In this picture taken on August 24, 2017, Liang Fengen, a ranger at the Nuanquan River Forestry Centre, shows a heat sensor camera as he surveys an area in Suiyang town, Mudanjiang municipality. In the northern mountains bordering Russia, everyone knew the spry Chinese man as a skilled and ruthless hunter -- the kind who once killed a mother black bear as her cubs looked on. But instead of stalking the woods for prey, Liang Fengen now roams the hills without a rifle, working as a ranger to save the area's endangered Siberian tiger population and protect other wildlife. / AFP PHOTO / Nicolas ASFOURI / TO GO WITH China-conservation-animal, FEATURE by Yanan WANG (Photo credit should read NICOLAS ASFOURI/AFP/Getty Images)