Only prey runs from a lion. You might escape a buffalo with a desperate sprint for a nearby tree, while a dash and body swerve could evade the full-blooded charge of an angry rhino. But lions are different. Faced with a wild lion, millions of years of evolutionary pressure crushes your senses and floods your brain with urgent messages to fight or take flight. Either would be suicide. A lion will wait for you to make that first move, so you must stand your ground, avoid eye contact and wait for the beast, tired of the game, to lose interest. Then, and only then, edge slowly backwards towards the rest of your lucky, lucky life. That, at least, is the theory.

Lawrence Anthony, a rugged South African with decades of experience with wild animals, knows the theory well. In spring 2003, he was walking through a patch of knee-high grass when he saw the distinctive twitch of an ear. He knew it belonged to a large male lion. He saw another of the animals, and then a third. Without knowing it, Anthony had wandered into a pride of four starving lions, two of which were slowly padding towards him.

"The golden rule is that you stay dead still, you don't make a fuss, then you gently back off," he says. "Well, that all went out of the window. I didn't know how big they were and then one stood up. I thought, that's big enough, and I just turned and bolted."

These were no ordinary lions, and they, and Anthony, were far from their African home. The lions were in an enclosure in downtown Baghdad, at the grand palace of the late and unlamented Uday Hussein, son of the former Iraqi dictator.

Anthony had travelled to Iraq not as a soldier, but as a conservationist. And he had gone to Uday's palace to save the lions as part of an unlikely wartime animal rescue. Just days after the US and Britain launched their invasion of Iraq, Anthony was leading a ragtag group of locals, former Iraqi fighters and off-duty US soldiers, united by their love of wildlife, in an extraordinary effort to save the Baghdad zoo and the terrified animals that called its wrecked cages home.

Home for Anthony is the South African game reserve, Thula Thula, which he shares with his wife Françoise, some 30 miles inland from the port town of Richards Bay, 100 miles along the coast from Durban. A sprawling oasis of brown scrub and trees amid an unnatural green desert of planted sugar cane, the reserve and its animals offer a focus for his lifelong passion for conservation and wildlife. Tall, bearded and a heavy smoker, Anthony looks every inch a bushman.

Sat on the terrace at Thula Thula's tourist lodge, as monkeys chatter in the trees, Anthony recalls how he watched the 2003 US's shock and awe bombardment of Baghdad on TV.

"I knew Baghdad had the biggest zoo in the Middle East and I couldn't stand the thought of the animals dying in their cages. I contacted the Americans and the British and said, 'You have any contingency plans?' Nobody was interested. I couldn't get any support from anybody so I thought, I'll just go. I went there for the animals."

Stories of how thousands of animals perished in Berlin and other German zoos during the second world war made a big impression on him as a child. "I remember being shocked that the animals weren't in Africa, that they were in zoos and that they were killing them there. When Iraq invaded Kuwait they killed all the animals in the zoo. The same thing happened in Kosovo and the same thing happened in Afghanistan. I just thought that somebody should be taking responsibility."

Within days he was on the Kuwait-Iraq border, in a hire car packed with veterinary supplies, trying to talk his way into a rapidly emptying country. "When I got there the tanks were going into Baghdad already and the Americans wouldn't let me cross the border. Nobody would let me in. Then I realised it wasn't the American border, it's the Kuwaiti border, so I went to the Kuwaitis and they said, 'Sure you can go in'."

Television pictures of smiling Baghdad citizens cheering US troops suggested the situation in the city was under control. So, with two Kuwaiti zoo workers, Anthony joined the tanks and convoys in his car and began the all-day drive to the Iraqi capital. A US soldier at the border, after incredulously asking if they realised the country was at war, said to keep their heads down as the trio were the first civilians in, apart from journalists. "And they don't count."

Ignoring advice to drive on the main roads for fear they would be targeted, they took back roads to Baghdad. "It was just like a holocaust had gone through. We got half way and realised we shouldn't be there. This war is still very much on. But we'd come through some areas there was no way we could go back through, so we just had to keep going. There was no bravery involved. It was just naivety. I thought I could get in easily. And then when I got in I found I couldn't get out."

Anthony worked in Baghdad for six months, during which time he transformed the fate of the zoo, in the ruins of the city's once majestic al-Zawra park. Of 650 animals at the zoo before the invasion, just 35 were still alive when he arrived. The rest had died in their cages of thirst and hunger, or had been stolen. There was no food, no water and the remaining animals, the ones with teeth and claws to defend themselves from hungry looters, were lame, starving and dying of thirst. By the time he left, the animals were healthy, the cages clean and the zoo a viable operation once again.

The story, outlined in Babylon's Ark, a 2007 book which Anthony wrote with journalist Graham Spence, has attracted the attention of Hollywood, with a major film, Good Luck, Mr Anthony, in the works. US banks and corporations now pay Anthony to talk to their employees, hoping the lessons of how to bring order from chaos could turn round failing businesses. And the zoo itself is a thriving attraction in the recovering city, with 5m visitors last year and regular loans of animals from zoos abroad.

It looked very different when Anthony and his two Kuwaiti guides arrived in 2003, having picked their way through the bombed city by asking baffled locals and "driving in the opposite direction whenever we heard shooting". Met by Husham Hussan, the zoo's deputy director, who burst into tears when he saw the carload of supplies, Anthony initially saw little hope. Black clouds of flies swarmed over the carcasses of dead animals that had been tossed into dens to feed the live ones. Rubbish littered the ground, baboons and monkeys were running free, while parrots, falcons and other escaped birds circled overhead. Lying near a massive bomb crater, an off-target product of shock and awe, was a decomposing pony. The surviving animals, including lions, tigers and an Iraqi brown bear, were listless and scrawny.

"I said it was so bad that we were wasting our time," recalls Anthony. "I thought we should borrow an M16 from a soldier and just shoot them all. I'm not used to seeing animals, lions and tigers looking like that. Husham persuaded me not to and said we've got to try. We started from there."

With a handful of Iraqi zoo staff, he worked on the vital needs for captive animals: water, food and hygiene. With the city's infrastructure smashed, water had to be dragged by bucket from a stagnant canal, while donkeys provided meat for the carnivores. "We went out and bought donkeys off the street and the donkey always had a cart, so the guys wouldn't sell the donkey without the cart. I still think of how we left those carts all over Baghdad."

Anthony was not the only South African working in the city. General Jay Garner, the US commander, had a dozen former South African special forces soldiers as personal bodyguards. "They would come and hang out at the zoo. And they'd bring their machine guns."

US soldiers also pitched in. "They were amazing. They were out fighting a war all day and they would come and lay their rifles down, pick up a shovel and ask, 'What can I do?' Think about it, America and Britain, two first world countries with the strongest animal rights records. Everybody's got pets and everybody understands animals, and they had no provision whatsoever for any wild animals in Baghdad."

He adds: "Then something amazing happened. Iraqi civilians started arriving as well, and then the Republican Guard. We had Republican Guard soldiers working with American troops in the zoo two weeks after they were killing each other on the battlefield." As the situation improved, so did outside and official interest. Anthony convinced the US to revive the adjacent park, while international conservation groups sent staff and supplies. The zoo reopened in July 2003 and has not been attacked since. The US spent $2.5m on it last year.

A child of colonial southern Africa, 57-year-old Anthony grew up in a series of small towns where his father opened insurance offices. His grandfather, a miner from Berwick-upon-Tweed, emigrated to South Africa to work in the gold mines in the 1920s. "I remember as a kid you couldn't go to the dustbins at night because of the hyenas. I grew up in the bush and it just stayed with me." Property development followed. "But I was always interested in conservation." When the Thula Thula reserve was put up for sale in the mid-1990s, he sold his property business and turned his hobby into an uncertain career.

This is Zulu country. Rorke's Drift, the mission station immortalised in Zulu, where 139 British soldiers held firm against 5,000 Zulu warriors in the 1879 Anglo-Zulu war, is less than two hours' drive across rolling hills that could be Wales or Devon. Several Zulu tribes farm the surrounding land, and goats wander between the clay and cement buildings that scatter either side of the dusty road connecting the reserve to the local village.

On the far side of the tribal land stands the Umfolozi nature reserve, the oldest game park in Africa. Originally a hunting ground for Zulu royalty, the park was formed in 1895 and is credited with saving the white rhino from extinction. A sanctuary in the early 20th century when widespread butchery reduced numbers to a few dozen, Umfolozi has raised and released hundreds of white rhinos throughout southern Africa, helping to bolster numbers to more than 10,000.

For 15 years, Anthony has been trying to convince five surrounding Zulu tribes to pool their land and form a new game reserve. Called Royal Zulu, it would offer jobs and income through tourism, as well as securing the future of the region's wildlife from creeping development. "About 90% of game reserves are still run on colonial lines with big fences and big guns," he said. "Those old days are over. Conservation is only going to survive if we involve local communities." Zulus and other black people were excluded from reserves during colonial times and apartheid, he says. "Children are growing up having never seen a giraffe or zebra."

Anthony says poaching from Thula Thula has been controlled by showing the community the benefits tourists bring. Poachers are tried in the local Zulu court by Nkosi Biyela, a disapproving tribal chief. At his family home a few miles along the main road from Thula Thula, with a widescreen television showing tribal dances with the volume turned right up, the chief says: "I want to beat them [the poachers]. I beat them a lot." Biyela, the great-great grandson of the famous chief, Mkhosana Kamvundlane, who rallied a Zulu army at the battle of Isandlwana, just before Rorke's Drift, is an important supporter of the Royal Zulu reserve. The land is better suited to wild animals than for farmed cattle or goat, he says, and they will not need expensive medicine.

Baghdad isn't Anthony's only experience of working for wildlife in war zones. In 2006, he convinced the leaders of the Lord's Resistance Army (LRA), which has fought a bloody struggle with the Ugandan government for more than two decades, to sign up to a conservation project to save one of the world's rarest animals. The LRA, notorious for its use of child soldiers and accused of atrocities including rape, mutilations and the mass murder of civilians, had taken up residence in the Garamba National Park, home to the last of the northern white rhino. Only four northern white rhinos are thought to remain.

The LRA shot dead 12 of the park's game rangers and then eight Guatemalan UN soldiers sent to the region to keep order. "It was a desperate, impossible situation," Anthony says. "The UN withdrew from the area and the LRA controlled the park. The fate of the rhino lay entirely in the hands of this rebel army. If this species goes extinct they will be the largest land mammal to die out since the woolly mammoth."

Anthony heard that LRA leaders were meeting the Ugandan government in Sudan and, with no visa and no invitation, gatecrashed the talks. Ignoring warnings of a possible kidnap plot, he met the rebels on the banks of the White Nile river. "When I explained there were only four rhinos left in the wild they were genuinely shocked. They thought there were still hundreds of them."

The LRA said the rhino was the totem of the largest tribe in their area, giving them an affinity with the animal. When LRA officials signed a ceasefire with the Ugandan government, it included pledges to protect the endangered rhino and allow the park rangers to resume their work unmolested.

In late 2007, Anthony visited the LRA senior leadership to discuss the rhino. He spent several days living with Vincent Otti, LRA deputy commander, and addressed the military high command in their secret jungle camp, the first outsider ever to do so. "We talked about rhinos and then for many hours about peace." The day after Anthony left the camp, Otti was killed. The ceasefire has since collapsed, but Anthony says he was assured that protection for the rhino granted in the 2007 agreement is holding. The apparent success, and the interest of international legal experts, has encouraged him to submit a draft resolution to the UN to request that animals in war zones, wild or captive, are given formal protection.

His direct approach does not please everyone. Conservation and politics go hand in hand in Africa, and some conservationists from larger groups criticised Anthony's contact with the LRA as dangerous meddling. "When you do the sort of work I do, you'll always get criticised," he says. "There are a lot of good [conservation] people out there who I look up to and respect. But I don't want to work with them. In Baghdad I really learnt a bad lesson about some of the bigger groups and how they operate."

Representatives of rival groups sent to help the zoo project squabbled over access to the dozens of film crews which, with the invasion over and insurgent violence yet to build, were short of stories. Then there were the bunny huggers. "Horrific people. Crazy bunny huggers. Guys who felt they were on a mission and if they died on their mission then their lives would have been worth it to save the tiger." After his return to South Africa, Anthony founded the Earth Organisation, a conservation group that encourages pragmatic local action. "The focus is not on getting piles of members, but getting people who are going to do something."

Anthony does hold controversial views of his own. "I've been a Scientologist for 40 years. My sense of adventure and exploration is not limited to geographical areas. It's a subject which I find logical and sensible." He does not believe in the "aliens and all that", but simply liked the way L Ron Hubbard described the concept of the survival of life. "I very much got the thing that lifeforms are a special entity that are a combination of minerals, chemicals and God, or the lifeforce that animates them. I like to see the world that way."

Like many who spend their time in the bush, Anthony talks of a sense of connection with nature. "There's some sense that the animals have, and people who spend time with animals get better at tuning into it." It's easy to dismiss such talk, until you see him with the elephants. His elephants.

Thula Thula has a herd of former delinquent elephants which would otherwise have been shot for dangerous misbehaviour. Anthony has worked to rehabilitate them, to the extent that they will even come when he calls. He is convinced the animals, and Nana, the giant matriarch of the herd, in particular, know him. When Nana gave birth, she brought her three-day-old calf to show off. When Anthony had his first grandchild, he reciprocated. Last month, we were granted a rare glimpse of the bond between Anthony and the herd. We are deep in the African bush when Anthony cups his hands to his mouth and calls: "Come baba, come girls." The elephants were last sighted a mile or so away, and for 10 minutes there is silence. Then, on the far side of a clearing, the trees rustle and the first giant grey head breaks above the bushes. Another follows, pausing only to rip a branch from a tree. Soon, as seven or eight of the herd approach, Anthony ushers us from open ground into the relative safety of the vehicle. Within seconds, the animals are poking their trunks through the open windows, their wrinkled faces and eyelashed brown eyes just yards away. We pull forward, and the elephants follow. Only when Anthony guns the engine do they give up the chase.

"This is not a carnival or a circus, these are extremely dangerous wild elephants. Nobody goes that close to wild elephants. You just don't do it," Anthony says. He has written a book called The Elephant Whisperer, to be published this summer, about his work. He is keen to stress that the title refers not to him, but to the way Nana and the others respond. "When the elephants come to me it is their decision. It's always their decision."

People, he says, have lost a vital connection to animals. And it could have dire consequences. "Frogs are dying all over the world, bees are dying all over the world, and nobody gives a shit. Who's doing something? Why is it a boy from Zululand has to go to Baghdad to save animals? It's the biggest zoo in the Middle East with hundreds and hundreds of exotic animals and nobody was interested. Why do I have to go and see the bloody LRA? If I have to do this stuff then we really are screwed."

His frustration has a hard, personal edge. The day Anthony left Baghdad in 2003, some American soldiers had a barbecue at the zoo. Accounts differ on what happened, but what is known is that one soldier was drinking and put his hand too close to the cage that held Malooh, a Bengal tiger. The animal, Anthony's favourite, bit the soldier's finger off and mauled his arm. A second soldier took out his pistol and fired into the cage. The tiger bled to death overnight. "Can you believe it, after all the work we did?" He heard the news when he arrived home at Thula Thula. The elephants were waiting at the gate.