Forget The Lion King and its "Circle of Life" – Disney's depiction of a brave Africa kept perfectly in balance by nature's biggest predators may be no more than a fairy tale within a generation. This is the shocking prediction of Dereck and Beverly Joubert, the world's most famous living big cat conservationists. They have been in London this week to launch a show of Beverly's stunning wildlife photographs at the National Geographic, for which they are Explorers in Residence, but they are more anxious to get over an alarming message that has been falling on deaf ears.
For nearly 30 years living with lions, leopards and cheetahs in the bush, the impossibly glamorous but utterly dedicated couple has been watching the subjects of their life's work disappearing before their eyes.
"There were 450,000 lions when we were born and now there are only 20,000 worldwide," says Dereck, white-ponytailed and ramrod-straight at 55. "Leopards have declined from 700,000 to 50,000, cheetahs from 45,000 to 12,000 and tigers are down from 50,000 to just 3,000," his elegant wife and collaborator adds.
The bleak prospect is that our grandchildren will never be able to see these animals – or even the elephants, buffalo, zebra and antelope who survive by fleeing their predators – in the wild.
"We're expecting mass extinctions of big cats within 10 or 15 years unless something is done about it," Dereck says. He's looking to African governments to do this, without whose change of heart and legislation all efforts to save the beasts will be fruitless.
"Look at tigers – despite all the conservation efforts going on around them, there are less than 900 left in India, and whatever happens to tigers will happen to lions. We are in real trouble."
"Every year, 600 male lions are taken legally in safari hunts in Tanzania, Zimbabwe, Namibia, South Africa, Zambia – seven countries in total," Beverly adds. "You can shoot leopards in all those countries too, and 2,000 a year become a legal hunting trophy."
What does it mean? "If you take out the top predator, you remove the impetus for migrations to happen," says Dereck, who with his wife has won five Emmys, a World Ecology Award and an induction into the American Academy of Achievement as well as an order of merit from Botswana. This is now their permanent home; they live there among the cats for nine months at a time before venturing back into civilisation for a quick blast of editing and urban life.
"Take the predator pressure away and elephants and buffalos will stay in one place, picking up diseases," he explains. "They'll work the same waterhole, defecate in the ground they're feeding on and the parasite load will increase.
"The jackals and hyenas will multiply without lions preying on them, knock out the medium-sized prey like antelope, impala, zebra and wildebeest, and then start collapsing themselves.
"You'll end up with big prey species like elephants growing in intense numbers and then imploding, with everything below them wiped out. If we were systematically trying to kill off the world's top predators, we couldn't do a better job of helping the ecosystem towards destruction."
It's a story the couple claim the world just doesn't want to hear.
"No one's talking about it because they don't have any solutions. The story of Africa today is that the big cats are disappearing – and that's something we could take action to prevent."
With the National Geographic behind them to fund films such as The Last Lions, a cinematic release which this year gave them an opportunity to create some human empathy for the scary cats, the Jouberts pray the animals who have been their neighbours for more than a quarter of a century will still be around for them to study, film and learn from by the time they become pensioners.
"Lions – which are very social animals – and humans have so many parallels, we have been able to take many life lessons from them," Dereck says.
The first is the power of companionship to aid survival as well as lend comfort: "If a lioness is sick, she can be a passenger for a day or two and feed with the pride, unlike leopards, who are solitary animals hunting in the forest," he says. "The day she gets sick, that leopard is going to go hungry."
"When we watched the lions hunting buffalo, it was so hard for a single lioness, but we knew when they worked together they would be successful," Beverly adds. "At the same time, if the buffalo herd stayed strong, and kept all their horns facing out, they would be fine until one of them created fear and paranoia and they were disturbed – then we knew the lions would make a hit."
The second lesson is that humanity must hold together because fear and paranoia lead to self-destruction. "Governments, politicians, religious leaders build on the fear embedded on us when we're children – we need to understand the fear within ourselves and become more balanced."
The value of teamwork is a third lesson to be learnt, they say. "Eight to 10, the size lion prides form themselves into, is also the most effective size for a human team. At that size you can get things done and have personal relationships with the others in the group. A group of 50 will start to create a common enemy and break back down into groups of eight to 10."
While they are distinctly unsentimental – "we never intervene with what we see happening and make a conscious decision not to engage with the animals" – they have learnt that a little engagement is what may ultimately persuade humans to help to save threatened species.
"We had to deter the little leopard we followed for three years who astonished us by climbing into our vehicle, because we wanted to maintain her trust without compromising her integrity in the wild," Dereck explains.
They did it by turning on the engine of their vehicle to mimic the growl of a disapproving mother, and Legadema, the subject of their film Eye of the Leopard, never jumped into the car again.
"She convinced us we had to do something for them because we understand so clearly that with poaching for bush meat, poisoning by cattle farmers, safari hunts for sport and the trade in medicinal plants, only by creating real empathy for the cats do we have a hope of arresting what will otherwise be an irreversible decline," Beverly says.
The reason they allow themselves hope comes from a final life lesson they learnt from Legadema, who turned out not to be a very good hunter. "What we learnt from her is that with determination and perseverance, keeping on talking to more people, trying to put over the message even if no one appears to be listening, you can prevail," Dereck says. Given that these Emmy winners have cultivated an audience of more than a billion wildlife enthusiasts, you can only hope there's at least half a chance they might get heard.
'Living with Big Cats' and 'Big Cat Odyssey' are out now on DVD.
Visions of Africa will show at the National Geographic Store in London's Regent Street until 5 September