WHILE WORKING as a researcher for the Namibian government, Caitlin O’Connell-Rodwell observed elephants in Estosha National Park behaving strangely. When they gathered around a water hole, they would suddenly freeze, lean forward, and pick up their feet. O’Connell-Rodwell, who had earned a master’s degree in seismic communication in insects, began to suspect that—like insects — elephants could detect underground sound waves with their feet. Could it be possible that these elephants were responding to warning signals from a herd miles away?
Because elephants are such large animals, foot stomping and low-frequency vocalizations send a ripple across the surface of the earth similar to the ripple produced by an earthquake. Other elephants seem to be able to pick up the vibrations through their feet and respond to them as possible danger or as information about the location of a distant herd.
“Elephants may be able to detect stress from a herd many miles away,” says Caitlin O’Connell-Rodwell, now a visiting scholar at the Stanford Center for Conservation Biology and a postdoctoral fellow in the Department of Pediatrics. “They may be communicating at much farther distances than we thought.”
To test the theory, O’Connell-Rodwell recorded elephant vocalizations used as warnings and greetings and converted them into seismic waves that could be felt and not heard. The elephants reacted to the underground messages with varying degrees of interest and alarm. One female was so disturbed by the warning call that she bit the ground beneath her.
“There are huge advantages to detecting ground signals versus air signals,” O’Connell-Rodwell says. Seismic waves produced by elephants can travel up to 20 miles through the ground while acoustic communication can travel only 6 miles through the air. “It’s hard to say whether their vocalization is meant for the air or the ground or both and whether it’s purposeful or not,” O’Connell-Rodwell says. “[But] if they can detect it, they can use it as a tool.”
Published in Wildlife Conservation by Chris Hardman