Damien Mander removes his hat to cover his nose, an act of instinct and ceremony that does little to temper the thick stench of death. The cloudless sky is empty of vultures on this scorching Mozambique morning, and as Mander approaches the kill site, an orchestra of heavy wing beats reveals why. Scores of the scavengers have settled onto comfortable perches, frosted in days of bird shit and molt, for a macabre feast: two dead rhinos, mother and calf.

“The last minutes of their lives would’ve been bloody terrifying,” says Mander, 37, the founder of the International Anti-Poaching Foundation (IAPF), a non-profit organization dedicated to providing Africa’s wildlife rangers with military-style training, management, and resources. A former special-forces sniper who spent six years in the Australian military, followed by 12 tours in Iraq as a private contractor, Mander is now embroiled in Africa’s most volatile wildlife war.

The ridgeline where he stands represents perhaps the most critical strip of territory on the planet for rhinoceros conservation. To the west lies South Africa’s famed Kruger National Park, home to more than 8,000 rhinos, roughly one-third of the continent’s remaining population. To the east is Sabie Game Park, one of nine private borderland reserves that compose the 958-square-mile Greater Lembobo Conservancy in Mozambique, among the world’s poorest countries and home to sophisticated poaching syndicates that haunt Kruger and are hunting rhinos toward extinction.

Three nights prior, this rhino pair and two young bulls were just a quartet of peaceful grazers snacking their way along a narrow creek bed, oblivious to international borders and the bounty that an insatiable black market has placed, quite literally, on their head. Then, under a three-quarters moon, two poachers tracked the herd through the thorn scrub, took aim with a .375 hunting rifle, and fired. The mother went down with three shots, the calf with a fourth.

Mander, standing a hulking 6 feet 3 inches tall and weighing 240 pounds, slowly approaches the mother, lying on her side on a gentle slope overlooking the savanna. A giant crater rots where her 3-foot-long horn once grew. Machete wounds run up her back and across her hind legs. She was still alive when the poachers went to work. They cut her spinal cord and tendons in her legs to immobilize her, before carving out her horn. Scavengers made quick work of the carcass once the poachers left, rendering this 2-ton megaherbivore to little more than leather. Next to her lies her calf, deflated like a popped balloon and bearing matching wounds and missing horns. “It’s shattering,” says Mander. “It’s like you’ve been given something very important to take care of and someone’s come and taken that away.”