In an isolated wilderness in Chad, a war is being fought to save central Africa's decimated elephant herds from gangs of ivory poachers. The frontline is the southern Zakouma National Park: a 3,000-square-kilometre (1,900-square-mile) sanctuary that has lost 90 percent of its elephants in the last 10 years.
Numbers plunged from 4,300 in 2002 to some 450 a decade later, thanks to a poaching bloodbath.
The reserve now uses paramilitary-style tactics, with 60 guards who act like soldiers and a new 15-member rapid reaction force.
"The poachers are heavily armed, determined, motivated," said Patrick Duboscq, a former police officer from France who trained the group.
The shift to beef up the protection came two years ago when the South African conservation group African Parks took over management of Zakouma.
The first step was establishing a permanent presence in the reserve, which had been abandoned in the summer wet season when most of the park is under water.
Airstrips were built and the monitoring system was streamlined - including fitting 14 elephants with satellite tracking devices that transmit their location six times a day.
Being aware of the elephants' movements means that the anti-poaching patrols can be sent out to the right spots in and around the vast park.
"The only way we can save the elephants in Chad is by knowing where they are going," said Lorna Labuschagne, head of logistics in Zakouma.
As a result the elephant massacre has been stemmed - just 13 have been lost since 2011. And the once highly stressed animals have started to breed. More....