0:00:02 > 0:00:06'The natural world is full of extraordinary animals
0:00:06 > 0:00:08'with amazing life histories.
0:00:09 > 0:00:13'Yet certain stories are more intriguing than most.'
0:00:15 > 0:00:19The mysteries of a butterfly's life cycle.
0:00:19 > 0:00:23Or the strange biology of the Emperor penguin.
0:00:23 > 0:00:26Some of these creatures were surrounded by myth
0:00:26 > 0:00:30and misunderstandings for a very long time.
0:00:30 > 0:00:34And some have only recently revealed their secrets.
0:00:34 > 0:00:38These are the animals that stand out from the crowd,
0:00:38 > 0:00:44the curiosities I find most fascinating of all.
0:00:51 > 0:00:52'In this programme,
0:00:52 > 0:00:55'I examine the remarkable lives of two animals
0:00:55 > 0:00:58'that have mastered the problems of life in the dark.'
0:01:01 > 0:01:06'The giant squid, which lives in the deepest oceans...'
0:01:07 > 0:01:09..and owls.
0:01:09 > 0:01:13Highly specialised hunters that seek their prey at night.
0:01:20 > 0:01:23Some animals acquired frightening reputations
0:01:23 > 0:01:26almost as soon as they were discovered.
0:01:26 > 0:01:27In this episode,
0:01:27 > 0:01:30we investigate the stories surrounding two such creatures...
0:01:30 > 0:01:32GORILLA MOANS
0:01:32 > 0:01:35..the gorilla and the vampire bat.
0:01:35 > 0:01:38Why did they get such bad reputations?
0:01:38 > 0:01:40And were they justified?
0:01:48 > 0:01:53When you think of animals of the night, owls tend to come to mind.
0:01:53 > 0:01:56In fact, not all owls are nocturnal,
0:01:56 > 0:02:00but those that are have a very similar-shaped face,
0:02:00 > 0:02:02round and flat.
0:02:03 > 0:02:06And their most prominent facial features
0:02:06 > 0:02:09are the large, forward-facing eyes.
0:02:09 > 0:02:13These give them a seemingly wise look and in fact,
0:02:13 > 0:02:16owls have often been revered for their wisdom.
0:02:18 > 0:02:23But they have also been linked with legends of death and evil.
0:02:24 > 0:02:27They are birds of the night.
0:02:27 > 0:02:30To many, they seem eerie and mysterious.
0:02:32 > 0:02:35'But how good is an owl's eyesight?
0:02:35 > 0:02:39'Can they really see what we can't?'
0:02:39 > 0:02:43The colour picture that forms at the back of our eyes
0:02:43 > 0:02:47is very much like that that forms in the eyes of a bird.
0:02:47 > 0:02:50We have roughly the same number of colour receptors.
0:02:50 > 0:02:55But when day changes to night, the picture changes.
0:02:55 > 0:02:59Then, different receptors come into play, called rods.
0:02:59 > 0:03:02And owls have a much higher proportions of rods
0:03:02 > 0:03:04in their eyes than we do.
0:03:04 > 0:03:08So they're extremely good at seeing at low light levels.
0:03:08 > 0:03:09Aren't you?
0:03:12 > 0:03:15The barn owl sets off to hunt shortly after dusk.
0:03:16 > 0:03:20As the light fades, we struggle to see.
0:03:20 > 0:03:22But the owl has no such problem.
0:03:24 > 0:03:27Flying low, it keeps its eyes trained on the ground,
0:03:27 > 0:03:29looking for any movement in the grass.
0:03:32 > 0:03:34Its eyes now give it the edge over its prey,
0:03:34 > 0:03:38and it can hunt at a time when few other birds can.
0:03:43 > 0:03:45And there's another important difference
0:03:45 > 0:03:48between an owl's eye and ours.
0:03:48 > 0:03:50The pupil in the front of the eye, the hole,
0:03:50 > 0:03:53is very much bigger in an owl's.
0:03:53 > 0:03:56Ours measures around eight millimetres across.
0:03:56 > 0:04:00An owl's, like this tawny owl, is around 13.
0:04:00 > 0:04:03That means very much more light can get into the eye,
0:04:03 > 0:04:06so the picture formed on the retina is very much brighter.
0:04:06 > 0:04:09In fact, it's about three times as bright.
0:04:09 > 0:04:11OWL SQUEAKS Aw...
0:04:12 > 0:04:14OWL SQUEAKS Aw...
0:04:16 > 0:04:20So, unlike other birds, which cannot see so well in the dark,
0:04:20 > 0:04:23the owl can remain active throughout the night.
0:04:27 > 0:04:29But specialist eyes create problems.
0:04:29 > 0:04:32Squeezing a large eyeball
0:04:32 > 0:04:37into a relatively small skull requires changes.
0:04:37 > 0:04:42The shape of the owl eye is more tubular than round.
0:04:42 > 0:04:45This may help to increase the size of the image on the retina
0:04:45 > 0:04:47at the back.
0:04:47 > 0:04:51But the owl's eye shape and size presents certain problems.
0:04:51 > 0:04:53It doesn't fit snugly into the skull
0:04:53 > 0:04:57and there's no room in the socket for muscles to move it.
0:04:58 > 0:05:00And there's another problem.
0:05:00 > 0:05:03A closer look at an owl's skull
0:05:03 > 0:05:06shows that its ear openings are very big.
0:05:06 > 0:05:11So the only way for the tubular eyes to fit into the skull is for them
0:05:11 > 0:05:15to be placed in the middle of the face in a forward-looking position.
0:05:15 > 0:05:18This limits the owl's field of view.
0:05:21 > 0:05:24But owls have a trick that allows them
0:05:24 > 0:05:27to dramatically increase their field of view.
0:05:27 > 0:05:31They can rotate their heads nearly all the way round.
0:05:31 > 0:05:35Folklore has it that you can kill an owl
0:05:35 > 0:05:38by walking in circles round a tree in which one is perched
0:05:38 > 0:05:40and so make it twist its head off.
0:05:40 > 0:05:43That, of course, is not true.
0:05:43 > 0:05:45But owls can certainly turn their heads
0:05:45 > 0:05:48through 270 degrees in either direction.
0:05:48 > 0:05:54If we tried to do that, we'd tear our arteries and break our necks.
0:05:54 > 0:05:56So, how do owls do it?
0:05:57 > 0:06:01Recently, scientists have discovered that it's due
0:06:01 > 0:06:04to a remarkable adaptation of their bones.
0:06:05 > 0:06:09Owls' necks, as you can see in this skeleton of an eagle owl,
0:06:09 > 0:06:14have 14 vertebrae. That's twice the number that we have.
0:06:14 > 0:06:17This gives them greater flexibility.
0:06:17 > 0:06:19But only recently, CT scans have shown researchers
0:06:19 > 0:06:23how the owl can rotate its head without passing out.
0:06:24 > 0:06:28Cavities within the neck bones are ten times larger
0:06:28 > 0:06:30in an owl's neck than in ours,
0:06:30 > 0:06:33giving more room for vital blood vessels
0:06:33 > 0:06:35that run up to the owl's head.
0:06:35 > 0:06:39What's more, the carotid arteries enter the head
0:06:39 > 0:06:43much higher up the neck and are centrally positioned,
0:06:43 > 0:06:46and this may help avoid damage during twisting.
0:06:46 > 0:06:50And the owl's arteries seem to widen below the brain,
0:06:50 > 0:06:52allowing blood to pool.
0:06:52 > 0:06:57This may create a vital blood reservoir that guarantees blood flow
0:06:57 > 0:07:00to the brain, should the vessels below be squeezed
0:07:00 > 0:07:01while the head is turning.
0:07:01 > 0:07:05So the owl can turn its head almost all the way round
0:07:05 > 0:07:07without risk of injury.
0:07:08 > 0:07:11So, owls have successfully dealt with the problems
0:07:11 > 0:07:13created by having large eyes.
0:07:13 > 0:07:15OWL HOOTS
0:07:15 > 0:07:19But are these eyes really all they seem?
0:07:19 > 0:07:22It was long thought that owls can see perfectly,
0:07:22 > 0:07:25even on the darkest of nights.
0:07:25 > 0:07:26But that is not the case.
0:07:28 > 0:07:31On cloudy nights and beneath trees with dense canopies,
0:07:31 > 0:07:35they can only discern the faintest silhouettes.
0:07:35 > 0:07:38It's nowhere near detailed enough to hunt for prey.
0:07:40 > 0:07:44But the owl has another sense to help it...
0:07:44 > 0:07:45acute hearing.
0:07:47 > 0:07:49In the 18th century,
0:07:49 > 0:07:52the great French naturalist Count de Buffon wrote,
0:07:52 > 0:07:54"Their sense of hearing seems to be superior
0:07:54 > 0:07:59"to that of other birds and perhaps to that of every other animal,
0:07:59 > 0:08:00"for the drum of the ear
0:08:00 > 0:08:03"is proportionately larger than in quadrupeds
0:08:03 > 0:08:07"and besides, they can open and shut this organ at pleasure,
0:08:07 > 0:08:10"a power possessed by no other animal."
0:08:10 > 0:08:14Well, we know today that that's true, some owls,
0:08:14 > 0:08:17though not all, but Buffon was quite right
0:08:17 > 0:08:20to draw our attention to the remarkable hearing of owls.
0:08:22 > 0:08:23OWL HOOTS
0:08:23 > 0:08:26The owl's large ear openings are not visible
0:08:26 > 0:08:30because they're hidden beneath the face feathers.
0:08:30 > 0:08:36And unlike other birds, they have fleshy outer ears like our own.
0:08:36 > 0:08:39In many owls, they're positioned at slightly different levels
0:08:39 > 0:08:41on either side of the head.
0:08:42 > 0:08:44And it's these features that help them
0:08:44 > 0:08:47to accurately pinpoint their prey.
0:08:49 > 0:08:53Most owls have very similar shape faces, flat and round.
0:08:53 > 0:08:55It's called a facial ruff.
0:08:55 > 0:09:00It's formed from feathers that are particularly dense and bristly,
0:09:00 > 0:09:03and they lie flat on either side of the face,
0:09:03 > 0:09:06just behind the opening to the ears.
0:09:06 > 0:09:10It's thought that they deflect the sound into the ears.
0:09:10 > 0:09:14In fact, the facial ruff seems to be a kind of sound amplifier.
0:09:17 > 0:09:22The barn owl has a distinctive, heart-shaped ruff and its face
0:09:22 > 0:09:28acts like a satellite dish, focusing the sounds from below into the ears.
0:09:30 > 0:09:34Its soft flight feathers enable it to move through the air
0:09:34 > 0:09:37in almost complete silence so that it can hear
0:09:37 > 0:09:42the slightest rustle and approach its prey undetected.
0:09:48 > 0:09:52But few have as large a facial ruff as the great grey owl.
0:09:55 > 0:09:58Although it hunts during the day, its prey is hidden under
0:09:58 > 0:10:03cover of snow, so it has to rely entirely on its ears.
0:10:07 > 0:10:11Studies have shown that owls' hearing is particularly
0:10:11 > 0:10:14acute for very quiet sounds.
0:10:14 > 0:10:19In fact, part of an owl's brain that detects sound has three times
0:10:19 > 0:10:24as many neurones as its equivalent in, say, a crow's brain.
0:10:24 > 0:10:29The hairs of the inner ear which detect the vibrations
0:10:29 > 0:10:33of sound are particularly abundant in an owl.
0:10:33 > 0:10:37Not only that, whereas the equivalent hairs in my ear
0:10:37 > 0:10:42degrade with age, in an owl's they are regrown.
0:10:42 > 0:10:46So whereas my hearing gets worse as I get older,
0:10:46 > 0:10:49an owl's always remains very acute.
0:10:50 > 0:10:54The owl's ears may in fact be more crucial to its nocturnal
0:10:54 > 0:10:57lifestyle than its eyes.
0:10:57 > 0:11:00But by combining all its senses,
0:11:00 > 0:11:03it has solved the problems of living in the dark.
0:11:04 > 0:11:10So it seems that the shape of the face helps both the owl's sight
0:11:10 > 0:11:11and its hearing.
0:11:11 > 0:11:14So whether or not you think the owl is wise,
0:11:14 > 0:11:19it certainly has a head for life in the dark.
0:11:22 > 0:11:26Next we journey into the darkest of places to try and unravel
0:11:26 > 0:11:30the life of a creature that has long captured our imagination.
0:11:34 > 0:11:38Here in the Natural History Museum is a specimen of an animal
0:11:38 > 0:11:41that has fascinated humanity for thousands of years.
0:11:41 > 0:11:44It is a giant squid.
0:11:44 > 0:11:47This particular one was netted off the Falkland Islands,
0:11:47 > 0:11:49immediately put on ice,
0:11:49 > 0:11:52and then brought here to the museum in London.
0:11:52 > 0:11:56Few museums have complete or as perfectly preserved
0:11:56 > 0:11:58specimens as this one.
0:11:58 > 0:12:04This one measures about eight metres, the length of a London bus.
0:12:04 > 0:12:06But others have been caught even bigger,
0:12:06 > 0:12:09one about twice the length that weighed around a tonne.
0:12:11 > 0:12:15Very few people have ever seen one of these creatures alive.
0:12:15 > 0:12:19That's because they live at depths of around 1,000 metres
0:12:19 > 0:12:21and down there, it's pitch-black.
0:12:22 > 0:12:26So how do these animals manage to hunt in such conditions?
0:12:27 > 0:12:32That's a question that has proved exceedingly difficult to answer.
0:12:34 > 0:12:39Sailors a long time ago told stories of having seen a gigantic,
0:12:39 > 0:12:43squid-like creature known as the Kraken.
0:12:43 > 0:12:47It was said to have huge tentacles strong enough to grip
0:12:47 > 0:12:49and sink a ship.
0:12:49 > 0:12:53The tales seemed unlikely and far-fetched, but could the giant
0:12:53 > 0:12:57squid perhaps have been the source of these extraordinary reports?
0:12:58 > 0:13:02The first clues that this creature may in fact be real came from
0:13:02 > 0:13:05the tales of sailors on whaling ships
0:13:05 > 0:13:07in the 18th and 19th centuries.
0:13:07 > 0:13:11Some of them reported in their ships' logs that they often noticed
0:13:11 > 0:13:16strange, circular scars on the heads and jaws of captured sperm whales.
0:13:16 > 0:13:19The scars suggested a fierce wrestling match with
0:13:19 > 0:13:21some enormous beast.
0:13:21 > 0:13:24What creature could take on a 70-tonne whale?
0:13:24 > 0:13:28Inside the stomachs of the whales were clues.
0:13:28 > 0:13:33A number of hard, indigestible objects like this one.
0:13:34 > 0:13:37It looks a bit like the beak of a parrot.
0:13:37 > 0:13:40But in fact, it belongs to an entirely different
0:13:40 > 0:13:42kind of animal - to a cephalopod.
0:13:42 > 0:13:47Cephalopods are marine animals that include the octopus,
0:13:47 > 0:13:49the squid and the cuttlefish.
0:13:49 > 0:13:52This beak is the mouth part of one such creature
0:13:52 > 0:13:56and is used to tear its prey into small pieces.
0:13:56 > 0:13:58Sailors on the whaling ships immediately recognised
0:13:58 > 0:14:02the beak as being from a cephalopod.
0:14:02 > 0:14:04But its size suggested a creature
0:14:04 > 0:14:07many times bigger than any known species.
0:14:09 > 0:14:14Cephalopods have a ring of eight or ten arms, or tentacles, which they
0:14:14 > 0:14:17use to push food into their mouth in the centre of the ring.
0:14:18 > 0:14:22The arms are equipped with round suckers to help hold
0:14:22 > 0:14:24onto their prey.
0:14:24 > 0:14:28It is the marks from these that were found by sailors on the bodies
0:14:28 > 0:14:30of sperm whales.
0:14:30 > 0:14:34Could a gigantic squid have caused such injuries,
0:14:34 > 0:14:38and how massive must it be to tackle a sperm whale,
0:14:38 > 0:14:40one of the biggest animals on the planet?
0:14:42 > 0:14:46And then in 1873, fishermen caught what
0:14:46 > 0:14:51they called a sea monster off the coast of Newfoundland in Canada.
0:14:51 > 0:14:55After killing it with their knives, they lost the body,
0:14:55 > 0:14:59but they brought the head and tentacles to the local clergyman.
0:14:59 > 0:15:02The clergyman bought it off the fishermen for 10
0:15:02 > 0:15:05and displayed it in his living room by carefully draping it over
0:15:05 > 0:15:09a bath stand, to show off its many arms and tentacles.
0:15:09 > 0:15:14The photograph clearly proved that here was a gigantic squid with
0:15:14 > 0:15:18its beak at the top and over seven metre long tentacles.
0:15:18 > 0:15:23Here last was the evidence that the monster of the deep,
0:15:23 > 0:15:25the Kraken, really does exist.
0:15:27 > 0:15:31But the giant squid itself continued to evade scientists,
0:15:31 > 0:15:33even after its discovery.
0:15:33 > 0:15:36It's only since the invention of submersibles that we have
0:15:36 > 0:15:40been able to follow it down into its deep sea home.
0:15:40 > 0:15:42Even so, we seem to have had little
0:15:42 > 0:15:45success in finding the elusive giant.
0:15:45 > 0:15:48So scientists are now trying to piece together its biology
0:15:48 > 0:15:52by looking at other closely-related animals.
0:15:54 > 0:15:56This is an octopus.
0:15:56 > 0:16:01It uses both its eyes and tentacles to explore its surroundings.
0:16:01 > 0:16:04The octopus's brain is distributed throughout its body
0:16:04 > 0:16:08so that its arms can control much of their own movement.
0:16:08 > 0:16:13It also has a highly complex eyes and sees in much the same way
0:16:13 > 0:16:18as we do, with the lens projecting an image onto the retina behind.
0:16:18 > 0:16:21But while our eyes focus by squeezing the lens to
0:16:21 > 0:16:23change its shape, the octopus's eyes
0:16:23 > 0:16:27focus like a camera, with the lens moving in and out.
0:16:30 > 0:16:33The giant squid's eyes have much the same
0:16:33 > 0:16:38structure as those of an octopus, but when it comes to size, it has
0:16:38 > 0:16:42the biggest eye in the animal kingdom, as large as a football.
0:16:44 > 0:16:48For seeing in dim light, a large eye is better than the small one.
0:16:48 > 0:16:52So many animals of the deep have exceptionally big eyes.
0:16:57 > 0:17:00But in order to see at all, there has to be some light,
0:17:00 > 0:17:04and the giant squid lives at depths of 1,000 metres.
0:17:07 > 0:17:10Although very little sunlight reaches the deeper parts
0:17:10 > 0:17:14of the ocean, there is another kind of light there.
0:17:14 > 0:17:16It's produced by the deep sea animals
0:17:16 > 0:17:19and it's called bioluminescence.
0:17:19 > 0:17:22The light is produced by a chemical reaction in the same
0:17:22 > 0:17:24way as that in a glow stick does.
0:17:24 > 0:17:26When I shake and snap the stick,
0:17:26 > 0:17:31two chemicals called luciferin and luciferase react together to produce
0:17:31 > 0:17:34a bioluminescent glow like this...
0:17:36 > 0:17:38There.
0:17:38 > 0:17:42Some deep sea animals use their own luciferins to produce light, while
0:17:42 > 0:17:46in others it's produced by bacteria living in special light organs.
0:17:48 > 0:17:53A flashing light can act as a lure or confuse a predator.
0:17:53 > 0:17:58It's thought about 90% of deep sea creatures produce
0:17:58 > 0:18:02bioluminescence and they use it in a number of different ways.
0:18:05 > 0:18:09All these fish come from the deep sea.
0:18:09 > 0:18:12They all produce light in one way or another.
0:18:12 > 0:18:17This is the football angler fish and it has a modified
0:18:17 > 0:18:21ray from its dorsal fin which has lots of little tentacles on top.
0:18:21 > 0:18:25The tip of each tentacle produces a little green light
0:18:25 > 0:18:28so it looks as though there is little shoal of small creatures,
0:18:28 > 0:18:32maybe shrimps, hovering above it in the blackness.
0:18:32 > 0:18:35When another shrimp thinks it might join some friends
0:18:35 > 0:18:39and come along that way, the angler fish simply tilts up,
0:18:39 > 0:18:42opens its immense jaw and has its breakfast.
0:18:43 > 0:18:46This, on the other hand,
0:18:46 > 0:18:50is a stoplight loosejaw, which operates in a different way.
0:18:53 > 0:18:58It produces red light from two little organs at the front.
0:18:58 > 0:19:02Hardly any other species of fish in the sea can see red light,
0:19:02 > 0:19:05so it can hunt that way and find its prey.
0:19:05 > 0:19:10When it does, it opens this immense loose jaw and engulfs it.
0:19:10 > 0:19:13There you are. Back you go.
0:19:16 > 0:19:18But what about the giant squid?
0:19:18 > 0:19:22Could it also be producing bioluminescence?
0:19:22 > 0:19:25Some of its close relatives apparently can.
0:19:27 > 0:19:29This is the vampire squid.
0:19:29 > 0:19:33It has eight arms lined with tooth-like projections.
0:19:36 > 0:19:39When threatened, it turns itself inside out,
0:19:39 > 0:19:41wrapping its body in a dark cloak.
0:19:46 > 0:19:48If that doesn't work, the squid has another trick.
0:19:50 > 0:19:53Small lights at the end of its arms
0:19:53 > 0:19:56flash like eyes to distract the predator.
0:20:02 > 0:20:05With so many creatures of the deep producing light, you might think
0:20:05 > 0:20:08that the giant squid would do so as well.
0:20:10 > 0:20:13But scientists studying their carcasses have not been
0:20:13 > 0:20:16able to find any evidence of light-producing bacteria or
0:20:16 > 0:20:18pigments in their bodies.
0:20:20 > 0:20:26So it seems that the ocean's elusive giant truly hides in the dark.
0:20:31 > 0:20:35Although it may not produce its own light, the giant squid can surely
0:20:35 > 0:20:37see the bioluminescence of others
0:20:37 > 0:20:40and this may help it to locate its prey.
0:20:45 > 0:20:48With no sightings of a living giant squid since it was
0:20:48 > 0:20:52first discovered, we seem to be no closer to discovering the truth.
0:20:53 > 0:20:58But in 2004, Japanese scientists finally made a breakthrough.
0:20:59 > 0:21:02Using small squid as bait,
0:21:02 > 0:21:06they were able to attract a live giant squid.
0:21:09 > 0:21:11These first images are tantalising,
0:21:11 > 0:21:15but they still reveal little of the animal's true behaviour.
0:21:15 > 0:21:18Where does it live and how does it feed?
0:21:18 > 0:21:21Questions such as these remain unanswered.
0:21:23 > 0:21:25In spite of its great size,
0:21:25 > 0:21:29the giant squid has proved remarkably difficult to find.
0:21:29 > 0:21:32No doubt scientists will continue to search for it
0:21:32 > 0:21:34and discover more about it.
0:21:34 > 0:21:39But my guess is that the giant squid is likely to remain ahead of
0:21:39 > 0:21:42the game, that this natural curiosity
0:21:42 > 0:21:45is likely to see us before we see it.
0:21:50 > 0:21:55Both the owl and the giant squid live in a world with little light
0:21:55 > 0:21:58and both have evolved large eyes, the better to
0:21:58 > 0:22:00see the world around them.
0:22:01 > 0:22:05But while we've unravelled the owl's ways of surviving in the dark,
0:22:05 > 0:22:10much about giant squid still remains a mystery.
0:22:24 > 0:22:28This statue in the London Zoo is of Guy the Gorilla.
0:22:28 > 0:22:31He was perhaps the zoo's most well-known resident
0:22:31 > 0:22:35and became one of the world's most famous gorillas.
0:22:35 > 0:22:39In his prime, Guy weighed in at over 200 kilos.
0:22:39 > 0:22:43His neck, as you can see, was thicker than a man's waist.
0:22:43 > 0:22:47He stood five feet four inches tall, over a metre and a half.
0:22:48 > 0:22:51That was with his knees bent.
0:22:51 > 0:22:55When Guy arrived here in 1940, little was known about gorillas.
0:22:55 > 0:22:57The reports from Africa hinted of
0:22:57 > 0:23:00a creature that was shockingly brutal.
0:23:00 > 0:23:02So it's hardly surprising that
0:23:02 > 0:23:05people flocked to see this fearsome monster for themselves.
0:23:05 > 0:23:10But Guy proved to be a gentle giant who won
0:23:10 > 0:23:12the affection of the public.
0:23:12 > 0:23:14So how and why did the gorilla gain
0:23:14 > 0:23:17this reputation as a fearsome savage?
0:23:19 > 0:23:24Today we know a lot about gorillas and their way of life.
0:23:24 > 0:23:26There are, in fact, a number of different kinds,
0:23:26 > 0:23:30some of which live in the lowlands and others in the mountains.
0:23:30 > 0:23:33The stay in small family groups
0:23:33 > 0:23:36and spend much of their days feeding on leaves and shoots.
0:23:38 > 0:23:42Many people, including myself, have travelled a long way to meet
0:23:42 > 0:23:44these close relatives of ours.
0:23:54 > 0:23:58Remarkably, despite being the largest living ape,
0:23:58 > 0:24:02the gorilla was one of the last to be described by science.
0:24:05 > 0:24:09In 1847, an American missionary and naturalist, Thomas Savage,
0:24:09 > 0:24:11was travelling back home from Africa
0:24:11 > 0:24:14when he stopped off to stay with some friends in the Congo.
0:24:17 > 0:24:21His friends' house was decorated with African curiosities
0:24:21 > 0:24:25and one of them caught his eye, a skull.
0:24:25 > 0:24:28But it was not like one he'd ever seen before in Africa.
0:24:28 > 0:24:34It had two huge eye sockets, a crest like a Mohawk haircut running
0:24:34 > 0:24:38from front to back and another transversely across here.
0:24:38 > 0:24:43These are anchor points for huge muscles for the jaw and neck.
0:24:43 > 0:24:47He knew immediately he was looking at a spectacular new species
0:24:47 > 0:24:50but he had no time to go in search of it.
0:24:50 > 0:24:54He frantically negotiated with some African hunters and managed to
0:24:54 > 0:24:58acquire further skulls and bones of the same kind of animal.
0:25:00 > 0:25:03When he got back to the States, Savage handed the specimens
0:25:03 > 0:25:06to an anatomist friend who immediately
0:25:06 > 0:25:09recognised that they belonged to some kind of ape.
0:25:09 > 0:25:12He gave it the scientific name, Gorilla,
0:25:12 > 0:25:15a Greek word meaning wild, hairy people.
0:25:18 > 0:25:22He then sealed the reputation of the gorilla with
0:25:22 > 0:25:26the convention of adding the surname of the person who discovered it.
0:25:26 > 0:25:29In this case, Thomas Savage.
0:25:32 > 0:25:36But many people misguidedly assumed that the scientific name,
0:25:36 > 0:25:40Gorilla savagei, was a description of the nature
0:25:40 > 0:25:42of this newly found ape.
0:25:45 > 0:25:48Though gorillas had somehow remained unknown to science
0:25:48 > 0:25:53until Victorian times, other great apes were already quite familiar.
0:25:53 > 0:25:57They were all commonly called orangs after the most famous of them,
0:25:57 > 0:25:59the orangutan, which the Dutch
0:25:59 > 0:26:05had encountered in Indonesia in the 17th century.
0:26:08 > 0:26:14Shortly afterwards, the Portuguese discovered chimpanzees in Africa
0:26:14 > 0:26:17and by the time reports of the gorilla appeared, both chimps
0:26:17 > 0:26:20and orangs had been appearing in circuses
0:26:20 > 0:26:23and the courts of European royalty for over 200 years.
0:26:28 > 0:26:33The first gorillas to arrive in Britain were dead specimens
0:26:33 > 0:26:38and unlike these late arrivals, they will often badly preserved.
0:26:38 > 0:26:41They went on display at the Crystal Palace and their grotesque
0:26:41 > 0:26:45appearance was supported by horrific accounts of their nature.
0:26:47 > 0:26:50One of the early collectors of gorillas was an American
0:26:50 > 0:26:52anthropologist called Du Chaillu.
0:26:54 > 0:26:57He made numerous expeditions to Africa and returned with
0:26:57 > 0:27:00tales of terrifying encounters with gorillas.
0:27:03 > 0:27:09In this, his bestseller, Exploration And Adventure In Equatorial Africa,
0:27:09 > 0:27:14amongst sensational tales of cannibalism, charging buffalo
0:27:14 > 0:27:17and tropical fevers, is the very first eyewitness
0:27:17 > 0:27:20account of man meeting male gorillas in their jungle home.
0:27:22 > 0:27:25"He was a sight, I think, I shall never forget.
0:27:25 > 0:27:28"Nearly six feet high with immense body,
0:27:28 > 0:27:32"huge chest and great, muscular arms,
0:27:32 > 0:27:36"with fiercely glaring, large, deep grey eyes and a hellish
0:27:36 > 0:27:40"expression of face that seemed, to me, like some nightmare vision.
0:27:40 > 0:27:46"Thus stood before us this king of the African forest."
0:27:46 > 0:27:50To be fair, Chaillu did dispel some of the more ridiculous stories
0:27:50 > 0:27:53and myths about the gorilla, but his compelling
0:27:53 > 0:27:57tales of their fierce nature was just what the public wanted to hear.
0:28:00 > 0:28:01GORILLA CALLS
0:28:03 > 0:28:06Du Chaillu's vivid description of the gorilla in the wild
0:28:06 > 0:28:11reinforced its image as a fearsome beast and confirmed its reputation.
0:28:15 > 0:28:17GORILLA CALLS
0:28:20 > 0:28:24These displays may look fearsome, but in fact,
0:28:24 > 0:28:27they're only rarely followed by physical violence.
0:28:29 > 0:28:32Du Chaillu's description may have wowed readers,
0:28:32 > 0:28:36but the scientific establishment were rather less easy to impress.
0:28:36 > 0:28:41He was branded a braggart, a plagiarist and a charlatan.
0:28:41 > 0:28:43Some suggested he never even visited Africa
0:28:43 > 0:28:47and that his ferocious creatures were, in fact, gentle.
0:28:47 > 0:28:51But he had his strongest support right at the top.
0:28:51 > 0:28:55Professor Richard Owen, founder of the London Natural History Museum.
0:28:58 > 0:29:01Owen was one of the most respected figures
0:29:01 > 0:29:05of Victorian science, but also one of the most widely disliked.
0:29:05 > 0:29:09He was vehemently opposed to Darwin's theory of evolution,
0:29:09 > 0:29:12which suggested that apes and humans were closely related.
0:29:15 > 0:29:19Du Chaillu's description of a ferocious gorilla suited Owen,
0:29:19 > 0:29:22because it seemed to support his view that we could not
0:29:22 > 0:29:25possibly be related to such dreadful monsters.
0:29:26 > 0:29:28But he could hardly deny the anatomical
0:29:28 > 0:29:31similarity between gorillas and humans.
0:29:32 > 0:29:37This illustration from 1855, shows the skeleton of a man
0:29:37 > 0:29:39and gorilla side-by-side.
0:29:39 > 0:29:41It was published by Owen himself
0:29:41 > 0:29:44and makes clear the likeness between the two species.
0:29:50 > 0:29:54But Owen was still not willing to accept that man could have
0:29:54 > 0:29:56ape-like ancestors.
0:30:07 > 0:30:11In 1860, a great debate about evolution and man's place
0:30:11 > 0:30:17in the natural world took place in this very room in Oxford.
0:30:17 > 0:30:20Richard Owen presented compelling evidence for the presence of
0:30:20 > 0:30:25three structures in the human brain that were absent in a gorilla's.
0:30:25 > 0:30:29According to Owen, this made the descent of man from apes impossible.
0:30:30 > 0:30:34As the only anatomist with access to gorilla specimens,
0:30:34 > 0:30:36he was confident he was on firm ground,
0:30:36 > 0:30:40but he hadn't counted on biologist Thomas Henry Huxley.
0:30:41 > 0:30:47Huxley, known as Darwin's bulldog, was, in his own words,
0:30:47 > 0:30:52waiting for this opportunity to nail that mendacious humbug, Owen,
0:30:52 > 0:30:56like a kite to a barn door, and immediately challenged his
0:30:56 > 0:30:59findings, vowing to prove him wrong.
0:30:59 > 0:31:02In the years that followed, Huxley doggedly pursued Owen
0:31:02 > 0:31:05and did indeed prove him wrong on all counts.
0:31:05 > 0:31:09He found all three brain structures in the apes
0:31:09 > 0:31:13and proved apes were closer to men than to monkeys.
0:31:13 > 0:31:18Richard Owen had, according to Huxley, been guilty of wilful
0:31:18 > 0:31:20and deliberate falsehood.
0:31:24 > 0:31:28Owen and Du Chaillu's misleading descriptions of the gorilla
0:31:28 > 0:31:31failed to disprove our relationship to apes.
0:31:32 > 0:31:35On the contrary, they became a turning point
0:31:35 > 0:31:38in our acceptance that they are our cousins.
0:31:42 > 0:31:46But, sadly, the damage to the gorilla's reputation had
0:31:46 > 0:31:48already been done.
0:31:53 > 0:31:57When Guy arrived in London almost 100 years after the discovery
0:31:57 > 0:32:03of gorillas, people still regarded him as a fearsome and savage beast.
0:32:09 > 0:32:13It took the next 30 years of Guy's life for a more accurate
0:32:13 > 0:32:15picture of the gorilla to emerge.
0:32:15 > 0:32:19Although gorillas can, indeed, be dangerous when angry or threatened,
0:32:19 > 0:32:22most of the time, they are mild and peaceful creatures
0:32:22 > 0:32:27and nowhere is this shown more clearly than in a charming story
0:32:27 > 0:32:29from Guy's time here at the zoo.
0:32:29 > 0:32:34Guy's cage often attracted sparrows that then became trapped inside.
0:32:34 > 0:32:38But rather than kill them, Guy would lift the tiny birds
0:32:38 > 0:32:42carefully onto his hand, examine them and then release them.
0:32:42 > 0:32:44He was, indeed, a gentle giant.
0:32:49 > 0:32:52Over time, thanks to the determination of field researchers
0:32:52 > 0:32:57like Dian Fossey, people have seen another side to gorillas.
0:33:04 > 0:33:08By the time I met them, many of us were ready to see them
0:33:08 > 0:33:11not as savages, but as animals that are equally
0:33:11 > 0:33:14suited to their environment as we are to ours.
0:33:20 > 0:33:24So, now, at last, the gorilla, which was once labelled a fearsome
0:33:24 > 0:33:29beast, has managed to shake off its undeserved reputation.
0:33:35 > 0:33:40Our second subject, the vampire bat, has also had an undeservedly
0:33:40 > 0:33:46bad reputation and been the inspiration behind tales of evil.
0:33:49 > 0:33:53Bats have had a bad reputation for a very long time.
0:33:53 > 0:33:57As creatures of the night, they are connected with dark mysteries
0:33:57 > 0:34:00and devilish goings-on.
0:34:00 > 0:34:02But there was never any real evidence to support these
0:34:02 > 0:34:05claims of their evil nature, that is
0:34:05 > 0:34:09until the Conquistadors returned from South America with
0:34:09 > 0:34:14tales of giant bats that dropped down on you as you slept
0:34:14 > 0:34:17and sucked the very blood from your veins.
0:34:17 > 0:34:19Tales of vampire bats.
0:34:22 > 0:34:25Stories of giant, bloodsucking bats have long been
0:34:25 > 0:34:29part of the culture of South American people.
0:34:29 > 0:34:31Images of them with savage fangs are common
0:34:31 > 0:34:35and a bat god was associated with death.
0:34:37 > 0:34:41But it wasn't until the 18th century that a detailed description of a
0:34:41 > 0:34:46vampire bat was published in Europe and it came from one of its victims.
0:34:49 > 0:34:53An Englishman by the name of John Gabriel Stedman came
0:34:53 > 0:34:58back from South America with reports of having been bitten by a vampire.
0:34:59 > 0:35:04He described a bat of monstrous size that sucked the blood of men
0:35:04 > 0:35:06and cattle when they're fast asleep.
0:35:06 > 0:35:10And he proudly declared that he'd managed to catch the beast
0:35:10 > 0:35:11and cut off its head.
0:35:12 > 0:35:15Stedman's descriptions were detailed,
0:35:15 > 0:35:17but nonetheless misleading.
0:35:17 > 0:35:20His drawing shows, in fact, the bat that feeds on nectar
0:35:20 > 0:35:22and is only a few centimetres long.
0:35:24 > 0:35:28He had been bitten by a vampire, but he had blamed the wrong bat.
0:35:32 > 0:35:37Clouded by their own ideas of what a vampire should look like,
0:35:37 > 0:35:41early naturalists jumped to all sorts of conclusions and assumed
0:35:41 > 0:35:46that it was the biggest and the most ugly that were the bloodsuckers.
0:35:46 > 0:35:49In fact, the name "vampire" was sometimes given to bats that
0:35:49 > 0:35:54looked the part, but had never so much as sniffed blood.
0:35:54 > 0:35:57These bats, for example, drawn by the 19th-century German
0:35:57 > 0:36:01naturalist Ernst Haeckel, belonged to a group called
0:36:01 > 0:36:05the leaf nosed bats, because of these strange protrusions
0:36:05 > 0:36:06around the end of the nose.
0:36:06 > 0:36:10This gives them a particularly menacing appearance and some early
0:36:10 > 0:36:14naturalists thought the nose leaf was, in fact, the mark of a vampire.
0:36:16 > 0:36:20The leaflike object on its nose was thought to be so sharp,
0:36:20 > 0:36:24the bat could use it to puncture a victim's skin,
0:36:24 > 0:36:26and since many bats have such nose leaves,
0:36:26 > 0:36:31over 100 species were mistakenly described as vampires.
0:36:31 > 0:36:35In fact, the nose leaf is made of nothing more than soft flesh
0:36:35 > 0:36:37and couldn't possibly draw blood.
0:36:37 > 0:36:40It's used for echolocation.
0:36:41 > 0:36:44Echolocation works like sonar.
0:36:44 > 0:36:48The bats produce high-frequency calls and use the returning
0:36:48 > 0:36:51echoes to build up a mental map of their surroundings,
0:36:51 > 0:36:55so they are able to find their way in the pitch dark and hunt for prey.
0:36:57 > 0:37:00Most bats produce these calls in their throats,
0:37:00 > 0:37:04but leaf nosed bats project them out through their nose in a beam.
0:37:05 > 0:37:09By doing so, they can feed and echolocate at the same time.
0:37:15 > 0:37:19So many leaf nosed bats had been discovered that the arrival
0:37:19 > 0:37:23in Europe of a specimen of another, smaller species
0:37:23 > 0:37:26in 1810 attracted very little attention.
0:37:26 > 0:37:29It was simply named Desmodus rotundus,
0:37:29 > 0:37:31on account of it being a little portly.
0:37:33 > 0:37:36Some 30 years later, when Charles Darwin was travelling
0:37:36 > 0:37:38around the world aboard the Beagle,
0:37:38 > 0:37:43he observed Desmodus feeding in the wild for the first time.
0:37:43 > 0:37:46He saw it drinking the blood of sleeping horses and cattle.
0:37:48 > 0:37:51He had, at last, identified the true vampire.
0:37:53 > 0:37:57We know that there are only three species of vampire bats
0:37:57 > 0:38:00and they all live in South America.
0:38:00 > 0:38:04They're totally unique in being the only mammals to feed exclusively
0:38:04 > 0:38:08on blood, but feeding on blood is not as easy as you might think.
0:38:08 > 0:38:11It's actually a pretty challenging diet.
0:38:11 > 0:38:16Blood is made up of water and protein and has virtually no fat,
0:38:16 > 0:38:20so, vampires find it hard to get enough energy.
0:38:20 > 0:38:23They must consume 50% of their own body weight in blood each night,
0:38:23 > 0:38:26or they'll die within a few days.
0:38:31 > 0:38:35Under the cover of darkness, the vampire sets out to hunt.
0:38:40 > 0:38:47The nose leaf and echolocation help it to home in on its prey.
0:38:53 > 0:38:55The bat approaches carefully.
0:38:55 > 0:38:58Unlike most other bats, it can use its wings as legs
0:38:58 > 0:39:00and it walks on its elbows.
0:39:08 > 0:39:12Once near its victim, it uses its nose leaf in another way.
0:39:14 > 0:39:16It acts as a heat-seeking device,
0:39:16 > 0:39:18guiding the bat to the warmth of its prey.
0:39:22 > 0:39:26Today, livestock have largely replaced wild jungle animals,
0:39:26 > 0:39:30but even livestock can be dangerous to a small bat.
0:39:36 > 0:39:40Patiently, the vampire stalks its prey.
0:39:44 > 0:39:46And, at last, it's close enough.
0:39:46 > 0:39:50The teeth are so sharp that a nick is all that's needed.
0:39:54 > 0:39:59Blood from the wound doesn't clot, but continues to flow, and within
0:39:59 > 0:40:04a quarter of an hour, the bat can drink 40% of its body weight.
0:40:05 > 0:40:09That is the equivalent to one of us drinking over 20 litres.
0:40:14 > 0:40:18Having had its fill, it's back to the roost.
0:40:21 > 0:40:24Finding a meal every night is not easy,
0:40:24 > 0:40:27but vampires have come up with a solution to that problem.
0:40:27 > 0:40:31Those which have been successful share the blood they've drunk
0:40:31 > 0:40:33with those who had failed to collect any.
0:40:35 > 0:40:38Vampires are most likely to share with those
0:40:38 > 0:40:41they know well from roosting and grooming together.
0:40:41 > 0:40:44It's an act of apparent kindness,
0:40:44 > 0:40:46but the colony, as a whole, benefits.
0:40:49 > 0:40:52So, it seems that there is another, gentler side to these bats
0:40:52 > 0:40:54than anyone could have imagined.
0:40:57 > 0:41:00Unfortunately, just as light was being shed on the true
0:41:00 > 0:41:04nature of the vampire, an Irish novelist published the book
0:41:04 > 0:41:08that would seal their reputation for the foreseeable future.
0:41:08 > 0:41:13Bram Stoker's classic, Dracula, leaves little doubt as to
0:41:13 > 0:41:15where his inspiration came from.
0:41:17 > 0:41:21His story combined European myths of vampires that come to haunt
0:41:21 > 0:41:25the living, with stories of bloodsucking bats
0:41:25 > 0:41:29from South America, and it's an association that the real
0:41:29 > 0:41:32vampire bats have struggled to shed.
0:41:40 > 0:41:45More recently, vampire bats have made headlines once again.
0:41:45 > 0:41:48It's been discovered that their saliva contains the remarkable
0:41:48 > 0:41:53blood-thinning agent that's been named Draculin.
0:41:53 > 0:41:56And it's proving to be the most successful treatment
0:41:56 > 0:41:57for stroke victims.
0:41:57 > 0:42:00How ironic that a creature we once believed to be a deadly threat
0:42:00 > 0:42:05may turn out to save human lives in the future.
0:42:05 > 0:42:09Maybe it's time we re-evaluated the reputation of the much
0:42:09 > 0:42:11maligned vampire bat.
0:42:13 > 0:42:18Vampire bats and gorillas were long pursued by unfair reputations,
0:42:18 > 0:42:23but while our fear of gorillas has turned into respect and admiration,
0:42:23 > 0:42:28the vampire bat, for many of us, continues to evoke mixed emotions.