Biology
The Role of Infrasound Communication in Elephant Herds
Quick fact
Elephants can communicate across distances of up to 10 kilometers using infrasound calls below 20 Hz, which are inaudible to human ears.
Why this is interesting
Imagine being able to 'talk' to a friend miles away, through dense forest, without a phone. Elephants do this every day using sounds so low you can't hear them.
Read the full explanation
Understanding The Role of Infrasound Communication in Elephant Herds
Elephants produce a variety of vocalizations, but the most remarkable are their low-frequency calls, known as infrasound. These sounds are so deep that humans cannot hear them—our hearing typically ranges from about 20 Hz to 20,000 Hz, while elephant infrasound calls are often below 20 Hz, some as low as 5 Hz. Because low-frequency sound waves travel farther than high-frequency ones, these calls can traverse kilometers of savanna or forest. Elephants generate these sounds in their larynx, similar to how we speak, but the large size of their vocal cords and resonating chambers produces these deep tones. On the receiving end, elephants have specially adapted ears and also sensitive nerve endings in their feet that can detect vibrations traveling through the ground. This dual system allows them to pick up both airborne and seismic signals. The result is a communication network that keeps the herd connected over vast areas, enabling them to coordinate movements, warn of danger, and maintain social bonds.
A deeper explanation
The key to infrasound's reach lies in physics: lower-frequency sounds have longer wavelengths, which means they are less absorbed by the atmosphere and can diffract around obstacles like trees and hills. This allows an elephant's call to remain detectable across several kilometers, far beyond the range of higher-pitched sounds. The elephant's vocal apparatus is essentially a large resonator; the size of the larynx and the length of the vocal tract lower the fundamental frequency of the sound produced. When an elephant calls, it can also generate ground vibrations through its feet, and these seismic waves travel even farther through the solid earth. To detect these signals, elephants possess an exceptionally thick tympanic membrane and a specialized inner ear structure that is sensitive to low frequencies. Additionally, they have vibration-sensitive mechanoreceptors in their feet and trunk, which can pick up the seismic component. This integrated system allows elephants to not only send long-distance messages but also to receive them even when the airborne sound has faded. Behaviorally, infrasound is crucial for maintaining the complex social structure of elephant herds. Matriarchs use infrasound to guide their family groups, coordinating movements towards water or away from danger. Females in estrus produce specific low-frequency calls to attract males from afar, and males use infrasound to assert dominance and communicate with rivals. The ability to communicate over long distances without visual contact is vital in the vast landscapes elephants inhabit, and it strengthens the bonds that hold their social units together. Understanding this mechanism reveals a hidden layer of elephant society and highlights the importance of quiet environments for their well-being.