Elephants can communicate across distances of up to five kilometers using airborne sound. But they also send signals through the ground: seismic vibrations that travel from their feet through their legs and skull bones directly into the inner ear, perceptible across 10 kilometers or more — a phenomenon called bone-conduction hearing. A new study in Frontiers in Audiology and Otology finds that this ability comes down largely to size and a special muscle.

“Elephants may use the ability to close their ear canals to their advantage in long distance communication. We found that elephants’ bone-conduction hearing is significantly improved through their larger middle ear structures and possibly further enhanced by voluntarily closing the ear canal.”

Dr. Sunil Puria, Harvard Medical School and Massachusetts Eye and Ear

Using temporal bones from deceased elephants and human donors, researchers measured how tiny reflective markers on the middle ear bones moved in response to vibrations mimicking sound traveling through the body. Elephant middle ear bones vibrated most effectively around 400 Hz, compared with about 1.2 kHz for humans, and below these frequencies the elephants’ stapes — a small middle-ear bone that transmits vibrations to the inner ear — moved three to four times more than the human equivalent, transmitting more vibration to the cochlea.

The anatomical explanation appears straightforward: elephants’ middle ear bones are nine times heavier and their eardrums seven times larger than those of humans, scaling with their much larger body size rather than reflecting any special structural adaptation. Elephants can also voluntarily close their ear canals, a capacity humans lack, which the researchers hypothesize could enhance low-frequency bone-conduction hearing by up to 30 times when listening to the infrasonic vocalizations — in the 10 to 20 Hz range — that elephants use to communicate.

The team cautioned that the cochlea samples had been drained of fluid due to a lengthy preparation process, which may have led to an underestimation of the results, and that elephant tissue remains scarce, limiting sample sizes.

Publication

The study, “Bone-Conduction Hearing in Elephants and Humans: A Middle-Ear Comparative Study,” was published in Frontiers in Audiology and Otology (DOI: 10.3389/fauot.2026.1744613).