Temporal integration of tone signals by a killer whale (Orcinus orca).

This article focuses on measuring how pure-tone detection thresholds in a killer whale (Orcinus orca) vary with both signal frequency and duration, using a psychophysical procedure. The study found that detection thresholds decrease as signal duration increases, but only up to a frequency-dependent auditory integration time, which ranges from about 241 ms at 1 kHz to 4 ms at 100 kHz. These findings align with data from other odontocete species and have implications for assessing the impact of short-duration anthropogenic noise on marine mammals, as current auditory weighting functions may overestimate sensitivity to such signals. The research involved a 30-year-old male killer whale housed at SeaWorld San Diego and employed adaptive hearing tests with pure-tone signals across a wide frequency and duration range, resulting in duration-dependent audiograms that preserve the characteristic "U" shape but show elevated thresholds for shorter durations.