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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 by myth
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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,
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'I examine the remarkable lives of two animals
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'that have mastered the problems of life in the dark.'
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'The giant squid, which lives in the deepest oceans...'
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..and owls.
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Highly specialised hunters that seek their prey at night.
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Some animals acquired frightening reputations
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almost as soon as they were discovered.
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In this episode,
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we investigate the stories surrounding two such creatures...
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GORILLA MOANS
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..the gorilla and the vampire bat.
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Why did they get such bad reputations?
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And were they justified?
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When you think of animals of the night, owls tend to come to mind.
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In fact, not all owls are nocturnal,
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but those that are have a very similar-shaped face,
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round and flat.
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And their most prominent facial features
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are the large, forward-facing eyes.
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These give them a seemingly wise look and in fact,
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owls have often been revered for their wisdom.
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But they have also been linked with legends of death and evil.
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They are birds of the night.
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To many, they seem eerie and mysterious.
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'But how good is an owl's eyesight?
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'Can they really see what we can't?'
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The colour picture that forms at the back of our eyes
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is very much like that that forms in the eyes of a bird.
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We have roughly the same number of colour receptors.
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But when day changes to night, the picture changes.
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Then, different receptors come into play, called rods.
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And owls have a much higher proportions of rods
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in their eyes than we do.
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So they're extremely good at seeing at low light levels.
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Aren't you?
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The barn owl sets off to hunt shortly after dusk.
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As the light fades, we struggle to see.
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But the owl has no such problem.
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Flying low, it keeps its eyes trained on the ground,
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looking for any movement in the grass.
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Its eyes now give it the edge over its prey,
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and it can hunt at a time when few other birds can.
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And there's another important difference
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between an owl's eye and ours.
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The pupil in the front of the eye, the hole,
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is very much bigger in an owl's.
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Ours measures around eight millimetres across.
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An owl's, like this tawny owl, is around 13.
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That means very much more light can get into the eye,
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so the picture formed on the retina is very much brighter.
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In fact, it's about three times as bright.
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OWL SQUEAKS Aw...
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OWL SQUEAKS Aw...
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So, unlike other birds, which cannot see so well in the dark,
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the owl can remain active throughout the night.
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But specialist eyes create problems.
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Squeezing a large eyeball
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into a relatively small skull requires changes.
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The shape of the owl eye is more tubular than round.
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This may help to increase the size of the image on the retina
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at the back.
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But the owl's eye shape and size presents certain problems.
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It doesn't fit snugly into the skull
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and there's no room in the socket for muscles to move it.
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And there's another problem.
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A closer look at an owl's skull
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shows that its ear openings are very big.
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So the only way for the tubular eyes to fit into the skull is for them
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to be placed in the middle of the face in a forward-looking position.
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This limits the owl's field of view.
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But owls have a trick that allows them
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to dramatically increase their field of view.
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They can rotate their heads nearly all the way round.
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Folklore has it that you can kill an owl
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by walking in circles round a tree in which one is perched
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and so make it twist its head off.
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That, of course, is not true.
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But owls can certainly turn their heads
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through 270 degrees in either direction.
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If we tried to do that, we'd tear our arteries and break our necks.
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So, how do owls do it?
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Recently, scientists have discovered that it's due
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to a remarkable adaptation of their bones.
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Owls' necks, as you can see in this skeleton of an eagle owl,
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have 14 vertebrae. That's twice the number that we have.
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This gives them greater flexibility.
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But only recently, CT scans have shown researchers
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how the owl can rotate its head without passing out.
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Cavities within the neck bones are ten times larger
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in an owl's neck than in ours,
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giving more room for vital blood vessels
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that run up to the owl's head.
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What's more, the carotid arteries enter the head
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much higher up the neck and are centrally positioned,
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and this may help avoid damage during twisting.
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And the owl's arteries seem to widen below the brain,
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allowing blood to pool.
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This may create a vital blood reservoir that guarantees blood flow
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to the brain, should the vessels below be squeezed
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while the head is turning.
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So the owl can turn its head almost all the way round
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without risk of injury.
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So, owls have successfully dealt with the problems
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created by having large eyes.
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OWL HOOTS
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But are these eyes really all they seem?
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It was long thought that owls can see perfectly,
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even on the darkest of nights.
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But that is not the case.
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On cloudy nights and beneath trees with dense canopies,
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they can only discern the faintest silhouettes.
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It's nowhere near detailed enough to hunt for prey.
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But the owl has another sense to help it...
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acute hearing.
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In the 18th century,
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the great French naturalist Count de Buffon wrote,
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"Their sense of hearing seems to be superior
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"to that of other birds and perhaps to that of every other animal,
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"for the drum of the ear
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"is proportionately larger than in quadrupeds
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"and besides, they can open and shut this organ at pleasure,
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"a power possessed by no other animal."
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Well, we know today that that's true, some owls,
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though not all, but Buffon was quite right
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to draw our attention to the remarkable hearing of owls.
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OWL HOOTS
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The owl's large ear openings are not visible
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because they're hidden beneath the face feathers.
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And unlike other birds, they have fleshy outer ears like our own.
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In many owls, they're positioned at slightly different levels
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on either side of the head.
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And it's these features that help them
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to accurately pinpoint their prey.
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Most owls have very similar shape faces, flat and round.
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It's called a facial ruff.
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It's formed from feathers that are particularly dense and bristly,
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and they lie flat on either side of the face,
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just behind the opening to the ears.
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It's thought that they deflect the sound into the ears.
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In fact, the facial ruff seems to be a kind of sound amplifier.
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The barn owl has a distinctive, heart-shaped ruff and its face
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acts like a satellite dish, focusing the sounds from below into the ears.
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Its soft flight feathers enable it to move through the air
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in almost complete silence so that it can hear
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the slightest rustle and approach its prey undetected.
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But few have as large a facial ruff as the great grey owl.
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Although it hunts during the day, its prey is hidden under
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cover of snow, so it has to rely entirely on its ears.
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Studies have shown that owls' hearing is particularly
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acute for very quiet sounds.
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In fact, part of an owl's brain that detects sound has three times
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as many neurones as its equivalent in, say, a crow's brain.
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The hairs of the inner ear which detect the vibrations
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of sound are particularly abundant in an owl.
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Not only that, whereas the equivalent hairs in my ear
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degrade with age, in an owl's they are regrown.
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So whereas my hearing gets worse as I get older,
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an owl's always remains very acute.
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The owl's ears may in fact be more crucial to its nocturnal
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lifestyle than its eyes.
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But by combining all its senses,
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it has solved the problems of living in the dark.
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So it seems that the shape of the face helps both the owl's sight
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and its hearing.
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So whether or not you think the owl is wise,
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it certainly has a head for life in the dark.
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Next we journey into the darkest of places to try and unravel
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the life of a creature that has long captured our imagination.
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Here in the Natural History Museum is a specimen of an animal
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that has fascinated humanity for thousands of years.
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It is a giant squid.
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This particular one was netted off the Falkland Islands,
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immediately put on ice,
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and then brought here to the museum in London.
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Few museums have complete or as perfectly preserved
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specimens as this one.
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This one measures about eight metres, the length of a London bus.
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But others have been caught even bigger,
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one about twice the length that weighed around a tonne.
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Very few people have ever seen one of these creatures alive.
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That's because they live at depths of around 1,000 metres
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and down there, it's pitch-black.
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So how do these animals manage to hunt in such conditions?
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That's a question that has proved exceedingly difficult to answer.
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Sailors a long time ago told stories of having seen a gigantic,
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squid-like creature known as the Kraken.
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It was said to have huge tentacles strong enough to grip
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and sink a ship.
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The tales seemed unlikely and far-fetched, but could the giant
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squid perhaps have been the source of these extraordinary reports?
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The first clues that this creature may in fact be real came from
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the tales of sailors on whaling ships
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in the 18th and 19th centuries.
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Some of them reported in their ships' logs that they often noticed
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strange, circular scars on the heads and jaws of captured sperm whales.
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The scars suggested a fierce wrestling match with
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some enormous beast.
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What creature could take on a 70-tonne whale?
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Inside the stomachs of the whales were clues.
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A number of hard, indigestible objects like this one.
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It looks a bit like the beak of a parrot.
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But in fact, it belongs to an entirely different
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kind of animal - to a cephalopod.
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Cephalopods are marine animals that include the octopus,
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the squid and the cuttlefish.
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This beak is the mouth part of one such creature
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and is used to tear its prey into small pieces.
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Sailors on the whaling ships immediately recognised
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the beak as being from a cephalopod.
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But its size suggested a creature
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many times bigger than any known species.
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Cephalopods have a ring of eight or ten arms, or tentacles, which they
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use to push food into their mouth in the centre of the ring.
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The arms are equipped with round suckers to help hold
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onto their prey.
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It is the marks from these that were found by sailors on the bodies
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of sperm whales.
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Could a gigantic squid have caused such injuries,
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and how massive must it be to tackle a sperm whale,
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one of the biggest animals on the planet?
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And then in 1873, fishermen caught what
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they called a sea monster off the coast of Newfoundland in Canada.
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After killing it with their knives, they lost the body,
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but they brought the head and tentacles to the local clergyman.
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The clergyman bought it off the fishermen for 10
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and displayed it in his living room by carefully draping it over
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a bath stand, to show off its many arms and tentacles.
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The photograph clearly proved that here was a gigantic squid with
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its beak at the top and over seven metre long tentacles.
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Here last was the evidence that the monster of the deep,
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the Kraken, really does exist.
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But the giant squid itself continued to evade scientists,
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even after its discovery.
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It's only since the invention of submersibles that we have
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been able to follow it down into its deep sea home.
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Even so, we seem to have had little
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success in finding the elusive giant.
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So scientists are now trying to piece together its biology
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by looking at other closely-related animals.
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This is an octopus.
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It uses both its eyes and tentacles to explore its surroundings.
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The octopus's brain is distributed throughout its body
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so that its arms can control much of their own movement.
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It also has a highly complex eyes and sees in much the same way
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as we do, with the lens projecting an image onto the retina behind.
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But while our eyes focus by squeezing the lens to
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change its shape, the octopus's eyes
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focus like a camera, with the lens moving in and out.
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The giant squid's eyes have much the same
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structure as those of an octopus, but when it comes to size, it has
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the biggest eye in the animal kingdom, as large as a football.
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For seeing in dim light, a large eye is better than the small one.
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So many animals of the deep have exceptionally big eyes.
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But in order to see at all, there has to be some light,
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and the giant squid lives at depths of 1,000 metres.
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Although very little sunlight reaches the deeper parts
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of the ocean, there is another kind of light there.
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It's produced by the deep sea animals
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and it's called bioluminescence.
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The light is produced by a chemical reaction in the same
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way as that in a glow stick does.
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When I shake and snap the stick,
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two chemicals called luciferin and luciferase react together to produce
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a bioluminescent glow like this...
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There.
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Some deep sea animals use their own luciferins to produce light, while
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in others it's produced by bacteria living in special light organs.
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A flashing light can act as a lure or confuse a predator.
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It's thought about 90% of deep sea creatures produce
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bioluminescence and they use it in a number of different ways.
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All these fish come from the deep sea.
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They all produce light in one way or another.
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This is the football angler fish and it has a modified
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ray from its dorsal fin which has lots of little tentacles on top.
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The tip of each tentacle produces a little green light
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so it looks as though there is little shoal of small creatures,
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maybe shrimps, hovering above it in the blackness.
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When another shrimp thinks it might join some friends
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and come along that way, the angler fish simply tilts up,
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opens its immense jaw and has its breakfast.
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This, on the other hand,
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is a stoplight loosejaw, which operates in a different way.
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It produces red light from two little organs at the front.
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Hardly any other species of fish in the sea can see red light,
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so it can hunt that way and find its prey.
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When it does, it opens this immense loose jaw and engulfs it.
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There you are. Back you go.
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But what about the giant squid?
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Could it also be producing bioluminescence?
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Some of its close relatives apparently can.
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This is the vampire squid.
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It has eight arms lined with tooth-like projections.
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When threatened, it turns itself inside out,
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wrapping its body in a dark cloak.
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If that doesn't work, the squid has another trick.
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Small lights at the end of its arms
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flash like eyes to distract the predator.
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With so many creatures of the deep producing light, you might think
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that the giant squid would do so as well.
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But scientists studying their carcasses have not been
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able to find any evidence of light-producing bacteria or
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00:20:16,800 --> 00:20:18,720
pigments in their bodies.
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00:20:20,520 --> 00:20:26,280
So it seems that the ocean's elusive giant truly hides in the dark.
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00:20:31,080 --> 00:20:35,280
Although it may not produce its own light, the giant squid can surely
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see the bioluminescence of others
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00:20:37,960 --> 00:20:40,800
and this may help it to locate its prey.
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00:20:45,120 --> 00:20:48,040
With no sightings of a living giant squid since it was
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00:20:48,040 --> 00:20:52,120
first discovered, we seem to be no closer to discovering the truth.
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00:20:53,680 --> 00:20:58,640
But in 2004, Japanese scientists finally made a breakthrough.
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Using small squid as bait,
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they were able to attract a live giant squid.
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00:21:09,280 --> 00:21:11,680
These first images are tantalising,
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but they still reveal little of the animal's true behaviour.
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Where does it live and how does it feed?
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Questions such as these remain unanswered.
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00:21:23,080 --> 00:21:25,120
In spite of its great size,
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the giant squid has proved remarkably difficult to find.
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No doubt scientists will continue to search for it
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and discover more about it.
331
00:21:34,280 --> 00:21:39,320
But my guess is that the giant squid is likely to remain ahead of
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the game, that this natural curiosity
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00:21:42,520 --> 00:21:45,760
is likely to see us before we see it.
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Both the owl and the giant squid live in a world with little light
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00:21:55,160 --> 00:21:58,600
and both have evolved large eyes, the better to
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see the world around them.
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00:22:01,480 --> 00:22:05,600
But while we've unravelled the owl's ways of surviving in the dark,
338
00:22:05,600 --> 00:22:10,000
much about giant squid still remains a mystery.
339
00:22:24,880 --> 00:22:28,640
This statue in the London Zoo is of Guy the Gorilla.
340
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He was perhaps the zoo's most well-known resident
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and became one of the world's most famous gorillas.
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00:22:35,400 --> 00:22:39,320
In his prime, Guy weighed in at over 200 kilos.
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00:22:39,320 --> 00:22:43,640
His neck, as you can see, was thicker than a man's waist.
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He stood five feet four inches tall, over a metre and a half.
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That was with his knees bent.
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00:22:51,120 --> 00:22:55,720
When Guy arrived here in 1940, little was known about gorillas.
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00:22:55,720 --> 00:22:57,880
The reports from Africa hinted of
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00:22:57,880 --> 00:23:00,440
a creature that was shockingly brutal.
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So it's hardly surprising that
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people flocked to see this fearsome monster for themselves.
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But Guy proved to be a gentle giant who won
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the affection of the public.
353
00:23:12,160 --> 00:23:14,680
So how and why did the gorilla gain
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00:23:14,680 --> 00:23:17,600
this reputation as a fearsome savage?
355
00:23:19,680 --> 00:23:24,080
Today we know a lot about gorillas and their way of life.
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00:23:24,080 --> 00:23:26,480
There are, in fact, a number of different kinds,
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some of which live in the lowlands and others in the mountains.
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00:23:30,400 --> 00:23:33,240
The stay in small family groups
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00:23:33,240 --> 00:23:36,480
and spend much of their days feeding on leaves and shoots.
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00:23:38,320 --> 00:23:42,160
Many people, including myself, have travelled a long way to meet
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00:23:42,160 --> 00:23:44,560
these close relatives of ours.
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00:23:54,160 --> 00:23:58,320
Remarkably, despite being the largest living ape,
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00:23:58,320 --> 00:24:02,360
the gorilla was one of the last to be described by science.
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00:24:05,040 --> 00:24:09,720
In 1847, an American missionary and naturalist, Thomas Savage,
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00:24:09,720 --> 00:24:11,720
was travelling back home from Africa
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when he stopped off to stay with some friends in the Congo.
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00:24:17,720 --> 00:24:21,600
His friends' house was decorated with African curiosities
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00:24:21,600 --> 00:24:25,480
and one of them caught his eye, a skull.
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00:24:25,480 --> 00:24:28,840
But it was not like one he'd ever seen before in Africa.
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00:24:28,840 --> 00:24:34,400
It had two huge eye sockets, a crest like a Mohawk haircut running
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00:24:34,400 --> 00:24:38,200
from front to back and another transversely across here.
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These are anchor points for huge muscles for the jaw and neck.
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He knew immediately he was looking at a spectacular new species
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but he had no time to go in search of it.
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00:24:50,280 --> 00:24:54,800
He frantically negotiated with some African hunters and managed to
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00:24:54,800 --> 00:24:58,600
acquire further skulls and bones of the same kind of animal.
377
00:25:00,200 --> 00:25:03,880
When he got back to the States, Savage handed the specimens
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00:25:03,880 --> 00:25:06,520
to an anatomist friend who immediately
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00:25:06,520 --> 00:25:09,720
recognised that they belonged to some kind of ape.
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00:25:09,720 --> 00:25:12,280
He gave it the scientific name, Gorilla,
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00:25:12,280 --> 00:25:15,280
a Greek word meaning wild, hairy people.
382
00:25:18,480 --> 00:25:22,600
He then sealed the reputation of the gorilla with
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00:25:22,600 --> 00:25:26,200
the convention of adding the surname of the person who discovered it.
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In this case, Thomas Savage.
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00:25:32,960 --> 00:25:36,880
But many people misguidedly assumed that the scientific name,
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00:25:36,880 --> 00:25:40,480
Gorilla savagei, was a description of the nature
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00:25:40,480 --> 00:25:42,000
of this newly found ape.
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00:25:45,000 --> 00:25:48,240
Though gorillas had somehow remained unknown to science
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00:25:48,240 --> 00:25:53,600
until Victorian times, other great apes were already quite familiar.
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00:25:53,600 --> 00:25:57,960
They were all commonly called orangs after the most famous of them,
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00:25:57,960 --> 00:25:59,920
the orangutan, which the Dutch
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00:25:59,920 --> 00:26:05,240
had encountered in Indonesia in the 17th century.
393
00:26:08,640 --> 00:26:14,080
Shortly afterwards, the Portuguese discovered chimpanzees in Africa
394
00:26:14,080 --> 00:26:17,640
and by the time reports of the gorilla appeared, both chimps
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and orangs had been appearing in circuses
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00:26:20,120 --> 00:26:23,640
and the courts of European royalty for over 200 years.
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00:26:28,600 --> 00:26:33,320
The first gorillas to arrive in Britain were dead specimens
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00:26:33,320 --> 00:26:38,280
and unlike these late arrivals, they will often badly preserved.
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00:26:38,280 --> 00:26:41,800
They went on display at the Crystal Palace and their grotesque
400
00:26:41,800 --> 00:26:45,520
appearance was supported by horrific accounts of their nature.
401
00:26:47,960 --> 00:26:50,920
One of the early collectors of gorillas was an American
402
00:26:50,920 --> 00:26:52,520
anthropologist called Du Chaillu.
403
00:26:54,120 --> 00:26:57,800
He made numerous expeditions to Africa and returned with
404
00:26:57,800 --> 00:27:00,920
tales of terrifying encounters with gorillas.
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00:27:03,680 --> 00:27:09,320
In this, his bestseller, Exploration And Adventure In Equatorial Africa,
406
00:27:09,320 --> 00:27:14,000
amongst sensational tales of cannibalism, charging buffalo
407
00:27:14,000 --> 00:27:17,200
and tropical fevers, is the very first eyewitness
408
00:27:17,200 --> 00:27:20,840
account of man meeting male gorillas in their jungle home.
409
00:27:22,560 --> 00:27:25,880
"He was a sight, I think, I shall never forget.
410
00:27:25,880 --> 00:27:28,600
"Nearly six feet high with immense body,
411
00:27:28,600 --> 00:27:32,120
"huge chest and great, muscular arms,
412
00:27:32,120 --> 00:27:36,200
"with fiercely glaring, large, deep grey eyes and a hellish
413
00:27:36,200 --> 00:27:40,960
"expression of face that seemed, to me, like some nightmare vision.
414
00:27:40,960 --> 00:27:46,400
"Thus stood before us this king of the African forest."
415
00:27:46,400 --> 00:27:50,440
To be fair, Chaillu did dispel some of the more ridiculous stories
416
00:27:50,440 --> 00:27:53,000
and myths about the gorilla, but his compelling
417
00:27:53,000 --> 00:27:57,040
tales of their fierce nature was just what the public wanted to hear.
418
00:28:00,120 --> 00:28:01,280
GORILLA CALLS
419
00:28:03,400 --> 00:28:06,000
Du Chaillu's vivid description of the gorilla in the wild
420
00:28:06,000 --> 00:28:11,600
reinforced its image as a fearsome beast and confirmed its reputation.
421
00:28:15,040 --> 00:28:17,200
GORILLA CALLS
422
00:28:20,640 --> 00:28:24,160
These displays may look fearsome, but in fact,
423
00:28:24,160 --> 00:28:27,400
they're only rarely followed by physical violence.
424
00:28:29,160 --> 00:28:32,080
Du Chaillu's description may have wowed readers,
425
00:28:32,080 --> 00:28:36,400
but the scientific establishment were rather less easy to impress.
426
00:28:36,400 --> 00:28:41,080
He was branded a braggart, a plagiarist and a charlatan.
427
00:28:41,080 --> 00:28:43,800
Some suggested he never even visited Africa
428
00:28:43,800 --> 00:28:47,800
and that his ferocious creatures were, in fact, gentle.
429
00:28:47,800 --> 00:28:51,600
But he had his strongest support right at the top.
430
00:28:51,600 --> 00:28:55,720
Professor Richard Owen, founder of the London Natural History Museum.
431
00:28:58,400 --> 00:29:01,600
Owen was one of the most respected figures
432
00:29:01,600 --> 00:29:05,240
of Victorian science, but also one of the most widely disliked.
433
00:29:05,240 --> 00:29:09,320
He was vehemently opposed to Darwin's theory of evolution,
434
00:29:09,320 --> 00:29:12,960
which suggested that apes and humans were closely related.
435
00:29:15,560 --> 00:29:19,320
Du Chaillu's description of a ferocious gorilla suited Owen,
436
00:29:19,320 --> 00:29:22,240
because it seemed to support his view that we could not
437
00:29:22,240 --> 00:29:25,320
possibly be related to such dreadful monsters.
438
00:29:26,360 --> 00:29:28,600
But he could hardly deny the anatomical
439
00:29:28,600 --> 00:29:31,120
similarity between gorillas and humans.
440
00:29:32,160 --> 00:29:37,080
This illustration from 1855, shows the skeleton of a man
441
00:29:37,080 --> 00:29:39,440
and gorilla side-by-side.
442
00:29:39,440 --> 00:29:41,360
It was published by Owen himself
443
00:29:41,360 --> 00:29:44,400
and makes clear the likeness between the two species.
444
00:29:50,360 --> 00:29:54,720
But Owen was still not willing to accept that man could have
445
00:29:54,720 --> 00:29:56,040
ape-like ancestors.
446
00:30:07,560 --> 00:30:11,920
In 1860, a great debate about evolution and man's place
447
00:30:11,920 --> 00:30:17,000
in the natural world took place in this very room in Oxford.
448
00:30:17,000 --> 00:30:20,640
Richard Owen presented compelling evidence for the presence of
449
00:30:20,640 --> 00:30:25,760
three structures in the human brain that were absent in a gorilla's.
450
00:30:25,760 --> 00:30:29,840
According to Owen, this made the descent of man from apes impossible.
451
00:30:30,960 --> 00:30:34,200
As the only anatomist with access to gorilla specimens,
452
00:30:34,200 --> 00:30:36,280
he was confident he was on firm ground,
453
00:30:36,280 --> 00:30:40,920
but he hadn't counted on biologist Thomas Henry Huxley.
454
00:30:41,960 --> 00:30:47,080
Huxley, known as Darwin's bulldog, was, in his own words,
455
00:30:47,080 --> 00:30:52,680
waiting for this opportunity to nail that mendacious humbug, Owen,
456
00:30:52,680 --> 00:30:56,800
like a kite to a barn door, and immediately challenged his
457
00:30:56,800 --> 00:30:59,480
findings, vowing to prove him wrong.
458
00:30:59,480 --> 00:31:02,720
In the years that followed, Huxley doggedly pursued Owen
459
00:31:02,720 --> 00:31:05,520
and did indeed prove him wrong on all counts.
460
00:31:05,520 --> 00:31:09,200
He found all three brain structures in the apes
461
00:31:09,200 --> 00:31:13,720
and proved apes were closer to men than to monkeys.
462
00:31:13,720 --> 00:31:18,320
Richard Owen had, according to Huxley, been guilty of wilful
463
00:31:18,320 --> 00:31:20,040
and deliberate falsehood.
464
00:31:24,960 --> 00:31:28,560
Owen and Du Chaillu's misleading descriptions of the gorilla
465
00:31:28,560 --> 00:31:31,240
failed to disprove our relationship to apes.
466
00:31:32,840 --> 00:31:35,120
On the contrary, they became a turning point
467
00:31:35,120 --> 00:31:38,800
in our acceptance that they are our cousins.
468
00:31:42,800 --> 00:31:46,320
But, sadly, the damage to the gorilla's reputation had
469
00:31:46,320 --> 00:31:48,360
already been done.
470
00:31:53,000 --> 00:31:57,480
When Guy arrived in London almost 100 years after the discovery
471
00:31:57,480 --> 00:32:03,680
of gorillas, people still regarded him as a fearsome and savage beast.
472
00:32:09,800 --> 00:32:13,040
It took the next 30 years of Guy's life for a more accurate
473
00:32:13,040 --> 00:32:15,200
picture of the gorilla to emerge.
474
00:32:15,200 --> 00:32:19,800
Although gorillas can, indeed, be dangerous when angry or threatened,
475
00:32:19,800 --> 00:32:22,840
most of the time, they are mild and peaceful creatures
476
00:32:22,840 --> 00:32:27,600
and nowhere is this shown more clearly than in a charming story
477
00:32:27,600 --> 00:32:29,640
from Guy's time here at the zoo.
478
00:32:29,640 --> 00:32:34,720
Guy's cage often attracted sparrows that then became trapped inside.
479
00:32:34,720 --> 00:32:38,120
But rather than kill them, Guy would lift the tiny birds
480
00:32:38,120 --> 00:32:42,000
carefully onto his hand, examine them and then release them.
481
00:32:42,000 --> 00:32:44,440
He was, indeed, a gentle giant.
482
00:32:49,200 --> 00:32:52,640
Over time, thanks to the determination of field researchers
483
00:32:52,640 --> 00:32:57,080
like Dian Fossey, people have seen another side to gorillas.
484
00:33:04,080 --> 00:33:08,240
By the time I met them, many of us were ready to see them
485
00:33:08,240 --> 00:33:11,400
not as savages, but as animals that are equally
486
00:33:11,400 --> 00:33:14,480
suited to their environment as we are to ours.
487
00:33:20,560 --> 00:33:24,880
So, now, at last, the gorilla, which was once labelled a fearsome
488
00:33:24,880 --> 00:33:29,360
beast, has managed to shake off its undeserved reputation.
489
00:33:35,640 --> 00:33:40,880
Our second subject, the vampire bat, has also had an undeservedly
490
00:33:40,880 --> 00:33:46,160
bad reputation and been the inspiration behind tales of evil.
491
00:33:49,160 --> 00:33:53,600
Bats have had a bad reputation for a very long time.
492
00:33:53,600 --> 00:33:57,840
As creatures of the night, they are connected with dark mysteries
493
00:33:57,840 --> 00:34:00,240
and devilish goings-on.
494
00:34:00,240 --> 00:34:02,840
But there was never any real evidence to support these
495
00:34:02,840 --> 00:34:05,880
claims of their evil nature, that is
496
00:34:05,880 --> 00:34:09,600
until the Conquistadors returned from South America with
497
00:34:09,600 --> 00:34:14,280
tales of giant bats that dropped down on you as you slept
498
00:34:14,280 --> 00:34:17,440
and sucked the very blood from your veins.
499
00:34:17,440 --> 00:34:19,520
Tales of vampire bats.
500
00:34:22,040 --> 00:34:25,640
Stories of giant, bloodsucking bats have long been
501
00:34:25,640 --> 00:34:29,000
part of the culture of South American people.
502
00:34:29,000 --> 00:34:31,880
Images of them with savage fangs are common
503
00:34:31,880 --> 00:34:35,080
and a bat god was associated with death.
504
00:34:37,400 --> 00:34:41,280
But it wasn't until the 18th century that a detailed description of a
505
00:34:41,280 --> 00:34:46,240
vampire bat was published in Europe and it came from one of its victims.
506
00:34:49,560 --> 00:34:53,160
An Englishman by the name of John Gabriel Stedman came
507
00:34:53,160 --> 00:34:58,480
back from South America with reports of having been bitten by a vampire.
508
00:34:59,800 --> 00:35:04,120
He described a bat of monstrous size that sucked the blood of men
509
00:35:04,120 --> 00:35:06,480
and cattle when they're fast asleep.
510
00:35:06,480 --> 00:35:10,440
And he proudly declared that he'd managed to catch the beast
511
00:35:10,440 --> 00:35:11,680
and cut off its head.
512
00:35:12,720 --> 00:35:15,360
Stedman's descriptions were detailed,
513
00:35:15,360 --> 00:35:17,320
but nonetheless misleading.
514
00:35:17,320 --> 00:35:20,680
His drawing shows, in fact, the bat that feeds on nectar
515
00:35:20,680 --> 00:35:22,680
and is only a few centimetres long.
516
00:35:24,640 --> 00:35:28,280
He had been bitten by a vampire, but he had blamed the wrong bat.
517
00:35:32,720 --> 00:35:37,160
Clouded by their own ideas of what a vampire should look like,
518
00:35:37,160 --> 00:35:41,720
early naturalists jumped to all sorts of conclusions and assumed
519
00:35:41,720 --> 00:35:46,320
that it was the biggest and the most ugly that were the bloodsuckers.
520
00:35:46,320 --> 00:35:49,960
In fact, the name "vampire" was sometimes given to bats that
521
00:35:49,960 --> 00:35:54,040
looked the part, but had never so much as sniffed blood.
522
00:35:54,040 --> 00:35:57,360
These bats, for example, drawn by the 19th-century German
523
00:35:57,360 --> 00:36:01,120
naturalist Ernst Haeckel, belonged to a group called
524
00:36:01,120 --> 00:36:05,120
the leaf nosed bats, because of these strange protrusions
525
00:36:05,120 --> 00:36:06,960
around the end of the nose.
526
00:36:06,960 --> 00:36:10,360
This gives them a particularly menacing appearance and some early
527
00:36:10,360 --> 00:36:14,880
naturalists thought the nose leaf was, in fact, the mark of a vampire.
528
00:36:16,800 --> 00:36:20,480
The leaflike object on its nose was thought to be so sharp,
529
00:36:20,480 --> 00:36:24,120
the bat could use it to puncture a victim's skin,
530
00:36:24,120 --> 00:36:26,760
and since many bats have such nose leaves,
531
00:36:26,760 --> 00:36:31,840
over 100 species were mistakenly described as vampires.
532
00:36:31,840 --> 00:36:35,560
In fact, the nose leaf is made of nothing more than soft flesh
533
00:36:35,560 --> 00:36:37,840
and couldn't possibly draw blood.
534
00:36:37,840 --> 00:36:40,080
It's used for echolocation.
535
00:36:41,920 --> 00:36:44,560
Echolocation works like sonar.
536
00:36:44,560 --> 00:36:48,400
The bats produce high-frequency calls and use the returning
537
00:36:48,400 --> 00:36:51,560
echoes to build up a mental map of their surroundings,
538
00:36:51,560 --> 00:36:55,720
so they are able to find their way in the pitch dark and hunt for prey.
539
00:36:57,200 --> 00:37:00,640
Most bats produce these calls in their throats,
540
00:37:00,640 --> 00:37:04,640
but leaf nosed bats project them out through their nose in a beam.
541
00:37:05,800 --> 00:37:09,760
By doing so, they can feed and echolocate at the same time.
542
00:37:15,920 --> 00:37:19,320
So many leaf nosed bats had been discovered that the arrival
543
00:37:19,320 --> 00:37:23,360
in Europe of a specimen of another, smaller species
544
00:37:23,360 --> 00:37:26,480
in 1810 attracted very little attention.
545
00:37:26,480 --> 00:37:29,600
It was simply named Desmodus rotundus,
546
00:37:29,600 --> 00:37:31,800
on account of it being a little portly.
547
00:37:33,640 --> 00:37:36,560
Some 30 years later, when Charles Darwin was travelling
548
00:37:36,560 --> 00:37:38,400
around the world aboard the Beagle,
549
00:37:38,400 --> 00:37:43,080
he observed Desmodus feeding in the wild for the first time.
550
00:37:43,080 --> 00:37:46,960
He saw it drinking the blood of sleeping horses and cattle.
551
00:37:48,040 --> 00:37:51,920
He had, at last, identified the true vampire.
552
00:37:53,920 --> 00:37:57,520
We know that there are only three species of vampire bats
553
00:37:57,520 --> 00:38:00,000
and they all live in South America.
554
00:38:00,000 --> 00:38:04,440
They're totally unique in being the only mammals to feed exclusively
555
00:38:04,440 --> 00:38:08,600
on blood, but feeding on blood is not as easy as you might think.
556
00:38:08,600 --> 00:38:11,480
It's actually a pretty challenging diet.
557
00:38:11,480 --> 00:38:16,320
Blood is made up of water and protein and has virtually no fat,
558
00:38:16,320 --> 00:38:20,360
so, vampires find it hard to get enough energy.
559
00:38:20,360 --> 00:38:23,720
They must consume 50% of their own body weight in blood each night,
560
00:38:23,720 --> 00:38:26,120
or they'll die within a few days.
561
00:38:31,360 --> 00:38:35,040
Under the cover of darkness, the vampire sets out to hunt.
562
00:38:40,080 --> 00:38:47,160
The nose leaf and echolocation help it to home in on its prey.
563
00:38:53,120 --> 00:38:55,080
The bat approaches carefully.
564
00:38:55,080 --> 00:38:58,680
Unlike most other bats, it can use its wings as legs
565
00:38:58,680 --> 00:39:00,040
and it walks on its elbows.
566
00:39:08,400 --> 00:39:12,360
Once near its victim, it uses its nose leaf in another way.
567
00:39:14,320 --> 00:39:16,200
It acts as a heat-seeking device,
568
00:39:16,200 --> 00:39:18,600
guiding the bat to the warmth of its prey.
569
00:39:22,240 --> 00:39:26,400
Today, livestock have largely replaced wild jungle animals,
570
00:39:26,400 --> 00:39:30,440
but even livestock can be dangerous to a small bat.
571
00:39:36,560 --> 00:39:40,880
Patiently, the vampire stalks its prey.
572
00:39:44,000 --> 00:39:46,800
And, at last, it's close enough.
573
00:39:46,800 --> 00:39:50,400
The teeth are so sharp that a nick is all that's needed.
574
00:39:54,560 --> 00:39:59,800
Blood from the wound doesn't clot, but continues to flow, and within
575
00:39:59,800 --> 00:40:04,040
a quarter of an hour, the bat can drink 40% of its body weight.
576
00:40:05,800 --> 00:40:09,280
That is the equivalent to one of us drinking over 20 litres.
577
00:40:14,720 --> 00:40:18,040
Having had its fill, it's back to the roost.
578
00:40:21,400 --> 00:40:24,080
Finding a meal every night is not easy,
579
00:40:24,080 --> 00:40:27,520
but vampires have come up with a solution to that problem.
580
00:40:27,520 --> 00:40:31,360
Those which have been successful share the blood they've drunk
581
00:40:31,360 --> 00:40:33,680
with those who had failed to collect any.
582
00:40:35,320 --> 00:40:38,360
Vampires are most likely to share with those
583
00:40:38,360 --> 00:40:41,920
they know well from roosting and grooming together.
584
00:40:41,920 --> 00:40:44,240
It's an act of apparent kindness,
585
00:40:44,240 --> 00:40:46,880
but the colony, as a whole, benefits.
586
00:40:49,120 --> 00:40:52,840
So, it seems that there is another, gentler side to these bats
587
00:40:52,840 --> 00:40:54,760
than anyone could have imagined.
588
00:40:57,720 --> 00:41:00,880
Unfortunately, just as light was being shed on the true
589
00:41:00,880 --> 00:41:04,440
nature of the vampire, an Irish novelist published the book
590
00:41:04,440 --> 00:41:08,720
that would seal their reputation for the foreseeable future.
591
00:41:08,720 --> 00:41:13,080
Bram Stoker's classic, Dracula, leaves little doubt as to
592
00:41:13,080 --> 00:41:15,080
where his inspiration came from.
593
00:41:17,600 --> 00:41:21,320
His story combined European myths of vampires that come to haunt
594
00:41:21,320 --> 00:41:25,680
the living, with stories of bloodsucking bats
595
00:41:25,680 --> 00:41:29,680
from South America, and it's an association that the real
596
00:41:29,680 --> 00:41:32,560
vampire bats have struggled to shed.
597
00:41:40,920 --> 00:41:45,480
More recently, vampire bats have made headlines once again.
598
00:41:45,480 --> 00:41:48,840
It's been discovered that their saliva contains the remarkable
599
00:41:48,840 --> 00:41:53,000
blood-thinning agent that's been named Draculin.
600
00:41:53,000 --> 00:41:56,320
And it's proving to be the most successful treatment
601
00:41:56,320 --> 00:41:57,680
for stroke victims.
602
00:41:57,680 --> 00:42:00,800
How ironic that a creature we once believed to be a deadly threat
603
00:42:00,800 --> 00:42:05,560
may turn out to save human lives in the future.
604
00:42:05,560 --> 00:42:09,600
Maybe it's time we re-evaluated the reputation of the much
605
00:42:09,600 --> 00:42:11,360
maligned vampire bat.
606
00:42:13,800 --> 00:42:18,160
Vampire bats and gorillas were long pursued by unfair reputations,
607
00:42:18,160 --> 00:42:23,160
but while our fear of gorillas has turned into respect and admiration,
608
00:42:23,160 --> 00:42:28,080
the vampire bat, for many of us, continues to evoke mixed emotions.
53455
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