36why don't many other animals adopt them?
0:18:36 > 0:18:40The answer seems to be connected with the difficulties
0:18:40 > 0:18:42of life with spines.
0:18:44 > 0:18:48Spines may be something of a hindrance when it comes to mating.
0:18:50 > 0:18:54Indeed, early naturalists thought that the hedgehogs must mate
0:18:54 > 0:18:58belly to belly to avoid being impaled on each other's spines.
0:19:00 > 0:19:02We now know that that's not the case.
0:19:02 > 0:19:04The spines seem to do nothing
0:19:04 > 0:19:08to hinder the ardour of a male hedgehog.
0:19:08 > 0:19:12If she is willing, he tries to oblige.
0:19:12 > 0:19:17But it still looks like a tricky and uncomfortable operation.
0:19:24 > 0:19:27Despite the limitations of a spiny coat,
0:19:27 > 0:19:30hedgehogs have remained largely unchanged
0:19:30 > 0:19:34for almost 15 million years.
0:19:34 > 0:19:37New evidence suggests that the spines may play another
0:19:37 > 0:19:40rather surprising role in their lives.
0:19:43 > 0:19:47Hedgehogs, when encountering an unfamiliar or toxic object,
0:19:47 > 0:19:52sometimes behave in a very strange way.
0:19:52 > 0:19:56They will lick and bite it until they start to foam at the mouth.
0:19:56 > 0:20:00The froth is then transferred to their spines.
0:20:01 > 0:20:05We still don't fully understand this strange behaviour.
0:20:06 > 0:20:10It may help to camouflage the hedgehog's smell,
0:20:10 > 0:20:13or make the spiny coat more distasteful to predators.
0:20:17 > 0:20:21Or maybe it helps hedgehogs communicate with each other.
0:20:21 > 0:20:24Or make them more attractive to the opposite sex.
0:20:25 > 0:20:30We might one day discover its true purpose but we haven't yet.
0:20:36 > 0:20:41Our familiar British hedgehog has provoked some very strange
0:20:41 > 0:20:44and far-fetched ideas, but, for many of us,
0:20:44 > 0:20:49it remains one of the most engaging animals in the British countryside,
0:20:49 > 0:20:52and its prickly coat makes it that much more attractive.
0:20:55 > 0:20:59So, it turns out that some of the early ideas about the purpose
0:20:59 > 0:21:01of the rhino's armour and the hedgehog's spines
0:21:01 > 0:21:04were only partly correct.
0:21:04 > 0:21:09Their true functions are far more complex than we yet realise.