Saving Elephants You Can’t See
By Hugh Powell
April 1, 2012
For a field biologist working on an endangered species, it’s not always easy even to get a clear look at your subject. That’s long been the case for Peter Wrege, who leads the Elephant Listening Project at the Cornell Lab of Ornithology. For years, he and his team have studied elephants by listening for them with increasingly sensitive equipment. On a recent trip to Gabon, he added another tool: thermal imaging cameras that deliver bright, beautiful images of elephants in the dark.
Wrege and his colleagues study the African forest elephant. Forest elephants live in dense jungles and are often active at night. Because they’re hard to see, we know little about them beyond that they are frequent targets of poachers, and that logging operations threaten their forest home.
So Wrege uses sound to tell him what vision can’t. Forest elephants stay in touch with each other by making deep rumbling calls, much the way a flock of sparrows uses chip notes. The researchers place synchronized, weatherproof recording units around forest clearings, called bais, and let them run for a month.
Later, by analyzing the sounds and the time they were recorded at each unit, the researchers can triangulate the exact positions of each elephant call, producing a clear map of elephant locations from out of the darkened forest. Some recordings even captured closely spaced calls likely made by the same elephant. By plotting the calls in sequence, Wrege has been able to track the probable paths of these animals.
In February, Wrege and longtime collaborator Andrea Turkalo of the Wildlife Conservation Society brought out a new tool that finally allows them to see elephants at night. Just a couple of weeks into the expedition, the thermal imaging camera made its first breakthrough, capturing clear images of a baby elephant’s first hours of life—only the second forest elephant birth ever witnessed directly.
Together these new tools are revealing the lives of an elephant that science still knows little about. “It’s a little peek into why we love working on these animals and are committed to keeping them roaming the forests the way they should,” Wrege said.
Originally published in the April 2012 issue of BirdScope.