But it is possible. And the fact that many animal species behave strangely before other natural events, such as storms, and that they have the ability to detect others of their species at distances which the familiar human senses could not manage, is well established. Such observations have led some to suggest that these animals have a kind of extra-sensory perception. The best guess is that they can feel and understand vibrations that are transmitted through the ground. Good vibrations Almost all the research done into animal signalling has been on sight, hearing and smell, because these are senses that people possess.
Humans have no sense organs designed specifically to detect terrestrial vibrations.
Until recently, the only large mammal known to produce seismic signals was the elephant seal, a species whose notoriously aggressive bulls slug it out on beaches around the world for possession of harems of females. But Caitlin O'Connell-Rodwell of Stanford University, who is one of the speakers at the symposium, suspects that a number of large terrestrial mammals, including rhinos, lions and elephants, also use vibration as a means of communication. Elephants, according to Dr O'Connell-Rodwell, can transmit signals through the ground this way for distances of as much as 50km when they trumpet, make mock charges or stomp their feet. Seismic vibrations do not qualify as signals unless they are being received and understood. One way this was found out was by vibrating whole frogs while recording the electrical impulses from particular cells in their inner ears that were suspected of responding to seismic stimulation.