The following is a script from "Bonobos" which aired on Dec. 6, 2015. Anderson Cooper is the correspondent.Michael Gavshon and David M. Levine, producers.
Most people know that chimpanzees are our close cousin. They share over 98 percent of our DNA. But you may not know that we also have another primate cousin, just as close. They're called bonobos. They may look like chimpanzees but they are an entirely separate species of ape and their behavior couldn't be more different.
Bonobos are the only great apes that live in female-dominated groups and unlike chimps and humans, which are often violent and aggressive with each other, bonobos would rather make love than war. As Anderson Cooper on assignment for 60 Minutes discovered, they are an endangered species and only found in one place: the Democratic Republic of Congo in Central Africa. Congo's been torn apart by war for decades, keeping researchers away, which is why bonobos are the least-understood apes on the planet.
The world's only sanctuary for bonobos sits on the outskirts of Congo's capital, Kinshasa.
It's called Lola Ya Bonobo, Bonobo Paradise, and for these endangered apes, that's exactly what it is.
This refuge was created by conservationist Claudine Andre, she's Belgian-born but has lived in Congo most of her life. If you ask her why she cares so much about bonobos, she'll tell you: just look into their eyes.
Claudine Andre: The way they look in your eyes, deeply in your -- just like they look in your soul.
Anderson Cooper: In your soul.
Claudine Andre: Yeah.
Anderson Cooper: And it's rare that, most primates don't maintain eye contact like that.
Claudine Andre: Yeah, because don't try to do this with gorilla, you know. And--
Anderson Cooper: Right. It's a threatening gesture if you do it with a gorilla.
Claudine Andre: Yeah.
Anderson Cooper: But bonobos look right at you.
Claudine Andre: Oh yeah.
Bonobos may have a brain that's a third the size of ours, but they're remarkably intelligent.
Those high-pitched screeches are a sophisticated form of communication and their gestures are unmistakable.
Like chimpanzees, bonobos use tools in a wide variety of ways, and are capable of abstract problem-solving.
Claudine Andre: She have a baby. So she cannot go deeply...
Anderson Cooper: So she's breaking the stick actually?
Claudine Andre: Yeah, she shows the stick is too short.
Anderson Cooper: OK. So she got a longer stick. That's amazing. So she's using the stick to see how deep the water is?
Claudine Andre: Yeah.
Bonobos are unique among great apes because they are not dominated by males. And according to Brian Hare, a Duke University evolutionary anthropologist who studies them at Lola, it's the females who run the show.
Brian Hare: Here if you try to be in -- an alpha male, you will be, as the Congolese say, "corrected" by the females.
Anderson Cooper: Not just by one female, but by a sort of alliance of females?
Brian Hare: That's right. That's right. And one of the -- they -- they -- bonobos really violate a rule of nature where usually if you're bigger, you're going to be dominant. But here, females are actually smaller. But they're still not dominated by males because they work together.
What's more, bonobos have never been observed to kill each other. The same can't be said of chimpanzees, or of humans for that matter.
Brian Hare: Bonobos, on the other hand, they don't really have that darker side. So that's where they could really help us is how could it be that a species that has a brain a third of the size of ours can do something that with all our technological prowess we can't accomplish? Which is to not kill each other.
The answer might be found in bonobos' favorite pastime. These apes have more sex, more often, in more ways than any other primate on the planet. Their sexual contact is so frequent, Brian Hare refers to it as the "Bonobo Handshake"...
Anderson Cooper: It's not that they want to procreate or have kids, it's not that they even find each other attractive?
Brian Hare: No.
Anderson Cooper: It's -- it's just --
Brian Hare: No, it's a negotiation.
And it's hardly surprising that many of these negotiations take place over food.
Anderson Cooper: Chimpanzees will fight each other over food.
Brian Hare: That's right. They--
Anderson Cooper: Bonobos won't necessarily fight each other--
Brian Hare: That's right. So they -- so, basically, chimpanzees get primed for competition, testosterone increases. Bonobos, they get really stressed out. And if they feel like they're not going to be able to share, they get really anxious, and then that drives them to want to be reassured. And they then happen to have a bonobo handshake to feel better.
Anderson Cooper: And males do that with females, males will do that with males, females will do that with females, doesn't matter, even the ages?
Brian Hare: Any combination. Any age.
It's an irony that this peace-loving primate is being hunted to extinction. Though it's illegal to kill or capture bonobos in Congo, that hasn't slowed their rapid decline.
Forest animals are sold in bustling bush-meat markets for food. At the largest in Congo's capital, Kinshasa, you can buy monkeys, porcupines, even alligators -- dead or alive.
"[Bonobos] are not us and we are not them, but we have a line in the middle of the two world that we cross all the time."
Bonobos aren't openly sold here anymore, but you can still buy them in many parts of Congo. Their orphaned babies often end up in the only place that can care for them, Lola Ya Bonobo. The babies arrive traumatized, often injured. Each is assigned a surrogate human mother, and their job is to raise the babies as their own, showering them with the love and attention the orphan apes so desperately need.
Anderson Cooper: It's incredible to see them up close like this. I mean, they are so--
Claudine Andre: Yeah, human?
Anderson Cooper: Yeah.
Claudine Andre: Yeah, you know, I say all the time that, for sure, they are great apes. They are not us and we are not them, but we have a line in the middle of the two world that we cross all the time.
Baby bonobos are as playful as any human toddler and just as curious.
Suzy Kwetuenda would know. She's in charge of the bonobos' welfare at Lola and oversees their rehabilitation.
Anderson Cooper: You have a child of your own?
Suzy Kwetuenda: Yes, I have.
Anderson Cooper: How are they different?
Suzy Kwetuenda: I can say there is no more difference.
Anderson Cooper: There's not difference--
Suzy Kwetuenda: The same.
Anderson Cooper: Course really have to be a mother to--
Suzy Kwetuenda: Yes.
Anderson Cooper: --to this baby?
Suzy Kwetuenda: Yes, and most of time, you need experienced mother to--
So, they give love and affection, and this is the only way to save them.
Anderson Cooper: That-- that's what saves these--
Suzy Kwetuenda: Yes.
Anderson Cooper: --these babies?
Suzy Kwetuenda: And make them in life.
Anderson Cooper: They need love?
Suzy Kwetuenda: They-- yeah. They-- yeah. Absolutely. Without that, they die.
Suzy decided to study bonobos because she felt they could teach us a lot about human evolution. After five years at Lola, she realized that their behavior is closer to ours than she'd ever imagined.
Anderson Cooper: Is it hard not to think of them as human?
Suzy Kwetuenda: Yes. Yes, because we share most of time with them. We share time with them. Yeah--
Anderson Cooper: Right, you spend all day with them?
Suzy Kwetuenda: All day.
And at the end of that day...Suzy sees to it the babies are tucked into their hammocks for the night. At 6 p.m., it's lights out.
Anderson Cooper: Do you read them a story?
Suzy Kwetuenda: No, they don't need, 'cause they are tired. They spend all the time jumping in trees, playing so much as now--
Anderson Cooper: They're exhausted?
Suzy Kwetuenda: So that's-- yeah, they are very exhausted.
By age five, the orphaned apes move from Lola's nursery to the kindergarten where their peers teach them something their human mothers never could. They teach them how to be bonobos.
They still crave affection but they're also more confident, and have started developing their own distinct personalities.
Claudine Andre: He's the one who like jump.
Anderson Cooper: You want to jump? (laughter) I can't work under these conditions. It's very hard to conduct an interview like this.
Claudine Andre came across her first bonobo 20 years ago. The country was wracked by violence and on the verge of a brutal civil war. She volunteered to help at a local zoo and that's when she saw a baby bonobo, though the zoo director warned her about getting too close.
Anderson Cooper: He said, "Don't put your heart in this animal."
Claudine Andre: Yes. It's a bonobo. A bonobo. It was the first time for me I hear this word. And he say they never survive in captivity.
Anderson Cooper: So he was warning you, "Don't fall in love with a bonobo, because it's gonna die.
Claudine Andre: Yeah, but it was a sort of challenge.
There are now more than 70 bonobos at Lola. Many of the original orphans have children of their own.
But to save these primates from extinction, their numbers in the wild will have to grow. Six years ago, the team from Lola decided to try to release some back into the forest. Nothing like it had ever been done with bonobos before.
They hand-picked nine apes who they thought would do well on their own.
Anderson Cooper: They have to be able to get along in a group as well as be strong themselves--
Claudine Andre: Yeah. Yeah. Yeah. It's just like you chose people to go in the moon.
It's not quite the moon but the site they found to release the bonobos is about as remote a place as you can find on the planet.
It's a three-hour flight deep into the wilderness of Northern Congo. Then a long slow ride up the Lopori River in a dugout canoe.
Life along the river hasn't changed much in centuries. Congo is one of the least-developed countries in the world, and has millions of acres of virtually untouched forest.
It may look pristine, even peaceful, but many of the people who live in these parts have suffered from years of war. The wildlife here was decimated.
Anderson Cooper: So the bonobos disappear from this area because of hunting?
Claudine Andre: Yes, yes.
Anderson Cooper: For bushmeat. And also, during the war, soldiers would hunt here.
Claudine Andre: Yeah.
We were taken to the spot where that first group of bonobos was released.
For a while, we couldn't see anything just dense forest spilling over the banks of the winding river.
Then, Claudine began calling out the names of the apes she herself once mothered all those years ago.
Claudine Andre: Vous etes ou? They know it--
Anderson Cooper: That's crazy. They respond to you--
Claudine Andre: They responding to me. They know I'm here.
We still couldn't see them but they could hear Claudine and suddenly the forest was alive with the sound of apes, excited to hear her voice once again.
One by one, the bonobos came to the water's edge to see the people who'd saved their lives.
Claudine and her team weren't sure releasing bonobos back into the wild would work and although some had trouble adapting, most now seem to be thriving.
That's Etumbe, the bonobo Claudine is perhaps most proud of. For 17 years, she was trapped in a tiny cage at a Kinshasa laboratory. Now, she's the leader of the group.
Claudine Andre: And she give us a first baby born here. So-- is my friend. Or my sister.
Anderson Cooper: Your s-- your family.
Claudine Andre: My family.
This is as close as Claudine allows herself to get. Now that they're wild, she doesn't want the bonobos to get used to humans ever again.
Anderson Cooper: Do you still find it thrilling when you suddenly see them after all this time?
Claudine Andre: Oh yes, oh yes. It's also-- so nice present to return to the wild and be free.
Anderson Cooper: This is what you dreamed of?
Claudine Andre: Yes.