NOVA

What really makes them tick?

MAN

Oh, look at that face!

NARRATOR

Is there any way to get inside the animal mind?

MAN

What I really want to know is what is it like to be an animal, what's it like to be inside their head and what are the problems they have to solve, and how do they think, and are they like us or are they like something totally different?

NARRATOR

They have some amazing abilities. Is it instinct... training... or something else? Cutting-edge animal science reveals new answers, getting inside their heads in ways never before possible.

MAN

Without proper training, the dogs would just run scared from the MRI.

NARRATOR

We put different species to the test in search of the roots of animal intelligence. Who are the best problem solvers? Who wins the battle of the super senses? Dive deep into the animal experience to explore their language... (dolphin squeaking) relationships... even emotions.

MAN

If you start giving one of them grapes, which are far better than cucumber, then the one who gets cucumber becomes very upset.

NARRATOR

Are they more like us than we ever thought possible?

WOMAN

Having a sense of self might go with complex understanding of others.

NARRATOR

On this episode... How smart is this bird brain?

MAN

Imagine that you're a crow. Here's your food in a deep hole. How would you go about solving this problem?

NARRATOR

They use tools and pick locks. But what happens in a brainy smackdown between this bird and man's best friend? How did a creature with such a tiny brain get so smart?

WOMAN

A crow's brain in relative terms is as big as that of a chimpanzee.

MAN

Why is it that that animal can solve those problems? Why would we observe that level of flexibility in that species of bird that we don't observe in another species?

NARRATOR

"Inside

Animal Minds

Bird Genius," right now on NOVA.

Major funding for NOVA is provided by the following

It's one of the most amazing things we build, But we don't usually think of them as incredibly bright. After all, isn't "bird-brained" the very essence of stupidity? But now, scientists are discovering bird brains that put most other animals to shame. That's no surprise to Lloyd Buck. There it is.

NARRATOR

Lloyd handles birds for TV and film, and one of his stars is a raven named Bran. There's a good boy. Well this is Bran, and he's a three-year-old raven. We've had him since he was about ten days old, so he's what you call complete social imprint on humans, but he's particularly bonded with me. We share a very, very close bond. Captive ravens can live 60 years or more, so Lloyd and Bran are in for a long-term relationship. Are you going to do it again? But right now, Bran wants to explore his relationship with the camera. Going to hold finger? No. Sorry, he likes your camera. It's the highest point. That's a good boy. To keep his demanding bird occupied, Lloyd gives Bran puzzles to solve on his own. Here's a problem Lloyd first presented to Bran a few months ago in his aviary, where he has a bird bath. Lloyd places a piece of food inside a plastic bottle and crushes it so the food is trapped. But this doesn't stop Bran. First, he adds water. Next, he swishes it around. And the liquid carries the food past the restriction and out. That is a clever piece of problem solving. Good boy. You're clever. Bran wasn't taught to solve this problem. Lloyd just gave him the challenge one afternoon and left Bran alone to try to find a solution himself.

BUCK

So we've presented him with that problem, and through his own intelligence and problem solving abilities he worked out to use his own water, what he had around him to his advantage, which I think shows a lot of intelligence.

NARRATOR

People who've observed crows and ravens closely have said that they are pretty clever creatures. But in recent years, new experiments are probing deeper, trying to solve the secrets of their problem-solving brains. And beyond birds, researchers are discovering more and more animals doing things we once thought were strictly human. So how smart are these creatures? Inside their minds, are they analyzing and solving problems the way we do? Or are these animals' skills more like parlor tricks, the result of training and fueled by instinct?

BRIAN HARE

What I really want to know is what is it like to be an animal, what's it like to be inside their head and what are the problems they have to solve, and how do they think, and are they like us or are they like something totally different?

NARRATOR

From the beginning, one way that humans have solved problems has been by using tools. It was once considered proof of our superior intellect. But it turns out, all kinds of animals use tools. Even an octopus-- a close relative to clams and oysters-- can do it. Off the coast of Indonesia, this veined octopus finds a discarded coconut shell on the sea floor and uses it to protect itself from predators. First it crawls inside the hard shell. Then it uses its eight arms to carry it off.

JUSTIN GREGG

People used to think that tool use was unique to humans, but of course that has never been the case. Ever since Darwin, we've known that animals have been using tools. But what's really unique is tool manufacturing. Humans, of course, manufacture a huge array of tools for different purposes.

NARRATOR

And for centuries, we thought that only humans were smart enough to make a tool. All that changed in the 1960s, when Jane Goodall discovered chimpanzees breaking all the rules.

JANE GOODALL

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.

NARRATOR

Not only did Goodall see chimps using blades of grass as tools to fish for termites, but she also witnessed them making tools by stripping leaves off twigs. Her research supervisor was amazed. 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 smarter than we'd given them credit for.

HARE

She created basically an environment that we have to think about their minds, and we have to recognize the fact that in many cases, animals may have abilities that we thought were the province of humans.

NARRATOR

Today, animals with impressive skills and brainpower can be found on land......and sea......and air.

And some of the most surprising can be found here

New Caledonia. Lying nearly 1,000 miles east of Australia, this remote Pacific island is home to an animal hailed by some as one of the smartest on Earth, in part because along with humans and chimps, it is an expert tool maker. Meet the New Caledonian Crow. In the wild, the crows shape hooked sticks and use them to spear grubs. But today, biologist Alex Taylor is designing an experiment to see if crows can use tools in new ways to solve problems. Alex works with wild birds, which he releases after a three month period. This one is nicknamed 007. 007's mission is to get a tasty piece of meat out of this narrow plastic box.

ALEX TAYLOR

What we have here is our deep hole. This has got some meat in.

NARRATOR

The meat is positioned so deep in the narrow box, it's out of reach of 007's beak. But Alex has placed a number of other objects nearby. The question is, can 007 use them to get the piece of meat?

TAYLOR

Imagine that you're a crow. Here's your food in a deep hole. How would you go about, with the tools available to you on this table, solving this problem?

NARRATOR

007's toolkit includes a short stick hanging on a piece of string, three stones inside wooden cages and a longer stick trapped in a plastic box. First, the crow must use the short stick to get the stones. And then use all three stones to get the long stick.

TAYLOR

And now the crows can take this and probe it into the hole and roll-- much better than I can-- the food out of the hole and get themselves a nice tasty reward.

NARRATOR

It's a complicated task. 007 is familiar with the individual pieces of the puzzle. He's done each of them separately for a treat. For example, he's used stones to get a piece of meat out of the trap door box. But this is the first time he's seen the tools

arranged like this

eight separate stages that must be completed in a particular order if the puzzle is to be solved. At first, he takes time to check things out. Then goes for the little stick. He tries to use it to reach the meat, but it's too short. So he sets off to get the first stone. Got it! But he doesn't seem to know what to do with it. He gets another stone. But he appears to be stuck. Now, something seems to click. He puts the first stone into the box where the long stick is trapped. Then the second stone. And returns to collect the last one. He's got the long stick and goes right for the meat. The final stage. Success. 007 successfully executed all eight tasks to collect the out of reach treat. How did he do it? One of the striking things is how skillfully 007 employs a number of different tools to get what he wants. That's because New Caledonian crows are born tool-users. Auguste von Bayern is an expert in corvids, the family of birds that includes crows, ravens, jays and rooks like this one. New Caledonian crows have evolved with several physical features that allow them to more easily manipulate objects-- particularly sticks. New Caledonian crows are famous for their very straight beak, and it turns out this is an adaptation to their tool use. This is really striking because other corvids have curvy beaks. You can see that very well in the rook.

NARRATOR

The straight beak allows the New Caledonian crow to hold tools in front of it, in its line of vision. But that's not all. New Caledonian crows have eyes set closer together th other birds, which means there is a significant overlap of what their two eyes can see. This helps the crow to focus on the end of a tool. They can see the working end of the tool extremely well and look into the narrow holes and see what they're doing. Tools aren't a recent discovery for the New Caledonian crow. They've been using them for so long, they have physically adapted to tool use.

BAYERN

No other adaptation like this has been described in any other tool-using animal, so this is fairly special.

NARRATOR

So the eight stage puzzle didn't pose too much of a physical challenge for the crow. But how did it figure out which order to perform the tasks? What was going on in its mind? Did it imagine the entire solution to the puzzle? Was it just using trial and error step-by-step? Was it conditioned by its training on the individual parts? Or is the answer somewhere in between? Can animals essentially imagine or infer or reason about how to solve a problem they've never seen before and come up with a solution that then they can act on? On the face of it, the crow's abilities seem impressive. But look closely enough, and the natural world is filled with examples of animals behaving in what look like clever ways. The spider spins a web that is precision-engineered to catch flies. Turtles navigate through thousands of miles of featureless ocean, returning to the same beaches every year to lay eggs. It's as if they hold a nautical map in their heads. So are the crows really so unusual? To begin to find out, we need to delve into the animal mind and see how other animals solve problems.

Like the honeybee

a small animal that is able to do something that seems incredibly smart. Insect expert Adam Hart is interested in how bees solve a very difficult problem. Inside a typical hive, there are about 40,000 honeybees. Every day, they face the challenge of having to feed themselves. The pollen and nectar that bees eat is only available when flowers are in bloom. So in spring and summer, the bees have to collect enough of it to eat and enough to turn into honey to keep the hive going through the winter. Sometimes they can fly more than six kilometers to get enough nectar and pollen back, because they need a plentiful and vast supply.

NARRATOR

Finding enough food is a huge logistical challenge, but the bees have an almost incredible solution. Adam has set up an observation hive. It's completely dark inside, so infrared cameras reveal what's going on.

HART

Initially, it looks very chaotic. It looks like bees are everywhere. But you can see some vibrations going on and some movements that are actually part of a very sophisticated communication system.

NARRATOR

The bees perform a striking behavior that's key to solving the problem of gathering enough food. It's called the waggle dance.

HART

The waggle dance is a very sophisticated way of directing foragers towards nectar in the environment. So it's telling them where to go.

NARRATOR

This bee has found a good source of food and she's performing a set of very precise movements to tell the others exactly where to find it.

HART

It tells them the direction and the distance of the nectar. The best way to understand how the waggle dance actually works is to get up high, because then you can get a view of the landscape in which the bees are operating.

NARRATOR

The meaning of the waggle dance was first proposed in the 1940s. But it wasn't proven until 2005, when scientists were able to track bees using radar technology. This church tower gives Adam a bee's eye view of the countryside. From up here, it's easy to see where the sun lies over the landscape, and where it would be if it were on the horizon. One of the dancing bees in the hive was waggling at an angle of five degrees from the vertical line. So if this tower were a massive bee hive, the waggle dance would be telling us that the nectar is five degrees from the relative position of the sun.

HART

But they can also advertise distance because the duration of that waggle run, that central component, tells the bees how far away the resource is. The closer it is, the shorter the waggle run.

NARRATOR

So honeybees survive the winter by using what we call geometry. They compute angles and distances and then transmit that information to their hive-mates. How can a small insect with such a tiny brain do something so incredibly sophisticated? It's instinct. It's hardwired into the bee's brain. And we know that because if you take older bees out of the hive, the younger bees who have never been exposed to a waggle dance will spontaneously begin waggle-dancing and doing this behavior. It's absolutely built-in, it's instinctive. This is an evolved behavior, an evolved instinct, that leads to high survival of honeybees. Instinctive behavior is often crucial to the survival of a species. But the animals don't need to have any real understanding of what they're doing.

MARIO PESENDORFER

Animal behavior often appears very complex, but there might be very simple rules underlying the pattern that we see.

NARRATOR

So what about the New Caledonian crow? Researchers have found that like bees and their waggle-dance, young crows will instinctively pick up sticks with their beaks even if they've never seen another crow do it. But was 007 acting just on instinct when he solved the eight-stage problem? Nicky Clayton, one of the world's leading experts on corvids, is convinced that it's something more.

CLAYTON

The behavior of the New Caledonian crow when it's solving one of these problems is far more complex than anything that would be solved by an instinctive mechanism.

NARRATOR

So if it isn't pure instinct, what is it? Scientists disagree about what exactly is going on in the mind of a crow like 007 or a raven like Bran when they're solving problems. Some researchers think the animals are instinctive tool-users and can be conditioned by training to use them in ways that just appear clever. But others believe that animals show real smarts when they tackle novel problems that they've never seen before. To demonstrate this, we set up a little competition to solve another puzzle between Lloyd Buck's raven Bran

and an animal a lot of people think of as pretty smart

a dog. Actually,

two dogs

French poodles named Itchy and Scratchy. It's a specially designed puzzle box. Inside the blue ball, there's a tasty snack

that each contestant likes to eat

rat meat for Bran, a doggy treat for Itchy and Scratchy. The challenge is to remove the blue ball from the two plastic boxes. First, the contenders have the chance to familiarize themselves with parts of the puzzle box. As usual, Lloyd leaves Bran to investigate on his own. Good boy.

NARRATOR

The dogs are introduced to the components by their owner. Itchy, concentrate, look. The outer box has a hinged door that can be opened by pulling on a pink ball tied to the door with a string. Another ball and string can then be used to pull out the inner box. Then a third ball and string must be pulled to remove the lid, freeing the blue ball which holds the treat. And now, the moment has come. The animals are about to face the test for the first time. This is dog versus raven. Itchy, solve this. Solve that, I'll be back. Solve it. Bran gets the tasty treat. The dogs didn't seem to even realize there was prlem there to solve, despite some guidance. But Bran was so quick, we have to use a high-speed camera just to see how he did it. An emphatic win for Bran and s corvid kind. It's clear that corvids like these have a knack for solving problems that involve getting food out of hard-to-get places, even in situations they've never seen before. While dogs are very good at paying attention to humans and can be trained to carry out complicated tasks, they're not so good at tackling novel problems like this one, despite the fact that there's food involved.

HARE

Why is it that that animal can solve those problems? Why would we observe that level of flexibility in that species of bird that we don't observe in another species?

NARRATOR

Here at Cambridge University in England, Nicky Clayton is trying to find out how the corvid mind works. She sets up experiments to break down the different abilities these birds use to solve problems. And she gives one of them-- a Eurasian jay named Hoy-- a particular challenge. First, he's presented with a plastic tube. When he puts a rock in at the top, a tasty food reward-- a worm-- comes out at the bottom. When he's got the hang of that, Nicky gives him a new test. She drops some worms-- his favorite food-- into a tube of water out of reach, and leaves a pile of stones next to it. There's a delicious, tasty worm floating on the top. At the moment, it's out of reach. Then, Hoy picks up a stone and drops it in the tube. Does Hoy actually understand that a sinking stone will cause the water level to rise, and this in turn will allow him to reach the worm? When Nicky gives him the same tube, buthis time with the worm sitting on sand instead of water Hoy does not use the stones. Nicky believes he understands the difference. He seems to understand that it's only any good if there's a liquid in the tube. It's a very useful skill

when it comes to solving problems

the ability to make a connection between cause-- the stone-- and effect-- the rising water level.

TAYLOR

Cause and effect is the ability to understand what causes what, why did a particular event occur, if you can identify that so you know what causes it. And that means as humans, we're able trecreate that same use to get that same effect, and that's a really powerful skill.

NARRATOR

To figure out step one, putting stones in the tube, Hoy took the knowledge from the training task and transferred it to the new one. This is another skill many corvids display

when tackling problems

the ability to think flexibly, to use information learned in one situation and apply it to another.

NICOLA CLAYTON

Flexible thinking is the ability to transfer information, knowledge, from one problem to a brand new problem. So it's applying knowledge to new contexts.

NARRATOR

And this is how the New Caledonian crow solved the multistage problem.

BRIAN HARE

New Caledonian crows need flexibility in their environment they evolved in to process food, and to be able to get access to food in new ways using tools in settings they may not have encountered before.

NARRATOR

This also explains how Bran quickly solved the puzzle box. The birds were thinking flexibly, an ability that seems to be missing in dogs. So why are some animals better at solving problems than others? It's something we don't yet fully understand. But one thing we do know is that the answer lies somewhere in here... The animal brain itself. So what you can see here are a couple of pickled brains. That's a crow brain and that's a dog brain. The dog's brain is clearly bigger than the crow's brain and so you might expect dogs to be smarter than crows. But we've seen that's not the case. Crows can solve complex problems that dogs can't. So there must be more to cleverness than just brain size. To explore what that might be, Nicky's gathered a range of preserved animal brains collected by Victorian naturalists. The first thing we see is that the brains are all different sizes. But when they're arranged in order of the size of the animal they come from, we see a pattern.

CLAYTON

So, the bigger the body, the bigger the brain. And it seems that, in fact, the bigger the body, the more brain you need to control it.

NARRATOR

Most of the time, there's a straight-line relationship between the mass of the body and the mass of the brain. Larger animals need more extensive nervous systems to coordinate their bigger bodies. Their sense organs are also bigger, so they require greater amounts of neural tissue to process all the extra information being gathered. You can calculate how big you'd expect any animal's brain to be by its body size.

CLAYTON

This is where the dog occurs. It's bang on the line, just what you'd expect given its body size.

NARRATOR

Most animals are more or less on the line, but not all. Some animals sit above the line, as we humans do. Our brains are very large for our body mass. The difference between expected brain size and actual brain size is known as the encephalization quotient, or EQ. The further above the line, the greater the EQ. So where is the crow?

CLAYTON

The crow's brain is above the line, so that means that it's got a much bigger brain than you'd expect for its body size. In fact, it's twice as big.

NARRATOR

As bizarre as it may seem, while the dog's brain is about ten times as big as the crow's brain in absolute size, in relative terms, the crow's brain is twice as big as the dog's. So maybe evolution has really forced them to invest more in their brains and that's partly what makes them so flexible. And the crow isn't alone in having a brain twice as big as we'd expect.

CLAYTON

The crow is the same distance above the line as that of the chimpanzee. In other words, a crow's brain, in relative terms, is as big as that of a chimpanzee.

NARRATOR

These big-brained animals share some impressive skills, including the manufacture of tools. This highlights another key concept in problem solving... The ability to innovate. Alice Auersperg works with an endearing and inquisitive type of bird, the Goffin's Cockatoo, an Asian parrot. Like the crows, these are big-brained birds, but with a playful personality. Alice studies these animals to find out how adept they are at innovating. My Goffin Cockatoos are very, very curious. So when they see an object, for example, let's say a human, they go for shoelaces, watches, glasses. To investigate what's going on in the minds of these parrots, Alice created this, the lock box. Trapped inside is a tasty nut securely held behind this elorate locking mechanism. To see how it opens, we need to employ the services of a master safe-cracker-- or Muppet, as he's known. Before Muppet begins, any humans in the room have to put sunglasses on. This is so the bird can't take any cues from eye movement. Muppet has done this before. He wasn't taught by Alice, but watched other birds do it, and now he delivers a master class in operating the lock box. He quickly removes the pin. Then the screw. He easily discards the central bolt, which in turn allows him to shift the locking wheel. This then releases the final bolt. And, voi, he's reached the nut inside. Now for the second part of the experiment, the transfer test.

AUERSPERG

After the cockatoos had cracked the problem, we tested whether they were only running through a sequence of learned behaviors or whether they could react flexibly to changes.

NARRATOR

To make sure Muppet hasn't just learned the sequence by heart, Alice can change the lock sections around or even remove them entirely. This creates a completely new challenge for Muppet. Alice removes the middle part, the bolt. With the bolt gone, the upper section is now redundant, leaving only the lower parts in operation. The question is whether Muppet can see the new problem and work out a new solution. If he doesn't understand how the locks work, he'll repeat what he did before and go for the pin at the top. If he recognizes that the problem has changed and that removing the pin at the top is unnecessary, he'll go right for the wheel. So now, the moment of truth. Muppet ignores the pin and screw at the top and goes straight for the wheel. And then, the bolt. And he's in, in less than ten seconds. This is the first time Muppet's seen this configuration and he gets it right. Alice believes this provides crucial insight into his mind.

AUERSPERG

The birds in the transfer test spontaneously reacted to novel changes that they had never encountered before that indicates that this cannot be trial-and-error learning.

NARRATOR

Since Muppet went straight for the middle bolt, it seems he has some understanding of how the lock system works and can apply it to different problems. He's one of a small group of animals that can do this. But the problems are right in front of them. We humans can take problem solving a step further. We use our minds to project into the future. And anticipate problems before they even happen, and plan to avoid them. It's something we long thought only humans could do. But can these clever animals do it, too? There's a common behavior in the animal world which seems to be all about planning for the future. It's called caching. It's what squirrels do in autumn, hiding nuts in the ground so they can be dug up and eaten in the winter. Here on the island of Santa Cruz off the coast of California lives a bird that has caching down to a fine art-- the Island Scrub Jay, another clever corvid. Mario Pesendorfer is in the middle of a three-year project to find out more about them. We're looking at habitat called oak chaparral, which is home to the Island Scrub Jay, and it's dominated by these scrub oaks. And this is where the island scrub jays get their acorns. Scrub jays love acorns. But they aren't available all year round. On Santa Cruz, boom time comes in autumn when the oak trees drop their acorns. This is when the jays get busy.

PESENDORFER

They pick up the acorns and they fly with them somewhere and they hide them in the ground. And that's what we call scatter hoarding because they scatter their hoards all over the place. So they store their food for the winter all over their territory and then they come and get it back when it's raining and cold and there's nothing else that they can eat.

NARRATOR

Mario uses GPS to keep an inventory of the acorns the jays put away in hidden caches. There's quite a few to keep track of. In fact, each jay caches thousands of acorns. They take out 5,000 to 6,000 acorns a year out into this landscape and hide them all over in little cracks and crevices and below other plants. But of all of these, how many can they find again?

PESENDORFER

Of the 6,000 acorns that they cache, we think that they recover about a third.

NARRATOR

These scrub jays aren't the only corvids that cache food. Another American corvid, the Clark's nutcracker, caches seeds in even greater numbers.

PESENDORFER

It remembers up to 10,000 caching locations a year quite accurately, and they are often spaced up to 20 kilometers or 30 kilometers apart.

NARRATOR

The ability to remember thousands of locations is impressive enough. But these corvids go further. They have a sense of when they buried each piece of food and ow when they need to retrieve it.

JUSTIN GREGG

They know that if they hide certain kinds of food, they have a time frame, that they need to get worms, for example, faster than nuts because worms will rot. So they have to be faster about getting the worms. So it suggests they have a more sophisticated idea about the way that they are hiding their food.

NARRATOR

But how sophisticated? Could these birds really have a sense of time? It's a question that's greatly intrigued Nicky Clayton. She studies Western Scrub-Jays, close relatives of the Santa Cruz birds, also renowned for their caching behavior. Nicky wants to discover whether they can do more than just remember where and when they've buried food in the past.

CLAYTON

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 plan ahead?

NARRATOR

To find out, Nicky creates an experiment based on a very human annoyance-- waking up to find breakfast is off the menu. For six days, the birds are housed in this aviary, split into three zones. In the middle is the dining room where the birds are fed during the day. And at either end are the bedrooms where they are kept at night. But there's a twist. Kept overnight in this bedroom on the right, the birds are served an early breakfast. But kept overnight in this room on the left, they get no breakfast, and they go hungry till mid morning. The birds experience this daily routine for almost a week.

CLAYTON

So we give them three lots of experiences of waking up in the hungry room, and three lots of experiences of waking up in the room that serves breakfast. But the important point is that the birds themselves didn't know which room they'd end up in on any given day.

NARRATOR

But then, Nicky starts allowing the birds to cache food. She places trays full of sand in both the hungry and breakfast rooms. The birds can use these to bury dead grubs in. The question is, where will they choose to store the food? Nicky wants to know if the birds can use their experience of the hungry and breakfast rooms and plan for the future. For Nicky, the results are clear. The birds cache about five times as much in the hungry room as they cache in the breakfast room. The scrub jays store five times more grubs in the room where no breakfast is served than in the room where they are well-fed.

CLAYTON

They can imagine what they're 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.

NARRATOR

Nicky believes the jays' caching behavior is far more than mere instinct. She thinks they have a grasp of the past but can also anticipate future need.

CLAYTON

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.

NARRATOR

It's a skill that is very important to us humans.

TAYLOR

We're able to remember what we were doing yesterday, we're able to plan what we want to do tomorrow. And this ability to mentally travel in time has really allowed humans to take over the world in a way that no other animal species has.

NARRATOR

In humans, mental time travel is not a skill we're born with. It takes a while to develop. To demonstrate this, these children are about to undergo the candy challenge. The task is simple. Each child is given a piece of candy. They're told if they leave it uneaten, then they'll get a second one 15 minutes later. The question is whether they'll imagine their future selves happy with two candies, or will the lure of instant gratification be too much. It's a skill that some are clearly better at than others.

CLAYTON

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're at least four years of age.

NARRATOR

So whether you're a bird or a human, mastering mental time travel has its advantages. To solve new problems, it really helps if you can understand cause and effect, think flexibly, apply what you've learned to new situations, and plan into the future. It's a rare skill set, and the animals that have it are a diverse group-- from the chimps to the parrots to the corvids. So what's special about these animals? What could they possibly have in common?

CLAYTON

On the face of it, of course, crows and chimpanzees are very different.

NARRATOR

The key is not the physical nature of these animals, but the conditions that have made them what they are. There's some common pressure, there's something common about the environments or the experience of those animals through their life that's pushing them to become more intelligent. These animals live in challenging environments. Sometimes their favorite foods aren't readily available. They have to be flexible in order to survive.

GREGG

So there is definitely a relationship between having to find food in complicated ways, having to deal with new, ever-changing environments, and those things that we would put under the definition of intelligence.

NARRATOR

Having a varied diet and being flexible in their search for food seems to have increased their chance for success. But there's something else that chimps, crows and parrots seem to share. They live in groups.

HARE

When we see animals that can solve more complex problems than others, one of the threads that people are excited about is maybe it's something about the complexity of their social organization-- that animals that have to deal with social complexity are the same animals, the same species, that are solving many of these difficult problems.

NARRATOR

Whether they walk or fly, some of the best problem-solvers in the animal kingdom may not be quite so different from one anoer as they first appear. Researchers are trying to figure out exactly why complex social lives might create better problem solvers. Could one explanation be that the animals share knowledge? If they come up with a good idea, can they pass it on? New Caledonian crows have lots of good ideas. They are precision tool makers. This one is in the process of crafting something we'd normally expect only of humans. It's making a hook that it will use to catch prey. Alex Taylor is investigating whether these birds are able to share their tool making skills with each other. What the crows have done is, they've rounded off the end and they've actually carved out a tip onto the end of the tool. This tool works as a functional hook. Now, this is really impressive because no other species actually makes hook tools apart from ourselves, not even chimpanzees. And of even more interest to Alex are these-- intricately cut tools from the leaves of the pandanus tree. Unlike the hooks, there are distinctly different types of pandanus tool. This is a single-step pandanus tool. Essentially, it's a rectangular piece of leaf that's been cut out from a larger piece of leaf. But the crows have gone further than making a simple rectangle. They also make two-stepped tools. What we've got is a step. So now the end is nice and fine so the crow can get the tool into small areas. The third and most elaborate type of tool is called a multistep pandanus tool.

TAYLOR

This tool has a series of steps cut into it and it has that very fine tip and again that broad end.

NARRATOR

And across the island, different groups of crows use different types of these tools. In the south, more simple fragments are found, but as we move north the crows start to favor more complex, multistepped tools. That means that different groups of crows have their own ways of doing things. And in human society, we call this culture.

HARE

Animals are creating innovations, and they're actually passing them on to future generations by learning from one another. And basically what we can conclude is that there are many species of animals that have simple forms of culture. Humans are not alone for having culture, not at all.

TAYLOR

So we're seeing different populations that have a single tradition. We've been collecting tools for the last 15, 20 years and these traditions have persisted.

NARRATOR

So, are parents passing down these tool designs to their offspring? A rare glimpse of how this might happen has been captured on camera. Of all the birds, these crows have one of the longest juvenile periods, or childhoods. Youngsters stay with their parents for two years. Here, an adult bird is using a stick to probe for grubs hidden inside a log. A juvenile stands by and watches. The adult departs and leaves the stick in the hole. The younger bird can now try the tool out. Although this one has some way to go before becoming an expert like its parents. It looks like one way ideas spread through the crow population is through family groups, the social circle. And Alex's research suggests something even more extraordinary-- that with each generation of crows, the tools are honed and improved. The crow's tools have got progressively better over time. As they've passed on these tool designs between them, they've added small tweaks and this has made the designs more and more efficient. The New Caledonian Crow has only been closely studied since the early 1990s. In that short period, scientists have revealed problem-solving skills that seem similar to those of our closest cousin, the chimpanzee. But perhaps the most exciting thing is that we're just beginning to get a glimpse into the minds of these animals.

HARE

We keep finding over and over again that we share the planet with other animals that do remarkable things that we thought only we do.

NARRATOR

And who knows what else they might be capable of? The adventure continues online, This NOVA program is available on DVD. To order, visit shopPBS.org, or call 1-800-play-PBS. NOVA is also available for download on iTunes.