Enrichment with classical music enhances affiliative behaviours in bottlenose dolphin.

Environmental enrichment is a crucial element for the promotion of welfare of animals kept under human care. While a large variety of environmental enrichments has been proposed and studied for terrestrial animals, including a growing area represented by acoustical enrichment such as music, the same is not true for marine mammals. The purpose of this study was to evaluate the ability of classical music to act as an enrichment for bottlenose dolphins under human care (Tursiops truncatus); its effect on the dolphins’ behaviour were compared with that of a less complex auditory stimulus (rain sound), another novel, but visual enrichment (slideshow of photographs), and an already known form of enrichment (floating objects). The study was conducted on 8 dolphins housed in a dolphinarium in Riccione, Italy. Enrichments were provided for 20 minutes/day, on 7 days for each enrichment type. Their effect was evaluated by observing changes in behaviours expressed during or shortly after the provision of the enrichment. Some effects were unspecific, being shared by most, or all types of enrichment, including an increase of activity levels and synchronous swimming. However, only classical music was able to increase several social affiliative behaviours both during its presentation and after its removal. The results indicate that classical music has positive effects on behaviour, that qualify it as an effective environmental enrichment for dolphins in this context. Some aspects remain to be elucidated, including the mechanisms by which music exerts its effects, and how specific to classical music the latter are. Nonetheless, the specificity of effects on social behaviour suggest that classical music could be particularly useful when an improvement in social behaviours is needed