Something strange is happening in the forests of Africa.

Chimpanzees are doing things no one has seen them do before:

they're in a partying mood.

But that's not all.

At a site called Fongoli, in Senegal,

they have also invented a remarkable way of catching a meal.

They are making spears and hunting, just like our ancestors.

Are these apes developing human-like skills in their own environment?

After all, the great apes- chimpanzees, orangutans,

gorillas, and bonobos- seem so much like us,

it's hard not to feel a deep connection.

We have come to see that we're much more similar to them than we ever imagined.

But for every revelation about the power of their minds,

another shows up a stunning difference.

If you think that human genetics and ape genetics are 99 percent the same,

what we've managed to achieve in our current position on Earth is so strikingly different from that of apes.  (genetics-almost identical;  achievement-strikingly different)

We're trying to figure out, "What is it that makes us human?

What's the little difference that makes the big difference?"

How big is the gap between them and us?

What's holding them back?

 

In a remote part of Africa, there's something new under the sun.

Our closest living relatives are getting bold.

Chimps are supposed to be afraid of water,

but this young male is climbing down for a dip.

He keeps a hand on a natural safety line as he overcomes his fear.

Has a boy or girl ever had so much fun in a swimming hole?

Wild chimps have never before been seen playing like this.

At Fongoli, Senegal, anthropologist Jill Pruetz and psychologist Andrew Whiten

are getting an extraordinary glimpse of chimp emotions.

The personality of a chimpanzee is extremely excitable.

I've hardly ever seen a facial expression like that.

I mean, that was extreme excitement to the stage of kind of losing control.

It's not merely just to cool off. The juveniles have fun.

I mean, they play in the water. They play a lot in the water.

This is only one of a rush of discoveries

that is painting a surprising picture of ape minds.

They are more like us than most researchers ever imagined.

One by one, the skills and emotions we once thought were uniquely human

are being found in apes.

Still, specific mental gaps-

the little differences that make the big difference-

will ultimately explain why we study them and not the other way around.

 

While the swimming hole is revealing chimps' emotions in the field,

a new laboratory study is showing off their amazing rational powers.

At the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany,

psychologist Josep Call places a peanut inside a clear tube.

How can the chimpanzee get the snack?

She has never seen this puzzle before.

For 10 minutes, there is no solution in sight.

And all of a sudden, boom, they solve it.

They have to understand that they can use the water as a tool.

This is interesting, because the water itself, it doesn't have any shape.

Using water as a tool seems like something we would do... on a good day.

Another tool is being put to remarkable use by wild chimps in their quest for a meal.

Back in Senegal, Jill Pruetz has been keeping a close eye on chimps' eating habits.

Throughout Africa, chimps eat almost anything,

and they have a particular taste for meat.

Here, their favorite prey is the bush baby, a small nocturnal primate.

But these chimps aren't catching bush babies barehanded.

Pruetz has seen chimps making spears and using them to hunt.

Andrew Whiten hopes to join the ranks of the few who have witnessed this extraordinary behavior.

To make a spear, a chimp starts by breaking off a branch, then sharpening the tip.

All on the quest to capture a bush baby in its day time sleeping hollow.

So the next step would be that the chimp would approach the cavity

and sometimes look in,

take the tool,

jab forcefully into the cavity, multiple times.

It may not be ice-pick-sharp,

but when driven by an arm up to five times as strong as a human's,

it's a potentially lethal weapon.

They always either sniff it or lick it when they withdraw the tool.

What they may do is actually break open the entire cavity,

and if they're lucky, find a bush baby inside.

Break, strip, sharpen, stab:

these chimps take a series of distinct steps in a carefully premeditated hunt.

Pruetz and Whiten are closing in on the answers.

Most of the 20 spear hunts observed by Pruetz

have taken place during the rainy season.

Over time she has seen every stage of the kill.

A chimp is inspecting a hollow, looking for a bush baby.

She breaks off a branch and makes a spear.

The first time I saw a chimp make a tool, I think I said something like,

"Where is she going, and what is she going to do with that tool?"

She nibbles the tip to sharpen it.

Then, with the aid of her foot, she aims the point into a hollow.

Pruetz has made a landmark discovery.

Never before has any non-human species been known to routinely make and use deadly weapons.

So what does spear-hunting reveal about how chimpanzees think?

Pruetz and her team have seen about half the chimps here brandishing weapons,

which means spear hunting has spread through much of the group.

That seems natural to us.

But generating ideas and sharing technologies

is one scientific definition of culture.

For Whiten, culture includes the human arts from beer to Beethoven,

but it also covers the rudimentary traditions of ape societies.

Whiten is trying to discover what kind of mind can lead an ape to culture.

Young watch their parents, sometimes very intently.

And over the following months and years, they acquire that behavior.

So you have to be able to copy.

To prove that one ape can copy another,

a student of Andrew Whiten's devised an experiment.

At the University of Texas,

Antoine Spiteri has built a kind of slot machine for apes.

He loads it with a grape.

To get the fruit,

a chimp must first turn a disk to allow the grape to drop through a hole.

Next, a chimp must move a door that opens a handle to release the fruit pay-out.

Spiteri now trains a chimp named Judy how to work the device.

On her own, she'd never work it out, but thanks to a sweet liquid reward,

she learns the sequence is two steps:

rotate,

then push.

Next, Judy's group mates enter.

Spiteri wants to know if, just by watching,

the spectators will learn the technique.

Can these apes ape to win this food-finding game?

One chimp seems to think she's got it and shoves Judy aside.

A minute ago, Judy was the only one with the knowledge.

Now another has it, and, quickly, the trick spreads throughout the group.

But for Spiteri, the most important question remains.

Have the next door neighbours also learned the solution?

They have no social ties to the original group.

In fact, they are hostile towards them.

Would they set that aside to keep up with the Joneses next door?

In no time at all, they're working the slot machine like old pros.

Rotating, then pushing the handle.

Learning by imitation is an essential skill for culture.

And culture, along with the complex thoughts and emotions behind it,

was long believed to be uniquely human.

The history of Western thought has always been premised on the idea

that there are beasts and there are humans;

and humans are touched by the spark of God, and beasts are just beasts.

Something of a revolution came in 1960, when a young researcher,

with support from the National Geographic Society, set up camp in Tanzania.

Jane Goodall observed that chimps' emotions seemed much like our own,

especially the tenacious bond between mother and baby.

At a site in Western Africa,

Japanese researchers reported the story of an ill two-year-old chimp.

Her mother touches her forehead as if to check for a fever.

As the baby's strength ebbs her mother remains devoted.

When I see the scene of the mother looking at the baby,

I really recognize the emotional life of chimpanzees are so similar to us.

For weeks after the baby's death, the mother carries her baby's body.

Is the mother grieving?

Can an ape be in denial?

It's impossible to say exactly what the mother is thinking,

but hard to dismiss her feelings.

Putting ape emotions on the map was just one of Goodall's accomplishments.

She also found powerful evidence of their intelligence.

Goodall was the first to report chimps making and using tools-

in this case to "fish" for termites.

When she found termite-fishing, people were so surprised,

and thought we should change the definition of humans,

or we should include chimpanzee as humans.

What Goodall couldn't have known was that at a place called Goualougo,

other chimps had an even more sophisticated way to catch termites.

First they use a big stick like a shovel to open the ground,

then they switch to a slender probe to pull up the insects.

Perhaps Goodall's most astonishing discovery was that chimps are hunters.

She watched a troop catching colobus monkeys by hand.

Although no one has established that they coordinate their efforts,

the chimps appear to be cooperating.

And cooperation is, after all, one of the key drivers of human culture.

Could apes speed up their culture by working together?

Imagine a group of chimps, armed and dangerous, hunting as a band.

So why isn't the Earth the Planet of the Apes?

Do apes even have the capacity to cooperate?

 

A series of new studies reveals the rudiments of teamwork in the great apes.

But they still come up short.

In an experiment at the Great Ape Research Institute in Japan,

a chimp knows that food is hidden under a stone.

Researchers replace it with a heavier stone.

If two chimps each know about the food, can they work together?

In repeated trials, no pair of chimps has ever cooperated to synchronize their pulling.

If one chimp is replaced with a person the other animal still doesn't collaborate,

at first.

But, eventually, it figures out the sweet rewards of cooperation.

Ultimately, the chimp learns to ask for a helping hand.

A needy chimp may well recruit help from a human,

but will it ever offer assistance?

One of the most surprising findings of all of my years of studying apes

has been that they will actually help humans.

If you're reaching for an out-of-reach object,

if they understand what your goal is, then they will help you.

Of course if you've dropped your banana,

you can forget it, you won't be getting it back.

Chimps can understand what someone else wants.

One study shows that they can even interpret another's actions as good or bad.

In Leipzig, Germany, a chimpanzee is about to receive a tray of food.

At the same time he's given a rope under the platform,

he can pull at anytime to collapse the platform and end the experiment.

Another chimp now enters the cage.

This chimp is free to pull a second rope on top of the tray.

The first chimp is ticked off.

He pulls the hidden rope, and the game is over.

Was he just generally outraged?  (general=not specific)

Or taking specific revenge on the thief?

To find out, it is the researcher that now moves the food.

Once again the first chimp has lost his meal to the second.

All that has changed is who is responsible.

In trials where the researcher moves the food,

the first chimp is much less likely to crash the platform.

That would punish an innocent chimp.

So chimps have a sense of justice, and they can cooperate with people.

Can they collaborate spontaneously with each other?

Researchers placed fruit on a board just out of a chimpanzee's reach.

The chimps are behind bars to keep them from the food,

and because they can be impulsive, strong and dangerous,

When a solo chimp can reach both ends of a rope, it hauls them in and gets all the food.

But on some trials the ends are too far apart.

If the chimp pulls just one end, the rope unthreads.

The chimp has another option.

He can unlock a door to bring in a helper who's been watching.

The two chimps now work together.

But a series of trials shows that this teamwork doesn't come easily.

The helper must be a friend, and the food divided into separate dishes.

Can a more loving ape cooperate better?

At Lola Ya Bonobo Sanctuary in the Congo,

victims of the pet trade are raised by human mothers.

When these bonobos grow up,

they will spend their days outdoors, becoming savvy about life in the forest.

Bonobos are the most social of the great apes.

And in their groups, all friends are "friends with benefits,"

a simple way to diffuse tension.

Calmer than chimps, how do bonobos fare on the cooperation test?

Food is placed in a central shared well.

Ok, are you ready? One, two, three!

All the food is in the same dish, so it's very easy for one individual

to bump the other individual out of the way and steal it all.

It takes the bonobos a while to get on task.

But soon they get the hang of it.

Yay, bonobos! Yay!

With their more congenial temperaments, bonobos are more cooperative than chimps are.

In fact, bonobos may take cooperation even further.

When a young male died at Lola Ya Bonobo, workers were trying to remove his body.

The staff decided to use sticks and try to move the bonobo towards a door.

They mounted an incredible defense of this body

that surprised everybody and was extremely moving.

That's a fascinating reaction on the part of the bonobos.

They were not related to that individual,

and yet, they took extreme risks to protect his body.

As they fend off the humans, it seems as if they're cooperating.

But what does it take to work together?

Are they comparing the number of staff to their own troops?

Can they calculate at all?

At Kyoto University, Tetsuro Matsuzawa's experiments

are revealing that chimps can in fact develop an astonishing facility for numbers.

He first trained a chimpanzee named Ai

to touch the numeral that matched the number of dots.

Once Ai knew zero through nine,

Matsuzawa displayed the numbers helter-skeltered on a screen.

Ai quickly learned to touch them in ascending order.

In the final test, as soon as Ai touches the numeral one,

white squares cover up the remaining numbers.

Can the chimp possibly remember all the numbers and their locations

and touch them in order?

The performance was really amazing.

Much, much better than we had expected.

But for Ai, learning numbers was a struggle.

Almost the same amount of training was necessary to teach three,

teach four or teach five.

Or, even worse, it takes more time to teach five and then six.

Ai never got the feeling that children get

when they realize you just add one to get to the next number.

In the United States, another ape shows a surprising gift for language.

Going to go help get some sticks?

Good.

A bonobo named Kanzi, now at the Great Ape Trust in Iowa,

picked up English without being directly taught.

Put the keys in the refrigerator.

Wearing a mask to avoid cueing Kanzi,

researcher Sue Savage-Rumbaugh tests his comprehension.

Good job!

Go get the ball that's outdoors.

Very nice. Thank you, Kanzi.

Savage-Rumbaugh measures Kanzi's vocabulary at 3,000 spoken English words.