“Perry the sloth, photographed for my book The Animal Kingdom. Most of my subjects could either stand on their legs or sit upright. Sloths, on the other hand, do neither. They lie or they hang—that’s it. It was impossible to create a shot of Perry lying down because he just melted into the floor. However, once I saw him hang, the light bulb went off. He moved constantly, though, literally spinning, which made it super challenging for me to capture just the right moment. I laughed at the irony of my hyperactive sloth, and after working patiently with him, finally captured a shot I was happy with.”