14 DAY TRIAL // Elephants can apparently communicate with each other easily, even over distances as long as 10 kilometers (6.2 miles). Oddly enough, they do not use the loud, trumpet-like sounds for which they are renowned, but infrasounds that they produce with their large vocal cords.
By definition, infrasounds are waveforms with a frequency of between 1 and 20 Hertz, or cycles per second. A well-trained human can hear frequencies between 20 and 22,000 Hertz. Sounds higher than 22 kHz are known as ultrasounds.
Apparently, elephants are able to produce infrasounds that travel over extremely large distances. A herd can therefore be spread apart over a large area, while its members are still able to communicate with each other directly.
The far-reaching infrasounds are usually emitted alongside a series of slightly-audible rumbles, which are produced at frequencies above 20 Hertz, ScienceNow reports.