Gorillas beating their chests, chimpanzees pant-hooting, elephants rumbling—and poachers firing assault rifles—these are some of the more than a million hours of sounds recorded by a grid of 50 microphones in the Congolese rainforest since 2017.
The massive acoustic monitoring effort covers about 480 square miles in the Republic of Congo’s Nouabalé-Ndoki National Park—an area about the size of Los Angeles. It’s part of Cornell University’s Elephant Listening Project, established in 1999 to detect communication among forest elephants and pinpoint poaching activity. The project, which includes collaborators from the Wildlife Conservation Society, has used acoustic methods to “estimate elephant populations, impacts of oil exploration and logging, and to quantify illegal gun-hunting in protected areas,” according to its website.
“For years I’ve
