Bbc: The country that brought its elephants back from the brink
Prince Harry is the new president of a conservation group called African Parks, which takes over national parks and gives rangers military-style training to take on poachers and protect wildlife. The BBC visited one of the parks it manages, at Zakouma in Chad.
A distant, guttural growl of elephants, and the occasional trumpet, drifted over the thick screen of lush trees and dry-scrub grass. The nearest calls were nearby, the furthest a mile or more away: this was the large herd we had been looking for.
Tracking collars had pinpointed them at dawn, but these elephants move quickly, and after centuries of hunting, run if they see, or even smell, humans.
The well armed rangers from the Mamba Two fast-response team fanned out ahead to the left and the right, not wanting to surprise, or be surprised by, a lone animal. They excitedly beckoned us to follow them slowly and carefully into a thicker section of trees.
It had been a three-hour flight in a small plane, from Chad's capital, N'Djamena, to Zakouma National Park, and a three-hour drive to this section in search of the herd, the last of the park's elephants.