Of the 20,000 lions left in the wild, only 3,500 are male. Poachers are partly responsible, but lions themselves are to blame for the fact that only one in eight male lions survive to maturity. As the new documentary “Game of Lions” depicts, lions fight for dominance of the pride, and those who lose are cast out are vulnerable. Premiering December 1 as part of Nat Geo Wild’s Big Cat Week, the feature is from award-winning wildlife documentarians and National Geographic Explorers-in-Residence Dereck and Beverly Joubert, who spent two years in the African Bush acquiring remarkable footage of lion behavior.

MNN: What was your approach and goal going into the film?

Dereck Joubert: We wanted to discover something ourselves, and investigate what happens to young males. What that means is that while we know the subject really well, we also want to keep it exciting for ourselves, so a journey of discovery is important to us. No one really knew what happened to young nomads and what makes a successful male challenger. We choose locations with great lions we live in one called Duba Plains in Botswana and we wait for a batch of young males and then throw everything at it, every moment we can. It’s a little like a professional sport: you prep, get fit, focus, then run onto the field ready for whatever nature can give us, knowing that we can capture it, get it in focus and will compose and make sense of it.

How does this compare to your previous films?

It isn’t different, really. Even though the last film, “The Last Lions,” was a theatrical feature film, it takes the same dedication and focus. Same cameras, different budget, perhaps, but for us this is a passion that verges on obsession.

How do you get such up-close and intimate footage?

There is no real substitute for doing the time. Living with lions in the bush gets one a lot of exposure, but it also allows you to get an intimate knowledge of each lion. Sometimes that means they get to know us well too, so often these lions are very comfortable around us. It takes weeks to get a new lion to accept us, but once they do, we can get quite close. Our average or ideal distance is about 30-40 meters.

How did you become interested in the big cats?

We went into the wild to discover the real Africa. From university and other education in textbooks, we understood that the top predators give the best indication of the ecosystem, so while I had studied geology and knew rocks and soil types, starting for real with big cats made sense. But what we found was a major life changer for us. I expected to find a large killing cat. What we found instead was a predator so socially complex we still have not found out everything we can about them. We found gentle animals that are professional and expert at what they do, which is largely killing (and sleeping), but mostly we went on a journey into a world icon and why it has captured the imagination of men, women, kings, everyone for hundreds of years. They are regal and we aspire to be like them. We also live in abject fear of them in many places in the world. For Beverly and me, looking into the eyes of a big cat is breathtaking. Literally, it takes our breath away because the sheer beauty and raw power is amazing, but it is also amazing that we are in the presence of a miracle, one that we are playing a part in, the eternal dance between Man and Lion that has been a 3-million-year one.

Did any of the behavior surprise you?

Definitely. We came through the bush and saw seven young males playing with something in the grass. At first I called it as a tortoise they were hassling. Then we heard the cries of an 8-day-old cub. They badgered this and two other cubs the whole day and finally killed and ate one. The big surprise I suppose was that the mother arrived and rescued two cubs from the jaws of death as they clung to the riverbank as the water was rising after a storm. It’s an incredible scene!

You include footage of poaching, how prevalent is it?

We have filmed poachers, although not very well because while our policy is to not interfere, that does not extend to people who are damaging or threatening wildlife, so we have seen poachers and driven or run at them to stop them. Mostly they run away, or used to. Who knows in the future; I think we are on the brink of what we are calling “The Battle for Africa,” where the poaching of lions, (now at five a day) elephants, (at five an hour) and rhinos (at one every nine hours) is an epidemic that will destroy Africa, not just African wildlife.

What does Jeremy Irons bring to “Game of Lions” as narrator?

More than you would imagine. He brings a perfection and voice, obviously, but he reads the script with such authority that it reeks of credibility, and so it should. Jeremy has been a friend and collaborator for 12 years now, on seven films. So he understands every sentence and the behavior that is being described. If he does not understand what I have written, we stop, I convince him that it is correct or we change it. We have come to know Jeremy as a man of such professional integrity and character and personal mettle that very few have.

What’s the takeaway for viewers?

That life is damned hard, for everyone, young males no less than some. We can all handle the obstacles because we are genetically attuned to handle things in our path that we have handled over generations. What throws us are the new things that we have never had to deal with before. In the young lions’ case, they survive incredible hardships and then when they make it because they are the strongest, the bravest, the best, they get killed for exactly those qualities--by hunters! The real takeaway is that we cannot keep killing these precious animals just because we think it’s a cool sport to do so; we are doing irreparable damage to the future survival of the species and of us all.

New film plays a 'Game of Lions'
The documentary, part of Nat Geo Wild's Big Cat Week, examines pride politics among Africa's vanishing lion populations.