National Geographic photographer Joel Sartore has spent the past ten years working on a massive project to document the world’s biodiversity, called the Photo Ark. The April issue of National Geographic magazine features Sartore’s portraits. Over the past decade, he has photographed more than 5,600 animals and says he won’t stop until he’s documented every one of the estimated 12,000 birds, fish, mammals, reptiles, amphibians and invertebrates in captivity. National Geographic has been kind enough to share a handful of these portraits with us, and they invite readers to take their online quiz: What Animal Is Most Like You? http://www.theatlantic.com/photo/2016/03/building-a-photo-ark/474126/