Abstract:

The ears of desert rodents are well adapted for receiving low-frequency vibrations created during footdrumming. Kangaroo rats drum species-specific patterns, ranging from single thumps to individual footdrumming signatures. The desert kangaroo rat, D. deserti, drums single thumps spaced 0.25 to 0.30 s apart. The giant kangaroo rat, D. ingens, drums long footrolls that can average over 100 drums at 18 drum/s. The banner-tailed kangaroo rat, D. spectabilis, drums footdrumming signatures consisting of 3--38 footdrums in a footroll combined into sequences of 2--13 footrolls. In playback tests, all three species stood alert and entered the burrow in response to footdrumming of their own and other species. The rats also responded in species-specific ways. D. spectabilis drummed to its own species' footdrumming, but not to playbacks of single drums of D. deserti. D. deserti did not footdrum in response to the playbacks, but approached the speaker more frequently than either of the other two species. D. ingens footdrummed equally to all footdrumming playbacks. The species' differences reflect differences in social tolerance and spacing. D. deserti chases visitors from the burrow, D. spectabilis engages in frequent footdrumming exchanges, and D. ingens tolerates close neighbors and footdrums periodically.