Analysis of target recognition via echolocation by an Atlantic bottlenose porpoise (Tursiops truncatus)

Abstract

The targets used in the “Target recognition via echolocation by an Atlantic bottlenose porpoise (Tursiops truncatus)” study were acoustically examined in order to determine the salient features of the targets that would allow the animal to recognize and differentiate between the different targets. The echoes from the targets were obtained by using a broadband dolphinlike echolocation signal that had a similar waveform, peak frequency, and bandwidth with measured echolocation signals. The waveshape, frequency spectrum, target impulse response, and the matched‐filter response of the echoes were analyzed to determine features of the echoes that could be used by the animal to discriminate between targets. The echoes usually consisted of the major specular reflection for the front of the target followed by echoes of progressively diminishing amplitudes for the exterior of the target. The first two echo components, from the front face and interior boundary of the rear face, had the predominant influence of the shape of the spectrum. The results of the matched‐filter analysis showed a close correspondence with the animal's performance.