In this November 30, 2007 file photo, a gorilla looks on at Volcanoes National Park in Ruhengeri, Rwanda. The eastern gorilla has been listed as critically endangered, making four of the six great ape species only one step away from extinction, according to the International Union for the Conservation of Nature's Red List of Endangered Species, released Sunday September 4, 2016. (Photo by Themba Hadebe/AP Photo)
