Discovering the secrets of lions

The following script is from "Lion Kings" which aired on Nov. 25, 2012. Lara Logan is the correspondent. Max McClellan, producer.

Dereck and Beverly Joubert have spent more time filming and living among lions in the wild than anyone alive today. The discoveries they've made over 30 years of wildlife filmmaking have challenged conventional wisdom about Africa's big cats.

They've made more than 20 films for National Geographic, where they are "Explorers in Residence."

They live in Botswana in the heart of southern Africa, a country about the size of Texas.

The Jouberts often go long stretches without seeing another human being, but they made an exception for us, and allowed us to join them in a wild place they call home.

For information on the Big Cats Initiative, click here

Their films are known for these spectacular cinematic moments. But what distinguishes their work is their belief that all the animals have untold stories which they bring to life in their films.

To get to the Jouberts, we flew to this remote landing strip, but we couldn't land until these wild baboons were cleared from the runway.

It didn't take us long to discover why they decided to make Botswana's Okavango Delta their home. This is one of the last untouched places on earth, a labyrinth of watery channels and rolling savannahs that are home to some of Africa's most beautiful creatures.

But it was the lions that drew the Jouberts here and for most of their lives they have lived among these animals, making some of the greatest wildlife films ever made.

Dereck Joubert: We've spent thousands and thousands of hours with them. We've spent more hours with lions than we've done at university, school, with either of our parents. So this is our family in many ways.

Dereck does the filming and writes the scripts for their movies. Beverly records sound and takes pictures. She's a world class photographer.

Each film takes years to make. They followed this lioness they call Ma di Tau for seven years and they made a movie about her called, "The Last Lions."

[Jeremy Irons: Today, Ma di Tau, "Mother of Lions," earns her name as protector of her young.]

The film told the moving story of her battle to survive alone with her three cubs.

Beverly Joubert: One thing that we have learned, and it's been a hard lesson, is that we can never predict what is going to happen.

Dereck Joubert: First of all, a cub was taken by a crocodile. And then later on, sadly, another one was injured.

Stampeding buffalo had badly wounded the cub. Just as any mother would, you see Ma di Tau go over to it. She tries to take it with her. But there's nothing she can do and her survival instincts take over.

Dereck Joubert: When we filmed it, I sort of said to Beverly, "Let's just cover this, because we'll never use this. This is too, too sad, and too -"

Beverly Joubert: Too traumatic at the time. I mean, it's too traumatic for us to even witness it.

Lara Logan: Tell me about that moment.

Beverly Joubert: It broke our hearts in so many ways because we knew that it was hopeless. I mean a little cub dragging its body, a broken back. What, what could she do?

Dereck Joubert: She was struggling with what we can only assume is emotions. And coming to terms with it. Because after that, she blinks, she, she swallows, she looks around. And then she steps away from her cub for the last time.

Dereck and Beverly took us deep into the delta to see the lions. First, we had to cross this bridge which you can't see, because it's mostly underwater.

Beverly Joubert: Think of crossing this at four in the morning in wintertime.

Lara Logan: And it's pitch dark

Beverly Joubert: And it's pitch dark.

The channel is full of crocodiles.

Dereck Joubert: And it's about four meters deep here. So if we tipped in now we would lose the vehicle.

Lara Logan: And how safe is this bridge?

Dereck Joubert: No, it's not too good, ay?

Water has claimed three of their trucks already. And out here, their vehicle is everything. It's where they work and often sleep, staking out the animals for months at a time, waiting for those rare moments that make their films so memorable. They have no doors and no protection.

Dereck Joubert: We've been charged by lions a lot but they've never scratched us.

Lara Logan: What is it liked to be charged by a lion?

Dereck Joubert: It's fairly dramatic ya know. We've had some where they come out of nowhere and it's roaring and, and fiery eyes and right in your face and, and flared up manes and kicking dust all over you. Very dramatic.

They told us they never want to influence the lions' natural behavior, so they usually try to keep their distance, but as we found, you never really know what's going to happen.

Beverly Joubert: She's coming to us for shade. Yep. She's lying in our shade.

As Dereck leaned down to get a closer shot...

Dereck Joubert: Can someone hang on to my belt?

His camera was staring straight into the young lion's face.

Dereck Joubert: It's rare, we almost never get this top angle.

Lara Logan: It takes you years, huh, to make these movies?

Dereck Joubert: Takes us forever. And it's slowly piecing together good scenes and good opportunities like this. Unusual angles. And just getting to know the lions well and understanding what they do.

They've been searching for stories in the African bush since they were in their twenties. Early on they decided to concentrate on documenting lions at night.

For the next 15 years, they worked in the dark, and what they documented changed what we know about these wild animals.

Beverly Joubert: The night opened up a veil of what was happening and nobody had ever seen that in Africa before.

They filmed these bloody nighttime battles between lions and hyenas, images that inspired the producers of "The Lion King" and shattered the myth that hyenas were just scavengers.

Dereck Joubert: And we were finding exactly the opposite. A lot of the times hyenas were making the kills. And the lions were rushing in and scavenging from the hyenas.

In the middle of another hot summer night, they documented something else that surprised the scientific world.

Beverly Joubert: All of a sudden, I saw eight lions just move forward.

Dereck Joubert: It was a spectacular scene.

A pride of lions attacked this fully grown elephant.

Dereck Joubert: We'd never seen an elephant this size being attacked by lions.

Dereck Joubert: Halfway through the sort of elation of us, bleary eyed, saying, "We're capturing something amazing here," I heard her start to say, "Come on, get up--"

Beverly Joubert: Get up.

Dereck Joubert: "--now. Get up now." So she started to root for the elephant.

Beverly Joubert: Yeah, the compassion towards that elephant. You know, I was filled with it. And I was just rooting for her.

Dereck Joubert: I say that death begins in the eyes. And we've seen this so many times with animals where they give up hope.

Beverly Joubert: And all of a sudden you saw her swing her body and she rocked and rocked. And she fought for her life. She truly did. She pulled herself up.

Dereck Joubert: And forces through. Goes through that wall and survives. And, and then she charged off into the darkness.

They still film at night when they need to but most of the time they work long days that begin before dawn. Their refuge is their home, this tent sitting in the middle of nowhere, looking out over the delta. It's what they call 'their paradise.'

Lara Logan: It doesn't get better than this. No you're right. No, this is fantastic.

Beverly Joubert: This is our bedroom

Dereck Joubert: This is our bedroom and office ... and sort of research area as well.

Lara Logan: Wow, it's beautiful.

Dereck Joubert: So yea, this is largely where we spend our time.

Lara LOgan: OK, so I'm being nosy now, do you have a bathroom back here?

Beverly Joubert: We have a bathroom. It's not necessarily what you would be used to.

Beverly Joubert: Showering and bathing with nature all around you is just truly fantastic.

Dereck and Beverly have been together for 36 years, and most of the time, they're within about three feet of each other.

Dereck Joubert: You know, we wanted to go out into Africa. And we fell in love and we fell in love with that lifestyle and with this place. And that means together-- not separately. And I think that's, in many ways, what defines us.

They told us what keeps them going after all these years is the thrill of making new discoveries. They were among the first to discover and document these large lions, some call "super lions," who've learned how to live and hunt in water.

Lara Logan: It was thought that lions hated water?

Dereck Joubert: Yes, exactly. And rightly so, we've filmed lions in other areas that after a rainstorm, they put their paw in and they hate it. They - you know what cats are like.

Lara Logan: But not here?

Dereck Joubert: But not, not in Duba. And so we saw these lions swimming in deep, ya know, just getting their noses out.

Beverly Joubert: Their physique started to change. You could see that they were getting huge pectoral muscles and huge necks. These lions were at least 15 percent larger than any other lions we had been working with.

It's not only lions they film. They spent three years following this leopard and captured one of the most extraordinary moments in wildlife filmmaking. This baby baboon's mother had just been killed by the leopard. Instead of killing the baby, the leopard cared for it throughout the night, trying to keep it alive.

Dereck Joubert: But another example of a scene that, that we were able to capture that nobody had ever seen before, nobody had ever heard about before, and is almost unimaginable.

Lara Logan: Before you documented it, no one would have believed that was possible.

Dereck Joubert: I think that very often when we start talking about the things that we've filmed, we do get pushback from some scientists saying, "That's impossible." And thankfully, then you show the film and it advances science in many ways.

Today, they feel an urgency to do more than make films. And they've teamed up with the National Geographic Society to create the Big Cats Initiative, trying to draw attention to the fact that the number of big cats in the wild is falling fast, particularly lions.

Dereck Joubert: In our lifetimes, we've seen those numbers go down from 450,000 to just 20,000 so we are in fact filming the last of those lions. I mean this could be the very last couple of generations of a species that's been on the planet for three and a half million years.

For their next film, Dereck and Beverly were going back to the story of their lioness, Ma di Tau, trying to find out what happened to her last surviving cub. This is him two years ago, the last time they saw him. When we joined them they were starting to believe he might be dead.

Beverly Joubert: It's physically hard, and it's emotionally hard. Because, we're getting to know an animal and then see some, desperate, traumatic situation happening to it and that is emotionally draining.

It's Dereck's job to track and on our second day, he spotted lion prints in the sand. Beverly is constantly scanning and searching the bush.

Beverly Joubert: This might be our cub, oh my gosh. This is giving me chills.

Dereck Joubert: Oh, This is him. This is him, all right.

They know it's him from his whisker pattern which is like a fingerprint.

Dereck Joubert: He's developing his mane--

Dereck Joubert: --quite a mane.

Beverly Joubert: Yeah.

Dereck Joubert: He's looking quite good. He's looking handsome as hell.

Lara Logan: He is. He is handsome.

Dereck Joubert: I had actually written him off. I thought that he was gone. And so seeing him is a bit like reuniting with family. We spent a lot of hours with this guy.

As we watched, more lions wandered towards us. And we realized, we were exactly where the Jouberts like to be.

Lara Logan: Are we literally surrounded by lions in every direction at this point.

Dereck Joubert: We are aren't we.

Beverly Joubert: We are.

Dereck Joubert: So we've got Ma di Tau and her cubs out there.

Beverly Joubert: With another female.

Dereck Joubert: We've got the male and female here, the young male over there and the little female out in that direction. So there's no way outta this one.

Lara Logan: How long can you two keep doing this?

Dereck Joubert: I think forever. I think that this is our calling in life. I can't imagine doing anything different. Giving this up and then what? Living in New York? I don't think I'd fit in there.