Masked tonal thresholds in the bottlenosed porpoise.

Masked thresholds were obtained for a bottlenosed porpoise at 15 frequencies between 5 and 100 kHz, using continuous broad‐band noise to mask tonal stimuli. Critical bandwidths were calculated from the ratio of the tonal threshold level to the masking noise level per hertz at each frequency. At 5, 10, 20, 50, and 100 kHz, six different noise levels were used; from the resulting data, a plot of the amount of masking versus the effective noise level was obtained. The data are compared to those from similar experiments with human subjects.