The Atlantic bottlenose dolphin Tursiops truncatus is the best studied example of successful adaptation of biosonar to the reverberant and variable VSW/SW environment. With evolved and learned adaptations, it can successfully search for, detect and classify objects in conditions that usually defeat the best artificial sonars. The adaptations of the transmitting, receiving and analysing systems that reduce reverberation and noise are reviewed as background for recent studies of the dynamics of biosonar performance in open-fields; work that suggests still further means of enhancing the S/N ratio. The open-field work uses new experimental methods that control for additional extraneous variables as well as instruments that continuously record the animal's location, head-attitude, head-azimuth, interpulse intervals and emission spectra. The instruments include a high- speed data acquisition package that is carried by the animal and a guide boat that is equipped with a high-accuracy DGPS, an interactive field-display for the driver and a computer that coordinates time, position and data acquisition. Systematic measurements with these methods allow for the analysis of the animal's distribution of biosonar energy in 3D space, time and frequency as a function of practice effects, object distance, grazing angle and environmental variables.
John E. Sigurdson (1998). Analysing the dynamics of dolphin biosonar behaviour during search and detection tasks [abstract]. Bioacoustics 9(3): 222-223