Airborne and Seismic Properties of Kangaroo Rat Footdrums and Potential Impacts of Anthropogenic Noise

Acoustic signals mediate important social interactions between animals and often propagate through multiple media like the air and the ground. Similarly, anthropogenic noise can travel through diverse media to interfere with animal communication. However, most work on terrestrial vertebrate acoustic signaling and noise focus on the airborne component, while fewer studies have addressed propagation through the ground. In our first study, we assessed how acoustic properties of banner-tailed kangaroo rat (Dipodomys spectabilis) footdrums varied between airborne and seismic media relative to the sex and size of senders. We found that temporal footdrum properties were generally consistent between media, while amplitude and dominant frequency differed between media and depended on sender sex. Results of this first study highlight the importance of studying acoustic animal signals in all potential modalities as signal components in discrete media can convey distinct information to receivers. In our second study, we assessed how acoustic properties of vehicle noise varied between airborne and seismic media in kangaroo rat habitat. We found that the effect of the medium on vehicle noise amplitude and dominant frequency depended on the distance from the noise source. In relation to footdrums, vehicle noise was louder and similar in frequency in both airborne and seismic media, indicating potential interference with both signal components. Results of the second study highlight the importance of studying impacts of anthropogenic noise on wildlife in multiple media.