Lateralization in accuracy, reaction time and behavioral processes in a visual discrimination task in an Indo-Pacific bottlenose dolphin (Tursiops aduncus).

Perceptual and behavioral asymmetry has been observed in a wide range of vertebrate and invertebrate species with its origin estimated to go back over 500 million years. Previously, hemispheric lateralization in marine mammals has been recorded during foraging, parental care, preferred swimming direction as well as when solving cognitive challenges. Visual laterality has been demonstrated in preferred eye use and performance accuracy. A female Indo-Pacific bottlenose dolphin was trained to associate eight pairs of non-identical visual stimuli. Her performance was tested and compared under binocular and monocular conditions. No significant difference was found in accuracy, while a clear left eye advantage was demonstrated in reaction time. In addition, behavioral asymmetry was observed in movement pattern preference during the stimulus discrimination.