For centuries, we thought animals were creatures of pure instinct,
with no understanding of how the world works.
Simple beasts with simple minds.
We thought that only we humans could actually think,
analyse, reason, use imagination and solve problems.
But new scientific research is revealing there is
a small group of animals with extraordinarily clever minds -
octopus, great apes
and even some birds.
It's a bizarrely diverse group.
But they share a remarkable ability to analyse
and solve problems in a very human-like way.
I want to get inside these animals' minds
and see just how clever they are.
Starting with perhaps the cleverest of all - the crow family.
How on earth did that crow do that?
I want to push them to the limit, to find out how
they measure up to other animals that we think are pretty clever.
All you've got to do is lift the ball!
I'll discover what makes some animals capable of brilliant
ingenuity that seems almost human.
It's a sort of Satnav for bees.
I want to uncover why this special group of animals
have such superb problem solving minds.
Now, if we can do this, we might just unlock one of nature's
greatest mysteries - how we ourselves came to be so clever.
Welcome to a lost world.
The island of New Caledonia.
Lying nearly 1,000 miles east of Australia, it is a tropical
paradise, bursting with exotic life found nowhere else on the planet.
I'm here to find one of these unique animals.
It has an almost legendary status,
thanks to an amazing ability to solve problems.
The animal that I am looking for is truly remarkable.
The problem is, it is very, very difficult to find.
It's cunning. And it's quick.
Agile.
If I'm honest with you, there could be one right here somewhere,
just looking down at me, and I've never ever seen one.
Many experts think that these are the cleverest animals on earth.
I've been told I might see that intelligence in action
on the island's high mountain roads.
It is this - a crow.
But not just any crow.
This is the New Caledonian crow.
It is not the same species we find a Britain.
These are jungle birds.
And here, in isolation on the island,
they have evolved some remarkable abilities.
This one is holding a nut in its claw.
It drops it onto the tarmac,
seemingly to crack open the hard shell.
But in truth, it is what the bird does next that is really ingenious.
Now, look at this, this is interesting because,
having broken the nut open on the road,
these birds are then carrying it to the Armco here,
where there are small depressions, man-made cuts, in it.
And they're using these as a vice to stop the nut from rolling
around whilst they access the fruit on the inside of it.
Now, that strikes me as pretty clever.
But the question is, of course, just how clever are these birds?
To find out, I have come to visit Dr Alex Taylor
at his field aviary here on the island.
To study how these birds solve problems,
he has put a tasty morsel of food deep in a container.
He is testing whether they can work out how to reach it
using a variety of objects he has pleased in the aviary.
But first, he is trying his puzzle out on me.
Imagine that you are a crow.
Here is your food, in a deep hole. How would you go about,
with the tools available to you on this table,
solving this problem?
This is part of it, obviously. Mm-hm.
At my disposal, I have a short stick on a piece of string,
three stones inside the cages...
..and a longer stick trapped in a box.
Which means, then, that the crow is going to use this stick...
..to get the stones out of there. Absolutely.
Next, the crow needs to drop the stones onto a trap door
to release the long stick.
It is going to need all three stones.
And then it probably will drop that one out. Excellent.
And using this long stick, it will finally be able to reach the food.
This is a tough one. All right, can I stay in here?
Absolutely, you can sit and watch. We will see what happens. Come on, then.
Send in your mastermind, because it is going to need that.
Alex studies wild birds,
which he releases after three months of research.
This one is nicknamed 007,
and it is about to attempt what Alex believes is one of the most
complex tests of the animal mind ever constructed.
The bird is familiar with the individual objects,
but this is the first time he has seen them arranged like this.
Eight separate stages that must be completed in a specific order
if the puzzle is to be solved.
And if the bird succeeds, it will be a world first.
He takes time to have a look and then starts with the short stick.
Stage I.
He finds it is too short to reach the food.
He then sets off to get the first stone.
But he drops it.
And another. He seems to be stuck.
But then something seems to click.
He deploys the first stone.
And then another.
Got it!
The eighth and final stage.
Success!
Eight individual stages of one complex puzzle completed.
That was remarkable.
I've never ever seen anything like it.
Of all of the bird behaviour I've seen, nothing matches that.
I can hardly believe it.
I'm still just running that sequence through my mind.
It happened really quickly.
But the immediate question is, of course,
how on earth did that crow do that?
You see, on the face of it,
the crow's problem-solving abilities seem mind boggling.
But look close enough and the natural world is filled with
examples of animals behaving in clever ways.
The spider spins a web that gets stronger when it catches prey.
It's precision engineered to catch flies.
Turtles navigate through thousands of miles of featureless ocean,
returning every year to the same beaches to lay their eggs.
It is as if they hold a nautical map in their heads.
So are the clever crows really so unusual?
Well, to find out,
I need to investigate how animals solve problems.
And I am starting back in Britain with the honeybee,
a small animal that seems to be able to do something staggeringly clever.
The pollen and nectar that bees eat
is clearly only available whilst the flowers are in bloom,
so it's there throughout the spring and the summer.
But the bees have to get enough of it
so that the hive can make it through the winter.
And frankly, if that isn't a massive task, then I don't know what is.
But the bees have an almost incredible solution.
To see with that is, I have come to meet Professor Adam Hart.
Hello, Adam. Hi, Chris.
One of his specialisms is the hidden world of the honeybee.
That is a very intimate view of the interior of the hive.
Yes, it's like Big Brother for bees. It is! It's great, isn't it, really?
Adam has set up an infrared camera to spy on the bees inside the hive.
And we are hoping to see a striking behaviour that is key to
solving the problem of gathering enough food.
It is called the waggle dance.
Adam, look at this one. This one is waggle dancing, isn't it?
Yeah, this is the waggle dance.
You have got this lovely figure of eight dance,
sometimes getting in the way of other bees, but generally speaking,
keeping this nice kind of rhythm going.
The waggle dance isn't just for show.
This bee has found a good source of food, and she is performing
a set of very precise movements to tell the others
exactly where to find it.
And this is all about communicating the whereabouts of a food source.
Yeah, this is like GPS for bees, basically.
They are telling other bees not just that there is food out there,
which is quite a useful signal, but where that food is.
So they can communicate the direction and the distance of that nectar.
But how can a dance communicate where a food source is?
To find out, we need to get a better view of the horizon.
Super view, well worth the climb. Yeah.
But what about the mechanics of this dance, then?
The bee we saw in the hive was doing this figure of eight,
and that central section was where she was vibrating her abdomen.
When you think about it, the only frame of reference bees have
in the hive is gravity, up and down.
The frame of reference they have out here is the position of the sun,
or more accurately, where the sun would be if it was projected down
on the horizon, what is called the azimuth.
From up here, it is easy to see where the sun lies over
the landscape and where it would be if it dropped to the horizon.
Now, our dancing bee was waggling at an angle of five degrees.
So, if this tower were a massive beehive,
the waggle dance would be telling us that the nectar is five degrees
from the relative position of the sun.
That is somewhere in that direction.
All right, that is the direction, what about the distance?
That's that duration of that central waggle run, as it is called.
The longer they dance for, the longer that waggle run goes on for,
the farther away the food is.
So, a very short waggle run, like we saw down in the hive,
is maybe a couple of kilometres, whereas they can sometimes
waggle for much longer, perhaps nine, ten kilometres even.
So, honeybees survive the winter
by using what we'd call mathematics.
They compute angles and distances
and then communicate that information to their nest mates.
It seems incredibly clever, but in fact,
it doesn't involve any thought at all.
You see, the waggle dance is so important to the survival
of the hive, that it comes built into the brain of the honeybee.
Every worker bee is born
with the ability to perform the dance automatically.
In other words, the bees are acting on instinct -
a set of behaviours
that are so important to the animal's survival
that they are hard wired.
Think of them as a simple set of rules that are tattooed
onto its genes by evolution.
It is what makes these bees do the waggle dance.
The animals have no real understanding
of what they are doing.
But what about our New Caledonian crow?
It solved a complex eight-stage problem.
Is it really possible that the bird was acting only on instinct,
without any real understanding of what it was doing?
In short, the answer is no.
Because, unlike bees with their waggle dance, these birds are not
dependent on solving a multistage puzzle in order to survive,
for the very simple reason that you don't find multistage
puzzles like this out there in the wild. They are not natural.
They are a man-made artefact.
And for that very obvious reason, there is no chance whatsoever
that these birds could have evolved an instinct to solve them.
But solve them they do. So if it isn't instinct, what is it?
To begin to discover what is really going on in the crow's mind,
I have come to Somerset to meet Lloyd Buck.
He handles birds for TV and film.
And this is Bran.
He is a raven, one of the largest members of the crow family,
a group known as the corvids.
Oh, what a stunner!
Hold my finger.
Are you going to do it again?
No, he just wants... Oh, ups, sorry.
You want to hold my finger? No.
You like that camera, it's the highest point.
Bran is clearly a bird who knows his own mind.
In fact, it is hard to know who is in charge.
Myself and my dogs, you know, I am the pack leader.
What about you and Bran, who's boss?
Oh, well, I think obviously Ban.
But as far as he is concerned, I am his mate.
Right. His mate? Yeah. His partner? His partner.
It is going to be a long-term relationship
because they're a long-lived bird, aren't they?
Yeah, in captivity up to 40, 50, even 60 years.
He is going the distance with you. Yeah.
And they are really time intensive.
You can't just forget him and leave him in his aviary.
He likes to go out for his fly, his walk every day.
He wants to see, he wants to spend time with you.
Cos they are so intelligent.
To keep his demanding bird occupied,
Lloyd likes to set Bran difficult problems to solve,
like this one.
Lloyd places a piece of food inside a plastic bottle
and then crushes it.
And you give him a bowl of water. A bowl of water? Yes.
With the bottle crushed, the food is trapped behind the restriction.
But this doesn't stop Bran.
First, he adds water.
Next, he spins it,
and the liquid carries the food past the restriction and out.
That is a clever piece of problem-solving.
Oh, he's got it. He's got it!
Honestly!
What about that? Now, that is impressive.
The thing is, Lloyd, how long did it take him to work that out?
Well, presented with the crushed bottle,
it took him basically an afternoon.
He got frustrated, he couldn't work it out initially, and he left it.
So we left it with him in his aviary
and we went up to the house for lunch.
Come back down in the afternoon and, lo and behold, the food was gone.
But let's not forget that Bran is a tame raven.
Aren't you a clever boy? Yes, you are.
It is possible that, in spending so much time with humans,
he has been able to observe and copy some of their actions.
You are too clever for your own good half the time, that is your problem.
So, I'm going to set Bran a new challenge,
one that he has never seen before.
And this time,
I am going to pit his intelligence against another animal,
one that we tend to think is pretty clever,
certainly brighter than birds -
the dog,
or to be more precise, my dogs - Itchy and Scratchy.
Amongst the dogs, poodles are about the smartest. Are they? So they say.
Bran, he just finished War And Peace.
LAUGHTER I can see how this is going to go.
To make things even more interesting,
I am also going to put the same test to Fletcher here,
who is two and a half,
which incidentally is nearly the same age as Bran.
They are all going to face this - a puzzle box of my own design.
Here's how it works.
The prize is in the green ball in the centre.
But to get to it, they firstly have to pull this drop door down here.
And then, pull this smaller box out.
And then, remove the lid from that
to get the ball.
Simple, isn't it?
Well, let's find out.
We've given all of our contenders
the chance to familiarise themselves with parts of the puzzle box.
As usual, Lloyd leaves Bran to it.
Fletcher is also showing an interest in how it works.
Itch, concentrate.
'Whereas I need to be a bit more hands-on.'
Now, look, look.
Pull that. What this. Look, watch.
This is the sort of thing my mother would have done. Look, watch.
That's your lesson over for today.
And now, the moment of truth has come.
The contenders are about to face the test proper for the first time.
This is raven versus dog versus human.
Itchy, solve this.
Solve that. OK? I'll be back. Solve it.
And that, I'm afraid to say, is an emphatic win for Bran
and all of his corvid kind.
In truth, my dogs didn't even seem to realise there was
a problem to solve, despite all of my training efforts.
And Fletcher, well, he played around with the box a bit,
but soon seemed to lose interest.
Whilst Bran was so quick that we will have to use a high-speed
camera just to see how he did it.
So the question is,
why are ravens like Bran able to solve problems on their own when
other species, including clever dogs and even young humans, can't.
To find out what abilities the corvids have
that other animals seem to lack, I have come to Cambridge
to meet Professor Nikki Clayton.
She is a world expert on the crow family,
which includes these Eurasian jays.
She sets up experiments to break down the different abilities
that these birds use to solve problems.
And she set one of them, Hoy, a fiendish challenge.
One that wouldn't be out of place in a physics lesson.
She has dropped some wax worms, his favourite food,
into a tube of water, out of reach.
So the bird needs to work out how to raise the water level.
Nikki, let's see what's going on, then.
Fire up the laptop and see what he is up to. I will do.
Nikki's birds have minimal human contact,
so we're watching Hoy from a safe distance.
Straight away, he starts dropping stones into the water.
They are quite specific
about what they use, actually,
and how many stones.
They don't put more stones in than they need.
He is checking the water rise every time he puts the stone in. Yeah.
He pops up and you can see the eye looking down. Look at that.
Look at that, the small stone wasn't going to be enough. No.
There we go, go on.
No, can't quite reach.
You know, Nikki, it is almost
as if he understands the effect of dropping that stone in.
That's right. He only does this when there is liquid in the tube.
If there is a worm in the tube and it's filled with sand,
he doesn't bother. He knows that it needs to be a liquid
in that tube in order for the stones to work.
Hoy understands that a sinking stone will cause the water level
to rise, and this in turn will allow him to reach the wax worm.
He also knows the same technique won't work with sand.
And this reveals the first skill animals need to solve problems -
the ability to understand the rules of cause and effect.
But I am intrigued to know
how Hoy worked all of this out in his mind.
He was trained that, if he drops or knocks a stone
into a tube, he gets a worm.
But in the training apparatus, the worm comes out the bottom,
not out the top, and there is no water.
And having learned to associate stones with tubes to get food,
what he has been able to do is then to transfer this to a novel problem,
where there is water,
where the worm comes out a totally different place.
But he has been able to use his information flexibly
and transfer it to novel problems.
He can join up his knowledge. Exactly.
So, Hoy was able to solve this problem,
because he already knew how to use the stones.
He is able to learn rules for one situation
and then apply those rules to a new scenario.
Scientists call this flexible thinking,
and it is the second skill that animals need to solve problems.
It is how the New Caledonian crow solved the multistage problem
and also how Bran made such short work of my puzzle box.
The birds were thinking flexibly,
using previous experience to solve new problems.
And it is an ability that seems sadly missing in my dogs.
Lift the ball, please! Lift it! Lift it!
Is that why Bran, the raven, so convincingly trounced my dogs?
It's exactly that, yeah.
So, the dogs can learn to do something,
but what they can't do is to transfer it to a novel problem.
Yes, I will be gracious in defeat on this account,
given the quality of the opposition.
I suspect, if you had been competing against a pigeon,
you'd have been all right.
They would've even that, that would've been fine.
So, why are some animals better at solving problems than others?
It is something we don't yet fully understand.
But one thing that we do know is that the answer lies
somewhere in here -
the animal brain itself.
Here are a couple of very interesting specimens.
This one is the brain of a dog, in this case a terrier.
And this one here is the brain of a crow.
And it is immediately apparent that the dog's brain is about twice
the size of that of the bird.
So, we might imagine, simplistically, therefore,
that the dog is a more intelligent animal.
But we already know that the crow
can solve problems that the dog can't.
So, clearly, there is
more to cleverness than just the size of the brain.
To investigate what that could be, I have gathered together
a range of preserved animal brains.
If I arrange them in order of body size, a pattern emerges.
The bigger the animal, the bigger the brain.
It seems that the more body you have, the more brain cells
you need to control it.
In other words, there is
a relationship between the mass of the body and the mass of the brain.
And roughly speaking, it is a straight line.
The dog lies pretty much bang on the line here, which is
where you'd expect it, given its body size.
And in fact, most animals lie very close to the line.
But some sit above the line, like we humans.
Our brains are very large for our body size.
But what about the crow?
The crow's brain is also above the line. It is up here,
which means that its brain is bigger
than we would expect just given its body size.
In fact, it is about twice the size.
Now, bizarre as it may seem,
the dog's brain is physically twice the size of the crow's,
but relative to its body size, the crow's brain is bigger than the dog.
So, perhaps this extra mental power will allow the crow to
think in a more complicated and more flexible way than the dog.
And the crow isn't alone in having a brain twice as big as we'd expect.
In fact, it is in the company of another animal
known not only for its big brain but also its cleverness.
It is our nearest relative - the chimpanzee.
And the chimpanzee holds a special place in the history of science.
In the 1960s, a young British scientist, Jane Goodall,
observed chimps doing something that no-one thought animals capable of -
using tools.
I saw this dark shape hunched over a termite mound.
He's making arm movements as though he's sliding it
across the ground and obviously eating.
But that was all I saw.
And I went up to the heap and there were
the pieces of grass lying there, termites moving about the surface.
So I picked up one of these abandoned tools
and pushed it into the mound, and the termites bit on.
It was pretty obvious.
Goodall had observed the chimps using blades of grass as tools
to fish for termites.
It was a discovery of immense significance,
as her PhD supervisor immediately realised.
And he sent his famous reply, "Now we have to redefine man,
"redefine tool or accept chimpanzees as humans."
Goodall's discovery shattered our ideas about what sets us
apart from the rest of the animal kingdom.
We had to accept that animals were cleverer
than we'd given them credit for.
It also gave researchers new insights into how
our ancient ancestors might themselves have solved problems.
And as we have discovered,
chimps are not alone in being able to use tools.
It is something that crows can do, too.
To me, what is so important about using tools is that it reveals
the next crucial ability that an animal needs to solve problems.
For example, take this stick.
If I want to use this as a tool,
I need to be able to see it for more than what it is.
More than just a piece of wood, what a piece of wood might be.
What might it be?
Well, I could sharpen one end and I could perhaps use it as a spear.
Or I could set fire to it to generate some heat.
When I'm going through these thought processes,
there is no doubt that I am using flexible thinking,
understanding the rules of cause-and-effect,
but I am also using a type of thinking which is innovative.
What I am using is imagination.
I'm not just seeing the world as it is now,
I am seeing the world how it could be.
And this raises a very profound question.
Could any other species of animal have an attribute
so significantly human as imagination?
To answer this question, I have come to Austria to meet a rather
inquisitive and endearing type of bird.
And this time it is not a member of the crow family.
These are Goffins cockatoos, a type of parrot.
Big-brained birds with a very curious nature.
Can I have that back? Thank you.
And I am here to meet Dr Alice Auersperg,
an expert in these animals.
She is studying their ability to innovate.
And I am intrigued to know what that might reveal
about their powers of imagination.
Alice, these birds are very keen to get to know me, it seems. Yes.
They are especially interested in you because you are new.
And it is not just me that is new.
So is the entire crew.
And everything that we are wearing.
My watch, in particular, has caught the attention of Olympia here.
And within minutes,
she has worked out how to release the clasp.
When they find you, a human, inside the aviary,
they look for everything that looks different on your body,
like your shirt buttons or the shoe laces or your watch.
They go specifically for that
and they stay with it for a very long time.
You like my shiny watch, don't you?
Alice, I think I've had enough of being pecked and probed
and pulled by your rather wonderful cockatoos.
I'd like to see them in action now, mental action.
Look, the watch is off again.
Come on, I know you can steal my watch, but what more can you do?
To investigate what is going on in the minds of these parrots,
Alice created this - the lockbox.
Trapped inside is a tasty nut,
held securely behind this elaborate locking mechanism.
To see how it opens,
we need to employ the services of a master safe-cracker.
Or Muppet, as he is perhaps inappropriately called.
Before we begin, though, there is the question of eyewear.
If you want to start, we have to put sunglasses on
because we could cue the birds with our eye movements.
Can they see where we are looking? Do they have the ability to do that?
We don't know whether this species can,
but it has been proven that some can follow the eye movement of humans.
Better safe than sorry.
We'll forgive fashion for that and make scientific progress.
And here comes Muppet. He's out.
Oh, he is displaying towards you. A little bit of display.
Yes, he's a boy now.
Very nice, yes. That is a crest of some distinction.
I had one like that in the 1980s myself.
But perhaps, Muppet, you could take your attention to the lock?
Muppet has done this before,
and he delivers...a masterclass.
He quickly removes the pin and then the screw.
He discards the central bolt before shifting the locking wheel.
And this releases the final bolt.
Voila!
He has reached the nut inside.
Wow. I should have timed it, shouldn't I?
But to make sure that Muppet can't learn the sequence by heart,
Alice can swap the lock sections around or even remove them entirely.
So now I want to change the way in which the box works
and set Muppet a new challenge, one that he has never seen before.
There are five parts. Why don't we take out the middle bit?
Take out the bolt. Yes, let's.
The upper section is now redundant,
leaving only the lower parts in operation.
It may look like we have made it easier, but in fact,
we have created an entirely new problem with a different solution.
If Muppet can't see this, he will just repeat what he did before,
and robotically go for the pin at the top.
But if he can see the new problem
and imagine a new solution,
then he will go straight for the wheel.
OK, Alice, let's... let's give him a go.
So now, the moment of truth.
He has gone straight for the wheel.
And then the bar.
And he's in in less than ten seconds.
Muppet got it right first time.
And that gives us a crucial insight into his mind.
He must have looked at the problem, worked it out in his head
and imagined the solution.
That was a hard-earned nut.
So imagination is the third ability that animals need to solve problems.
It's a skill that seems to allow them to work out
new solutions in their heads before putting them into practice.
Up until now, all of the animals that we've looked at
have used their imagination to solve problems
which are sat right in front of them
but we humans can do so much more than that.
We use our imagination to project into the future,
to see problems coming
and think about how we are going to solve them.
Until now, we've always thought of that as a purely human attribute
but what I want to know is can these clever animals do that too?
There is a common behaviour in the animal world
that seems to be about planning for the future.
It's called caching.
It's what squirrels do in the autumn,
hiding nuts in the ground so they can be dug up
and eaten over the winter months.
But if caching were an Olympic sport
then the corvids would be the gold medallists.
Most of them seem to do it, much to the annoyance of the squirrels.
And this American corvid, the Clark's nutcracker,
is the caching king.
Researchers have observed how every year it can store
and remember the location of thousands of different seeds.
This bird truly is the master of memory.
But is this just another example
of instinctive behaviour to survive the winter?
Or is there something far more complex going on?
It's a question that's greatly intrigued Professor Nicky Clayton.
She studies Western scrub-jays,
another American corvid renowned for its caching behaviour.
Nicky wanted to discover whether they could do more
than just remember where they buried food in the past.
If they can travel back in their mind's eye to think about the past,
can they also travel forward in the mind's eye to think about the future?
Can they imagine the future, if you like? Can they plan ahead?
To find out, Nicky created an experiment
based on a very human annoyance -
waking up to find that breakfast is off the menu.
For six days, the birds were housed in this aviary,
split into three zones.
In the middle is the dining room,
where the birds were fed during the day,
and at either end are the bedrooms, where they were kept at night.
But there is a twist.
Kept overnight in this bedroom,
the birds were served an early breakfast
but kept overnight in this one,
they got no breakfast and went hungry until mid-morning.
The birds experienced this daily routine for almost a week.
We give them three experiences of waking up in the hungry room
and three experiences of waking up in the room that serves breakfast.
But the important point is the birds themselves
didn't know which room they would end up in on any given day.
But then Nicky changed the test.
She allowed the birds to cache food in the evening before bedtime.
She placed caching trays in both the hungry and breakfast rooms.
The question was where would they choose to store the food?
Nicky wanted to know if the birds could use their past experience
of the two different rooms and plan for the future,
namely for breakfast time tomorrow.
The results left no doubt.
What we found is that the birds cache about five times
as much in the hungry room as they cache in the breakfast room.
They can imagine what they are going to need the following morning when
they wake up hungry so they can solve a problem before it's even happened.
So what this experiment shows is that the birds can plan for the future.
So the jays' caching behaviour is far more than mere instinct.
They have a grasp of the past,
but can also anticipate future needs and, crucially, plan for it.
This skill is very rare in the animal kingdom
and it's the fourth key ability needed to solve problems.
It's called mental time travel.
It's the ability to go backwards
and forwards in the mind's eye, so it's about projecting yourself
in time to remember the past and to imagine the future.
In humans, mental time travel is a skill that takes a while to develop.
We're not born with it.
These children are about to undergo the sweetie challenge.
The task is simple.
Each child is given a sweet.
They are told that, if they leave it uneaten,
they will get a second one 15 minutes later.
The question is, can they plan for a future in which they have two sweets
or will the lure of instant gratification be too much?
It's a skill that children acquire as they get older.
I think this kind of cognitive capacity is highly sophisticated.
We know that young children don't start developing
these kind of skills until they are at least four years of age.
Clearly, if you are a bird or a human,
it's no bad thing to be a mental time traveller.
When we look at the world's cleverest creatures,
we see a group of very different animals -
the great apes, the corvids, the parrots.
And yet, they all think a little bit like we do.
They have the ability to understand cause and effect
and can utilise this understanding in new and novel situations.
They can also implement imagination and this allows them
to think ahead, to plan in the future.
Now, together, these abilities allow them
something which is incredibly rare in the animal world.
It's the power to reason, the power to solve problems.
But of course, it also raises another question -
what is so special about this group of animals?
What could they possibly have in common?
To answer that, I want to look in a very different environment.
'Here on the island of Bimini in the Bahamas,
'I'm seeking out an elusive creature.'
It's a creature that's as different from a bird or a chimp
as it's possible to be.
Now, this beautiful animal is a common octopus.
Don't worry too much about it being out of water.
They will frequently move over land, between rock pools like these,
so he will be OK for a while.
It lives in a world which is very alien to us -
rock pools and rocky caverns on the coast here.
And as a consequence, its anatomy is very different.
Inside this animal, there are three hearts
but perhaps the most profound difference of all is its brain.
The octopus brain is spread around the body.
Each leg even has its own mini brain to control it.
It's nothing like the one-stop shop that we have.
But what's extraordinary is this animal has problem-solving abilities
similar to those of the great apes...
..the parrots and the crows.
This is a veined octopus just off the coast of Indonesia.
In this environment, it is very exposed to predators
but it has worked out a solution.
It's found a discarded coconut shell
and despite being an unfamiliar object,
the octopus sees its potential.
It tries it on for size before picking it up and carrying it away.
Now, when a threat appears, it has a place to hide
and it can retreat inside its coconut sanctuary.
This is an example of an octopus using tools.
It seems to be using all the key abilities we've seen
in the cleverest animals on land.
So what can the octopus, with its strange brain,
possibly have in common with apes and birds?
When animals are very different,
then the similarities can actually be a lot easier to see
and we have to look beyond the fact that birds can fly,
apes have dextrous hands
or that octopus actually move on their eight arms.
We have to not concentrate so much
on the physical nature of these animals,
but look at the things that have made them what they are.
And when we do that, a pattern emerges.
For instance, all these animals eat a wide variety of foods
and need to master different techniques in order to obtain them.
They crack, they pluck and they hunt.
Our own omnivorous diet isn't too different.
And all these animals tend to be both predator and prey.
Which is also true of our own ancient ancestors
on the plains of Africa, millions of years ago.
So it seems that, to live flexibly,
you have to be able to think flexibly.
But there is something else that the supreme problem solvers -
the apes, the corvids and the parrots - share.
They live in groups.
So whether they walk, swim or fly,
the supreme problem solvers of the animal kingdom are not
so different from one another as we might have first imagined
and, although their minds are not as potent as ours,
their powers to reason
and even exercise imagination are quite remarkable.
But then, up until now, we have been looking at them as individuals.
What I want to understand next is do they have the capacity,
like humans, to actually share the solutions to problems?
In short, if they come up with a good idea, can they pass it on?
On New Caledonia, the crows have lots of good ideas.
They are precision tool makers.
This one is in the process of doing something
we would normally expect only of humans.
It's crafting a hook that it's going to use to catch its prey.
It's an astounding behaviour.
Dr Alex Taylor and his colleagues are now investigating whether
these birds are able to share their tool-making skills with each other.
That is amazing.
So they have sculpted a little hook out of another piece
of the twig that formerly would have run out here.
It's beautiful. It's almost like a primitive human tool, isn't it?
It does appear that way.
We talk about the imposition of three-dimensional form
onto a natural object.
That's something that humans have only been able to do
for the last 100,000 or 200,000 years
and here we have a crow doing something very similar.
And you can see how that can be useful because a crow would be able
to insert that into a hole and quite literally use that hook
to draw out a grub or anything else it was after.
Absolutely.
Made by a bird! That is absolutely brilliant! Absolutely brilliant!
And of even more interest to Alex are these -
intricately cut tools from the leaves of the pandanus tree.
Unlike the hooks,
there are distantly different types of pandanus tool.
They differ in complexity,
ranging from a simple leaf fragment to multistep implements like these.
And across the island,
different groups of crows use different types of these tools.
In the south, many different fragments are found
that, as we move north,
the crows start to favour more complex, multi-staged tools.
It means the different groups of crows
have their own ways of doing things.
In human society, we would call this culture.
What we are seeing across New Caledonia is populations
of crows that appear to have traditions
of making single-step tools or two-step or three-step tools
and these traditions are persisting over 10 or 15 years at least,
that's as much...how long we've been studying them for
and we believe they have been there for a lot longer.
It appears there's some kind of transmission of tool design
across the population.
A rare and fascinating glimpse of how this might happen
has been captured on camera.
Here an adult bird is using a stick to probe for grubs inside a log.
A youngster stands by, watching,
as the adult seems to demonstrate the right way to use the tool.
And when the adult departs,
she leaves behind the stick in the hole.
The youngster can now have a go itself.
Although this one has some way to go
before it becomes an expert like its parents.
It seems as though one way ideas can travel through the crow population
is via family groups, the social circle.
But Alex's research suggests something even more extraordinary -
that, with each new generation, the ideas don't stand still
but are honed and improved.
When we talk about this, we talk about the ratchet effect,
which is this idea that it's a really good idea
to be able to copy each other and, as a group, you can end up
being able to build better and better tools.
Obviously, we don't invent the wheel every generation ourselves,
we make it better and better.
Potentially, this is what's going on here with the crows.
There's no concrete evidence that any animal species
is able to actually show this ratcheting up of their technology,
to make it more and more sophisticated.
So it would just be crows and humans?
No chimpanzees? Nothing? At the moment, no.
It's something we think is unique to humans,
but maybe is going on with these crows as well.
The New Caledonian crow has only been studied since the early 1990s.
In that short period, scientists have revealed an animal mind
that rivals the problem-solving skills of our closest cousin,
the chimpanzee.
And for me, the really exciting thing
is that we are just beginning to understand these animals.
Who knows what else they might be capable of?
On this journey, I've come to an understanding
about what makes some animals cleverer than others
and even where that cleverness actually comes from.
And whilst we might reign supreme across the animal kingdom
when it comes to complex thought, we are certainly not alone.
It also seems we may not hold a monopoly
on the ability to share ideas and learn from one another.
So perhaps it's no surprise at all
that the most intelligent animals on our planet are the social ones.
And next time I'll be investigating
the minds of some very social animals.
I'll uncover the secrets of dolphin society,
discover how chimps deceive one another
and learn that we are not alone in mourning our dead.