Hearing in prairie dogs: transition between surface and subterranean rodents.

Behavioral audiograms were determined for four black-tailed and one white-tailed prairie dogs (Cynomys ludovicianus and C. leucurus) using a conditioned avoidance procedure. The hearing of black-tailed prairie dogs ranges from 29 Hz to 26 kHz and that of the white-tailed prairie dog from 44 Hz to 26 kHz (at sound pressure levels of 60 dB). Both species have good low-frequency hearing, especially black-tailed prairie dogs which can hear as low as 4 Hz and are more sensitive than any other rodent yet tested at frequencies below 63 Hz. In contrast, prairie dogs are relatively insensitive in their midrange and have poor high-frequency hearing. It is suggested that the reduced midrange sensitivity and high-frequency hearing are related to their adaptation to an underground lifestyle with its reduced selective pressure for sound localization. In this respect they appear to be intermediate between the more exclusively subterranean rodents (such as gophers and mole rats) and surface dwellers (such as chinchillas and kangaroo rats).