International Journal of Comparative Psychology

Behavior is lateralized when it is performed preferentially by one side of the body, and this phenomenon is seen across a wide range of vertebrate taxa. Furthermore the brain and body are contralateral in many animals, meaning that the left brain hemisphere most dominantly controls the right side of the body and vice versa. Lateralized behavior in humans and nonhuman primates reveals a population right-hand bias. Recent studies in primates have also begun to link differences in lateralized behavior to task complexity, and responses to novel versus familiar stimuli. Parallel research on cetaceans is sparse although evidence accrued over the last decade suggests captive dolphins have a preference for swimming counter-clockwise, a right-eye advantage in spatio-cognitive tasks and a right-eye preference for viewing novel objects, although this is the reverse of the general vertebrate pattern. Lateralized behavior was examined in a group of six male bottlenose dolphins ( Tursiops truncatus ) in response to a novel underwater maze, and compared to behavior during a baseline condition (no maze present). Dolphins were significantly more likely to swim counter-clockwise round their pool during both the baseline and maze condition, interpreted as a right eye bias. Swimming rotation was also weaker in dolphins during the maze condition, suggesting that the maze may have disrupted routine circular swimming behavior. There was no clear preference for using the left or right side of the maze, except in two high- using subjects with a strong right preference. Modifications and extensions to the methods are discussed.