Bottlenose dolphins (Tursiops truncatus) wore opaque suction cups over their eyes while stationing behind an acoustically opaque door. This put the dolphins in a known position and orientation. When the door opened, the dolphin clicked to detect targets. Trainers specified that Dolphin S emit a whistle if the target was a 7.5 cm water filled sphere, or a pulse burst if the target was a rock. S remained quiet if there was no target. Dolphin B whistled for the sphere. She remained quiet for rock and for no target. Thus, S had to choose between three different responses, whistle, pulse burst, or remain quiet. B had to choose between two different responses, whistle or remain quiet. S gave correct vocal responses averaging 114 ms after her last echolocation click (range 182 ms before and 219 ms after the last click). Average response for B was 21 ms before her last echolocation click (range 250 ms before and 95 ms after the last click in the train). More often than not, B began her whistle response before her echolocation train ended. The findings suggest separate neural pathways for generation of response vocalizations as opposed to echolocation clicks.
Vocal reporting of echolocation targets: Dolphins often report before click trains end
S. H. Ridgway, W. R. Elsberry, D. J. Blackwood, T. Kamolnick, M. Todd, D. A. Carder, Monica Chaplin, T. W. Cranford; Vocal reporting of echolocation targets: Dolphins often report before click trains end. J. Acoust. Soc. Am. 1 January 2012; 131 (1): 593–598. https://doi.org/10.1121/1.3664074
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