In the wild, California sea lions (Zalophus californianus) are exposed to a wide variety of sensory information, which cannot be replicated in captive environments. Therefore, unique procedures are necessary for maintaining physiological and psychological health in nonhuman animals in captivity. The effects of introducing natural scents to captive enclosures have been investigated in a variety of species, yet they have not been examined in marine mammals. This project explored the behavioral effect of scent added to the environment, with the goal of improving the welfare of sea lions in captivity. Two scent types were introduced: (a) natural scents, found in their native environment, and (b) non-natural scents, not found in their native environment. This study examined not only scent enrichment but also the possible evolutionary underpinnings of pinniped olfaction. Scent enrichment was found to significantly impact sea lion behavior as demonstrated by a reduction in pattern swimming, an increase in habitat utilization, and a reduction in stereotypical behavior. However, there were no differences in behavior between natural and non-natural scent conditions.

Bottlenose dolphins (Tursiops truncatus) are viewed as a highly intelligent species, capable of complex behaviors, requiring marine parks to maintain dynamic environmental enrichment procedures in order to ensure their optimal psychological and physiological well-being in human care. In this study, two experiments were conducted to determine the effects of different forms of enrichment on the behavior of bottlenose dolphins. In Experiment 1, the most successful enrichment included highly novel items, which resulted in avoidance, but also what is frequently considered positive behavioral changes including a reduction in circle swimming and an increase in social behavior. In Experiment 2, the use of choice resulted in negative unintended social consequences. These two experiments together demonstrate that the results of deploying enrichment may not be as clear-cut as previously presumed. In order to maintain positive benefits of enrichment, the results of this study suggest that unique forms of enrichment should be implemented on a variable schedule that is offered several times a year and consistently evaluated for effectiveness.