The bottlenosed dolphin's (Tursiops truncatus) understanding of gestures as symbolic representations of its body parts

Abstract

We assigned gestural symbols to nine body parts of a bottlenosed dolphin (Tursiops truncatus). The dolphin was first trained to touch any floating object it chose with the body part indicated by a gestural symbol. In Experiment 1, we tested the dolphin's ability to now touch specific gesturally referenced objects using specific gesturally referenced body parts. In Experiment 2, we tested its ability to either touch or toss gesturally referenced objects with gesturally referenced body parts or to simply display those body parts or shake them back and forth. The acts of touching, tossing, displaying, and shaking were each associated with specific gestures and appeared in random sequences within test sessions. The results demonstrated highly significant levels of performance throughout these tasks, including many successes on the first occasions of new body-part uses. These findings provided strong evidence that the gestural symbols we used for body parts were semantically processed and understood by the dolphin as representing those body parts.