The Balule Reserve covers over 100,000 acres of wooded savannah in the Limpopo Province of South Africa. It is a vast, open space within the Greater Kruger National Park, home to some of the world's most charismatic megafauna, including lions, elephants and the endangered white and black rhinoceroses.

It also is roamed by poachers, who ruthlessly slaughter the rhinos and hack off their horns, which are coveted throughout Asia by those who believe they can cure all manner of illnesses. It's a lucrative business—a rhino horn can bring $60,000 per pound—and 1,175 rhinos were killed in South Africa alone last year. But poaching is declining at Balule, thanks in part to the work of the Black Mambas, which is said to be the world's first predominantly female anti-poaching unit.

"These women are trying to save South Africa’s natural heritage," says Julia Gunther, a photographer who spent a week with the squad in July. She followed the team—which includes 24 women and two men—as it patrolled, dismantled snares, and kept vigilant watch over the park. It's dangerous work, but the Black Mambas relish it. “They are risking their lives to conserve nature instead of exploiting it,” Gunther says.

The anti-poaching group Transfrontier Africa launched the Black Mamba Anti-Poaching Unit in 2013. It grew from the idea that the usual approach, which relies upon armed guards patrolling an area, wasn't especially effective and led to an escalation in tactics—if poachers used increasingly powerful or sophisticated weapons, those working against them had to follow suit. Why not de-escalate the situation and focus on preventative policing. "A Black Mamba is a 'bobby on the beat,' walking down the high street, as it were, and showing a presence," says Transfrontier project administrator Amy Clark. "Their eyes and ears are the first line of defense."

The Mambas, who receive combat training, patrol the park and alert wardens and guards to trouble. Certain members also visit schools in the area, educating people about the issue, the need to preserve the wildlife, and the impact of poaching on their communities. "When we said we were going to hire women for an anti-poaching unit, all the old-school conservationists in the reserves surrounding us just laughed at us," Clark says. "They said it’s never going to work to have a woman doing this job, and within a year we proved them wrong."

To try and stop rhino’s from being hunted to extinction, Balule head warden and founder Craig Spencer uses specially trained local women, who often come from the same community as the poachers, to patrol the reserve, instead of men with guns, in the hope of gaining the upper hand in the war between conservationists and poachers. Three Black Mambas crouch behind a fallen tree at the Balule Nature Reserve in South Africa. Julia Gunther

Beyond protecting rhinos and other wildlife, the young women are breaking down stereotypes and elevating the status of women in towns and villages bordering the reserve. The mambas each earn around $200 a month, and all are the primary breadwinners in their families. Many hope to become nurses, paramedics, pilots, field guides, or rangers at Kruger National Park. None of them could be reached for comment, but one Mamba, a 21-year-old named Leitah, told Gunther, "We are fighting for the animals and showing people that women can be beautiful and strong."

Gunther learned about the mambas a year ago when the The Guardian wrote about them. She has visited South Africa several times since 2008 for her ongoing series Proud Women of Africa series, which has featured everything from a woman dying of breast cancer to lesbian girls growing up in rural townships. The Black Mambas seemed a perfect fit. “I thought, how much more Proud Women of Africa can you get?” Gunther says.

The women weren't too keen on the publicity, having been deluged with requests after The Guardian piece. But Gunther was persistent, and after several months trying to contact them she was invited to visit in July. That gave her just a few weeks to scrape together enough money to cover the week-long trip. “It was all very hectic, but it was worth every minute,” she says.

She followed them into the bush, joining them on patrols through the reserve and relaxing with them in camp, talking and listening to the radio (she swears she heard some Rihanna). She also made their portraits, each woman standing tall and proud in battle fatigues. Gunther used a speedlight with her Canon 5D Mark II to overcome the sun's harsh shadows. It's a remarkable effect, one that makes the women look fierce yet protective. “I felt justified flashing them, putting them onto a pedestal," Gunther says.

To try and stop rhino’s from being hunted to extinction, Balule head warden and founder Craig Spencer uses specially trained local women, who often come from the same community as the poachers, to patrol the reserve, instead of men with guns, in the hope of gaining the upper hand in the war between conservationists and poachers. Black Mamba member Lukie is 26 years old. Julia Gunther

Patrols started at first light. A team of four to eight women would march along the park’s boundary fence, or on varying routes through its interior. They kept vigilant watch for any signs of poachers, and for the snares they often leave near watering holes. They also checked on the camera traps hidden through the park that snap high-def images of anyone, or anything, that passes by. “You see [poachers] on the camera traps all the time," Gunther says.

Gunther also went out with the Black Mambas on night patrols, which started at dusk. The moon was full and bright while she was there, increasing the odds of encountering poachers. The women would survey the landscape with bright spotlights, or simply sit in silence in the dark, listening. Gunther found the night full of unnerving sounds, and was mindful of the wildlife just beyond sight. One night, she and the squad came upon a pride of lions blocking the road ahead. “They were very intrigued with us and came closer,” she says. “It was a bit more safari than I asked for.”

The risk is ever-present. Poachers carry machetes and rifles, while the Black Mambas have nothing more dangerous than pepper spray. Although they may apprehend hunters, they tend to let the parks armed guards handle any poachers. “It’s quite dangerous, if you think about it,” Gunther says. “I don’t know too many who would have the guts to do this.”

Transfrontier Africa says rhino poaching has fallen 65 percent and snaring 78 percent since it launched the Black Mambas, and the United Nations gave the squad its highest environmental honor, the Champion of Earth Award, for "sending the message to others in South Africa and beyond that communities themselves can prevent the illegal wildlife trade." Gunther hopes her photos help them continue their work, which largely relies on donations. “This is the first generation of Mambas,” she says. “There will be a second generation of Mambas, and I hope there will be another generation after that to achieve their work toward a better and brighter future, as cheesy as that sounds."