Schedule of human-controlled periods structures bottlenose dolphin (Tursiops truncatus) behavior in their free-time
Abstract
Behavioral patterns are established in response to predictable environmental cues. Animals under human care frequently experience predictable, human-controlled events each day, but very few studies have questioned exactly how behavioral patterns are affected by such activities. Bottlenose dolphins (Tursiops truncatus) maintained for public display are good models to study such patterns since they experience multiple daily human-controlled periods (e.g. shows, training for shows, medical training). Thus we investigated the effect of training session schedule on their ‘free-time’ behavior, studying 29 individuals within four groups from three European facilities. Our initial time budget analyses revealed that among the behaviors studied, dolphins spent the most time engaged in synchronous swimming, and within this category swam most at slow speeds and in close proximity to each other. ‘Slow-close’ synchronous swimming peaked shortly after training sessions and was low shortly before the next session. Play behavior had significantly higher frequencies in juveniles than in adults, but the effect was only seen during the in-between session period (interval neither shortly before nor after sessions). Anticipatory behavior towards sessions was significantly higher shortly before sessions and lower afterwards. We conclude that dolphin behaviors unconnected to the human-controlled periods were modulated by them: slow-close synchronous swimming and age-dependent play, which have important social dimensions and links to welfare. We discuss potential parallels to human-controlled periods in other species, including humans themselves. Our findings could be taken into account when designing welfare assessments, and aid in the provision of enrichment and maintaining effective schedules beneficial to animals themselves.