Environmental enrichment, training, and habitat characteristics of common bottlenose dolphins (Tursiops truncatus) and Indo-Pacific bottlenose dolphins (Tursiops aduncus)

Health and Welfare Benefits of Computerized Cognitive Enrichment in California Sea Lions (Zalophus californianus) at the US Navy Marine Mammal Program

Cognitive enrichment is becoming more prevalent in professional marine mammal facilities. Research with dolphins has suggested that such enrichment provides more welfare benefits than enrichment that does not incorporate cognitive challenge. However, there is little research supporting the use of cognitive enrichment as a means to improve the welfare of sea lions. Recently, a novel form of technological cognitive enrichment, the Enclosure Video Enrichment (EVE) system, was introduced to a population of California sea lions at the US Navy's Marine Mammal Program as a means to enhance welfare. Two of the initial focal animals introduced to EVE were selected based on their health history and the possible benefits of cognitive enrichment in improving health measures. To evaluate this, information regarding the animals' consumption of their offered diet was compared to other animals in the population of similar age and the absence of a similar health history. Subsequently, the total diet consumption of the targeted animals was evaluated in the two years prior to the introduction to EVE and compared to the total diet consumption during the initial 2 years of regular EVE sessions. There was a significant decrease in the number of days in which the sea lions did not consume their entire offered diet in the two years after implementing regular EVE sessions, an increase in participation and performance of voluntary husbandry behaviors, and a reduction in the number of days animals were clinically ill. This study provides evidence of cognitive enrichment as a management tool to improve animal health and welfare as well as performance in training sessions.

Benefit of Cognitive Environmental Enrichments on Social Tolerance and Play Behavior in Bottlenose Dolphins (Tursiops Truncatus)

Social tolerance is an essential feature of social life that can determine the good functioning of a group of animals. Play behaviors, like social play and playing with objects, are frequently associated with positive emotional and welfare states. As a result, zoos use various strategies to promote both social tolerance and play with objects. Providing animals with cognitive environmental enrichment can be an effective tool to achieve these goals. Here we tested whether cognitive environmental enrichment can promote social tolerance and play with objects in bottlenose dolphins (Tursiops truncatus). To this end, we provided a group of five dolphins with two types of cognitive enrichment: one for individual use and one for cooperative use, both based on the rope-pulling task paradigm. Then we evaluated whether social tolerance and play with objects had increased after we provided dolphins with the two enrichments. Our results go in this direction, showing that after we provided dolphins with the enrichments, their intolerance behaviors decreased, both during feeding sessions and play sessions, while their play with objects increased. As a result, the two enrichments we used could be useful for improving dolphins' housing conditions.

Using Anticipatory Behavior to Detect the Change in Interest in an Activity Repeated Several Times and Avoid Habituation in Bottlenose Dolphins (Tursiops Truncatus)

Environmental enrichment is an essential component of the management policies used by zoos and aquaria to promote animals' welfare. However, when enrichments are provided several times, they can cause habituation and lose their enrichment effects. A simple method to avoid it could be making a preventive assessment about the trend of animals' interest in a stimulus provided several times. Here, we hypothesized that anticipatory behavior could be used to assess the decrease in interest in playing with objects when the activity is repeated. Moreover, we also assumed that this could be done before providing objects to play with. Our results support this hypothesis. Specifically, we found a positive correlation between the time the 7 dolphins tested spent performing anticipatory behavior before the enrichment sessions and the time they spent playing with objects during those sessions. As a result, anticipatory behavior performed before enrichment sessions predicted dolphins' interest in the session and allowed us to assess whether the sessions had lost their enrichment effect.

Dolphin-WET-Development of a Welfare Evaluation Tool for Bottlenose Dolphins (Tursiops truncatus) under Human Care

Ensuring high standards of animal welfare is not only an ethical duty for zoos and aquariums, but it is also essential to achieve their conservation, education, and research goals. While for some species, animal welfare assessment frameworks are already in place, little has been done for marine animals under human care. Responding to this demand, the welfare committee of the European Association for Aquatic Mammals (EAAM) set up a group of experts on welfare science, cetacean biology, and zoo animal medicine across Europe. Their objective was to develop a comprehensive tool to evaluate the welfare of bottlenose dolphins (Tursiops truncatus), named Dolphin-WET. The tool encompasses 49 indicators that were either validated through peer review or management-based expertise. The first of its kind, the Dolphin-WET is a species-specific welfare assessment tool that provides a holistic approach to evaluating dolphin welfare. Inspired by Mellor's Five Domains Model and the Welfare Quality®, its hierarchical structure allows for detailed assessments from overall welfare down to specific indicators. Through combining 37 animal-based and 12 resource-based indicators that are evaluated based on a two- or three-level scoring, the protocol offers a detailed evaluation of individual dolphins. This approach allows for regular internal monitoring and targeted welfare management, enabling caretakers to address specific welfare concerns effectively.

Left or right, that is the question: use of egocentric frame of reference and the right-eye advantage for understanding gestural signs in bottlenose dolphins (Tursiops truncatus)

How do bottlenose dolphins visually perceive the space around them? In particular, what cues do they use as a frame of reference for left-right perception? To address this question, we examined the dolphin's responses to various manipulations of the spatial relationship between the dolphin and the trainer by using gestural signs for actions given by the trainer, which have different meanings in the left and right hands. When the dolphins were tested with their backs to the trainer (Experiment 1) or in an inverted position underwater (Experiments 2 and 3), correct responses from the trainer's perspective were maintained for signs related to movement direction instructions. In contrast, reversed responses were frequently observed for signs that required different sounds for the left and right hands. When the movement direction instructions were presented with symmetrical graphic signs such as " × " and "●", accuracy decreased in the inverted posture (Experiment 3). Furthermore, when the signs for sounds were presented from either the left or right side of the dolphin's body, performance was better when the side of the sign movement coincided with the body side on which it was presented than when it was mismatched (Experiment 4). In the final experiment, when one eye was covered with an eyecup, the results showed that, as in the case of body-side presentation, performance was better when the open eye coincided with the side on which the sign movement was presented. These results indicate that dolphins used the egocentric frame for visuospatial cognition. In addition, they showed better performances when the gestural signs were presented to the right eye, suggesting the possibility of a left-hemispheric advantage in the dolphin's visuospatial cognition.

Are Dolphins Kept in Impoverished Environments?

Numerous studies have demonstrated the negative effects of impoverished environments versus the positive effects of enriched environments on animals' cognitive and neural functioning. Recently, a hypothesis was raised suggesting that conditions for dolphins in zoological facilities may be inherently impoverished, and thus lead to neural and cognitive deficits. This review directly examines that hypothesis in light of the existing scientific literature relevant to dolphin welfare in zoological facilities. Specifically, it examines how dolphins are housed in modern zoological facilities, where the characteristics of such housing fall on the continuum of impoverished-to-enriched environments, and the extent to which dolphins show behavioral evidence characteristic of living in impoverished environments. The results of this analysis show that contrary to the original hypothesis, modern zoological facilities do not inherently, or even typically, house dolphins in impoverished conditions. However, it also notes that there is variation in animal welfare across different zoological facilities, and that "not impoverished" would be a particularly low bar to set as an animal welfare standard. To optimize cognitive well-being, strategies for providing additional cognitive challenges for dolphins in zoological facilities are suggested.

Acoustic Monitoring of Professionally Managed Marine Mammals for Health and Welfare Insights

Research evaluating marine mammal welfare and opportunities for advancements in the care of species housed in a professional facility have rapidly increased in the past decade. While topics, such as comfortable housing, adequate social opportunities, stimulating enrichment, and a high standard of medical care, have continued to receive attention from managers and scientists, there is a lack of established acoustic consideration for monitoring the welfare of these animals. Marine mammals rely on sound production and reception for navigation and communication. Regulations governing anthropogenic sound production in our oceans have been put in place by many countries around the world, largely based on the results of research with managed and trained animals, due to the potential negative impacts that unrestricted noise can have on marine mammals. However, there has not been an established best practice for the acoustic welfare monitoring of marine mammals in professional care. By monitoring animal hearing and vocal behavior, a more holistic view of animal welfare can be achieved through the early detection of anthropogenic sound sources, the acoustic behavior of the animals, and even the features of the calls. In this review, the practice of monitoring cetacean acoustic welfare through behavioral hearing tests and auditory evoked potentials (AEPs), passive acoustic monitoring, such as the Welfare Acoustic Monitoring System (WAMS), as well as ideas for using advanced technologies for utilizing vocal biomarkers of health are introduced and reviewed as opportunities for integration into marine mammal welfare plans.

Trainer Interaction Can Improve Welfare Outcomes of Toy Enrichment for Isolated Animals: A Case Study

In cases where social animals must be temporarily housed alone, environmental enrichment is particularly important. Providing animals with manipulable objects (“toys”) is a common form of environmental enrichment, but its effectiveness can be limited by animal disinterest or habituation. The current study examined whether caregiver interaction could increase the effectiveness of object-based enrichment for a quarantined bottlenose dolphin (Tursiops truncatus). Behavioral observations were conducted after a training session, after a trainer toy play session, and between interactive sessions. The results showed that the dolphin floated in place less and played with toys more after interacting with a caregiver than he did at times further removed from caregiver interaction. He was also more likely to play with the same toys that the trainer had played with, showing effects of stimulus enhancement and/or social referencing. Although this study is, of necessity, based on a single animal of a single species, these findings suggest that interacting with a caregiver can enhance the efficacy of object-based environmental enrichment for isolated animals.

Cognitive Foraging Enrichment (but Not Non-Cognitive Enrichment) Improved Several Longer-Term Welfare Indicators in Bottlenose Dolphins

Bottlenose dolphins are the most common cetacean kept globally in zoos and aquaria (hereafter zoos), and are gregarious animals with a mostly opportunistic, generalist feeding strategy in the wild. In zoos, they have limited to no opportunities to express natural foraging behaviours as they receive their daily food ration of dead fish in a series of training sessions. Enrichment provision has increased in recent years, but items are still predominantly simple and floating in nature, and do not always target the animals' problem-solving or food-acquisition behaviours. These discrepancies run concurrently with the intense debate about dolphin welfare in zoos and how to improve it. The current study used a within-subject design on 11 bottlenose dolphins at Kolmårdens Djurpark and measured how several welfare indicators differed between two treatments of "cognitive" and "non-cognitive" food-based enrichment. The treatments were provided on an alternating basis for eight consecutive weeks: during cognitive enrichment weeks, the animals received items which stimulated their problem-solving and foraging behaviours, and during non-cognitive enrichment weeks, they received simple items paired with fish (to eliminate bias due to food value). Data were taken related to several multidisciplinary welfare parameters during enrichment provision and training sessions, and to activity budget behaviours throughout the week. During the cognitive as opposed to non-cognitive enrichment weeks, the dolphins engaged more with the enrichment, were more motivated to participate in training sessions and performed less anticipatory and stereotypic behaviours, suggesting that cognitive enrichment improved several indicators of bottlenose dolphin welfare. Valuable lines of further investigation would be to understand how individual differences and different types of cognitive enrichment impact potential welfare benefits. Our results suggest that enrichment items promoting cognitive foraging behaviours may improve dolphin welfare, and therefore zoos might prioritise giving cognitive enrichment to this species as well as considering the same for other species with similar cognitive skills and foraging ecologies.

Environmental Enrichment Factors Associated with the Activity Level of Bottlenose Dolphins under Professional Care

Environmental enrichment can be used to improve the welfare of dolphins in zoos and aquariums. Bottlenose dolphins under professional care are typically provided with a range of enrichment that has a variety of features and levels of complexity at various frequencies. In the present study, a subset of data from a larger study entitled “Towards understanding the welfare of cetaceans in zoos and aquariums” (colloquially called the Cetacean Welfare Study) was used to examine the relationship between activity level and enrichment buoyancy as well as enrichment provisioning schedules. Survey data were collected from accredited zoos and aquariums related to the types of enrichment provided to the dolphins and the frequency and duration they were supplied. Non-invasive bio-logging devices were used to record the dolphin kinematics one day per week over the course of two five-week data collection periods. Activity level related positively with the total duration of time non-stationary enrichment was provided. In addition, providing a larger number of enrichment types each between 26% and 50% of the days in a month (i.e., rotating many different types of enrichment across days on a moderate schedule) was positively related to activity level. Activity level was negatively related to the number of times sinking enrichment was provided. Understanding how the temporal schedule and features of various types of enrichment are related to activity levels will aid in developing progressively more effective enrichment programs.