Abstract:

The evolutionary history of dolphins and whales is revealed through extensive adaptation of their sensory systems. Their auditory capabilities were hinted at through their acoustic repertoire after development of the hydrophone. The echolocation capabilities of dolphins, first induced by McBride in 1956, were demonstrated behaviorally in 1958, but nothing was known about their biosonar signals until technology caught up. The revelation that dolphins interrogated their environment using ultrasonic sonar pulses was complemented by demonstration of ultrasonic hearing acuity and sensitivity extending over 6 oct above that of humans. Our understanding of dolphin auditory-filter shapes and receiver-operating characteristics advanced apace with development of instrumentation for underwater acoustics. These findings formed a basis for contemporary research on cetacean psychophysics, anatomy, and acoustical ecology, which continues to reveal the intricacies and elegance of the auditory systems and capabilities of dolphins and whales.