Laterality of eye use has been increasingly studied in cetaceans. Research supports that many cetacean species keep prey on the right side while feeding and preferentially view unfamiliar objects with the right eye. In contrast, the left eye has been used more by calves while in close proximity to their mothers. Despite some discrepancies across and within species, laterality of eye use generally indicates functional specialization of brain hemispheres in cetaceans. The present study aimed to examine laterality of eye use in bottlenose dolphins ( Tursiops truncatus ) and rough-toothed dolphins ( Steno bredanensis ) under managed care. Subjects were video-recorded through an underwater window while viewing two different stimuli, one predictable and static and the other unpredictable and moving. Bottlenose dolphins displayed an overall right-eye preference, especially while viewing the unpredictable, moving stimulus. Rough-toothed dolphins did not display eye preference while viewing stimuli. No significant correlations between degree of laterality and behavioral interest in the stimuli were found. Only for bottlenose dolphins were the degree of laterality and curiosity ratings correlated. This study extends research on cetacean lateralization to a species not extensively examined and to stimuli that varied in movement and degree of predictability. Further research is needed to make conclusions regarding lateralization in cetaceans.

Dolphins are frequently described as curious animals; however, there have been few systematic investigations of how dolphins behave when they are curious and the extent to which individual differences in curiosity exist in dolphins. Previous research has described individual differences in dolphins’ frequency of interactions with environmental enrichment as well as quantifying curiosity-related traits of dolphins via personality assessments, though behavioral observation and trait rating components have not been part of the same study. The present study describes two different experiments designed to elicit curiosity in 15 bottlenose ( Tursiops truncatus ) and 6 rough-toothed ( Steno bredanensis ) dolphins. In Experiment 1, dolphins displayed more curiosity-related behavior toward a stimulus with spontaneous movement (jack-in-the box) compared to their reaction to a static control object; however, in Experiment 2, the subjects did not conform to hypotheses, and displayed few behavioral differences when shown expectation-violating stimuli compared to a control stimulus. The results of this study supported the hypothesis that there would be a wide range of individual differences in dolphins’ reactions to the stimuli, including differences between species and sex, as well as differences in trait ratings by trainers. These findings provide information that may be useful for future research aimed at assessing curiosity in dolphins, as well as for making environmental enrichment decisions for dolphins in human care.