(CNN) -- Last week, a hunter stunned the world by paying $350,000 to kill a black rhino. The deal went went viral and brought death threats against the hunter.
And that was just people trying to protect one endangered rhino. Imagine more than 1,000.
That is how many poachers in South Africa killed last year, authorities said, a harrowing record for the nation with the world's largest population of the animals.
As demand for the horn soars in China and Vietnam, so does the number of rhinos slaughtered.
In Asia, some believe the horn can cure ills such as cancer, diabetes and hangovers.
The 2013 record in South Africa is almost double the year before.
Last year, 1,004 rhinos were illegally killed in the nation compared with 668 the previous year, the environmental affairs ministry said in a statement. Most of the poaching occurred in Kruger National Park.
The black rhino is critically endangered, and conservationists are fiercely protective of it.
Hunter Corey Knowlton is the U.S. hunter who's now become the hunted. Last week, he paid $350,000 at the Dallas Safari Club's auction for a permit to hunt a black rhino in the southern African nation of Namibia.
Even though he said the money would go toward conservation, death threats against him escalated, forcing him to get extra security.
Knowlton stepped into a passionate debate.
Organized crime syndicates are using military-grade helicopters, night-vision equipment and guns fitted with silencers, taking rhino poaching to a whole new level and leaving conservationists struggling to keep up.
Kenya and South Africa have invested in unmanned drones, sniffer dogs and increased security. Despite stepped up efforts, they have failed to halt the rising tide of rhino slaughter.
Experts say the rhino horn is becoming more lucrative than drugs.
A kilogram fetches about $20,000 -- with a single horn weighing about 10 kilograms (22 pounds).