"Photo Ark" to capture Twenty Thousand animals

A photographer for National Geographic has embarked on decades-long project to shoot portraits of the most vulnerable species in the world. He's hoping that his "Photo Ark" of 20 thousand animals will serve as a poignant record of each creature's existence, and a powerful testament to the importance of saving them. No matter its size, he says, each animal is treated with the same amount of affection and respect