The vultures are startled and take flight as our pickup truck arrives at the giant carcass lying in the lowveld. They have had a week to pick its bones.
All that remains of Izzy, a 6-year-old white rhino, are the curved spears of her ribcage, dismembered feet and a head infested with flies and maggots.
"She was a beautiful cow, a magnificent specimen," says Barry Bezuidenhout, the estate manager of a sprawling game ranch near South Africa's Kruger Park. "When I think of her, I get a lump in the throat."
We are at the frontline of a conflict that is threatening to turn some of South Africa's most beautiful nature reserves, a draw for tourists around the world, into lawless battlegrounds - and drive a magnificent animal towards the brink of extinction.
About 265 rhinos have been poached this year, according to government figures, an average of more than one a day. This puts 2011 on course to surpass last year's record death toll of 333. In 2007, it was just 13.
Why? There is no mystery about it. Experts agree the carnage results from a false belief, widespread in the Far East, that rhino horn can cure cancer and other life-threatening illnesses.
There is now soaring demand from the newly moneyed consumers of China and Vietnam. Poaching gangs here are increasingly sophisticated, using helicopters, silent tranquillisers, body armour, night vision equipment and mercenaries.
Once a rhino's horn has been hacked off, they leave the animal to bleed to death. The horn is then smuggled out of the country by an international syndicate. The price of rhino horn is £35,000 ($70,000) a kilogram, making it more expensive than gold, according to the International Rhino Foundation.
The lucrative black market was the subject of intense debate at a meeting of the Convention on International Trade in Endangered Species (Cites) in Geneva last week.
Calls to action have come too late for Izzy, who was near breeding age and was expected to produce 10 calves in the next 30 years.
As a deterrent to poachers, her horn had been surgically removed under anaesthetic two years ago, but regrew to about 2.5kg - enough to sign her death warrant.
Three poachers came at dead of night, it is believed, shooting her and removing the horn with apparently clinical expertise (some rhinos are crudely hacked and disfigured). The animal appears to have walked for about 80m before collapsing and dying.
The killing was all the more shocking to Bezuidenhout and his staff at the Mauricedale Game Ranch in Malelane because it has seen no poaching incidents since 2007. The estate tries to dehorn all its rhino and employs rangers to patrol its 6500ha grounds and alert local police if they see anything suspicious.
Armed confrontations have been increasingly common. Seventeen poachers have been killed in Kruger Park alone this year by rangers acting in self-defence, South African National Parks said.
Tom Milliken, director of the wildlife trade monitoring network Traffic's east and southern Africa programme, said: "Heavily armed people are moving into protected areas to kill rhino. Those charged with their protection face great challenges and gunfights are part of the equation. There is a rhino war going on out there and it continues to get ugly."
SANParks believes its tough approach has resulted in a significant drop in poaching in the past two months. Police have made 131 arrests this year, ranging from poachers to couriers to kingpins.
But under such pressure, there are fears that gangs will be displaced to private game reserves such as Mauricedale, where a 3m electric fence and razor wire may not be enough. Mauricedale's owner, John Hume, says he is the biggest rhino farmer in the world with six estates in South Africa, although he is reluctant to give numbers.
The recent rhino death was a bitter blow. "You're devastated because it makes you realise how vulnerable you and your rhinos are," Hume said. "Poachers are becoming more sophisticated and that's worrying. An investigator told us they had identified 27 gangs operating here and have arrested three - and they are probably out on bail."
The 69-year-old said the true depth of the crisis was hidden. "I think the escalation in poaching is much worse than they officially know, and that's a problem for rhinos. The market is growing, the Chinese are growing affluent, the demand for horn is escalating at a horrific rate."
Hume has proposed a bold solution. "I am of the very firm opinion that the only way to save the rhinos from extinction is by legalising the trade in their horns. I am against the futility and stupidity of the current system."
Hume and other rhino farmers argue that legalising the trade would bring it under control, driving prices down and squeezing the black market. South Africa is studying the idea. Opponents have said supplying horn might stimulate further demand and it would be immoral to feed a false belief in the horn's medicinal value.
There are an estimated 25,000 rhinos left in Africa. About 20,800 are in South Africa, of which 19,000 are white and 1800 black.
Dr Joseph Okori, Africa rhino programme manager at the World Wide Fund for Nature, said: "There is no room for complacency on this issue. We believe the situation is still very alarming and we see it escalating."
Okori said Cites' meeting last week saw a strong commitment from African countries and a working group was set up, but warned that China had failed to come up with specific proposals. He added: "We believe that if the current escalation in poaching continues, rhinos will be faced with the threat of extinction down the line."