Elephants communicate using low-frequency rumbles that are silent to human ears.

Infrasound consists of sound waves with frequencies below 20 Hertz, which is the lower limit of human hearing. Elephants produce these calls using massive vocal folds that function similarly to human vocal cords but on a much larger scale. Research conducted by Dr. Katy Payne of the Cornell Lab of Ornithology in the 1980s first identified these 'silent' rumbles while she was observing elephants at the Washington Park Zoo in Portland, Oregon.These low-frequency waves are unique because they do not dissipate as quickly as high-frequency sounds. They can bypass physical obstacles like trees and hills by bending around them through a process called diffraction. Under ideal atmospheric conditions, such as the cool, still air of dusk, these signals can reach other elephants up to 6 miles (10 kilometers) away. This long-distance communication is vital for the survival of complex social structures in the wild.Elephants also possess specialized structures in their feet and trunks to detect these vibrations. Known as Pacinian corpuscles, these sensitive nerve endings allow elephants to 'hear' seismic waves traveling through the ground. A study published in the journal 'Nature' confirmed that elephants can distinguish between different types of seismic signals, helping them detect distant thunderstorms or the footsteps of other herds. This dual-channel communication system makes them masters of long-range coordination.