The field of welfare science and public concern for animal welfare is growing, with the focus broadening from animals on farms to those in zoos and aquaria. Bottlenose dolphins (Tursiops truncatus) are the most common captive cetaceans, and relevant regulatory standards are principally resource-based and regarded as minimum requirements. In this study, the farm animal Welfare Quality® assessment was adapted to measure the welfare of bottlenose dolphins, with a similar proportion of animal-based measures (58.3%). The ‘C-Well® ‘ assessment included eleven criterion and 36 species-specific measures developed in situ at three marine mammal zoological facilities, tested for feasibility and accuracy, and substantiated by published literature on wild and captive dolphins and veterinary and professional expertise. C-Well® scores can be calculated for each measure or combined to achieve an overall score, which allows for the comparison of welfare among individuals, demographics, and facilities. This work represents a first step in quantifying and systematically measuring welfare among captive cetaceans and can be used as a model for future development in zoos and aquaria, as well as a means to support benchmarking, industry best practices, and certification.

Application of environmental enrichment, as a means to successfully decrease undesired behaviors (e.g., stereotypic) and improve animal welfare, has been documented in a variety of zoological species. However, a dearth of empirical evidence exists concerning age, sex, and individual differences in response to various types of enrichment tools and activities in Atlantic bottlenose dolphins (Tursiops truncatus). This study involved a comparative assessment of enrichment participation of three resident, bottlenose dolphin populations, over the course of 17 months, with respect to sex and age class (calf, sub-adult, adult). Enrichment sessions were randomly assigned, conducted, and categorically assessed based on participation during seven, broad based enrichment classes (Object, Ingestible, Human, or a combination of the three). Overall, the proportion of participation in enrichment sessions was high (≥ 0.74), with individual differences in participation noted among the three populations. Sessions involving Humans and/or Ingestible items resulted in a significantly higher mean proportion of participation. Subadult and adult males were significantly more likely to participate in enrichment sessions, as well as engage in Human Interaction/Object sessions. Calves participated significantly more than adults or sub-adults across all enrichment classes with no noted differences between males and females. These data can serve as a tool to better understand the intricacies of bottlenose dolphin responses to enrichment in an effort to develop strategic enrichment plans with the goal of improving animal well-being and welfare.

Dolphin calves often wander away from their mothers, which can compromise their safety and survival. Mothers can retrieve their calves by actively pursuing them or by signaling their wandering calves to return. However, little is known about the retrieval techniques employed by mothers in specific calf recall contexts. We experimentally investigated maternal calf retrieval methods by assessing behavioral and acoustic strategies employed by three Atlantic bottlenose dolphin mothers to elicit their calf's return in a controlled, non-threatening setting. Three mothers were asked to retrieve their calves on cue in this setting, and could do so however they chose. Mothers were much more likely to use energetically less costly acoustic signals than physical retrievals. Each mother produced individually distinctive calls that incorporated the mother's signature whistle but often also involved additional whistles and clicks. The dolphin mothers' use of individually distinctive calls to request a calf's return is consistent with the notion that other dolphins can distinguish such calls and provides additional support for the notion that dolphin communication is flexible rather than fixed.

No abstract

When analyzing animal behavior, it is important to consider the influence of learning principles. The create response of bottlenose dolphins, elicited by a discriminative stimulus, or an SD (visual cue presented to an animal by a trainer), has been described as an elective, often novel response based on arbitrary preferences of individual animals. The goal of this study was to identify the potential influence of reinforcement theory, response class, and primacy and recency on the create responses of bottlenose dolphins. Three, male subjects with an established mastery of the create paradigm, identified in this study as a non-specific, non-repeat contingency, were assessed over the course of two months while under stimulus control (pre-assessment), followed by evaluations of the create response (create assessment) using a double-blind sampling model. During the pre- and create assessments, each response was quantified regarding response class, frequency of request, and reinforcement type, frequency, and magnitude. When presented with the create SD, the dolphins elected to produce behaviors predominantly associated with the more recent training context (create assessment) versus behaviors associated with training that occurred months prior (pre-assessment), which may demonstrate the effects of primacy versus recency. Additionally, the create trials were associated with reinforcement on a high frequency and magnitude, fixed, low ratio schedule, and the subjects most often performed the behaviors associated with the greatest magnitude of primary reinforcement, which highlights the influence of reinforcement and the law of effects. Lastly, two subjects never responded with high energy behaviors in the create contingency, and one subject performed significantly more low and medium energy responses when compared to high energy behaviors, capturing the effects of a response class characterized by intensity under a fixed ratio reinforcement schedule. Thus, the create response was not represented by arbitrary elective preferences but rather, partially driven by the learning theories examined.