Volunteers play with one-year-old elephant Gold at the Dak Lak Elephant Conservation Centre (ECC) in central Vietnam. Elephants used to roam freely in the area, mingling with potential mates, but human settlements have cut off once-popular breeding circuits. Now there are fewer than 100 elephants left in the wild here and just 80 or so in captivity, mostly used to ferry tourists around the leafy forests of Vietnam’s central highlands

Photograph: Hoang Dinh Nam/AFP/Getty Images