0:00:02 > 0:00:06The natural world is full of extraordinary animals
0:00:06 > 0:00:08with amazing life histories.
0:00:08 > 0:00:12Yet certain stories are more intriguing than others.
0:00:14 > 0:00:18The mysteries of a butterfly's life cycle.
0:00:18 > 0:00:20Or the strange biology of the Emperor Penguin.
0:00:22 > 0:00:25Some of these creatures were surrounded by
0:00:25 > 0:00:28fantastic myths and misunderstandings.
0:00:29 > 0:00:32Others have only recently revealed their secrets.
0:00:34 > 0:00:38These are the creatures that stand out from the crowd,
0:00:38 > 0:00:42the curiosities that I find particularly fascinating.
0:00:49 > 0:00:53Pigeons are so common that we tend to take them for granted.
0:00:53 > 0:00:56But in fact, they are superb navigators
0:00:56 > 0:01:00and can find their way home from hundreds of miles away.
0:01:01 > 0:01:05And the dung beetle will roll a dung ball in a straight line
0:01:05 > 0:01:08even though it's head down and walking backwards.
0:01:09 > 0:01:13How on earth do these creatures manage to find their way?
0:01:21 > 0:01:25Pigeon fanciers know that if they take homing pigeons
0:01:25 > 0:01:27to somewhere where they've never been before,
0:01:27 > 0:01:32even if it's tens, even hundreds of miles away, and then release them,
0:01:32 > 0:01:37they will, after circling in the sky, head for home.
0:01:38 > 0:01:41These come from over there.
0:01:41 > 0:01:43Let's see what happens.
0:02:08 > 0:02:12Well, they certainly seem to be heading in the right direction.
0:02:12 > 0:02:15But how do pigeons find their way back home
0:02:15 > 0:02:18over totally unfamiliar territory?
0:02:18 > 0:02:22It seems the more mysterious to us because it's something we can't do
0:02:22 > 0:02:26unless we have all kinds of special equipment.
0:02:26 > 0:02:29But science is now beginning to find some of the answers.
0:02:31 > 0:02:36The homing pigeon is a domesticated descendant of the wild rock pigeon
0:02:36 > 0:02:40which lives on cliffs and ledges along our coasts.
0:02:40 > 0:02:44When humans started to domesticate them, they inevitably selected
0:02:44 > 0:02:49those birds that were particularly good at returning to their roosts.
0:02:52 > 0:02:56Pigeons are thought to be the very first birds
0:02:56 > 0:03:00to be domesticated by mankind, many thousands of years ago.
0:03:00 > 0:03:04Since then, they've been bred into many different varieties,
0:03:04 > 0:03:06including homing pigeons.
0:03:06 > 0:03:09And the varied appearance of this flock around me
0:03:09 > 0:03:13is evidence of that domesticated past.
0:03:13 > 0:03:18Since then, of course, they've come to live alongside us in our cities
0:03:18 > 0:03:21and giving many of us a lot of pleasure.
0:03:21 > 0:03:22Come on.
0:03:26 > 0:03:29It was not only their homing ability that made pigeons
0:03:29 > 0:03:34so popular with breeders, they are also superb flyers.
0:03:35 > 0:03:40Their powerful wing muscles make up nearly half their body weight
0:03:40 > 0:03:43and enable them to fly at speeds of 60mph.
0:03:44 > 0:03:47They're among the greatest long-distance athletes
0:03:47 > 0:03:49in the bird world.
0:03:54 > 0:03:58And pigeon fanciers have delighted in breeding them
0:03:58 > 0:04:00in order to race them competitively.
0:04:08 > 0:04:13Mankind has also used pigeons for a very practical purpose...
0:04:15 > 0:04:16..as messengers.
0:04:19 > 0:04:24It was during the two World Wars that pigeons played a crucial role
0:04:24 > 0:04:27in carrying messages home from the front line.
0:04:28 > 0:04:31Nearly a quarter of a million birds served in the wars
0:04:31 > 0:04:34and helped save thousands of lives.
0:04:34 > 0:04:37One such bird was Cher Ami,
0:04:37 > 0:04:41a female donated by a British pigeon fancier
0:04:41 > 0:04:45for use by the United States Army during World War I.
0:04:47 > 0:04:52During one battle in France in 1918, more than 500 soldiers
0:04:52 > 0:04:55from the US infantry became trapped behind enemy lines.
0:04:57 > 0:05:00Worse, they were then fired upon by their own troops
0:05:00 > 0:05:02who didn't know they were there.
0:05:03 > 0:05:07Within 24 hours, more than half of them had been killed.
0:05:10 > 0:05:13With no other options, the commander, Major Whittlesey,
0:05:13 > 0:05:17desperately tried to send messages back by pigeon.
0:05:17 > 0:05:21The first two birds were shot down and only Cher Ami was left.
0:05:22 > 0:05:26For several moments, she flew with bullets zipping all around her,
0:05:26 > 0:05:28and eventually she was brought down.
0:05:28 > 0:05:32She'd been shot through the breast, blinded in one eye
0:05:32 > 0:05:35and her leg was left hanging by a tendon.
0:05:36 > 0:05:40Astonishingly, the injured bird managed to take flight again
0:05:40 > 0:05:43and arrived back at her loft at the division headquarters
0:05:43 > 0:05:46in just 25 minutes.
0:05:47 > 0:05:52Cher Ami's message helped save the lives of 194 soldiers.
0:05:53 > 0:05:58Her name in French, of course, means Dear Friend.
0:06:01 > 0:06:04When the Second World War broke out,
0:06:04 > 0:06:06Britain's pigeon fanciers once again
0:06:06 > 0:06:09gave their pigeons to the war effort
0:06:09 > 0:06:13to provide what was called the National Pigeon Service.
0:06:13 > 0:06:18This elite squad of birds was extremely valuable and successful.
0:06:18 > 0:06:2198% of their messages got through.
0:06:24 > 0:06:28The Germans, realising how important the pigeons had become,
0:06:28 > 0:06:31fought back with specially trained pigeon snipers.
0:06:37 > 0:06:40They also retaliated in another way,
0:06:40 > 0:06:44by using the pigeon's natural enemies - peregrine falcons.
0:06:50 > 0:06:52Pigeons played such a vital role in the war
0:06:52 > 0:06:55that many were celebrated as heroes.
0:06:55 > 0:07:00In 1943, this medal, the Dickin Medal,
0:07:00 > 0:07:03was founded to honour these animals.
0:07:03 > 0:07:06It was awarded to individuals that appeared,
0:07:06 > 0:07:08if you'll allow a little anthropomorphism,
0:07:08 > 0:07:11to have displayed particular bravery.
0:07:11 > 0:07:16And it's sometimes referred to as the Victoria Cross for animals.
0:07:16 > 0:07:21Of the 54 medals presented during World War II,
0:07:21 > 0:07:2332 were given to pigeons.
0:07:25 > 0:07:28We may have prized pigeons for centuries
0:07:28 > 0:07:31for their skills in finding their way through the skies,
0:07:31 > 0:07:35but for a long time we had no idea how the birds did it.
0:07:38 > 0:07:40Some suggested that pigeons used the sun.
0:07:40 > 0:07:44Others that they were guided by the Earth's magnetic field.
0:07:46 > 0:07:49But proving either was surprisingly difficult.
0:07:53 > 0:07:55A breakthrough came from an American scientist
0:07:55 > 0:07:58at Cornell University in the 1960s.
0:08:01 > 0:08:04William Keeton attached magnets to the backs of some pigeons,
0:08:04 > 0:08:06but not to others,
0:08:06 > 0:08:08and found that when the sun was out,
0:08:08 > 0:08:12both groups were able to make their way home.
0:08:13 > 0:08:16But when the sun was hidden behind clouds,
0:08:16 > 0:08:18the birds carrying magnets got lost.
0:08:20 > 0:08:24Keeton deduced that this was because the signals from their magnets
0:08:24 > 0:08:27swamped the much weaker ones coming from the Earth.
0:08:29 > 0:08:33So he established that pigeons can use either the sun
0:08:33 > 0:08:37or the Earth's magnetism to find their way around,
0:08:37 > 0:08:38according to conditions.
0:08:40 > 0:08:45But how do the birds detect the Earth's magnetism?
0:08:48 > 0:08:51This compass has a magnetised needle,
0:08:51 > 0:08:54which is sensitive to the Earth's magnetic field.
0:08:54 > 0:08:56It will always point north,
0:08:56 > 0:08:59allowing you to check the direction that you're travelling in.
0:08:59 > 0:09:01But what about pigeons?
0:09:01 > 0:09:04What could they be using to detect magnetic fields?
0:09:04 > 0:09:08Scientists were puzzled because they couldn't find
0:09:08 > 0:09:11any cells or organs in birds that were sensitive to magnetism.
0:09:14 > 0:09:19Then, in 2007, microscopic clusters of iron-rich cells
0:09:19 > 0:09:23were found in the beaks of homing pigeons,
0:09:23 > 0:09:28and it was thought that these might help them to detect magnetic forces.
0:09:29 > 0:09:34But only five years later, new research shattered that idea.
0:09:34 > 0:09:37It seems that the cells in fact are a defence against infection
0:09:37 > 0:09:41and have nothing whatsoever to do with magnetism.
0:09:41 > 0:09:46So the search for the pigeon's magnetic compass still continues.
0:09:46 > 0:09:50But we are now beginning to understand the other aspects
0:09:50 > 0:09:52of their navigational skills.
0:09:55 > 0:09:59A compass is just one of the tools we need for navigation.
0:09:59 > 0:10:01But it's not much help
0:10:01 > 0:10:04unless you know in which direction your destination lies.
0:10:04 > 0:10:08And to know that, you need a map of some kind.
0:10:10 > 0:10:12One way of creating a map in your mind
0:10:12 > 0:10:15is to memorise the prominent features of a landscape.
0:10:17 > 0:10:22Scientists at Oxford University are now using GPS technology
0:10:22 > 0:10:24to discover if pigeons do this.
0:10:27 > 0:10:31This bird has a GPS transmitting device strapped to its back
0:10:31 > 0:10:33in a specially designed backpack
0:10:33 > 0:10:36which causes it very little discomfort.
0:10:36 > 0:10:41And that will record the progress of the bird, second by second,
0:10:41 > 0:10:43once I let it go.
0:10:43 > 0:10:48It comes from a loft over there about six miles away in Oxford.
0:10:48 > 0:10:51Let's see whether or not she heads in that direction.
0:10:51 > 0:10:53Off you go.
0:10:56 > 0:10:59Birds, like this, that are released in a new place
0:10:59 > 0:11:04still ahead confidently in the direction of their home loft.
0:11:04 > 0:11:05How do they do it?
0:11:08 > 0:11:09Data from GPS trackers
0:11:09 > 0:11:12and cameras attached to the backs of pigeons
0:11:12 > 0:11:15have helped to answer that question.
0:11:16 > 0:11:20At first, a bird released in an unfamiliar place
0:11:20 > 0:11:24will use the sun or the Earth's magnetic field to get its bearings.
0:11:25 > 0:11:28But if you plot its movements on a map,
0:11:28 > 0:11:32you can see that at first it doesn't find the shortest route home.
0:11:34 > 0:11:35Then something changes.
0:11:37 > 0:11:41After repeated releases, the bird is able to use its experience
0:11:41 > 0:11:43to take a more direct way back.
0:11:48 > 0:11:52So it appears that pigeons learn to recognise features of the landscape
0:11:52 > 0:11:56such as hedgerows and trees, or even roads and buildings.
0:11:59 > 0:12:03They then memorise these to create a mental map of the area
0:12:03 > 0:12:08and by following familiar landmarks, they find their way back home.
0:12:11 > 0:12:14It seems that pigeons are creatures of habit.
0:12:14 > 0:12:17They like to stick to the routes they know well.
0:12:18 > 0:12:22Here are some tracks of a pigeon that lives in its home loft up here
0:12:22 > 0:12:25and was taken repeatedly to this point here.
0:12:26 > 0:12:28Watch what happens.
0:12:30 > 0:12:33It consistently makes a beeline for the major A road
0:12:33 > 0:12:36that conveniently runs past its home loft.
0:12:38 > 0:12:41And even when released some distance from this road,
0:12:41 > 0:12:44it will cut across to it and then follow it all the way home,
0:12:44 > 0:12:46as shown by the red lines.
0:12:53 > 0:12:56Some birds even fly around roundabouts
0:12:56 > 0:12:59before choosing the exit that will lead them back.
0:13:01 > 0:13:04So it seems that pigeons use methods of navigation
0:13:04 > 0:13:08more like ours than we might have imagined.
0:13:11 > 0:13:13We now know that pigeons have
0:13:13 > 0:13:16a whole range of navigational techniques at their disposal
0:13:16 > 0:13:18and can call on them as needed.
0:13:19 > 0:13:22It's a remarkably sophisticated system
0:13:22 > 0:13:26that enables them to find their way in nearly any situation.
0:13:31 > 0:13:33We've learned a lot about the pigeon's homing skills,
0:13:33 > 0:13:36but some mysteries still remain.
0:13:37 > 0:13:42In 1997, over 60,000 British birds were released
0:13:42 > 0:13:44during a pigeon race in southern France.
0:13:47 > 0:13:50Most of them didn't make it and were never seen again.
0:13:52 > 0:13:58In pigeon racing terms, the loss of so many birds was unheard of.
0:13:58 > 0:13:59A disaster.
0:13:59 > 0:14:03One bird might get lost, but tens of thousands?
0:14:07 > 0:14:10To get back to their lofts nearly 500 miles away,
0:14:10 > 0:14:14the pigeons had to cross the English Channel.
0:14:14 > 0:14:17It was not an unusually long or difficult journey
0:14:17 > 0:14:21for a racing pigeon, so why did the birds not make it?
0:14:22 > 0:14:25Well, there was a strange coincidence.
0:14:27 > 0:14:30At the very same time the racing pigeons were crossing the Channel,
0:14:30 > 0:14:35a Concorde supersonic airliner was flying along the Channel
0:14:35 > 0:14:38on its morning flight from Paris to New York.
0:14:41 > 0:14:44The Concorde generates a shock wave almost 100 miles wide.
0:14:46 > 0:14:49The pigeons flying below could not have escaped it.
0:14:49 > 0:14:53Could it be that this enormous wave of sound blotted out
0:14:53 > 0:14:56all other acoustic information?
0:14:58 > 0:15:02We know that pigeons can hear low-frequency infra-sounds
0:15:02 > 0:15:05such as those generated by ocean waves.
0:15:06 > 0:15:12And these might provide them with an acoustic map of their surroundings.
0:15:14 > 0:15:17The jury is still out as to whether pigeons really do use
0:15:17 > 0:15:19infra-sound to navigate
0:15:19 > 0:15:23and whether that explains the case of the disappearing pigeons.
0:15:24 > 0:15:27But it's an intriguing possibility.
0:15:30 > 0:15:34The familiar pigeon continues to surprise us.
0:15:34 > 0:15:37And even today, we're a long way off from understanding
0:15:37 > 0:15:40all its route-finding techniques.
0:15:42 > 0:15:47The small dung beetle has a brain no larger than a grain of rice.
0:15:47 > 0:15:53But, like the pigeon, it is capable of astonishing navigational feats.
0:15:57 > 0:16:00Moving large loads by walking head down and backwards
0:16:00 > 0:16:03must surely be one of the most bizarre ways
0:16:03 > 0:16:04of collecting your food.
0:16:07 > 0:16:08Dung beetles are well known
0:16:08 > 0:16:11for rolling their balls of dung in this way.
0:16:11 > 0:16:13But why do they do so?
0:16:13 > 0:16:16And how can they see where they are going?
0:16:19 > 0:16:22Ball rolling by dung beetles is probably
0:16:22 > 0:16:26one of the oldest recorded accounts of animal behaviour,
0:16:26 > 0:16:29dating back nearly 2,000 years.
0:16:29 > 0:16:32These insects were held sacred by the ancient Egyptians,
0:16:32 > 0:16:37and in the fifth century, an Egyptian scholar called Horapollo
0:16:37 > 0:16:42described the dung beetle as rolling its ball from east to west.
0:16:42 > 0:16:45It seems that he was suggesting that the beetles always
0:16:45 > 0:16:48moved their dung in a particular direction.
0:16:48 > 0:16:50But how true is that?
0:16:50 > 0:16:55In the following 2,000 years, little was done to examine the question.
0:16:57 > 0:17:01Dung beetles feed on what is, to the animals that produce it,
0:17:01 > 0:17:04a waste product - dung.
0:17:04 > 0:17:08But in fact, there's more than enough nourishment in one dropping
0:17:08 > 0:17:10to sustain a great number of beetles.
0:17:12 > 0:17:16They locate a newly dropped pile using their sense of smell.
0:17:17 > 0:17:20Their strong and powerful legs enable them
0:17:20 > 0:17:21to break up the dropping
0:17:21 > 0:17:24and their mouthparts are specially shaped
0:17:24 > 0:17:27to extract the nutrients and moisture that they need.
0:17:29 > 0:17:33They are, in fact, one of our planet's great recyclers.
0:17:38 > 0:17:41Dung beetles are found all over the world.
0:17:42 > 0:17:47There are over 6,000 species and they come in all shapes and colours.
0:17:49 > 0:17:51But they have one thing in common -
0:17:51 > 0:17:54they all feed on dung.
0:17:57 > 0:17:59Some of them, like this scarab beetle...
0:18:01 > 0:18:04..have rows of projections on the head,
0:18:04 > 0:18:07which were likened by the ancient Egyptians
0:18:07 > 0:18:10to the rays of the rising sun.
0:18:10 > 0:18:13The broad front legs also carry spines.
0:18:13 > 0:18:18These are adaptations for digging and shaping dung balls,
0:18:18 > 0:18:21while the back legs are flattened
0:18:21 > 0:18:24and have tiny hairs for controlling the ball.
0:18:26 > 0:18:30But most dung beetles don't roll balls.
0:18:30 > 0:18:32They live either in the dung itself
0:18:32 > 0:18:36or tunnel directly into the soil beneath the dropping.
0:18:36 > 0:18:39Only 10% transport dung above ground.
0:18:39 > 0:18:43And they do so because competition near a pile of dung
0:18:43 > 0:18:45can be very fierce.
0:18:47 > 0:18:51The first ones at the scene are usually the rollers.
0:18:54 > 0:18:59They take a little lump, mould it into a ball and then start rolling.
0:19:04 > 0:19:07But that's easier said than done.
0:19:09 > 0:19:11Rivals are on the lookout for an easy meal
0:19:11 > 0:19:15and will only too quickly steal a ball if they can.
0:19:28 > 0:19:32With competition so intense, some species roll their ball away
0:19:32 > 0:19:35as quickly as possible and then bury it.
0:19:37 > 0:19:39They can then eat it later
0:19:39 > 0:19:42without the risk of another stealing their meal.
0:19:45 > 0:19:50Dung beetles appear to roll their balls of dung with great purpose.
0:19:50 > 0:19:54But it's only recently been discovered just how determined
0:19:54 > 0:19:58they can be to do so in one particular direction.
0:19:58 > 0:20:02Watch what happens if I put this dung beetle
0:20:02 > 0:20:03on this board here.
0:20:05 > 0:20:09And then put an obstacle in its way.
0:20:11 > 0:20:13And what does it do?
0:20:14 > 0:20:16It's going to go around.
0:20:16 > 0:20:17Excellent.
0:20:18 > 0:20:22And it resumes its previous direction.
0:20:24 > 0:20:26It's clear that the beetle knows exactly
0:20:26 > 0:20:29in which direction it wants to travel
0:20:29 > 0:20:33and will continue to do so even when it's deflected by obstacles.
0:20:35 > 0:20:38Now, let's make things even more difficult
0:20:38 > 0:20:39using this turntable.
0:20:41 > 0:20:43Let's see which direction
0:20:43 > 0:20:44he wants to go.
0:20:46 > 0:20:48He's going to come towards my hand.
0:20:48 > 0:20:52Now I'll turn the world through 90 degrees beneath his feet
0:20:52 > 0:20:55and yet he maintains
0:20:55 > 0:20:57the same direction.
0:20:57 > 0:20:59Why should it want to do that?
0:20:59 > 0:21:02It's quite extraordinary.
0:21:02 > 0:21:05He corrects his course instantaneously.
0:21:05 > 0:21:07How does he know how to do this,
0:21:07 > 0:21:11and why is he so determined to travel in a set direction?
0:21:15 > 0:21:17The answer is, in fact, quite simple.
0:21:18 > 0:21:21The fastest way to make a getaway
0:21:21 > 0:21:23is to roll your ball in a straight line.
0:21:26 > 0:21:29And that is exactly what the beetles try to do.
0:21:34 > 0:21:36Using only its front legs,
0:21:36 > 0:21:40a beetle can move a dung ball that is up to 60 times its own weight.
0:21:43 > 0:21:48But walking head down and backwards has its own problems.
0:21:48 > 0:21:50You can't see where you're going...
0:21:53 > 0:21:55..or watch out for danger.
0:22:10 > 0:22:13With competition around the pile of dung so intense,
0:22:13 > 0:22:17it's obviously a good thing to get away from it as quickly as possible.
0:22:17 > 0:22:21But how do the beetles decide in which direction to go?
0:22:21 > 0:22:25Well, it seems it's all to do with a little dance that they perform
0:22:25 > 0:22:27on top of their dung balls.
0:22:27 > 0:22:29Let me see if I can persuade this one to do it.
0:22:32 > 0:22:35I'll try to get it to walk up this ramp
0:22:35 > 0:22:37until it falls off the end
0:22:37 > 0:22:39and is separated from its ball.
0:22:42 > 0:22:44Watch what it does then.
0:22:48 > 0:22:50This little dance was once
0:22:50 > 0:22:52regarded as being a sign of happiness,
0:22:52 > 0:22:55that the beetle was delighted to have found a dung ball.
0:22:55 > 0:22:58But actually, it's much more than that.
0:22:58 > 0:23:02It's a way of deciding which direction it should go.
0:23:02 > 0:23:06And what does it use as a cue to make that decision?
0:23:06 > 0:23:10Well, recent research is beginning to produce the answer.
0:23:13 > 0:23:16What appears to be a dance is actually
0:23:16 > 0:23:19a way of looking around to get its bearings.
0:23:22 > 0:23:24But what exactly is it looking for?
0:23:29 > 0:23:32We can test what the beetles are using for a cue
0:23:32 > 0:23:34by fitting them with caps.
0:23:34 > 0:23:38This cap allows the beetle to see the ground beneath,
0:23:38 > 0:23:40but not the sky above.
0:23:40 > 0:23:43Compare that with this one without a cap.
0:23:46 > 0:23:47Making up its mind.
0:23:47 > 0:23:49And away it goes.
0:23:50 > 0:23:52This one is still baffled.
0:23:55 > 0:23:57The beetle with the cap clearly can't decide
0:23:57 > 0:23:59in which direction to go.
0:24:05 > 0:24:07Such experiments show
0:24:07 > 0:24:11that dung beetles have to see the sky in order to orientate.
0:24:14 > 0:24:19Their eyes are split in two halves by shovel-like extensions
0:24:19 > 0:24:21on the sides of the head.
0:24:22 > 0:24:25So, as they roll their balls of dung,
0:24:25 > 0:24:29the upward-facing half can watch the sky above
0:24:29 > 0:24:32and use the sun as a celestial compass.
0:24:34 > 0:24:38But, contrary to what that ancient Egyptian scholar claimed,
0:24:38 > 0:24:41they don't always travel from east to west.
0:24:44 > 0:24:47Each beetle seems to choose a particular direction
0:24:47 > 0:24:50away from the dung heap and then keeps to that course.
0:24:56 > 0:24:58But why should anyone suppose
0:24:58 > 0:25:02that the dung beetle always rolls its dung from east to west?
0:25:02 > 0:25:07Well, the ancient Egyptians believed that their sun god, Khepri,
0:25:07 > 0:25:11was responsible for rolling the sun across the sky every day
0:25:11 > 0:25:13in just that direction.
0:25:14 > 0:25:17The scarab, the Egyptian dung beetle,
0:25:17 > 0:25:21similarly rolls its dung ball from dawn to dusk
0:25:21 > 0:25:23and came to symbolise the sun god.
0:25:26 > 0:25:31And so the god Khepri was often depicted with a scarab for a head.
0:25:34 > 0:25:37The Egyptians also saw the scarab
0:25:37 > 0:25:40as a symbol of life and resurrection.
0:25:40 > 0:25:44The adult beetle would disappear underground with the ball of dung,
0:25:44 > 0:25:47and when the eggs hatched, shiny, new scarab beetles
0:25:47 > 0:25:50would seem to appear magically out of nowhere.
0:25:50 > 0:25:55So the scarab came to symbolise creation, life
0:25:55 > 0:25:57and even rebirth.
0:25:59 > 0:26:02It's easy to see how the sun helps dung beetles
0:26:02 > 0:26:04to navigate during the day.
0:26:06 > 0:26:08But some beetles are nocturnal.
0:26:10 > 0:26:12How do they keep on a straight course?
0:26:19 > 0:26:20On a clear night,
0:26:20 > 0:26:24the moon and millions of stars illuminate the sky,
0:26:24 > 0:26:27just as they appear to do in this planetarium.
0:26:27 > 0:26:31This is a nocturnal scarab beetle.
0:26:31 > 0:26:34And scientists have recently discovered that it can use
0:26:34 > 0:26:38the light from the sky to navigate.
0:26:39 > 0:26:41But there is a puzzle.
0:26:41 > 0:26:45The scarab beetle has very, very small eyes.
0:26:45 > 0:26:48And whereas it can certainly see the moon,
0:26:48 > 0:26:51it can't distinguish individual stars.
0:26:51 > 0:26:53So how then does it navigate
0:26:53 > 0:26:56on a moonless night?
0:27:00 > 0:27:02The brightest light in the night sky
0:27:02 > 0:27:06comes from the great band of stars known as the Milky Way.
0:27:07 > 0:27:11And in the southern hemisphere, where these beetles live,
0:27:11 > 0:27:14the Milky Way is particularly vivid.
0:27:17 > 0:27:20Researchers have discovered that, as long as the Milky Way is in view,
0:27:20 > 0:27:24the beetle and its ball can roll along and stay on course.
0:27:26 > 0:27:28Without this bright band of light,
0:27:28 > 0:27:32the beetle has no reference point and is lost.
0:27:34 > 0:27:38The revelation that the beetles used starlight to navigate
0:27:38 > 0:27:41astonished the scientific world.
0:27:41 > 0:27:44How extraordinary that a tiny insect could use
0:27:44 > 0:27:48the edge of our galaxy to find its way around.
0:27:48 > 0:27:52Had the ancient Egyptians known that, surely they would have
0:27:52 > 0:27:57felt vindicated in giving the scarab the status of a god.
0:28:00 > 0:28:05So, the dung beetle and the pigeon are both ordinary creatures
0:28:05 > 0:28:08that have found extraordinary solutions
0:28:08 > 0:28:11to the problem that faces us all -
0:28:11 > 0:28:14how to find the way.