Target Recognition via Echolocation by Tursiops truncatus
Experiments were conducted to investigate the target echo recognition and discrimination behavior of Tursiops truncatus. Two specific hollow aluminum cylinders (3.81 cm and 7.62 cm O. D.) and two solid coral rock (3.81 cm and 7.62 cm diameter) cylinders, all 17.8 cm in length, were used as standard baseline targets. The coral rock targets were constructed of coral pebbles encapsulated in a degassed epoxy mix. Illustrated in Fig. 1 is the experimental pen with the two target funnels located at ranges of 6 and 16 m in front of the dolphin’s pen. The funnels were used to present the targets into the water at approximately the same location at each range. The two-alternative, forced-choice technique was used with the targets presented successively in a random sequence. The animal was required to echolocate on the targets and respond to paddle A for the aluminum and paddle B for the coral rock standards. After near errorless performance with the standard targets was achieved, probe sessions were conducted to investigate differential reporting of probe targets varying in structure and composition. All of the probe targets were cylinders of 17.8 cm length. Two probe targets were used in each probe session and only 8 of the 64 trials of the session were used for probe trials, 4 for each probe target.
KeywordsProbe Trial Probe Target Coral Rock Probe Session Standard Target
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