Exploring the Potential Use of Seismic Waves as a Communication Channel by Elephants and Other Large Mammals

SYNOPSIS. Bioseismic studies have previously documented the use of seismic stim- uli as a method of communication in arthropods and small mammals. Seismic signals are used to communicate intraspecifically in many capacities such as mate finding, spacing, warning, resource assessing, and in group cohesion. Seismic sig- nals are also used in interspecific mutualism and as a deterrent to predators. Al- though bioseismics is a significant mode of communication that is well documented for relatively small vertebrates, the potential for seismic communication has been all but ignored in large mammals. In this paper, we describe two modes of pro- ducing seismic waves with the potential for long distance transmission: 1) loco- motion by animals causing percussion on the ground and 2) acoustic, seismic- evoking sounds that couple with the ground. We present recordings of several mammals, including lions, rhinoceroses, and elephants, showing that they generate similar acoustic and seismic vibrations. These large animals that produce high amplitude vocalizations are the most likely to produce seismic vibrations that prop- agate long distances. The elephant seems to be the most likely candidate to engage in long distance seismic communication due to its size and its high amplitude, low frequency, relatively monotonic vocalizations that propagate in the ground and have the potential to travel long distances. We review particular anatomical fea- tures of the elephant that would facilitate the detection of seismic waves. We also assess low frequency sounds in the environment such as thunder and the likelihood of seismic transmission. In addition, we present the potential role of seismic stimuli in human communication as well as the impact of modern anthropogenic effects on the seismic environment.