Behavioral hearing range of the chinchilla

The audiograms of three chinchillas were determined using pure tones ranging from 32 Hz to 45 kHz. The animals were tested with a conditioned avoidance procedure in which their heads were fixed within the sound field by requiring them to place their mouths on a water spout. At a level of 60 dB SPL the average hearing range extended from 50 Hz to 33 kHz with none of the animals able to hear 45 kHz at 89 dB. Overall, the audiogram of the chinchilla appears to resemble the human audiogram more closely than do other rodent audiograms. An analysis of ten published chinchilla audiograms indicates that those procedures which do not fix an animal within the sound field may overestimate their sensitivity.