Around breakfast time on an August morning in Borneo’s Tanjung Puting National Park, Jayaprakash Joghee Bojan took off his shoes, hoisted his new camera, and slid into cold, chest-deep water stained an opaque brownish-red by the tannins of submerged roots.

Trusting the rangers to warn him if a crocodile appeared, Bojan inched along—gently, to avoid startling the male orangutan wading through the river only yards away.

“Honestly, sometimes you just go blind when things like this happen,” Bojan later tells National Geographic. “You don’t feel the pain, you don’t feel the mosquito bites, you don’t feel the cold, because your mind is completely lost in what’s happening in front of you.”

Bojan knew he was witnessing something special. Orangutans