Sartore is a National Geographic Explorer, wildlife photographer, and conservationist. In 2006, Sartore founded the Photo Ark project to show the world the beauty of biodiversity and inspire ...

To honor Koko's memory, National Geographic is republishing "Conversations With a Gorilla," our October 1978 cover story written by Francine Patterson, the psychologist who taught Koko how to sign.

The world's top expert on wild chimpanzees said she met the photographer, who was also passionate about the animals, while ...