The Secret Voice of the Elephant

The elephant is well known for its loud, high-pitched trumpeting call of alarm, usually accompanied by roaring and growling. However, the elephant also has a secret voice, one that is hidden from human hearing.

Researchers have discovered that elephants, both African and Asian types, often send signals to each other through "rumbles" that are too deep, or low in frequency, for humans to hear. Most people can detect sounds between 20 and 20,000 Hz. (vibration cycles per second). Elephant rumbles, though sometimes barely audible at about 20 to 24 Hz., are typically under 20 Hz. and are therefore inaudible to humans.

People can, however, see and feel certain signs that elephants are sending the signals. When elephants emit their rumbles, they tend to flutter the skin on their foreheads. The rumbles actually travel through the ground, where vibrations move much faster than sound does through the air. Other elephants, up to twelve miles away, receive the signals through sensitive skin on their feet and trunks. People standing near the "speaking" elephants can often feel, even though they cannot hear, the vibrations of the rumbles.

Researchers, however, have recorded the rumbles, and, when they play back the tapes at an increased speed (thus raising the frequencies of the sounds to an audible range), they can clearly hear the secret voice of the elephant. The sounds, though low in frequency, are tremendously high in volume (just like the elephant's familiar trumpeting calls), accounting for the vast distances that the sounds cover.