Gripping a semi-automatic rifle in his muscular right hand, anti-poaching instructor Simon Rood berates his students for not taking their gun lessons seriously.
"The problem with you is you don't want to grasp what we're trying to teach you," says Rood, an imposing man with a buzz cut and a Glock pistol on his belt.
"This thing is like your wife, you will treat it with respect," he stresses. "If you do not treat a firearm with respect, you can't be a ranger."
The students, a group of 19 dressed in forest-green fatigues with black military boots, nod their heads to show they understand.
Rood is one of a handful of entrepreneurs in South Africa specialising in producing armed anti-poaching rangers who patrol public and private nature reserves protecting rhinos.
"Unfortunately it's the kind of business where you have to fight fire with fire," said the 50-year-old owner of Nkwe Wildlife and Security Services.
"We've got armed 'terrorists' coming through our border with weapons to shoot our national heritage."
According to the South African government, a record 1,215 rhinos were poached in the country last year, fuelled by the booming demand in East Asia for their horns which have supposed medicinal qualities. Estimates vary but some say rhino horn can fetch up to $65,000 on the Asian black market.
Supported by international crime syndicates, poachers -- many of them based in neighbouring Mozambique -- are killing rhinos with increasingly sophisticated weapons and tactics.
"If you look at Kruger National Park -- South Africa's largest wilderness area -- they're coming across poachers carrying heavy calibre rifles or fully automatic military weapons," said Kevin Bewick, the Durban-based head of the Anti-Poaching Intelligence Group of Southern Africa, a non-profit organisation.
"The danger is very real."
The demand for armed rangers is growing, with rhino poaching rising fast. Officials meeting Wednesday at the Conference on Illegal Wildlife Trade (IWT) in Kasane, Botswana, said rhino poaching will figure high on their agenda.
At his anti-poaching training school on a remote farm outside Vaalwater, a small town three hours' drive north from Johannesburg, Rood teaches new recruits how to live for weeks at a time in the bush.
The day begins at 6:00 am with a five-kilometre (three-mile) run, sit-ups, pushups, and drill exercises -- followed by classes on everything from identifying animal tracks to apprehending poachers.
- In the line of fire -
On a sweltering afternoon in March, the students were listening to a South African police constable talk about firearm safety under the shade of a canvas lecture tent.
"When you are on duty and you see a dangerous person, call for backup because we are not heroes," the constable told students.
Under a similar classification as private security guards, accredited anti-poaching rangers have their firearm licenses and are legally allowed to carry and shoot a gun.
Wilfred Radebe, one of Rood's top anti-poaching rangers, has been working to hammer discipline into the recruits during the one-year course.
"Now I'm going to grind them," said Radebe with a mischievous grin. "Afterwards I'll give them a funny moment, so they don't think they're in jail."
Wearing high-top black canvas shoes and a floppy hat to protect him from the scorching sun, Radebe explains that he has to impart the seriousness of the job to the recruits who don't always appreciate that they will be putting themselves in the line of fire.
"They need to realise why they are here," said the 26-year-old. "We need men of character."
Peter Kgathi, a 34-year-old recruit, believes he is such a man.
"You must not be scared, you must be brave," said Kgathi, who plans to support his wife and children with his future ranger income, a monthly sum of around 4,000 rand ($350).
Kgathi, a tall man who stands ramrod straight, said he hopes to work in Kruger National Park, home to the majority of the country's rhinos -- and the place they are most likely to be killed.
"I'm always happy when I see rhinos," said Kgathi. "We still need our children to know about them."