Saspanda's blog: "My facination with the Elephant Lifestyle"

Communication It has been discovered that elephants can communicate over long distances by producing and receiving low frequency infrasound, a sub-sonic rumbling which can travel through the ground farther than sound travels in the air. This can be felt by the sensitive skin of an elephant's feet and trunk, which pick up the resonant vibrations in much the same way as the flat skin on the head of a drum. To listen attentively, the whole herd will lift one foreleg from the ground, and face the source of the sound, or often lay their trunks on the ground - the lifting presumably increases the ground contact and sensitivity of the remaining legs. This ability is thought to also aid their navigation by utilizing external sources of infrasound. Discovery of this new aspect of elephant social communication and perception is due to breakthroughs in audio technology, which can pick up frequencies outside the range of the human ear.