Heartbreaking photographs capture the facial expressions of animals

National Geographic photographer Joel Sartore has a mission: to shoot (with a camera) Earth's endangered species in a studio setting, so that human viewers are forced to confront exactly who's going extinct face-to-face. So far, Joel's photographed 1,800 species, and shooting these creatures presents its own set of… » 1/24/12 2:10pm 1/24/12 2:10pm