RANDALL, J.A.: Why do Desert Rodents Drum their Feet?

Vibrational signals are one of the more common modes of communication in rodents. Striking the feet on the ground to create mechanical vibrations seems to have evolved independently in several lineages of fossorial and semi-fossorial desert rodents on all continents except Australia. Footdrumming produces both substrate-borne and airborne acoustic energy in multiple contexts. In the social context, rodents footdrum to communicate territorial ownership, competitive superiority, familiarity, submission and predation risk to conspecifics. Footdrumming is species specific and ranges from single thumps to individually distinct footdrumming signatures that the banner-tailed kangaroo rat, Dipodomys spectabilis, uses to advertise its territorial ownership to neighbors. Footdrumming signatures are flexible and can be adjusted to changes in the social environment. Many desert rodents also footdrum in the presence of predators. Solitary kangaroo rats footdrum at snakes and kit foxes in individual defense to inform the predator that the rat is alert, not easy prey and to go away. In contrast to solitary rodents, the great gerbil, Rhombomys opimus, from Central Asia is highly social and uses a combination of footdrumming and vocalizations to communicate predation risk to offspring, relatives and mates. Great gerbils may footdrum in the presence of snakes and polecats that hunt in burrows to communicate predation risk to family members inside the burrow. There is much more to be learned about vibrational communication in rodents. Research on more species from different habitats and lineages should reveal the diversity and importance of this mode of communication in mammals.