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The natural world is full of extraordinary animals
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with amazing life histories.
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Yet certain stories are more intriguing than most.
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The mysteries of a butterfly's life cycle
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or the strange biology of the Emperor Penguin.
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Some of these creatures were surrounded
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by myth and misunderstandings for a very long time,
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and some have only recently revealed their secrets.
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These are the animals that stand out from the crowd,
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the curiosities I find most fascinating of all.
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In this programme, I investigate creatures
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that have taken the ordinary and made it extraordinary.
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The chameleon that has an extra long tongue to catch prey...
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..and the giraffe with a neck so long it can reach the top of trees.
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How and why have these animals stretched nature to the limit?
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And also in this programme,
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we explore the stories of two animals
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that sent shock waves through the scientific world and beyond.
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One is a toad that became the centre of a scientific storm
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and caused accusations of fakery in the early part of the 20th century.
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The other is an Australian animal
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that baffled the greatest thinkers of Victorian Europe
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and caused many to question whether it was even real.
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The chameleon is a truly bizarre creature,
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both in its behaviour and its appearance
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unlike anything else on earth.
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So, not surprisingly, it's given rise to all kinds of legends and myths,
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This is The History Of The Four-footed Beasts by Edward Topsell
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written in the 17th century.
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And he calls the chameleon,
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"A fraudulent, ravening and gluttonous beast,
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"impure and unclean by the law of God."
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Some believed it was constructed by the devil
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from parts of other animals,
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the tail of a monkey, the skin of a crocodile,
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the tongue of a toad, the horns of a rhinoceros,
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and the eyes of who knows what.
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It was a creature sent to the world to spy for a demon master.
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When I first came face to face with the chameleon more than 50 years ago,
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I was struck not only by its beauty,
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but intrigued by its strange body, particularly by its tongue.
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The outlandish appearance of the chameleon
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made it much sought-after by curiosity hunters,
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but scientists and naturalists too were greatly puzzled
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by its extraordinary behaviour and anatomy.
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It looked and behaved like no other reptile.
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Even today, we're still discovering new things about its unique eyes,
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its astonishing tongue,
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and its ability to change its appearance.
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Chameleons are notoriously hard to find,
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partly because they move so slowly,
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but also because they match their surroundings
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in terms of colour so very well.
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This one in front of me is a dwarf chameleon
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from Natal in South Africa.
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If that's threatened by a snake,
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it doesn't bother to change its colour very much,
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because a snake's colour vision is not very good,
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but if it's threatened by a bird,
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it does camouflage itself very well indeed.
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Some species of chameleon,
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and there are 85 different species in the family,
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can even fine tune their camouflage.
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If they detect a snake approaching from below,
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they become lighter in colour and so less noticeable against the sky.
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On the other hand, if the threat comes from a bird,
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they become darker to match the background beneath them.
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A chameleon's colour is affected not only by its surroundings,
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but by the temperature and the light and its emotional state.
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Behind this screen there's a rival male.
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Let's see what happens if I remove the screen
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and let them see one another.
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This highly-coloured male is dominant
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and he immediately adds bright, aggressive colours to his display.
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The other male remains dark
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and too frightened to change colour and fight back.
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It's clear who's the boss.
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Chameleons are emotional creatures,
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darker colouration signals anger.
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This female on the right is not in the mood
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to accept the approaches of this brightly coloured and hopeful male.
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Exactly how chameleons achieve such dramatic colour changes
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greatly puzzled early naturalists.
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An Englishman named Barrow,
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who travelled in Africa in the 19th century,
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thought the changing colour was caused by something to do with air.
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He wrote, "Previous to the chameleon assuming a change in colour,
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"it makes a long inspiration,
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"the body swelling out to twice its usual size,
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"and as this inflation subsides
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"the change of colour gradually takes place."
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Well, that's an accurate observation of what happens
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when a chameleon gets angry and then it's anger subsides,
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but actually the change of colour has nothing to do with air.
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A French biologist, Mel Edwards, soon after that got it about right.
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He wrote, "There exist two layers of membranous pigment
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"placed one above the other,
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"but disposed in such a way to appear simultaneously under the cuticle
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"and sometimes in such a manner that one may hide the other."
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Which is indeed so.
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Today, we know that the chameleon's skin has three layers
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of expendable pigmented cells called chromatophores.
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They contain red, yellow, blue and white pigments
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with a deeper layer of darker melanin,
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which controls the reflection of light.
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The chameleons use colour change not only to camouflage themselves,
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but also to communicate with one another.
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Anyone who looks closely at a chameleon
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is bound to be fascinated by its eyes.
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They protrude on either side of its head
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as though they were mounted on turrets.
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And, in fact, their eyelids are fused together
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except for one tiny spot right in the middle.
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But the most extraordinary thing about them...
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is that they move independently.
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So that means the chameleon at one and the same time
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can be viewing above it and below it.
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So any insect that lands nearby
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is going to be spotted almost immediately.
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It seems that its brain receives separate messages from each eye
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and views them and receives them alternately very fast
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but independent of one another, they're not integrated.
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But the advantage of that is that it does give this
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all-round, three-dimensional view
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which is unrivalled.
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This extraordinary vision is an essential element
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in the way the chameleon uses its most astonishing feature,
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it's hugely elongated tongue.
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How this tongue worked and its construction
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greatly intrigued early naturalists - and understandably.
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This remarkable preserved specimen shows us in detail
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the impressive elongated tongue of a chameleon.
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The physical structure of the chameleon's tongue
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was easy enough to explain,
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although it proved to be a somewhat complicated organ,
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a hollow tube with a tapered cartilaginous rod at its base.
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The pad at the end was thought to be rough and sticky,
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so that it could snag its prey.
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But the mystery of how a contraption like this
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could be lengthened and projected out of the mouth
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took a little longer to fully explain.
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Perhaps the way a frigatebird inflates the balloon under its beak,
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or how a calling frog blows up its throat sac could give clues,
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both do it with air.
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Or maybe the tentacles that carry a snail's eye,
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it projects them by using its blood as an hydraulic fluid.
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But none of them fitted the bill.
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It's a much more complex process.
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The tongue is a muscular tube
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that when relaxed sits on a rod of cartilage.
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When the chameleon is ready to strike,
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muscles at the back of the tongue push it into launch position.
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When the prey is lined up and the distance calculated,
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superfast muscles contract
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and propel the tongue forward at lightning speed.
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As the tongue shoots off the end of the cartilage,
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an extra wave of energy drives it forward to its target.
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Then, like a stretched elastic band,
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its elasticity pulls it back into the chameleon's mouth.
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Recently, high-speed images revealed a new detail.
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The tip of the tongue, once thought to be sticky,
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is covered in microscopic protrusions
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that generate suction and secures its prey.
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Chameleons really are the most extraordinary creatures
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and they hold surprises for us even today.
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Only this year, a scientist working in Madagascar
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discovered a tiny little chameleon only 29mm long.
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It's the smallest known vertebrate in the world.
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It's astounding to realise that all the organs of a vertebrate's body
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could be fitted into such a tiny little creature,
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including that extraordinary tongue.
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Next, is the story of another amazing elongated structure,
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not a tongue but a neck.
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The giraffe is an animal that can't fail to impress.
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Up to 6m or 19ft in height,
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it's hugely imposing, intriguing in appearance,
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and mysterious in its biology.
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Our attraction to this unusual creatures goes back centuries.
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And one feature in particular has piqued our curiosity -
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its elongated neck.
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Such a structure seemed an impossibility of nature,
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but now we better understand the complex biology
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behind the giraffe's bizarre body.
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Our growing knowledge of this creature
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can be traced back to three very special giraffes
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and the story of a royal fascination for the exotic.
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In the 19th century, a giraffe named Zarafa, Arabic for "charming one,"
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made a big impact on Europe socially and scientifically.
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She was one of three captured in 1826 at the order of the Viceroy of Egypt,
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who wanted to use them as gifts
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to curry favour with France, Austria and England.
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Zarafa, the strongest of the three, was given to the French,
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seen here in a painting by Jacques Raymond Brascassat.
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She travelled from Egypt to Marseilles by ship.
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On reaching France, her keepers felt it was too risky to continue by boat,
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so the decision was made to walk Zarafa from Marseille in the south
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all the way to Paris,
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an overland journey of more than 550 miles.
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To some, this looked like a journey doomed to failure,
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but careful planning and the unique biology of the giraffe
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were in its favour.
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Very wisely, a forward-thinking and eminent French scientist
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called Geoffroy Saint-Hilaire was put in charge of the giraffe.
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But there was something very significant about Zarafa
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that would be key to the success of her long journey,
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it was her age.
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She was a youngster, just eight months old.
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Baby giraffes are very robust
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and can stand up and run within an hour of being born.
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They have particularly long legs in relation to their bodies,
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only half a metre shorter than those of an adult.
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Such long legs help them keep up with their mothers,
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so young Zarafa was well-equipped for walking.
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Crucial too was the fuel for Zarafa's journey.
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Young giraffe suckle for up to a year and Zarafa was bottle-fed.
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Throughout the journey, she drank up to 25 litres of milk a day,
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supplied by three milking cows.
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She marched on at a steady pace with her trusty entourage.
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After nearly 200 miles, Zarafa reached Lyon
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and Saint-Hilaire broke the walk.
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He hoped to put Zarafa onto a boat
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to go down-river for the rest of the journey.
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As they waited, 30,000 people flocked to see Zarafa.
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To the public, she was a strange and exotic creature,
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and they were intrigued why such a long neck should exist,
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and curious about how an animal could support its weight.
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In those early days, giraffe were seen as freaks, strange horned camels
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whose humps had been flattened by the stretching of their necks.
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But this was exactly what attracted Saint-Hilaire to Zarafa.
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He was fascinated by genetic exaggerations
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and how they came to be.
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Clearly, the giraffe's long neck
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enables them to feed on leaves beyond the reach of other browsers.
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But how could they physically hold up such a long neck vertically?
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DAVID LAUGHS
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Studies of giraffe anatomy
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have revealed just how the neck is supported.
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A long thick ligament like a cable runs the whole length of the neck.
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This counterbalances the weight of the head and the neck,
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and in its relaxed position, it's tight.
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So keeping the neck straight and the head up
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involves very little muscular effort.
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Bending the neck to reach down is more difficult,
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because the tough ligament has to be stretched.
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But was the ability to feed from tall trees
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the only reason for having a long neck?
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As the habits of giraffe in the wild became better known,
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people discovered that rival males
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fought one another by jousting with their necks.
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Was that the reason that they had developed long necks?
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But then someone pointed out that the females had long necks too,
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so that suggestion was discarded.
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In truth, there isn't a neat single answer,
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but access to high food, better vigilance
255
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and temperature regulation may all have shaped the giraffe's long neck.
256
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As she walked on, Zarafa continued to attract inquisitive onlookers,
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few had set eyes on such a creature, she appeared a natural impossibility.
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How could a giraffe pump the blood up such a long neck to its brain?
259
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And why didn't the blood rush back down into its feet?
260
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The giraffe's neck may be very tall,
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but, in fact, it contains exactly the same number of bones as our own,
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that is to say seven.
263
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But its blood pressure is twice as high as ours.
264
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In fact, it's higher than any other known animal.
265
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The pump that produces this pressure, the heart,
266
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surprisingly is not particularly big but it is hugely powerful.
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This is the left ventricle that has been cut through
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and you can see how thick the muscle is, getting on for about 8cm.
269
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This great pump produces blood,
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squirts it up the artery to the head,
271
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and then when it comes down through the jugular vein
272
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there are pocket-shaped valves
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which prevent the blood from flowing backwards into the head
274
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if the animal lowers its head in order to have a drink.
275
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Giraffes find it very awkward to drink from the ground.
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And, in fact, they rarely do so,
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they get most of their water from leaves and shoots.
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The only way to get their mouth down to the water
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is to splay their forelegs or bend them at the wrist joint.
280
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The giraffe, in fact, has a relatively short neck compared to its legs.
281
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Antelope and zebra can reach down to the ground
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without bending their legs.
283
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Only the giraffe and its rainforest relative the okapi
284
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have necks that are so short relative to their legs
285
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that they must splay or bend them.
286
00:19:13,320 --> 00:19:16,600
So perhaps the most remarkable feature of the giraffe
287
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is the length of its legs.
288
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They certainly were key to Zarafa's success.
289
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At Lyon, there was a plan to rest her legs from walking
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and to finish the journey to Paris by boat,
291
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but all didn't go according to plan.
292
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The boat didn't appear in Lyon,
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so she walked on and finally got to Paris.
294
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It's took her a total of 41 days
295
00:19:40,840 --> 00:19:44,240
to complete the journey of 550 miles to Paris.
296
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Saint-Hilaire, her trusty companion, was exhausted,
297
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but the giraffe was very fit.
298
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He wrote, "She gained weight and much more strength from the exercise.
299
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"Her muscles were more defined, her coat smoother and glossier
300
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"upon her arrival than they were in Marseille."
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Zarafa was presented to King Charles X
302
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and temporarily installed in a greenhouse
303
00:20:10,200 --> 00:20:13,160
in the grounds of the Jardin des Plantes.
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She was a true animal ambassador
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and 60,000 people saw her in the first three weeks in Paris.
306
00:20:20,120 --> 00:20:24,480
In the early 19th century, giraffes were a novelty
307
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and their biology and lives in the wild was still a mystery.
308
00:20:28,680 --> 00:20:32,800
Zarafa's success was due to a unique interplay
309
00:20:32,800 --> 00:20:36,560
of the giraffe's unusual characteristics and good timing.
310
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Her youth, long legs and a diet with milk
311
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powered her journey right across France.
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A body that was first considered bizarre
313
00:20:49,640 --> 00:20:52,680
was revealed to be perfectly evolved.
314
00:20:54,560 --> 00:20:59,240
Our story began with three giraffe that were given to Europe.
315
00:20:59,240 --> 00:21:04,760
Zarafa was the most robust of them and she lived a further 18 years.
316
00:21:04,760 --> 00:21:08,400
The Austrian lasted just a year.
317
00:21:08,400 --> 00:21:13,160
And the one sent to King George IV of England died after two.
318
00:21:13,160 --> 00:21:16,240
Saint-Hilaire learnt much from Zarafa
319
00:21:16,240 --> 00:21:17,960
and he became a key figure
320
00:21:17,960 --> 00:21:21,040
in the blossoming zoological research in France.
321
00:21:21,040 --> 00:21:23,120
The giraffe brought to England
322
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triggered a surge of interest in animal research
323
00:21:25,600 --> 00:21:28,320
that shifted the centre of the zoological gravity
324
00:21:28,320 --> 00:21:30,400
from France to England.
325
00:21:30,400 --> 00:21:34,520
So we can thank Zarafa for her early role
326
00:21:34,520 --> 00:21:36,800
in unravelling the biological mysteries
327
00:21:36,800 --> 00:21:40,880
of the giraffe's extraordinary body and stretched neck.
328
00:21:50,640 --> 00:21:53,640
When the first Europeans arrived in Australia,
329
00:21:53,640 --> 00:21:56,920
they were shocked by the animals they found there.
330
00:21:56,920 --> 00:22:01,640
Nothing in Europe could compare with the bizarre upright grazers
331
00:22:01,640 --> 00:22:04,160
hopping across the grassland landscape
332
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carrying their young in pouches.
333
00:22:06,080 --> 00:22:08,680
Kangaroos were obvious oddities,
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but another even stranger creature
335
00:22:11,120 --> 00:22:13,840
also caught the attention of early settlers.
336
00:22:13,840 --> 00:22:18,040
It lived along river banks and swam in the water.
337
00:22:18,040 --> 00:22:22,360
Those first Europeans who saw it called it a "water mole,"
338
00:22:22,360 --> 00:22:25,000
but that name didn't last long.
339
00:22:26,600 --> 00:22:31,080
Inside this box is one of the first specimens of platypus
340
00:22:31,080 --> 00:22:33,960
ever to be seen outside Australia.
341
00:22:40,280 --> 00:22:44,960
It was sent to England in 1798 by Captain John Hunter,
342
00:22:44,960 --> 00:22:47,200
the Governor of New South Wales.
343
00:22:47,200 --> 00:22:51,880
This one small animal would take the scientific world by storm
344
00:22:51,880 --> 00:22:54,400
and transform the careers and reputations
345
00:22:54,400 --> 00:22:56,800
of some of the leading thinkers of the time.
346
00:22:58,720 --> 00:23:02,840
The platypus seemed to be a concoction of different animals,
347
00:23:02,840 --> 00:23:07,320
part bird with its bill and part mammal with its furry body.
348
00:23:07,320 --> 00:23:12,520
When Charles Darwin first encountered one in the wild, it baffled even him.
349
00:23:12,520 --> 00:23:16,960
"Surely," he wrote, "two distinct creators must have been at work."
350
00:23:20,120 --> 00:23:23,520
The task of describing the first platypus specimen
351
00:23:23,520 --> 00:23:25,600
fell to naturalist George Shaw,
352
00:23:25,600 --> 00:23:30,000
who worked in the Department of Natural History in the British Museum.
353
00:23:30,000 --> 00:23:32,840
And he viewed this remarkable specimen
354
00:23:32,840 --> 00:23:35,080
with a fair degree of caution.
355
00:23:36,200 --> 00:23:40,480
This is a first edition of a journal called A Naturalist's Miscellany,
356
00:23:40,480 --> 00:23:44,200
which was published a few years after his examination,
357
00:23:44,200 --> 00:23:46,920
and it contains not only an article by him
358
00:23:46,920 --> 00:23:50,000
but a nice picture of the animal concerned.
359
00:23:50,000 --> 00:23:55,280
And at the end he says, "On a subject so extraordinary as the present,
360
00:23:55,280 --> 00:23:59,760
"a degree of scepticism is not only pardonable but laudable.
361
00:23:59,760 --> 00:24:01,960
"And I ought perhaps to acknowledge
362
00:24:01,960 --> 00:24:05,480
"that I almost doubt the testimony of my own eyes
363
00:24:05,480 --> 00:24:08,960
"with respect to the structure of this animal's beak."
364
00:24:08,960 --> 00:24:11,920
It's said that Shaw was so determined to make sure
365
00:24:11,920 --> 00:24:14,680
that he was not a victim of some elaborate hoax
366
00:24:14,680 --> 00:24:16,920
that he actually cut behind the bill
367
00:24:16,920 --> 00:24:20,840
to make sure it hand't been sewn on by some mischievous forger.
368
00:24:22,120 --> 00:24:25,440
In the late 18th century, the world was opening up,
369
00:24:25,440 --> 00:24:29,840
travellers were returning from overseas with all kinds of wonders.
370
00:24:29,840 --> 00:24:34,680
Among them were specimens of creatures that people had come to think of as being myths,
371
00:24:34,680 --> 00:24:37,520
such as mermen and mermaids.
372
00:24:37,520 --> 00:24:39,360
These were, of course, hoaxes
373
00:24:39,360 --> 00:24:41,840
put together with parts from different animals,
374
00:24:41,840 --> 00:24:45,040
so it's understandable that Shaw had doubts
375
00:24:45,040 --> 00:24:48,440
about the authenticity of his new furry specimen.
376
00:24:50,160 --> 00:24:54,320
Despite his misgivings, he decided to give it a scientific name,
377
00:24:54,320 --> 00:24:57,480
platypus, which means "flat footed."
378
00:24:57,480 --> 00:25:01,560
He didn't know however that a beetle had already been given this name
379
00:25:01,560 --> 00:25:06,840
and some years later, another taxonomist very properly gave it a new one,
380
00:25:06,840 --> 00:25:10,840
Ornithorhynchus, which means "bird snout."
381
00:25:10,840 --> 00:25:15,160
But platypus is still the name that most people use.
382
00:25:15,160 --> 00:25:17,840
But what type of creature was it?
383
00:25:17,840 --> 00:25:22,280
George Shaw believed it to be a mammal because of its furry body.
384
00:25:24,200 --> 00:25:28,200
All mammals feed on milk during the first part of their lives,
385
00:25:28,200 --> 00:25:32,000
milk that is produced by their mother's mammary glands.
386
00:25:32,960 --> 00:25:36,520
But could an animal with a large flat bill really suckle?
387
00:25:36,520 --> 00:25:39,520
Some scientists thought that was impossible,
388
00:25:39,520 --> 00:25:42,880
and anyway they couldn't believe the platypus and the monkey
389
00:25:42,880 --> 00:25:45,440
could belong to the same group of animals.
390
00:25:45,440 --> 00:25:47,760
But that view was to change.
391
00:25:48,960 --> 00:25:52,600
Some 30 years after George Shaw described the platypus,
392
00:25:52,600 --> 00:25:55,280
a German naturalist, Johann Meckel,
393
00:25:55,280 --> 00:25:59,040
produced this wonderful collection of anatomical studies.
394
00:25:59,040 --> 00:26:01,800
Meckel's meticulous and detailed work
395
00:26:01,800 --> 00:26:05,280
would help identify the true nature of this animal.
396
00:26:05,280 --> 00:26:07,200
Here...
397
00:26:08,760 --> 00:26:15,320
..we can see his drawing of a male platypus showing clearly the claw.
398
00:26:15,320 --> 00:26:18,640
Meckel also reported the existence of simple glands
399
00:26:18,640 --> 00:26:21,120
beneath the thick fur of the female platypus,
400
00:26:21,120 --> 00:26:24,160
glands that he suggested secreted milk.
401
00:26:24,160 --> 00:26:28,480
There could be little doubt that these glands produced something,
402
00:26:28,480 --> 00:26:32,120
but even then several scientists doubted Meckel's claims
403
00:26:32,120 --> 00:26:34,160
and suggested rather desperately
404
00:26:34,160 --> 00:26:37,640
that the glands secreted not milk but a lubricant.
405
00:26:37,640 --> 00:26:40,320
Today, we know that Meckel was right.
406
00:26:40,320 --> 00:26:43,200
And I was once able to use an optical probe
407
00:26:43,200 --> 00:26:45,600
to peer into a platypus' burrow
408
00:26:45,600 --> 00:26:49,360
and see a female platypus nurturing her single baby.
409
00:26:50,720 --> 00:26:53,440
Yes! And there it is, it's milk.
410
00:26:54,400 --> 00:26:56,960
Milk is the perfect food,
411
00:26:56,960 --> 00:27:01,080
it provides the growing youngster with everything it wants.
412
00:27:01,080 --> 00:27:04,600
And only mammals produce milk.
413
00:27:04,600 --> 00:27:08,080
In most mammals, of course, it comes from a nipple,
414
00:27:08,080 --> 00:27:13,160
but in this very primitive mammal it simply oozes through the skin.
415
00:27:14,400 --> 00:27:19,240
But 19th-century biologists had no such tricks to help them,
416
00:27:19,240 --> 00:27:23,200
they had to unravel the strange biology of Australian mammals
417
00:27:23,200 --> 00:27:27,240
from just a few shrivelled remains of long-dead specimens.
418
00:27:28,280 --> 00:27:31,880
40 years after their discovery of the platypus,
419
00:27:31,880 --> 00:27:37,840
a brilliant young anatomist, who was to become a giant of 19th-century science, joined the debate.
420
00:27:37,840 --> 00:27:40,880
This is a statue of Richard Owen.
421
00:27:40,880 --> 00:27:43,040
Owen was a formidable man,
422
00:27:43,040 --> 00:27:46,360
the founding Director of the Natural History Museum in Britain,
423
00:27:46,360 --> 00:27:51,520
he was once described as having so much brain as to require two hats.
424
00:27:51,520 --> 00:27:56,240
The platypus would become a central character in Owen's career.
425
00:27:56,240 --> 00:27:58,120
His work on this small creature
426
00:27:58,120 --> 00:28:01,720
would help him secure election to the prestigious Royal Society,
427
00:28:01,720 --> 00:28:04,680
an exclusive group of scientists and thinkers.
428
00:28:06,200 --> 00:28:10,480
Owen had an advantage over his European colleagues.
429
00:28:10,480 --> 00:28:13,280
Australia was a British colony
430
00:28:13,280 --> 00:28:17,640
and Owen used his contacts to supply him with specimens.
431
00:28:19,720 --> 00:28:23,080
Eventually, two baby platypuses arrived
432
00:28:23,080 --> 00:28:27,320
and it was obvious to him that they would have no difficulty in suckling.
433
00:28:28,960 --> 00:28:32,520
They had not yet developed the bill that would have made it awkward.
434
00:28:32,520 --> 00:28:37,160
So he accepted that platypus babies like other mammal babies
435
00:28:37,160 --> 00:28:39,440
were indeed raised on milk.
436
00:28:41,960 --> 00:28:45,680
But the biggest mystery of the platypus was still unsolved.
437
00:28:46,880 --> 00:28:51,080
Did this animal lay eggs just like reptiles or birds,
438
00:28:51,080 --> 00:28:54,120
or did it give birth to live young?
439
00:28:54,120 --> 00:28:57,080
Owen was at the heart of that debate.
440
00:28:58,040 --> 00:29:01,160
These jars contain the bodies of several platypus
441
00:29:01,160 --> 00:29:03,880
that were shot and sent back here to the museum
442
00:29:03,880 --> 00:29:06,080
for Richard Owen to examine.
443
00:29:06,080 --> 00:29:09,160
His determination to prove whether or not they laid eggs
444
00:29:09,160 --> 00:29:13,320
was going to cause the death of quite a number of platypus.
445
00:29:13,320 --> 00:29:16,400
The Australian aborigines were absolutely clear,
446
00:29:16,400 --> 00:29:20,160
they did lay eggs, but that was not good enough for Owen,
447
00:29:20,160 --> 00:29:23,640
he knew better then any Australian aboriginal.
448
00:29:23,640 --> 00:29:26,440
He did concede that it might be
449
00:29:26,440 --> 00:29:29,440
that the eggs were retained inside the body and hatched there
450
00:29:29,440 --> 00:29:33,360
so that the young were born live, but that's as far as he would go.
451
00:29:33,360 --> 00:29:35,760
Eggs were also sent back.
452
00:29:35,760 --> 00:29:39,600
Some of them were fake and some of them belonged to snakes.
453
00:29:39,600 --> 00:29:41,800
It was going to be some decades
454
00:29:41,800 --> 00:29:45,360
before the puzzle of the platypus was finally solved.
455
00:29:47,440 --> 00:29:49,560
The platypus now became embroiled
456
00:29:49,560 --> 00:29:53,600
in the greatest scientific debate of the Victorian era.
457
00:29:53,600 --> 00:29:57,360
Did species evolve or were they created?
458
00:29:57,360 --> 00:29:59,720
Darwin's Theory of Evolution
459
00:29:59,720 --> 00:30:02,440
suggested that species could change over time,
460
00:30:02,440 --> 00:30:06,320
so an intermediate form that laid eggs but had fur like a mammal
461
00:30:06,320 --> 00:30:08,400
was to be expected.
462
00:30:08,400 --> 00:30:12,440
But that was too much of a stretch even for Owen's great brain.
463
00:30:13,720 --> 00:30:18,240
In 1884, more than 80 years after this first platypus specimen
464
00:30:18,240 --> 00:30:20,520
had been examined by George Shaw,
465
00:30:20,520 --> 00:30:26,520
William Hay Caldwell arrived in Australia funded by a Royal Society scholarship.
466
00:30:26,520 --> 00:30:31,480
One of his main aims was to solve the platypus egg question once and for all.
467
00:30:31,480 --> 00:30:33,160
After several months in Queensland,
468
00:30:33,160 --> 00:30:35,520
and with the help of the local aborigines,
469
00:30:35,520 --> 00:30:37,640
he finally got the answer.
470
00:30:37,640 --> 00:30:39,720
He shot a female platypus
471
00:30:39,720 --> 00:30:43,560
soon after she had laid an egg in her nest burrow
472
00:30:43,560 --> 00:30:46,880
with a second egg about to emerge from her vent.
473
00:30:46,880 --> 00:30:49,160
And they looked like this.
474
00:30:50,160 --> 00:30:55,720
It was at last visible evidence that this animal did indeed lay eggs.
475
00:30:55,720 --> 00:30:59,000
He sent a telegram to a scientific gathering in Montreal,
476
00:30:59,000 --> 00:31:01,240
it was brief and to the point,
477
00:31:01,240 --> 00:31:05,960
"Monotremes oviparous, ovum meroblastic."
478
00:31:05,960 --> 00:31:09,680
These four words to the scientifically initiated
479
00:31:09,680 --> 00:31:12,320
meant that the platypus laid eggs
480
00:31:12,320 --> 00:31:15,720
and that the eggs consisted of an undivided large yolk
481
00:31:15,720 --> 00:31:18,040
just like a bird's egg.
482
00:31:18,040 --> 00:31:21,000
The mystery was at last solved.
483
00:31:23,880 --> 00:31:27,960
Richard Owen, who had refused to believe a mammal could lay an egg,
484
00:31:27,960 --> 00:31:32,240
was by now 80 years old and he was no longer held in the same esteem
485
00:31:32,240 --> 00:31:35,040
as in the early part of his career.
486
00:31:35,040 --> 00:31:38,520
The platypus had helped establish his reputation,
487
00:31:38,520 --> 00:31:42,840
but now the riddle of this creature's reproduction had proved him wrong.
488
00:31:44,440 --> 00:31:47,360
It's extraordinary to think that this small animal
489
00:31:47,360 --> 00:31:52,200
fooled and confounded many of the great scientific minds of 19th-century Europe.
490
00:31:52,200 --> 00:31:57,840
Not a hoax, but a true curiosity and one like no other.
491
00:32:00,520 --> 00:32:05,080
The egg-laying platypus was hardly believable to Victorian researchers,
492
00:32:05,080 --> 00:32:09,680
but evolution has thrown up many unusual mating strategies
493
00:32:09,680 --> 00:32:12,880
and in the early part of the 20th century,
494
00:32:12,880 --> 00:32:16,800
the anatomy of a particular amphibian started an argument
495
00:32:16,800 --> 00:32:20,680
that, like the platypus, led to accusations of forgery.
496
00:32:20,680 --> 00:32:24,560
This is the curious tale of the midwife toad.
497
00:32:27,080 --> 00:32:29,640
Midwife toads are not native to Britain,
498
00:32:29,640 --> 00:32:32,080
they were introduce about a century ago
499
00:32:32,080 --> 00:32:35,200
and since then have been slowly spreading over England.
500
00:32:35,200 --> 00:32:39,680
Their natural home is Europe, from Germany to Spain.
501
00:32:39,680 --> 00:32:45,360
And in the 1920s, their mating habits caused a media sensation.
502
00:32:46,920 --> 00:32:50,440
Investigations into the way the body of the male toad
503
00:32:50,440 --> 00:32:54,680
changed according to its environment led some to believe
504
00:32:54,680 --> 00:32:58,920
it might be possible to breed a race of superhumans.
505
00:32:58,920 --> 00:33:01,600
To understand why, we must first know
506
00:33:01,600 --> 00:33:07,040
what makes the midwife toad so different from any other frog or toad.
507
00:33:07,040 --> 00:33:11,960
Amphibians were among the first backboned animals to take to the land.
508
00:33:11,960 --> 00:33:15,320
Since then, they've colonised most habitats
509
00:33:15,320 --> 00:33:19,640
from rainforests to deserts and mountains.
510
00:33:19,640 --> 00:33:22,080
Despite spending much of their lives on land,
511
00:33:22,080 --> 00:33:25,120
most frogs and toads need water to reproduce,
512
00:33:25,120 --> 00:33:28,560
whether it be in a small vase plant or a large lake.
513
00:33:28,560 --> 00:33:32,560
But mating in water is a slippery business.
514
00:33:32,560 --> 00:33:35,680
Male toads, however, have a special adaptation,
515
00:33:35,680 --> 00:33:39,880
black warty swellings on their wrists called nuptial pads,
516
00:33:39,880 --> 00:33:43,720
which enable them to grip their partners securely during sex.
517
00:33:43,720 --> 00:33:46,240
Once the female produces her eggs,
518
00:33:46,240 --> 00:33:50,680
the male releases his sperm and then let's go, his job is done.
519
00:33:50,680 --> 00:33:53,640
But midwife toads are different,
520
00:33:53,640 --> 00:33:57,000
the male does not have nuptial pads on his wrists.
521
00:33:58,120 --> 00:34:03,360
And that's because he doesn't mate in water, he mates on land.
522
00:34:03,360 --> 00:34:08,760
The female produces her eggs and then he takes them around his legs
523
00:34:08,760 --> 00:34:15,320
with an action that's been compared to a man trying to put on his trousers without using his hands.
524
00:34:17,000 --> 00:34:22,520
So it is the male toad that is the actual midwife, not the female.
525
00:34:22,520 --> 00:34:27,760
Midwife toads tend to live in places where open water is scarce.
526
00:34:29,000 --> 00:34:33,240
Once the male has successfully wrapped a string of eggs around his legs,
527
00:34:33,240 --> 00:34:37,200
he usually hides under a rock where it's suitably damp.
528
00:34:42,920 --> 00:34:46,240
He may have as many as 150 eggs
529
00:34:46,240 --> 00:34:49,920
and he hides away for up to two months while they develop.
530
00:34:49,920 --> 00:34:52,880
Then, just before the eggs hatch,
531
00:34:52,880 --> 00:34:56,560
he sets off to find water for his emerging tadpoles.
532
00:34:58,560 --> 00:35:02,360
Now, the tadpoles of most frogs and toads
533
00:35:02,360 --> 00:35:06,000
turn into the adult form within a matter of weeks,
534
00:35:06,000 --> 00:35:10,640
but not so the midwife toad - it takes much, much longer.
535
00:35:10,640 --> 00:35:16,280
In fact, sometimes they may even overwinter in the form of a tadpole,
536
00:35:16,280 --> 00:35:21,200
which is why perhaps midwife toad tadpoles are such whoppers.
537
00:35:22,840 --> 00:35:26,720
Frogs and toads are widely used in biological studies
538
00:35:26,720 --> 00:35:28,360
because they're easy to keep
539
00:35:28,360 --> 00:35:32,120
and the different stages of their life cycles are easy to observe.
540
00:35:32,120 --> 00:35:36,600
So it's no surprise that the unusual behaviour of the midwife toad
541
00:35:36,600 --> 00:35:39,520
should attract the attention of many biologists.
542
00:35:40,640 --> 00:35:43,760
One was an Austrian scientist called Paul Kammerer,
543
00:35:43,760 --> 00:35:47,720
who worked in Vienna in the early part of the 20th century.
544
00:35:47,720 --> 00:35:51,280
And his discoveries quickly brought him great fame.
545
00:35:52,880 --> 00:35:55,480
But the toad would become a curse
546
00:35:55,480 --> 00:35:58,760
that would haunt him until the end of his life.
547
00:36:00,560 --> 00:36:02,760
Kammerer was greatly influenced
548
00:36:02,760 --> 00:36:06,040
by the great French zoologist Jean-Baptiste Lamarck,
549
00:36:06,040 --> 00:36:09,560
who, in 1799, published his theory
550
00:36:09,560 --> 00:36:13,320
that characteristics acquired by an animal during its life
551
00:36:13,320 --> 00:36:16,000
could be inherited by its offspring.
552
00:36:16,000 --> 00:36:17,800
That a giraffe, for example,
553
00:36:17,800 --> 00:36:21,080
reaching upwards to nibble the topmost shoots of trees
554
00:36:21,080 --> 00:36:24,560
would, over time, lengthen its neck muscles
555
00:36:24,560 --> 00:36:28,360
and that this increase would then be inherited by its offspring.
556
00:36:28,360 --> 00:36:31,920
And so on for generation after generation.
557
00:36:31,920 --> 00:36:37,240
Lamarck's theory was largely rejected after Charles Darwin proposed
558
00:36:37,240 --> 00:36:39,600
a different mechanism for evolution
559
00:36:39,600 --> 00:36:43,560
based on changes to an animal's genetic make-up.
560
00:36:43,560 --> 00:36:48,320
Kammerer was keen to prove that Lamarck was right after all.
561
00:36:48,320 --> 00:36:51,800
But giraffes are not the ideal experimental animal,
562
00:36:51,800 --> 00:36:56,080
so he needed one he could keep in a lab and that would reproduce quickly.
563
00:36:56,080 --> 00:36:59,720
And his attention fell on the midwife toad.
564
00:36:59,720 --> 00:37:01,800
Kammerer became fascinated
565
00:37:01,800 --> 00:37:05,920
with the unusual nature of the midwife toad's reproduction.
566
00:37:05,920 --> 00:37:08,320
Why did males like this one
567
00:37:08,320 --> 00:37:12,920
carry eggs around his legs and could this be changed?
568
00:37:12,920 --> 00:37:18,880
He wondered if their biology might be related to their natural environment, which is largely arid.
569
00:37:18,880 --> 00:37:22,160
Kammerer decided to see what would happen
570
00:37:22,160 --> 00:37:24,600
if he kept the toads in a warm, humid tank
571
00:37:24,600 --> 00:37:27,560
with access to pools of cool water.
572
00:37:27,560 --> 00:37:30,360
His work with the toads would last many years
573
00:37:30,360 --> 00:37:34,800
and involve several generations, but eventually he noticed changes.
574
00:37:34,800 --> 00:37:38,760
Some male toads abandoned carrying the eggs
575
00:37:38,760 --> 00:37:42,760
and instead the females laid them directly in water.
576
00:37:44,560 --> 00:37:50,080
Over several generations, Kammerer had managed to change the midwife toad
577
00:37:50,080 --> 00:37:55,280
from being a land-breeding animal to one that bred in water.
578
00:37:55,280 --> 00:38:00,400
But the most extraordinary discovery came as he continued breeding these toads.
579
00:38:00,400 --> 00:38:04,240
He noticed that the wrists of some of the males
580
00:38:04,240 --> 00:38:06,400
developed warty-looking structures
581
00:38:06,400 --> 00:38:09,960
just like the nuptial pads of other frogs and toads
582
00:38:09,960 --> 00:38:12,000
which are normally used by males
583
00:38:12,000 --> 00:38:15,240
to grip females when fertilising her eggs.
584
00:38:15,240 --> 00:38:17,520
His work suggested that somehow,
585
00:38:17,520 --> 00:38:20,600
by altering the environment in which they lived,
586
00:38:20,600 --> 00:38:22,960
a toad's body could be changed
587
00:38:22,960 --> 00:38:27,760
and that change was then passed on to future generations.
588
00:38:27,760 --> 00:38:32,160
Kammerer's work was taking place at the end of the First World War
589
00:38:32,160 --> 00:38:34,720
and political movements on the left and the right
590
00:38:34,720 --> 00:38:38,200
were then keen to exploit scientific discoveries.
591
00:38:38,200 --> 00:38:41,240
Despite his subject being a small toad,
592
00:38:41,240 --> 00:38:46,240
some saw an opportunity to extend his findings beyond the laboratory.
593
00:38:47,320 --> 00:38:51,560
He was hailed as a second Darwin in the New York Times.
594
00:38:51,560 --> 00:38:53,520
Some newspapers got carried away
595
00:38:53,520 --> 00:38:56,960
and suggested that Kammerer's discoveries could apply to humans.
596
00:38:56,960 --> 00:39:02,000
His work could help, in other words, to breed a race of superhumans.
597
00:39:02,000 --> 00:39:06,840
Whether he liked it or not, Kammerer was now in the spotlight.
598
00:39:06,840 --> 00:39:11,040
He set off on a lecture tour across Europe and America.
599
00:39:11,040 --> 00:39:14,600
In Cambridge, the Professor of Zoology hailed his achievements
600
00:39:14,600 --> 00:39:17,600
and put one of Kammerer's toads on display.
601
00:39:17,600 --> 00:39:20,440
But not everyone was convinced.
602
00:39:20,440 --> 00:39:24,840
An American zoologist by the name of GK Noble wrote a damning article
603
00:39:24,840 --> 00:39:28,280
in the prestigious scientific journal Nature.
604
00:39:28,280 --> 00:39:31,200
Noble examined one of Kammerer's toad
605
00:39:31,200 --> 00:39:34,200
and declared that its black nuptial pads were fakes,
606
00:39:34,200 --> 00:39:36,800
produced by injecting a black dye.
607
00:39:38,040 --> 00:39:42,160
Kammerer denied this. Someone, he said, had interfered with his specimens
608
00:39:42,160 --> 00:39:44,880
and was trying to ruin him.
609
00:39:44,880 --> 00:39:48,120
But the damage to his name was done.
610
00:39:48,120 --> 00:39:51,960
Six weeks after the Nature article accusing him of forgery,
611
00:39:51,960 --> 00:39:55,680
Kammerer wrote a letter to another leading scientific journal.
612
00:39:55,680 --> 00:39:58,600
This is an extract of what it said.
613
00:40:00,040 --> 00:40:02,960
"On the basis of this state of affairs,
614
00:40:02,960 --> 00:40:09,360
"I dare not, although I myself have no part in these falsifications of my prior specimens,
615
00:40:09,360 --> 00:40:14,600
"any longer consider myself a proper man to accept your call.
616
00:40:14,600 --> 00:40:20,000
"I see that I'm also not in a position to endure this wrecking of my life's work,
617
00:40:20,000 --> 00:40:23,760
"and I hope I shall gather together enough courage and strength
618
00:40:23,760 --> 00:40:26,960
"to put an end of my wrecked life tomorrow."
619
00:40:28,320 --> 00:40:30,680
Soon after writing that letter,
620
00:40:30,680 --> 00:40:35,080
he walked into the hills around his home and shot himself.
621
00:40:35,080 --> 00:40:37,320
Whether or not Kammerer's suicide
622
00:40:37,320 --> 00:40:42,040
was purely down to the fallout from his midwife-toad experiments, we can't be sure -
623
00:40:42,040 --> 00:40:45,320
there were many other problems in his personal life -
624
00:40:45,320 --> 00:40:49,320
but there can be little doubt that the scandal surrounding his work
625
00:40:49,320 --> 00:40:52,640
would have weighed heavily on his mind.
626
00:40:52,640 --> 00:40:57,040
Since Kammerer's death, a specimen of male midwife toad
627
00:40:57,040 --> 00:41:00,600
WITH nuptial pads has been found in the wild.
628
00:41:00,600 --> 00:41:02,880
Some scientists now believe
629
00:41:02,880 --> 00:41:07,400
that environmental influences can change the way some genes behave
630
00:41:07,400 --> 00:41:12,360
and that these changes can indeed be passed on to the next generation.
631
00:41:12,360 --> 00:41:16,960
Perhaps midwife toads possess the gene to grow these structures,
632
00:41:16,960 --> 00:41:20,840
but it's only switched on in certain situations.
633
00:41:20,840 --> 00:41:23,720
Does this prove Kammerer was right?
634
00:41:23,720 --> 00:41:27,840
No-one has been able to repeat Kammerer's experiments with midwife toads,
635
00:41:27,840 --> 00:41:30,840
so we don't know for sure if he falsified his findings,
636
00:41:30,840 --> 00:41:35,160
or whether he had stumbled upon a quirk of inheritance ahead of its time
637
00:41:35,160 --> 00:41:38,760
and beyond the understanding of scientists of his era.
638
00:41:38,760 --> 00:41:44,080
What is certain is that the nature of how species inherit their characteristics
639
00:41:44,080 --> 00:41:49,440
is more complex than he or others at the time originally thought.
640
00:41:51,000 --> 00:41:55,160
The curious lives of the midwife toad and the duck-billed platypus
641
00:41:55,160 --> 00:41:59,840
perplexed and wrong-footed science for some considerable time.
642
00:41:59,840 --> 00:42:02,600
But in the end, both these creatures
643
00:42:02,600 --> 00:42:07,280
helped us to better understand the way animals evolve.
56837
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