0:00:07 > 0:00:10I've spent most of my life watching animals.
0:00:12 > 0:00:15And there's one question that obsesses me.
0:00:17 > 0:00:20What's it like being an animal?
0:00:21 > 0:00:24This is Itchy and Scratchy. I've had them
0:00:24 > 0:00:27since they were 6 weeks old, I've raised them, I love them
0:00:27 > 0:00:33so much and just like all dog owners I sometimes gaze into these
0:00:33 > 0:00:39little chestnut eyes and wonder - what's going on inside that head?
0:00:39 > 0:00:43And you know, I would give anything to be another
0:00:43 > 0:00:48animal for just five minutes, to be able to experience the world
0:00:48 > 0:00:52the way they perceive it, to know what they're thinking.
0:00:52 > 0:00:54To be INSIDE the animal mind.
0:00:56 > 0:01:00It's one of the great mysteries of the natural world
0:01:00 > 0:01:04and now, new research is starting to give answers.
0:01:04 > 0:01:06Wow.
0:01:06 > 0:01:08In this series, I'm going to seek out
0:01:08 > 0:01:11the most powerful animal minds on the planet
0:01:11 > 0:01:13and find out what they're capable of.
0:01:16 > 0:01:17Look at that!
0:01:17 > 0:01:20If I'm really going to get inside the minds of other animals,
0:01:20 > 0:01:23the first thing I need to do is to discover how
0:01:23 > 0:01:25they experience the world around them.
0:01:26 > 0:01:31I mean, imagine how different this world is to my dogs.
0:01:31 > 0:01:37To them, this is a landscape of smell.
0:01:37 > 0:01:39We both live in the same world
0:01:39 > 0:01:42but we experience it in completely different ways.
0:01:44 > 0:01:47In this first programme we'll investigate
0:01:47 > 0:01:51the sensory secrets of the animal we know best of all.
0:01:51 > 0:01:53Close your eyes.
0:01:53 > 0:01:54Dogs.
0:01:54 > 0:01:56Aww, what happened?!
0:01:56 > 0:01:57WOLF HOWLS
0:01:57 > 0:02:01And test them against their ancient ancestors.
0:02:01 > 0:02:03THEY HOWL
0:02:03 > 0:02:06We'll be discovering how the minds of very different animals
0:02:06 > 0:02:09perceive their world through their senses.
0:02:11 > 0:02:13And I'll come face-to-face
0:02:13 > 0:02:16with an animal that most people wouldn't want to meet in
0:02:16 > 0:02:20their nightmares as I learn about the remarkable sixth sense of sharks.
0:02:21 > 0:02:25Animal senses define the way they think.
0:02:25 > 0:02:28They're the gateway to the animal mind.
0:02:42 > 0:02:45Castlewellan Lake in Northern Ireland.
0:02:45 > 0:02:49I've come to its rain-swept shores to see a dog do something
0:02:49 > 0:02:51that I thought impossible.
0:02:52 > 0:02:54Now, obviously, Itchy and Scratchy
0:02:54 > 0:02:57have got a pretty good pair of noses.
0:02:57 > 0:02:59But what I've always wondered is
0:02:59 > 0:03:03just how good is the dog's sense of smell?
0:03:03 > 0:03:07Well, today we're going to put the dog's nose to the ultimate test.
0:03:10 > 0:03:13Neil Powell trains sniffer dogs.
0:03:13 > 0:03:16And one of his top performers is Fern.
0:03:16 > 0:03:20Now, Fern usually works for the Search and Rescue Dog Association.
0:03:20 > 0:03:24But today, she's going to try and sniff out something
0:03:24 > 0:03:25that Neil has hidden.
0:03:26 > 0:03:30What's extraordinary is that it's not on dry land.
0:03:30 > 0:03:32It's in the lake.
0:03:32 > 0:03:33It's underwater.
0:03:35 > 0:03:40Here she is, Fern. Oh, oh. Looking keen and all dressed up.
0:03:40 > 0:03:41What type of spaniel is she?
0:03:41 > 0:03:45She's a mixture between Cocker and Springer Spaniel.
0:03:45 > 0:03:47- So, she's known as a sprocker. - A sprocker.
0:03:47 > 0:03:50Now, let's get this straight. You've already been out this morning
0:03:50 > 0:03:52and you've hidden a lure IN the lake?
0:03:52 > 0:03:56- Hm.- And we're going to go out and she's going to sniff it?- Yeah.
0:03:56 > 0:03:58- And find it? - Yes, what we've done is,
0:03:58 > 0:04:03about two hours ago we hid a small canister in 20 feet of water.
0:04:03 > 0:04:07It's got some pork meat in it. I know where it is but she doesn't,
0:04:07 > 0:04:10so we're going to search the lake now with her and, hopefully,
0:04:10 > 0:04:12we'll get to within about 30 feet of it.
0:04:12 > 0:04:15- Come in then, Fern.- Let's go for it. - I really do need to see this.
0:04:19 > 0:04:23Can a dog really smell something on the bottom of a lake,
0:04:23 > 0:04:26in driving rain and strong winds?
0:04:26 > 0:04:28Sounds improbable.
0:04:30 > 0:04:33Neil and the dive team know precisely where the canister
0:04:33 > 0:04:36is hidden because they fixed a GPS position on it
0:04:36 > 0:04:38when they dropped it into the lake.
0:04:39 > 0:04:42The question is, can Fern find it?
0:04:45 > 0:04:47Of course, this isn't a stunt that Neil and Fern pull off
0:04:47 > 0:04:52for the joy of it, she's been trained to detect bodies that have come to rest
0:04:52 > 0:04:55beneath the surface of the water, there's a very serious side to this.
0:04:55 > 0:04:58Nevertheless, it's pretty counterintuitive, isn't it?
0:04:58 > 0:05:04Here we're asking a dog to smell through six metres, 20 feet of water.
0:05:04 > 0:05:07And when you think about it, in all those movies and cop shows
0:05:07 > 0:05:11we've always watched, when the criminal's fleeing, they run up the stream
0:05:11 > 0:05:14so they don't leave any scent because the dogs can't sniff them.
0:05:14 > 0:05:17Well - criminals, if you're watching this,
0:05:17 > 0:05:19you might have to think again.
0:05:27 > 0:05:31The team's technique is to systematically crisscross the lake.
0:05:31 > 0:05:32So, at some point,
0:05:32 > 0:05:36Fern will find herself directly downwind of the sunken canister.
0:05:39 > 0:05:41But will she pick up the scent?
0:05:44 > 0:05:47The lake is a mile long and half a mile wide.
0:05:47 > 0:05:51And only the tiniest quantities of chemicals from the meat
0:05:51 > 0:05:53might reach the surface.
0:05:55 > 0:05:59And of that minute trace, almost all of it will get blown away.
0:06:01 > 0:06:04And yet, around ten minutes after we start...
0:06:04 > 0:06:06DOG BARKS
0:06:06 > 0:06:08..Fern senses something.
0:06:08 > 0:06:09DOG BARKS
0:06:09 > 0:06:11That's the scent.
0:06:11 > 0:06:13Turn it up to the wind, John.
0:06:13 > 0:06:16We start circling, narrowing down the location.
0:06:17 > 0:06:20She's got the scent, how are you going to know when we're
0:06:20 > 0:06:23in the closest possible spot?
0:06:23 > 0:06:26When she arrives over the top of it you'll see her going over
0:06:26 > 0:06:29the side a little bit more and she's really focused on the water.
0:06:31 > 0:06:34- You're getting her right into the... see, there, see that?- Yeah.
0:06:34 > 0:06:36Bring her round there, John.
0:06:36 > 0:06:40Right round, John. I'd put her there, John.
0:06:40 > 0:06:42DOG CONTINUES BARKING
0:06:42 > 0:06:45Fern has made it quite clear where she thinks
0:06:45 > 0:06:48the source of the smell is.
0:06:48 > 0:06:52Fern is confident which in turn means Neil is very confident
0:06:52 > 0:06:55and they've dropped the marker in and the thought is that we
0:06:55 > 0:06:59could be within just a few metres of where the lure is hidden.
0:07:00 > 0:07:05But the one thing I will say is I'm sat here as any other human being
0:07:05 > 0:07:09would be, with no sense at all, using a sense
0:07:09 > 0:07:13of smell that we are in the right place. All I can smell is a
0:07:13 > 0:07:15slightly fresh, rainy, damp,
0:07:15 > 0:07:17very pleasant afternoon in Northern Ireland.
0:07:19 > 0:07:23There's only one way to know if Fern's chosen the correct spot -
0:07:23 > 0:07:27The dive team check it against the GPS fix they took
0:07:27 > 0:07:30when they threw the canister into the water.
0:07:30 > 0:07:34And, unbelievably, Fern is bang on top of it.
0:07:39 > 0:07:42The divers' final job is to retrieve the canister.
0:07:46 > 0:07:49But the lake bed has a surprise.
0:07:51 > 0:07:54The bottom is a metre of soft silt
0:07:54 > 0:07:57and the canister has sunk right into it.
0:07:59 > 0:08:03So, amazingly, Fern hasn't just sniffed the lure through
0:08:03 > 0:08:08six metres of water but also through a metre of mud as well.
0:08:09 > 0:08:12What an absolutely astonishing thing.
0:08:13 > 0:08:20Now, I've seen animals over the years pull off some remarkable feats
0:08:20 > 0:08:23but this has been something else, it really has.
0:08:26 > 0:08:29- There ye go, what a clever girl. - Good girl.- Clever girl
0:08:29 > 0:08:33'And the reward for all her efforts? Just an old tennis ball.'
0:08:35 > 0:08:38Fern's training might give her this special ability.
0:08:38 > 0:08:41But all dogs have an extremely powerful nose.
0:08:42 > 0:08:47They can smell in parts per trillion, the equivalent of being
0:08:47 > 0:08:53able to taste a spoonful of sugar in two Olympic-size swimming pools.
0:08:57 > 0:09:00So, how on earth can dogs do this?
0:09:00 > 0:09:04Well, it's all down to a nose that's nothing like ours.
0:09:07 > 0:09:12Each nostril can be controlled independently, allowing dogs
0:09:12 > 0:09:16to detect precisely the direction a smell is coming from.
0:09:18 > 0:09:21And what goes on inside is even more impressive.
0:09:22 > 0:09:26You see, dogs split the flow of air into two separate streams,
0:09:26 > 0:09:30one for breathing and one for smelling.
0:09:30 > 0:09:32So they can do both at the same time.
0:09:34 > 0:09:38It's a superb tool for gathering sensory information and it means
0:09:38 > 0:09:43a dog's mind understands the world in a completely different way to us.
0:09:44 > 0:09:49Their world is a complex smellscape in which they can sniff out
0:09:49 > 0:09:52an animal that's too far off to see.
0:09:52 > 0:09:56Or pick up the tiniest trace of odour left on a leaf.
0:09:58 > 0:10:02But although smell is vastly more powerful for dogs than it is
0:10:02 > 0:10:05for us, it's one of the five senses that we share
0:10:05 > 0:10:07with them and most other animals.
0:10:10 > 0:10:12And there's a reason for that.
0:10:14 > 0:10:17The senses are the front line in the way that animals interact
0:10:17 > 0:10:20with the physical world around them
0:10:20 > 0:10:24and this goes a long to explain how those senses actually work.
0:10:26 > 0:10:28Whatever kind of animal you are,
0:10:28 > 0:10:31you experience the same physical properties.
0:10:32 > 0:10:36I need vision to see light bouncing off objects -
0:10:38 > 0:10:41I need touch to feel surfaces and sense temperature.
0:10:43 > 0:10:47I need to smell and taste chemical substances.
0:10:49 > 0:10:52And I need hearing to detect shockwaves in the air.
0:10:53 > 0:11:00These are my five basic senses to guide me through the world.
0:11:00 > 0:11:02Perhaps it's not surprising that I share these with the
0:11:02 > 0:11:08vast majority of other animal species in some combination or other
0:11:08 > 0:11:13for the very simple reason that we all inhabit the same physical world.
0:11:15 > 0:11:20And yet - those five familiar senses can be used by
0:11:20 > 0:11:24some animals in ways that are totally foreign to the human mind.
0:11:26 > 0:11:29DOLPHINS CLICK AND CRY
0:11:29 > 0:11:33I've come to the Dolphin Research Centre in Florida to see
0:11:33 > 0:11:36something that dolphins can do with their sense of hearing.
0:11:40 > 0:11:43Now, it's hard to study dolphins in the open ocean.
0:11:43 > 0:11:46But keeping them in captivity is controversial.
0:11:46 > 0:11:48WHISTLE BLOWS
0:11:48 > 0:11:51And since 1988, aquariums in the United States
0:11:51 > 0:11:54don't take dolphins from the wild.
0:11:54 > 0:11:55DOLPHIN CRIES
0:11:55 > 0:11:58Dolphins like Tanner were born in captivity.
0:11:58 > 0:12:01Tanner, are you ready? No? Yes, you are ready.
0:12:01 > 0:12:03Researchers Armando and Wade want to show me
0:12:03 > 0:12:09an ingenious experiment to demonstrate how Tanner uses sound.
0:12:09 > 0:12:12I have a list of behaviours right here now, I can't see them,
0:12:12 > 0:12:14please don't show them to me...
0:12:14 > 0:12:17I'm going to select an action from a list for Wade to
0:12:17 > 0:12:19perform in the water.
0:12:19 > 0:12:21Wade, go ahead in.
0:12:21 > 0:12:23I'm only showing Wade,
0:12:23 > 0:12:27Armando and Tanner have no idea which one he's about to do.
0:12:27 > 0:12:31OK, Wade, let's go for this one, please? OK?
0:12:31 > 0:12:32Tanner, imitate.
0:12:32 > 0:12:36'With his eyes covered, Tanner will now attempt to imitate Wade.'
0:12:36 > 0:12:40Then the other one will go on the left eye, but I have to give him
0:12:40 > 0:12:43the signal first, which means imitate.
0:12:43 > 0:12:44Are you ready?
0:12:44 > 0:12:45Imitate...
0:12:45 > 0:12:49'So, will Tanner know what Wade is doing?'
0:12:52 > 0:12:57There he goes, Wade is upside down and Tanner is upside down as well.
0:12:59 > 0:13:03'OK. That's one out of one.
0:13:03 > 0:13:07'But for something this bizarre, I need a little more proof.'
0:13:07 > 0:13:09- Shall we try another? - Try another one?
0:13:09 > 0:13:11Let me put the eyecup on.
0:13:11 > 0:13:13Let's go for this one, Wade...
0:13:14 > 0:13:15And here we go...
0:13:16 > 0:13:21'Tanner appears to take a moment to listen before imitating
0:13:21 > 0:13:24'Wade's exact movements.'
0:13:24 > 0:13:25It's pretty impressive, I have to say.
0:13:25 > 0:13:29'And for the piece de resistance, the bob.'
0:13:29 > 0:13:31Next word...
0:13:33 > 0:13:36- Now, watch. He's reading. - He's reading, without
0:13:36 > 0:13:39a shred of a doubt. He's reading without seeing.
0:13:39 > 0:13:42There's no question of that, and getting it right.
0:13:42 > 0:13:43WHISTLE BLOWS
0:13:43 > 0:13:46- Good boy, Tanner.- Thank you very much, thank you.- Excellent!
0:13:46 > 0:13:48Tanner, you're the best.
0:13:48 > 0:13:51'So, how does Tanner do it?'
0:13:51 > 0:13:53DOLPHIN CLICKS AND BEEPS
0:13:53 > 0:13:57Scientists believe he's using sound in an unusual way.
0:13:59 > 0:14:01It's called echolocation.
0:14:04 > 0:14:07A specialised fat-filled organ called
0:14:07 > 0:14:11the melon behind the forehead emits focused pulses of sound.
0:14:13 > 0:14:17But the key to echolocation is listening to the
0:14:17 > 0:14:19echoes of those sound waves as they come back.
0:14:22 > 0:14:26Dolphins pick up and amplify those returning waves with
0:14:26 > 0:14:31a cavity in their jaw, before sending them on to the inner ear.
0:14:33 > 0:14:37They use echolocation to hunt down and pinpoint their prey
0:14:37 > 0:14:39even in darkness.
0:14:41 > 0:14:45Dolphins share this use of hearing with nocturnal animals like bats.
0:14:50 > 0:14:53But just how detailed a picture of their world can
0:14:53 > 0:14:58they build up in their mind, using this one sense?
0:15:01 > 0:15:05When we hear that burst of sound being pumped out by the dolphins
0:15:05 > 0:15:11it's no more than a rapid cacophony of random clicks as far as we're concerned,
0:15:11 > 0:15:14but this I think will surprise you, because if we process
0:15:14 > 0:15:20the return echo simply by slowing it down, this is what we can hear.
0:15:20 > 0:15:23QUICK RHYTHMIC BEATING
0:15:23 > 0:15:28This is a return echo from an Atlantic cod, whilst this...
0:15:28 > 0:15:31DIFFERENT FREQUENCY BEATING
0:15:31 > 0:15:34..is what's bouncing back to the dolphin from a mullet,
0:15:34 > 0:15:38so clearly for the dolphin it's a very sensitive sense, it can
0:15:38 > 0:15:41tell the difference between these two different species of fish,
0:15:41 > 0:15:44perhaps even choosing which one it wants to eat.
0:15:45 > 0:15:49The dolphin's echolocation is an extremely powerful sensory tool
0:15:49 > 0:15:54which allows its mind to build up a picture of the world.
0:15:54 > 0:15:57But at the moment I'm left thinking, what does a dolphin actually
0:15:57 > 0:16:02do mentally? What does it think with all of that echolocation?
0:16:02 > 0:16:05Does it turn it into a visual image?
0:16:05 > 0:16:07We don't know, we may never know.
0:16:07 > 0:16:10But one thing I'm sure of is that this will have
0:16:10 > 0:16:13a profound effect on the way that these animals think.
0:16:21 > 0:16:25Countless other animals use their five senses in ways which,
0:16:25 > 0:16:27to us, are unfamiliar.
0:16:31 > 0:16:34Starfish see, but not as we do.
0:16:35 > 0:16:40A basic eye at the end of each limb can form simple images,
0:16:40 > 0:16:41helping them find their way
0:16:41 > 0:16:43back to their feeding grounds.
0:16:46 > 0:16:49Butterflies and moths have no nose.
0:16:49 > 0:16:53But their sense of smell is many times more sensitive than
0:16:53 > 0:16:55even a dog's.
0:16:55 > 0:16:57And it's thanks to their antennae.
0:16:59 > 0:17:02In some species the antennae can respond to only a few
0:17:02 > 0:17:06molecules of scent from a potential mate.
0:17:06 > 0:17:08When I was a kid we called them "feelers"
0:17:08 > 0:17:11but they're actually being used for smelling.
0:17:13 > 0:17:17Across the animal world, species evolve the senses which give them
0:17:17 > 0:17:22the best chance of surviving in the environment where they live.
0:17:24 > 0:17:28But very often, individual species or groups of species will form
0:17:28 > 0:17:34a sort of a sensory hierarchy in that one or two senses will become
0:17:34 > 0:17:38far more sensitive than the others.
0:17:38 > 0:17:42So, if two animals have a different dominant sense,
0:17:42 > 0:17:46how far does that influence the way that they think?
0:17:46 > 0:17:49WOLF HOWLS
0:17:50 > 0:17:54I've come to Wolf Park in Indiana, to find out.
0:17:54 > 0:17:56WOLF HOWLS
0:17:56 > 0:17:58THEY HOWL
0:18:02 > 0:18:06Scientists here are studying a group of ten wolves
0:18:06 > 0:18:08that roam over a territory of a dozen acres.
0:18:12 > 0:18:14Wolves are fascinating
0:18:14 > 0:18:17because, biologically, they are the same as dogs.
0:18:19 > 0:18:23Around 10,000 years ago, humans began domesticating some wolves,
0:18:23 > 0:18:26and over time they created dogs.
0:18:30 > 0:18:33Now, wolves haven't changed much in that time.
0:18:37 > 0:18:39Dogs, on the other hand,
0:18:39 > 0:18:43have evolved into an astonishing variety of breeds.
0:18:43 > 0:18:45They look very different to wolves.
0:18:48 > 0:18:51But how differently do their minds work?
0:18:54 > 0:18:57To give us some insight, we're going to test dogs
0:18:57 > 0:19:00and wolves in a battle of the senses.
0:19:00 > 0:19:03So first, I want to establish the sensory abilities
0:19:03 > 0:19:07these two animals share, starting with smell.
0:19:07 > 0:19:12This couple of wolves down here are about, I don't know, 60m away
0:19:12 > 0:19:14and I'm going to test that sense of smell.
0:19:14 > 0:19:17They've got expensive tastes, these animals, because what I'm going
0:19:17 > 0:19:19to use is this, Chanel No 5.
0:19:19 > 0:19:22It's said that they have a real craving for it.
0:19:22 > 0:19:25So, I'm just going to sneak down here...
0:19:26 > 0:19:29..put some of this on the grass...
0:19:30 > 0:19:31..and see what happens.
0:19:39 > 0:19:41Well, there goes a tenner, at least,
0:19:41 > 0:19:42let's see what happens.
0:19:44 > 0:19:47But it's not so much picking up that scent, it's what they do
0:19:47 > 0:19:49when they find it that we're interested in.
0:19:49 > 0:19:51Oh, nose is up.
0:19:53 > 0:19:55Yes...
0:19:59 > 0:20:02Oh...
0:20:02 > 0:20:04Look at that...
0:20:06 > 0:20:09This is what we call scent rolling and I'm afraid to say that
0:20:09 > 0:20:12many of you have probably seen your dogs doing this
0:20:12 > 0:20:15in less pleasant things than expensive perfume.
0:20:17 > 0:20:19HE CHUCKLES
0:20:19 > 0:20:20It's brilliant, isn't it?
0:20:22 > 0:20:25On the face of it, it seems that dogs and wolves live in the
0:20:25 > 0:20:31same sensory world and it's a world dominated by the sense of smell.
0:20:31 > 0:20:32Let's go!
0:20:34 > 0:20:38But that's not the only sense that's important to dogs.
0:20:39 > 0:20:41Let's go.
0:20:41 > 0:20:44Any dog owner knows they watch us closely with their eyes.
0:20:46 > 0:20:50So, what role does vision play in how dogs understand the world?
0:20:52 > 0:20:58Dr Brian Hare has recruited dog owners from across the US to carry out
0:20:58 > 0:21:02some simple tests that show how they use visual information.
0:21:02 > 0:21:04OK, Sisu, stay.
0:21:05 > 0:21:10- OK.- One of the simplest is called the Pointing Test.
0:21:11 > 0:21:15And now watch where her gaze goes. Right at me. Stay.
0:21:15 > 0:21:18Right, so what we've got here is a very simple experiment.
0:21:18 > 0:21:21We've got two people, we've got two cups, we've hidden food in both
0:21:21 > 0:21:24cups and we have a dog, of course.
0:21:24 > 0:21:27And all I'm going to do is I'm going to gesture at one of the two cups
0:21:27 > 0:21:30and the question is, does the dog go where I gesture or to the other cup?
0:21:30 > 0:21:32Now, it can't be that she's just using her smell
0:21:32 > 0:21:35when she makes her decision because there's food in both cups.
0:21:35 > 0:21:36So, let's see what she does.
0:21:36 > 0:21:39Both cups smell equally appetising.
0:21:39 > 0:21:44So, there's only one reason for Sisu to choose between them.
0:21:44 > 0:21:46OK, Sisu, you ready?
0:21:46 > 0:21:49- This.- OK, Sisu.
0:21:49 > 0:21:52It's the visual signal that Brian is giving her.
0:21:52 > 0:21:55Good job. And there's one here too.
0:21:55 > 0:21:58All right, so she did use my gesture there.
0:21:58 > 0:22:00Sometimes I'll point to the right
0:22:00 > 0:22:01and sometimes I'll point to the left.
0:22:01 > 0:22:04But let's do it again because it could be chance.
0:22:08 > 0:22:10Hey. OK, Sisu.
0:22:11 > 0:22:13All right...
0:22:13 > 0:22:18So, what we've seen is that Sisu really relies on my visual gestures,
0:22:18 > 0:22:19she's not relying on her nose.
0:22:19 > 0:22:22If I'm there and telling her something, she's much more
0:22:22 > 0:22:25happy to use that information than to rely on her nose.
0:22:26 > 0:22:30Most dog owners will be familiar with this ability.
0:22:32 > 0:22:35- OK, Kai.- Dogs will readily follow visual information.
0:22:35 > 0:22:41- Callie, is it there?- But we also know they have great noses.
0:22:41 > 0:22:46So, which sense do dogs trust the most - vision or smell?
0:22:49 > 0:22:52In a new test, Brian is going to put Dexter's nose
0:22:52 > 0:22:55in direct conflict with Dexter's eyes.
0:22:56 > 0:22:59So, we're going to actually show Dexter where we're going to hide
0:22:59 > 0:23:01the food so he can remember where he saw it.
0:23:01 > 0:23:04But then what we're going to do is we're going to close his eyes
0:23:04 > 0:23:07and shift where it's hidden and move it to the other location.
0:23:07 > 0:23:10That means he could potentially smell where it is, the question is,
0:23:10 > 0:23:15does he use what he saw to find the food or does he rely on his nose?
0:23:15 > 0:23:19So, let's see what he does... All right, Dexter.
0:23:19 > 0:23:22Oh, look at that face. Oh, you're killing me.
0:23:22 > 0:23:25All right, Dexter, are you ready, buddy?
0:23:25 > 0:23:27OK, that's where it's going to be.
0:23:27 > 0:23:29This time there's food under only one cup.
0:23:29 > 0:23:32OK. Now close your eyes.
0:23:33 > 0:23:35And without Dexter seeing,
0:23:35 > 0:23:37Brian's now moving that food to the other cup.
0:23:39 > 0:23:42Poor Dexter's senses are in direct conflict.
0:23:42 > 0:23:47So, does he trust his eyes or follow his nose?
0:23:47 > 0:23:48OK, Dexter, find it!
0:23:50 > 0:23:53Aww, what happened? It's a trick!
0:23:53 > 0:23:56It's over here, it was a trick!
0:23:56 > 0:23:59Are you ready, Dexter? OK, we're going to put it over here.
0:23:59 > 0:24:01Here it is. Now, close your eyes.
0:24:04 > 0:24:06OK, Dexter, go get it.
0:24:06 > 0:24:11Again and again, Dexter, like most dogs, goes not to where
0:24:11 > 0:24:15he can smell the food but where he SAW the food.
0:24:15 > 0:24:16OK, Dexter, get it!
0:24:19 > 0:24:21Awww!
0:24:21 > 0:24:24It tends to be that if they have visual information
0:24:24 > 0:24:28they prioritise that, they actually put that in front of what
0:24:28 > 0:24:31information they might be getting from their nose.
0:24:33 > 0:24:34But what about wolves?
0:24:34 > 0:24:37Do they prioritise their senses in the same way?
0:24:41 > 0:24:44Well, back at Wolf Park, we're going to test them.
0:24:46 > 0:24:49Kathryn Lord from the University of Massachusetts
0:24:49 > 0:24:51reared this group of wolves
0:24:51 > 0:24:54from birth and they're certainly familiar with humans.
0:24:54 > 0:24:55THEY GROWL QUIETLY
0:24:55 > 0:24:57I know, I'm going to stand up for a second
0:24:57 > 0:24:59cos you're getting a little excited, I know.
0:24:59 > 0:25:03So, this grey wolf Fi can understand certain types of information
0:25:03 > 0:25:05that a wild wolf wouldn't.
0:25:05 > 0:25:07SHE CALLS WOLF
0:25:07 > 0:25:08WOLF HOWLS
0:25:08 > 0:25:10She comes when her name is called.
0:25:10 > 0:25:12Fi!
0:25:12 > 0:25:16And, remarkably, Fi can also follow Kathryn's pointing.
0:25:16 > 0:25:22She's just as capable as any dog of understanding what it means.
0:25:22 > 0:25:23Hey.
0:25:23 > 0:25:28We've seen that dogs trust this visual signal above smell.
0:25:28 > 0:25:31So is this also true of wolves?
0:25:32 > 0:25:37To find out, we're going to repeat the finger pointing test several times,
0:25:37 > 0:25:42just as we did with the dogs, with a snack under each can.
0:25:42 > 0:25:43Fi!
0:25:44 > 0:25:50So, will Fi the wolf respond like a dog to a series of finger points?
0:25:52 > 0:25:54She didn't appear to look then.
0:25:54 > 0:25:56That time she just went for the cheese.
0:25:56 > 0:25:57SHE LAUGHS
0:25:57 > 0:26:00Fi has quickly learned that in this experiment,
0:26:00 > 0:26:04the visual signal is irrelevant for finding the food,
0:26:04 > 0:26:07instead she chooses to follow her nose.
0:26:09 > 0:26:12What's interesting is what the wolf's doing in the approach
0:26:12 > 0:26:16because there's no doubt at all that she's looking at Kathryn,
0:26:16 > 0:26:19she can see her pointing.
0:26:19 > 0:26:25But it seems that the nose wins over the eye, because she's looking,
0:26:25 > 0:26:29but ignoring what she's seeing. But not what she's smelling.
0:26:29 > 0:26:31The reason she's probably ignoring me
0:26:31 > 0:26:34is because she's perfectly capable of solving the problem without my help.
0:26:34 > 0:26:36So she doesn't need to pay attention to me.
0:26:38 > 0:26:43So, visual information seems to have a lower priority for wolves
0:26:43 > 0:26:45than it does for dogs.
0:26:45 > 0:26:48Wolves give greater emphasis to smell.
0:26:50 > 0:26:53Kathryn believes she might have discovered why.
0:26:55 > 0:27:00It's all about what happens in the first few weeks of life.
0:27:00 > 0:27:03You investigated this by raising wolf cubs from that
0:27:03 > 0:27:07very young age and contrasting their behaviour with dogs.
0:27:07 > 0:27:08I did, yeah,
0:27:08 > 0:27:11so I actually hand-raised both wolves and dogs.
0:27:11 > 0:27:14The wolf pups are great, so we get them at about ten days of age
0:27:14 > 0:27:18so at that point they can't see, they can't hear, and they can't smell
0:27:18 > 0:27:20and they can't really walk either,
0:27:20 > 0:27:23they're just, kind of, little puddles of fur.
0:27:23 > 0:27:25But as her wolf cubs developed,
0:27:25 > 0:27:28Kathryn observed something fascinating.
0:27:29 > 0:27:33There's a brief window of time soon after they are born
0:27:33 > 0:27:37when the senses of both dogs and wolves are set for life.
0:27:39 > 0:27:43The window starts early for wolves, at just two weeks old.
0:27:43 > 0:27:47At this stage, only their sense of smell has fully developed.
0:27:47 > 0:27:52So, they can only understand their world through smell.
0:27:53 > 0:27:58But for dogs, this sensory window starts at four weeks, a small,
0:27:58 > 0:28:00but crucial, difference.
0:28:00 > 0:28:05Because by then, dogs have developed ALL of their senses.
0:28:05 > 0:28:08When the dogs start to explore their world,
0:28:08 > 0:28:10they can use their vision, they can use their smell
0:28:10 > 0:28:13and they can use their sounds all at the same time.
0:28:13 > 0:28:16So, it seems that since the process of domestication started,
0:28:16 > 0:28:19the dogs have developed a greater flexibility to involve
0:28:19 > 0:28:24all of their senses and to be able to prioritise more their vision
0:28:24 > 0:28:27and their hearing than the wolves, so you might argue that they're
0:28:27 > 0:28:31a slightly more successful animal when it comes to dealing with people.
0:28:31 > 0:28:35The ability of dogs to be flexible is what allowed them to come
0:28:35 > 0:28:37into our environment in the first place
0:28:37 > 0:28:40and probably allowed them to be domesticated.
0:28:43 > 0:28:49So, wolves are hard-wired to trust smell above all other senses.
0:28:50 > 0:28:54But dogs use their senses far more flexibly.
0:28:56 > 0:29:00The senses have shaped both these animals' minds.
0:29:00 > 0:29:05They've helped define dogs and wolves as very different animals.
0:29:12 > 0:29:16So far, we've seen how animal minds deal with sensory information
0:29:16 > 0:29:18that's manageable.
0:29:20 > 0:29:25But what happens if your mind is being BOMBARDED by your senses?
0:29:30 > 0:29:34Take these birds for example, zipping around in the sky here.
0:29:34 > 0:29:38For them and many other flying animals, it's all about economy of weight
0:29:38 > 0:29:43and by necessity, therefore, they have to have smaller brains
0:29:43 > 0:29:47and that will have an impact on how they perceive their world.
0:29:47 > 0:29:51It will present its own very peculiar challenges.
0:29:54 > 0:29:58Birds on the wing can move in any direction they choose.
0:30:01 > 0:30:05But being able to fly brings with it the constant risk of collision.
0:30:07 > 0:30:11And what's more, their predators in the air, like hawks,
0:30:11 > 0:30:13can also attack from anywhere.
0:30:14 > 0:30:18So bird brains need to take in visual information
0:30:18 > 0:30:21from every direction.
0:30:21 > 0:30:25Their eyes can see down, up, left, right,
0:30:25 > 0:30:28in front and behind, all at the same time.
0:30:30 > 0:30:36And yet, with nearly 300 degree vision, a swallow can pull complex
0:30:36 > 0:30:41manoeuvres at 70kmph within centimetres of buildings.
0:30:46 > 0:30:50It's an incredible amount of visual information to process...
0:30:50 > 0:30:53all achieved with a tiny brain.
0:30:53 > 0:30:57A swallow's brain weighs around one gram -
0:30:57 > 0:31:01a thousand times lighter than ours.
0:31:01 > 0:31:04So how on earth do birds do it?
0:31:08 > 0:31:13To find out, we've decided to carry out a rather bizarre experiment.
0:31:14 > 0:31:18It involves some big, stripy boards...
0:31:20 > 0:31:21..and some starlings.
0:31:21 > 0:31:23You ready?
0:31:23 > 0:31:27And to help, we've brought in Martin Stevens -
0:31:27 > 0:31:29an expert in animal senses.
0:31:31 > 0:31:35Oh, it's looking beautiful.
0:31:35 > 0:31:36Come on.
0:31:36 > 0:31:40I'm hoping that this is going to reveal how birds' brains
0:31:40 > 0:31:44process the vast amounts of visual information they need to handle.
0:31:45 > 0:31:49Ready to go? Look at that. What a splendid animal.
0:31:49 > 0:31:51Too keen. We weren't quite ready.
0:31:51 > 0:31:56We like that. That's what we like with our trial birds.
0:31:58 > 0:32:00Martin, what's the plan?
0:32:00 > 0:32:03What we're going to do to try and understand how birds process
0:32:03 > 0:32:05so much visual information,
0:32:05 > 0:32:07is we're going to get him to fly down this corridor.
0:32:07 > 0:32:10To begin with, we'll have these stripes horizontal,
0:32:10 > 0:32:14and we'll time using these precision timing gates how long it takes him.
0:32:14 > 0:32:18Then we're going to switch the boards, so that the stripes are
0:32:18 > 0:32:21vertical, so that it's a different type of visual information,
0:32:21 > 0:32:24and we'll see how that changes things.
0:32:24 > 0:32:26Well, it's quite dazzling as it is, so let's see how he does.
0:32:26 > 0:32:28We'll have to repeat this several times
0:32:28 > 0:32:31to get some precise timings, I presume, but he's very keen.
0:32:31 > 0:32:36So we can compare Arnie's speed down the horizontal
0:32:36 > 0:32:38and the vertical stripes.
0:32:38 > 0:32:42He'll have to break the light beam at the start...
0:32:43 > 0:32:46..and again at the finish...
0:32:48 > 0:32:52..to get a precise time for how fast he flies down the corridor.
0:32:52 > 0:32:55- Did it work?- Yes, that's successful. Got a time.- Excellent.
0:32:55 > 0:32:57Come on, Arnie.
0:32:57 > 0:33:01Good boy. Top work, top work. Down you get. On the perch.
0:33:05 > 0:33:08- Yes, that worked.- Yes? Excellent.
0:33:15 > 0:33:17Arnie is performing admirably.
0:33:17 > 0:33:20His flight times from one end of the corridor to the other
0:33:20 > 0:33:23are coming in at less than two seconds.
0:33:27 > 0:33:31- Everything they do is quick. Every motion is speedy.- Yeah.
0:33:33 > 0:33:34Good lad.
0:33:36 > 0:33:38- Excellent.- Slightly faster.
0:33:43 > 0:33:46- Yes, that worked.- Yes! Ten! He's a champion.
0:33:47 > 0:33:49Arnie's done well.
0:33:51 > 0:33:55We've got timings for ten flights through the horizontal stripes.
0:33:55 > 0:33:58Now we're flipping the stripes to vertical.
0:34:02 > 0:34:05So, how will that affect Arnie's speed?
0:34:06 > 0:34:09OK, we're ready here. We're going to repeat the whole thing
0:34:09 > 0:34:11- and contrast the results?- Exactly.
0:34:11 > 0:34:15Typical science. Fire up the starlings, Lloyd. Let's go.
0:34:15 > 0:34:19- Arnie? Good boy. Are you ready, Rose?- Yep.
0:34:24 > 0:34:27So we've started to get some readings from the verticals.
0:34:27 > 0:34:28Come on, there's a little scrap there.
0:34:28 > 0:34:31On you go. Look at that. Beautiful. On you go.
0:34:34 > 0:34:36The funny thing is that, even to my eyes,
0:34:36 > 0:34:40there's something very weird looking about those vertical stripes.
0:34:42 > 0:34:44Martin, I'm not sure about the starlings, but looking down here,
0:34:44 > 0:34:48this is certainly a far more dazzling environment.
0:34:48 > 0:34:50It's quite unpleasant, isn't it?
0:34:52 > 0:34:54And Arnie seems to agree.
0:34:55 > 0:34:59He's definitely not going as direct as he was the first run.
0:34:59 > 0:35:02- No, definitely. - That was the slowest time so far.
0:35:03 > 0:35:07Could Arnie really have slowed down?
0:35:10 > 0:35:14The results are in and we can now compare Arnie's flight times
0:35:14 > 0:35:17through the horizontals and the verticals.
0:35:19 > 0:35:21OK, so we've got a graph of the results.
0:35:21 > 0:35:24First of all, we've got the horizontal stripes,
0:35:24 > 0:35:26which is the blue line here.
0:35:26 > 0:35:30And then the red line shows how fast it flew through the vertical stripes.
0:35:30 > 0:35:33One thing that immediately strikes me is that it's very clear that,
0:35:33 > 0:35:35when it's flying through the vertical stripes,
0:35:35 > 0:35:38it never reaches the speed that it did through the horizontals,
0:35:38 > 0:35:43suggesting to me that it was easier for it to fly down here
0:35:43 > 0:35:45when the stripes were horizontal.
0:35:45 > 0:35:48That's right, and it comes down to a neat trick called optic flow.
0:35:48 > 0:35:52And that really relates to how much information passes over
0:35:52 > 0:35:54the eye as the animal is moving.
0:35:54 > 0:36:00Optic flow is a way the bird brain processes visual information
0:36:00 > 0:36:02so that it isn't overwhelmed.
0:36:02 > 0:36:05It filters out nonessential detail,
0:36:05 > 0:36:09so the bird perceives simple patterns.
0:36:09 > 0:36:13When Arnie flies through horizontal stripes,
0:36:13 > 0:36:16that pattern changes very little.
0:36:16 > 0:36:22He perceives the lines as a distant horizon, so it's safe to fly fast.
0:36:22 > 0:36:26The vertical stripes on the other hand, those stripes are passing over
0:36:26 > 0:36:29the eye really rapidly and changing very fast,
0:36:29 > 0:36:31and that's simulating a situation
0:36:31 > 0:36:35where there might be lot of objects very close to the bird,
0:36:35 > 0:36:38and so it has to slow down to avoid the risk of collisions.
0:36:38 > 0:36:42So when Arnie flies through the vertical stripes,
0:36:42 > 0:36:48the pattern changes constantly and he perceives it as nearby obstacles.
0:36:48 > 0:36:53This makes him fly cautiously - almost a metre per second slower.
0:36:53 > 0:36:56The bird's mind has evolved an elegant way
0:36:56 > 0:36:59to know how fast it's safe to fly.
0:37:00 > 0:37:02C'mon, Arnie.
0:37:03 > 0:37:06It's always fantastic to learn something new,
0:37:06 > 0:37:08and I've been watching birds for years now,
0:37:08 > 0:37:10and I've always wondered,
0:37:10 > 0:37:12how do they fly through such cluttered environments
0:37:12 > 0:37:15without ever bumping into things?
0:37:15 > 0:37:18And it's all about filtering information,
0:37:18 > 0:37:21not overloading their little bird brains.
0:37:29 > 0:37:31Every time I look at a new animal,
0:37:31 > 0:37:36I am constantly surprised by the sheer power of their senses...
0:37:37 > 0:37:40..and the ingenious ways that they use them.
0:37:42 > 0:37:46Some species seem to be able to interpret that sensory information
0:37:46 > 0:37:50to understand almost everything about the world around them.
0:37:50 > 0:37:53But there is one thing that I've always wondered.
0:37:53 > 0:37:57Can they use those senses to go beyond this, the physical world,
0:37:57 > 0:38:01and grasp abstract concepts like we do?
0:38:01 > 0:38:03Things like time, for example.
0:38:05 > 0:38:08For humans, time is a concept.
0:38:10 > 0:38:14To keep a close track of it, we depend on clocks.
0:38:14 > 0:38:19But can animals use their senses to understand time?
0:38:21 > 0:38:26To try to find out, I'm going to test an old myth about dogs -
0:38:26 > 0:38:31that they can tell exactly when their owner is about to return home.
0:38:34 > 0:38:39Meet the owners of Jazz, the Hungarian Viszla.
0:38:39 > 0:38:43Now, they're convinced that Jazz knows exactly
0:38:43 > 0:38:46when his master, Johnny, is about to come home.
0:38:46 > 0:38:50And to witness this, we've left cameras
0:38:50 > 0:38:53running all over their house for a week.
0:38:56 > 0:38:58The family have a regular routine.
0:38:58 > 0:39:01Christine and Johnny always leave the house
0:39:01 > 0:39:03at the same time in the morning...
0:39:05 > 0:39:08..leaving Jazz to his own devices.
0:39:11 > 0:39:15And every evening, Christine comes home at four o'clock.
0:39:18 > 0:39:21But it's what Jazz does next that really interests us.
0:39:23 > 0:39:26You see, every evening at around 4:40,
0:39:26 > 0:39:3020 minutes or so before Johnny comes home,
0:39:30 > 0:39:35Jazz always leaps up onto the sofa as if he's waiting for him.
0:39:35 > 0:39:39He's like a canine alarm clock.
0:39:40 > 0:39:44Between half four and five, Jazz is always looking out for Johnny.
0:39:44 > 0:39:49It seems Jazz somehow knows that Johnny's coming home.
0:39:49 > 0:39:52And it's a claim made by many dog owners.
0:39:52 > 0:39:55But how does Jazz do it?
0:39:58 > 0:40:01Now it could just be that Christine coming home
0:40:01 > 0:40:03sets Jazz's clock.
0:40:03 > 0:40:07We know it's not because he needs dinner or his walkies,
0:40:07 > 0:40:09because Christine's dealt with that.
0:40:09 > 0:40:16There is a theory that a dog's sense of smell could play a role.
0:40:16 > 0:40:18While Johnny is out of the house,
0:40:18 > 0:40:23the smell he leaves behind fades at a regular rate.
0:40:23 > 0:40:26So could it be that when Johnny's scent
0:40:26 > 0:40:32drops to a particular level, Jazz senses he's about to return?
0:40:39 > 0:40:43To test this theory, at the end of the week, we made a change.
0:40:43 > 0:40:47On her way home, Christine swung by Johnny's football club to get
0:40:47 > 0:40:50some of his freshly worn t-shirts.
0:40:53 > 0:40:58And then, when she got back at her usual time, she wafted them
0:40:58 > 0:41:01around the living room to spread Johnny's smell around.
0:41:01 > 0:41:04If Jazz is using the fading smell of Johnny
0:41:04 > 0:41:07to sense the passage of time,
0:41:07 > 0:41:11then this should be the equivalent of re-setting the clock.
0:41:11 > 0:41:15So will Jazz still know what time it is?
0:41:16 > 0:41:21It's now less than half an hour before Johnny normally comes home,
0:41:21 > 0:41:25but for the first time, Jazz stays dozing.
0:41:27 > 0:41:31It's now 4:48.
0:41:31 > 0:41:35Jazz only lifted his head for about 30 seconds.
0:41:35 > 0:41:40He's lying flat out again, enjoying the heat at the radiator.
0:41:46 > 0:41:48Now Johnny's back...
0:41:48 > 0:41:50Are you coming a walk?
0:41:50 > 0:41:54..and to Jazz, it seems to come as a complete surprise.
0:41:57 > 0:41:59Now, let's not pretend that this is scientific.
0:41:59 > 0:42:03There could be any number of things that Jazz is reacting to.
0:42:03 > 0:42:08But it's an intriguing idea that dogs' sense of smell
0:42:08 > 0:42:12might allow them to grasp something as abstract as time -
0:42:12 > 0:42:18a concept that we tend to assume only the human mind can understand.
0:42:20 > 0:42:25So how could an animal's mind take in information from the senses,
0:42:25 > 0:42:28and draw from it an understanding of something
0:42:28 > 0:42:30that's not physically present?
0:42:32 > 0:42:35Well, now, for the first time, we are beginning to uncover
0:42:35 > 0:42:39what might be happening inside their brains.
0:42:41 > 0:42:45In Atlanta, neuroscientist Greg Berns is adapting a harmless
0:42:45 > 0:42:48medical technique to study brain activity in dogs.
0:42:51 > 0:42:54OK, stand by. We're going to start the noise.
0:42:54 > 0:42:57LOUD DRONING SOUND
0:42:59 > 0:43:03MRI is a technique that's been used in humans for over 20 years.
0:43:03 > 0:43:07Normally, we use it to study what the brain looks like,
0:43:07 > 0:43:10but with a few tricks, we can do what's called functional MRI
0:43:10 > 0:43:13which looks at brain activity, and, by analysing the data,
0:43:13 > 0:43:16we can figure out what parts of the brain are doing what.
0:43:16 > 0:43:19But doing MRI on animals is an entirely different game,
0:43:19 > 0:43:21mainly because of the requirement that the subject
0:43:21 > 0:43:23has to hold absolutely still.
0:43:25 > 0:43:30The need to keep still makes it impossible to scan most animals
0:43:30 > 0:43:34unless they're sedated - not a good way to study their brains.
0:43:36 > 0:43:38One, two, three, steps!
0:43:38 > 0:43:42But Greg has teamed up with Mark Spivak to devise a programme
0:43:42 > 0:43:46to train dogs for the bizarre conditions they'll face.
0:43:47 > 0:43:51The key is a steady supply of snacks.
0:43:51 > 0:43:54Well, a lot of humans have difficulty taking MRI.
0:43:54 > 0:43:56First of all, there's the enclosure,
0:43:56 > 0:43:59which provokes anxiety in many humans.
0:43:59 > 0:44:02Second, there's the absolute motionlessness required.
0:44:02 > 0:44:04And then there's the noise.
0:44:04 > 0:44:06LOUD DRONING SOUND PLAYS
0:44:06 > 0:44:09Without proper conditioning and training,
0:44:09 > 0:44:11the dogs would just run scared from the MRI.
0:44:11 > 0:44:13Come here, girl.
0:44:14 > 0:44:19Those that pass the test graduate to the real thing, like Kady.
0:44:21 > 0:44:25MRI is painless and it does no harm.
0:44:25 > 0:44:27It's at the very cutting edge of animal science.
0:44:27 > 0:44:32And it's beginning to give us some fascinating insights.
0:44:32 > 0:44:35Patricia, we're going to begin the first scan with the localiser.
0:44:35 > 0:44:36Are you ready?
0:44:36 > 0:44:40One of Greg's earliest experiments is revealing important clues
0:44:40 > 0:44:42as to what happens in a dog's brain
0:44:42 > 0:44:45when it receives information from its senses.
0:44:46 > 0:44:50First, he's looking at a visual signal.
0:44:50 > 0:44:52So Kady's in the scanner right now
0:44:52 > 0:44:55and Patricia's actually giving Kady hand signals.
0:44:55 > 0:44:59We've already taught the dogs through lots of practice
0:44:59 > 0:45:01that this means food.
0:45:01 > 0:45:04OK? So every time Patricia makes this signal,
0:45:04 > 0:45:08we're going to be looking in her brain, what that response is,
0:45:08 > 0:45:11and we're actually going to be looking at a very specific area
0:45:11 > 0:45:12called the caudate nucleus.
0:45:15 > 0:45:18We also have another hand signal that looks like this,
0:45:18 > 0:45:20and that means no reward.
0:45:22 > 0:45:24After scanning many dogs,
0:45:24 > 0:45:28Greg's results show the area of the dog's brain that responds.
0:45:31 > 0:45:35If we look very closely, we find that the area that's common to all
0:45:35 > 0:45:39the dogs corresponds exactly to the same part of the human brain
0:45:39 > 0:45:42that responds to reward.
0:45:42 > 0:45:45Rewards like money, music, food...
0:45:45 > 0:45:50All the things that humans like, it's also activating in the dog's brain.
0:45:51 > 0:45:55Even though Kady isn't actually seeing food, she can take
0:45:55 > 0:45:59a piece of visual information and interpret it to anticipate
0:45:59 > 0:46:04that she will receive food and she's responding emotionally.
0:46:05 > 0:46:08Just like we do.
0:46:08 > 0:46:10This was pretty amazing because it didn't have to be that way.
0:46:10 > 0:46:14Dogs could be so different from us that they might have responded
0:46:14 > 0:46:18completely differently, but that doesn't seem to be the case.
0:46:19 > 0:46:23And when you think about what this requires the dog to do,
0:46:23 > 0:46:26it reveals a complex chain of thought.
0:46:27 > 0:46:31The results are showing that dogs, and probably most animals,
0:46:31 > 0:46:34have brains and minds that are far more sophisticated
0:46:34 > 0:46:36than we ever gave them credit for.
0:46:37 > 0:46:40These are remarkable and tantalizing insights.
0:46:42 > 0:46:43Yet, so far in this programme,
0:46:43 > 0:46:47we've been exploring how the animal mind is shaped by the senses
0:46:47 > 0:46:50we ourselves possess.
0:46:51 > 0:46:52Vision...
0:46:52 > 0:46:54hearing...
0:46:54 > 0:46:56smell...
0:46:56 > 0:46:57taste...
0:46:57 > 0:46:59and touch.
0:47:01 > 0:47:06But these are not the only senses in the natural world.
0:47:06 > 0:47:10Out here, there are other physical forces that we simply haven't
0:47:10 > 0:47:13evolved the ability to be able to detect.
0:47:13 > 0:47:17So what I want to do now is take a look at a group of animals
0:47:17 > 0:47:20that go beyond these five senses that we know,
0:47:20 > 0:47:25to perceive the world in a way that would be entirely alien to us.
0:47:34 > 0:47:37To do that, I've come to the island of Bimini in the Bahamas.
0:47:37 > 0:47:41It's a hot-spot for an animal that's always fascinated me.
0:47:44 > 0:47:47With me is scientist Eric Stroud.
0:47:48 > 0:47:52He's spent years studying sharks.
0:47:55 > 0:47:58Sharks are extremely successful predators.
0:47:58 > 0:48:03They can smell tiny quantities of blood over huge distances
0:48:03 > 0:48:07and follow minuscule vibrations of their prey in the water.
0:48:08 > 0:48:13But the shark sense that I want to investigate is very different.
0:48:13 > 0:48:17It's one that we humans have no experience of at all.
0:48:17 > 0:48:20Try and push them into here, yeah?
0:48:20 > 0:48:23If you can get him against the fence, you have a better shot.
0:48:23 > 0:48:28Eric is going to demonstrate that sense with a strange experiment.
0:48:29 > 0:48:33But first, we need our baby lemon shark to stay nice and still.
0:48:33 > 0:48:35- OK, got him.- Look at that!
0:48:40 > 0:48:46OK, so we're going to roll it over and place it into tonic immobility.
0:48:46 > 0:48:48Tonic immobility?
0:48:48 > 0:48:51- Go on, explain that one. - No-one's really sure why it happens,
0:48:51 > 0:48:54but when the sharks are inverted like this, they kinda go to sleep.
0:48:54 > 0:48:57Wow. It's just relaxed.
0:48:57 > 0:48:59It's like yoga for sharks.
0:48:59 > 0:49:02- Indeed.- And there's nothing to suggest that it's stressed.
0:49:02 > 0:49:04I'm barely holding it.
0:49:04 > 0:49:06I'm going to hand him to do you, OK?
0:49:06 > 0:49:09Just put your thumbs behind there and hold...
0:49:11 > 0:49:16- OK, ready?- These things obviously can bite. What would be the damage?
0:49:16 > 0:49:18A laceration, at this age.
0:49:18 > 0:49:21You might need stitches, actually, from this little shark.
0:49:21 > 0:49:24So, if anything goes wrong, just let it go.
0:49:24 > 0:49:25Let's do our experiment.
0:49:27 > 0:49:30Eric's experimental kit is really simple.
0:49:30 > 0:49:33Steel spoon and a magnet. Thanks.
0:49:33 > 0:49:36I've been left holding the shark!
0:49:36 > 0:49:40I'm not sure whether that's an enviable position to be in or not.
0:49:41 > 0:49:44We have a strong magnet here we're going to use for the experiment,
0:49:44 > 0:49:45and it's a pretty powerful magnet.
0:49:45 > 0:49:47It'll attract the spoon out of my hand.
0:49:47 > 0:49:52Eric wants to show me how our shark reacts to the magnet.
0:49:52 > 0:49:56So what we're going to do is put a blinder by the shark's eye
0:49:56 > 0:49:58so he can't see what I'm doing.
0:49:58 > 0:50:01So the shark won't be able see the magnet coming.
0:50:01 > 0:50:03OK, I'm going to put a blinder here.
0:50:03 > 0:50:05But will he sense it?
0:50:05 > 0:50:07I'm approaching...
0:50:07 > 0:50:08Oh!
0:50:10 > 0:50:11That was a reaction!
0:50:11 > 0:50:14- Wow, he jumped out of your hands. - He did.
0:50:15 > 0:50:18Our little shark is completely unharmed,
0:50:18 > 0:50:22but he's acutely sensitive to Eric's magnet.
0:50:22 > 0:50:25Why?
0:50:25 > 0:50:29Well, it's down to a clever piece of sensory anatomy.
0:50:31 > 0:50:35Sharks have organs called the ampullae of Lorenzini,
0:50:35 > 0:50:39which appear as dark openings along the front of their noses.
0:50:39 > 0:50:44These are the ends of jelly-filled tubes that can detect
0:50:44 > 0:50:48the voltage difference between the tube's opening and its base.
0:50:51 > 0:50:54They are exquisitely sensitive,
0:50:54 > 0:50:56able to pick up billionths of a volt.
0:50:58 > 0:51:02Biologically, we humans have no mechanism like this.
0:51:02 > 0:51:06To us, the ability is completely alien.
0:51:06 > 0:51:10But why would a shark need such a sense?
0:51:12 > 0:51:14It helps them to find food. It's predation.
0:51:14 > 0:51:18They can locate the heartbeat of a crab or stingray underneath the sand.
0:51:18 > 0:51:20When that animal is beating or moving,
0:51:20 > 0:51:24the muscles generate a very weak electromagnetic field,
0:51:24 > 0:51:26and that's what their noses are gearing in on.
0:51:26 > 0:51:28We're, in a sense, simulating that.
0:51:28 > 0:51:31The movement of the magnet across the shark's nose
0:51:31 > 0:51:33induces that electromagnetic current,
0:51:33 > 0:51:37but we're just doing it many times greater than a stingray or a crab.
0:51:37 > 0:51:40- So, it's sensory overload.- Exactly. - Hence the struggle.- Exactly.
0:51:40 > 0:51:45At low levels, this sense allows sharks to find their prey.
0:51:45 > 0:51:48But at high levels, it repels them,
0:51:48 > 0:51:50just as we need light to see,
0:51:50 > 0:51:53yet would recoil from dazzling headlights.
0:51:58 > 0:52:02But is this effect powerful enough to change a shark's behaviour?
0:52:07 > 0:52:09We're heading from Bimini to Triangle Rock -
0:52:09 > 0:52:13a well-known gathering place for large Caribbean reef sharks.
0:52:16 > 0:52:19We've been joined by marine biologist Pat Rice.
0:52:21 > 0:52:24We're going to pit a shark's magnetic sense
0:52:24 > 0:52:29against what must surely be their most powerful instinct -
0:52:29 > 0:52:31their urge to eat.
0:52:32 > 0:52:35Here they are. Look! Caribbean reef sharks.
0:52:35 > 0:52:37Slap it on the water.
0:52:38 > 0:52:40- Oh!- Beautiful sharks, aren't they?
0:52:40 > 0:52:42They're stunning. Absolutely stunning, aren't they?
0:52:42 > 0:52:44So, they're here. Let's get going.
0:52:53 > 0:52:55Stunning they may be, but to do the experiment,
0:52:55 > 0:52:59I'm going to have to jump in with that lot.
0:52:59 > 0:53:02I know they're only two metres, but they look a little bit bigger
0:53:02 > 0:53:04than I imagine a two metre shark. Maybe it's the water.
0:53:04 > 0:53:07Maybe it's acting as a lens and exaggerating their length.
0:53:10 > 0:53:12Pat now needs to set up the experiment
0:53:12 > 0:53:14eight metres down on the sea bed.
0:53:21 > 0:53:24What we're going to do here is perform a very simple,
0:53:24 > 0:53:26but hopefully effective, experiment.
0:53:26 > 0:53:30And what I've got in my hand here is an extremely powerful magnet.
0:53:30 > 0:53:33That's why I'm not coming too close to the camera or you will never
0:53:33 > 0:53:34see this, it'll wipe everything in there.
0:53:34 > 0:53:38And we're going to make a circle of these magnets on the bottom,
0:53:38 > 0:53:41and in the centre of that circle, we're going to place some food.
0:53:47 > 0:53:51On the sea floor, Pat and safety diver Vincent are setting up
0:53:51 > 0:53:54the circle of magnets, into which we'll put our bait.
0:54:00 > 0:54:02We need to be sure the sharks aren't simply
0:54:02 > 0:54:06deterred by a circle of black objects, so Pat's made
0:54:06 > 0:54:10a second circle of ordinary bricks covered in black tape.
0:54:11 > 0:54:17We'll put bait in the two circles and see what happens.
0:54:17 > 0:54:21The magnets are powerful, but will they repel the sharks?
0:54:21 > 0:54:24Essentially, what we're trying to test here is whether the sharks'
0:54:24 > 0:54:29sensitivity to these magnets will overcome their desire to feed.
0:54:34 > 0:54:38Time for me to join Pat - and a whole load of sharks.
0:54:38 > 0:54:40Jump!
0:54:48 > 0:54:53I'm told the sharks in this spot have never yet attacked a human.
0:54:53 > 0:54:56But to do this experiment, we need to deliberately
0:54:56 > 0:54:59tempt them in very close.
0:55:00 > 0:55:02We've arrived on the bottom.
0:55:02 > 0:55:05On this side is the ring of bricks - the placebo, if you like.
0:55:05 > 0:55:08And here on this side is the ring of magnets.
0:55:08 > 0:55:11And now what we've got to do is introduce the bait.
0:55:11 > 0:55:14OK, we've got sharks here already. They're coming in.
0:55:14 > 0:55:18Pat's got some bait here, some tasty tuna.
0:55:18 > 0:55:23We're going to try and fix this in the centre of each of the circles.
0:55:25 > 0:55:27We're in the water with hungry sharks,
0:55:27 > 0:55:30and in our bare hands, we've got some fish.
0:55:30 > 0:55:34This is like a peculiar game of Russian roulette, isn't it?
0:55:35 > 0:55:39All of those sharks up by the boat will now be able to smell
0:55:39 > 0:55:41the bait down here with us.
0:55:41 > 0:55:42Here comes a shark now.
0:55:44 > 0:55:47It's bypassed the magnets...
0:55:47 > 0:55:50and it's gone straight into the brick circle
0:55:50 > 0:55:52and it's taken the bait.
0:55:54 > 0:55:55Now there's no bait in the bricks,
0:55:55 > 0:55:59will they show an interest in the bait in the magnet circle?
0:56:00 > 0:56:05Look at that! It turned as if it could sense that bait,
0:56:05 > 0:56:07and it turned away.
0:56:07 > 0:56:09It can tell there's food there.
0:56:09 > 0:56:12It must be able to see all of the other fish currently
0:56:12 > 0:56:16feasting on it but it wouldn't go inside that ring of magnets.
0:56:21 > 0:56:24Time to put fresh bait in the bricks.
0:56:24 > 0:56:27And I've barely had a chance to retreat
0:56:27 > 0:56:30when a shark makes straight for the brick circle again.
0:56:32 > 0:56:35Look at that. It's a monstrous great animal.
0:56:35 > 0:56:41But so far they haven't touched the bait in the magnets.
0:56:41 > 0:56:42It's 2-0.
0:56:45 > 0:56:48It tweaked them and definitely flinched away.
0:56:50 > 0:56:53And yet, they're clearly hungry.
0:56:53 > 0:56:56Not me. No, not me...
0:56:58 > 0:57:02We're down to our last piece of bait for the brick circle...
0:57:02 > 0:57:04and it doesn't last long.
0:57:05 > 0:57:08It's snaffled the food from the brick circle.
0:57:11 > 0:57:15But there's no doubt the magnets are repelling the sharks.
0:57:15 > 0:57:18It seems almost confused by those magnets.
0:57:20 > 0:57:22And the bait remains in the circle.
0:57:24 > 0:57:27Although undetectable by us,
0:57:27 > 0:57:32in the sharks' mind, our magnetic force-field is overwhelming.
0:57:32 > 0:57:37So strong, it even overrides the shark's primal urge to feed.
0:57:47 > 0:57:50This exploration of animal senses has been a first
0:57:50 > 0:57:53and a fascinating insight into the animal mind,
0:57:53 > 0:57:54and I've been surprised.
0:57:54 > 0:57:58The way that they experience and understand their world
0:57:58 > 0:58:01is far more sophisticated than I would have imagined.
0:58:01 > 0:58:03But above all,
0:58:03 > 0:58:08I've learned that it's the animal senses that shape the animal mind.
0:58:08 > 0:58:12It's those senses that make every single species,
0:58:12 > 0:58:16including our own, unique and special.
0:58:18 > 0:58:22Next, we'll be meeting the animals with the most powerful
0:58:22 > 0:58:25problem-solving minds on the planet.
0:58:25 > 0:58:29How on earth did that crow do that?
0:58:29 > 0:58:31We'll find out how apparently
0:58:31 > 0:58:35simple animals can crack problems that would baffle humans...
0:58:36 > 0:58:41..and pit them against other animals I'd like to think of as clever.
0:58:41 > 0:58:43All you've got to do is lift the ball!