Audiogram of the fox squirrel (Sciurus niger).

The behavioral audiograms of 2 fox squirrels (Sciurus niger) were determined with a conditioned avoidance procedure. The squirrels were able to hear tones ranging from 113 Hz to 49 kHz at a level of 60 dB sound-pressure level or less, with their best sensitivity of 1 dB occurring at 8 kHz. Their ability to hear frequencies below 150 Hz indicates that they have good low-frequency hearing, as do the 2 other members of the squirrel family (black-tailed and white-tailed prairie dogs) for which audiograms are available. This suggests that the ancestral sciurid may also have had good low-frequency hearing.