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 4 groups from 3 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 toward sessions was significantly higher shortly before sessions and lower afterward. 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. (PsycINFO Database Record

Cognitive judgement bias is associated with frequency of anticipatory behavior in bottlenose dolphins

“…Although dolphins react positively to applause and eye contact, this is considered a secondary reinforcement compared to food rewards (Brando, ; Neto, Silveira, & dos Santos, ). In order to complete Step 2 and pass to the final testing phase of Step 3, evidence was needed that the dolphins were discriminating between the extreme cues: this would be assessed from the recorded return times to the trainer, with the criteria that they must return ≥2 s faster from the Positive than the Less‐positive cue (Clegg, Rödel, Delfour, et al, ). The animals were not separated from their regular social groups during testing (advantages discussed in Roelofs et al, ), in order to avoid inducing stress from social isolation, which has often been recorded with dolphins (e.g., Waples & Gales, ).…”

“…The animals were not separated from their regular social groups during testing (advantages discussed in Roelofs et al, ), in order to avoid inducing stress from social isolation, which has often been recorded with dolphins (e.g., Waples & Gales, ). The test dolphin would undergo the test while the other dolphins would remain with their trainers in other parts of the pool (no gates used, see Figure in Clegg, Rödel, Delfour, et al, for layout). Interference from the other dolphins, and thus the possibility of social learning, was limited as much as possible in the methods: a visual cue, the target, was chosen (as opposed to a sound, which all dolphins would hear); some dolphins were always taken to the inside pool, and the rest stayed on the opposite side of the pool to the test, and thus not in the visual field of the test dolphin.…”

“…The overall response variable reflecting cognitive bias was the dolphins' return latency (in s) from the target to the trainer, where it would receive the reward (the same as in Clegg, Rödel, Delfour, et al, , and measured from video footage). For the current study, the return latencies of each dolphin were averaged for each of the Near‐positive, Middle, and Near‐negative cues (instead of taking an average of all three ambiguous cues as in Clegg, Rödel, Delfour, et al, ).…”

“…For the current study, the return latencies of each dolphin were averaged for each of the Near‐positive, Middle, and Near‐negative cues (instead of taking an average of all three ambiguous cues as in Clegg, Rödel, Delfour, et al, ). This approach was chosen to fully investigate any associations between our one behavior variable (as opposed to multiple behaviors tested in Clegg, Rödel, Delfour, et al, ) and cognitive bias. If correlations are present it would be fruitful to be able to see whether they are conserved among the different ambiguous cues, yielding as much information as possible on the link between cognitive bias and anticipatory behavior as it is clearly a species‐independent topic of interest (Wichman et al, ).…”

“…To examine the potential links between anticipatory behavior frequency and cognitive bias, we measured the frequency of anticipatory behaviors of captive bottlenose dolphins toward upcoming training sessions and correlated them to the animals' results from cognitive bias tests. Previous studies suggest dolphins view the multiple daily training sessions positively as the sessions provide food, cognitive stimulation, and anticipatory behaviors are exhibited prior to sessions (Brando, ; Clegg, Rödel, Cellier, et al, ; Jensen, Delfour, & Carter, ; Laule, Bloomsmith, & Schapiro, ; Miller, Mellen, Greer, & Kuczaj II, ). Therefore we hypothesized that based on the reward‐sensitivity theory (Spruijt et al, ), dolphins showing the higher frequencies of anticipatory behavior would also make more pessimistic judgements in the cognitive bias task.…”