The effect of age‐related hearing loss on echolocation: Changes in click parameters and echolocation discrimination abilities are initiated by changes in auditory filters.

Abstract

High‐frequency hearing loss has been correlated with a reduction both in echolocation click parameters and in echolocation discrimination abilities in a false killer whale. During a 15‐year time period, the whale demonstrated a significant decrease in peak frequency, center frequency, and source level of outgoing clicks between two studies. Echolocation clicks were analyzed from the most recent phase of the discrimination study to determine if there were significant differences for click parameters according to target condition. The whale consistently produced clicks with the same peak and center frequencies and source levels but varied the number of clicks according to experimental condition. The data suggest that the whale does not use spectral adaptations during discrimination. Likely, a gradual shift in click parameters resulted from a change in the auditory filtering processes initiated with age‐related hearing loss.