Environmental Enrichment

Agonistic interactions and social behaviors in the Saharan Dorcas gazelle (Gazella dorcas neglecta): Using social network analysis to evaluate relationships and social structure in captive male groups

Social interactions, including agonistic behavior, are very important for the management and welfare of individuals forming groups in captivity. One of the main concerns for the stability and durability of adult male groups is a noticeable level of intraspecific aggression. This study comprises a Social Network Analysis to illustrate social structure in different groups of captive Saharan Dorcas gazelles (Gazella dorcas neglecta). Our main objectives were to examine the relationship between agonistic, affiliative, and association networks and their reciprocity, assessing also whether the agonistic networks can conform to a linear dominance hierarchy. For these purposes, we recorded the behavior of 23 adult males organized in five herds, three composed only of Saharan Dorcas gazelle males and two mixed herds in which there were also Mhorr gazelle males (Nanger dama mohor). Observations were carried out during 295 h through scan sampling. We found no correlation between the affiliative and association networks in any group, although there was a significant correlation between the agonistic and association networks in mixed-species groups which was not present in single-species groups. Overall, there was no consistent reciprocity in either affiliative nor agonistic networks and none of the agonistic networks showed a linear structure. These results indicate that affiliative behavior in Saharan Dorcas gazelles offers distinctive and valuable information about the bonds between individuals, however, their dominance structure is far more complex than previously thought. As information provided by affiliative and proximity behaviors is different in this species, we suggest considering affiliative interactions to stablish affinity between individuals. Evaluating different social behaviors and not only agonistic interactions in later studies, is also recommended to develop a more accurately daily management in zoos that guarantee group stability and individuals' welfare, which will improve the conservation of captive populations.

Quantifying animals' perception of environmental predictability using anticipatory behavior

Animals under human care often experience predictable daily husbandry events, which can promote the development of anticipatory behavior. Previous research suggests even short delays in the arrival of a predictable, desired outcome can lead to negative welfare outcomes for animals. As such, providing reliable information to animals regarding the onset of important events may be a simple but useful method to support positive welfare. Here we evaluated the quantitative characteristics of anticipatory behavior of a California sea lion at the San Francisco Zoo in three situations (1) when the animal had accurate information about the occurrence of the event (temporally predictable training sessions), (2) when the information was semi-reliable (unscheduled training session), and (3) when a reliable signal was offered before unscheduled sessions. Results showed that providing a reliable cue resulted in a stronger temporal correlation of anticipation before the beginning of the unscheduled session, similar to the temporally predictable training session. However, providing a reliable cue did not reduce the intensity of the anticipatory behavior. We propose to take into account two aspects of the quantitative characteristics of anticipatory behavior: correlation with time until a desired event (correlation) and intensity, where the correlation indicates the ability of an individual animal to predict the occurrence of an event, and the intensity indicates the degree of sensitivity of the animal to reward. We discuss the implications for animal welfare and husbandry.

Improving Animal Wellbeing Using Behavior-Based Methodologies: A Discussion on Enrichment and Bears under Human Care

This communication discusses the Bear Care Group’s “behavior-based” enrichment philosophy, focusing on the importance of enrichment programs built on the knowledge of species’ natural histories, living strategies, and observed daily and seasonal routines. Methods for program development are discussed, detailing the benefits to animal wellbeing, including the reduction of chronic stress and frustration that lead to abnormal or stereotypical behaviors. The concepts are illustrated through a discussion of bear natural history and living strategies, but these methods are applicable to a wide range of taxa. The Bear Care Group encourages facilities to consider behavior-based enrichment programs to promote positive welfare for their animals.

Cognitive enrichment in a social setting: assessing the use of a novel food maze in sanctuary-housed chimpanzees

Foraging devices are effective enrichment tools for non-human primates, as they provide both cognitive and manipulative stimulation that may enhance these animals’ welfare. We assessed the behavioral effects of a novel tool-based enrichment on 14 chimpanzees (Pan troglodytes) housed at Fundació Mona (Girona, Spain). The device consisted of a vertical maze filled with food rewards, which chimpanzees could extract by using tools. We conducted behavioral observations in two conditions over an approximately 2.5-month period: when the food maze was loaded (12 enrichment days), and when it was empty (12 baseline days). Data were collected using 2-min scan sampling and untimed-event focal sampling during two daily sessions of 80 min each. We expected that the chimpanzees’ interest in the enrichment would decrease over time, but that its use would be linked to an increase in the occurrence of species-typical behaviors, a reduction in negative indicators of welfare, and changes in social behaviors. We found that participation widely varied among subjects, being higher in females and decreasing through time. Furthermore, participation was linked to an increase in tool use and a decrease in inactivity, but also to an increase in aggression-related behaviors. In contrast, participation had no effect on the occurrence of abnormal behaviors, social proximity or affiliation-related behaviors. Finally, we detected an increase in self-directed behaviors only when subjects actively interacted with the device. We conclude that, in future studies, these types of devices should be evaluated for longer periods of time and more attention should be paid to individuals’ preferences and abilities.

Welfare Through Competence: A Framework for Animal-Centric Technology Design

Digital technologies offer new ways to ensure that animals can lead a good life in managed settings. As interactive enrichment and smart environments appear in zoos, farms, shelters, kennels and vet facilities, it is essential that the design of such technologies be guided by clear, scientifically-grounded understandings of what animals need and want, to be successful in improving their wellbeing. The field of Animal-Computer Interaction proposes that this can be achieved by centering animals as stakeholders in technology design, but there remains a need for robust methods to support interdisciplinary teams in placing animals' interests at the heart of design projects. Responding to this gap, we present the Welfare through Competence framework, which is grounded in contemporary animal welfare science, established technology design practices and applied expertise in animal-centered design. The framework brings together the “Five Domains of Animal Welfare” model and the “Coe Individual Competence” model, and provides a structured approach to defining animal-centric objectives and refining them through the course of a design project. In this paper, we demonstrate how design teams can use this framework to promote positive animal welfare in a range of managed settings. These much-needed methodological advances contribute a new theoretical foundation to debates around the possibility of animal-centered design, and offer a practical agenda for creating technologies that support a good life for animals.

Rehabilitation of Marine Turtles and Welfare Improvement by Application of Environmental Enrichment Strategies

Simple Summary

Sea turtles are vital members of the marine ecosystem since they contribute to keeping balance in such environments. Unfortunately, they are endangered species whose absence may be detrimental. Conservation efforts aim to preserve sea turtles both at the population and individual levels. Rescue and rehabilitation aim to reduce individual morbidity and mortality as a result of injuries mainly caused by interactions with humans, in order to preserve their genetic diversity and help maintain and/or increase their population size. Environmental enrichment (EE) is a set of methodologies aimed to improve animal welfare during captivity/rehabilitation. This review presents successful cases of sea turtle environmental enrichment and its applications to improve their welfare in captivity and to increase their fitness prior to release into the wild. EE is a valuable tool that enhances welfare during the captivity and/or rehabilitation of sea turtles and improves their chances of survival and reintegration back into wild populations upon release. EE may be adopted in rescue and rehabilitation facilities around the world to improve individual survival and help boost conservation efforts.

Abstract

Sea turtles perform various ecological services in several marine environments and are considered architects of the marine landscape. At present, they are endangered species due to anthropogenic threats, pollution and degradation of marine habitats. These impacts make it urgent to increase protection and conservation efforts. Protective actions include the rescue and rehabilitation of injured individuals as a result of their interactions with humans and other threats. Environmental enrichment (EE) is a series of techniques and methods aimed to improve the welfare of animals in captivity and/or under rehabilitation. It uses external stimuli to enhance their psychological and physiological wellbeing to promote natural abilities and behaviors. These may increase the survival chances of rehabilitated animals upon release in the wild. This review presents data of studies where EE has been applied during the rehabilitation processes of different species of sea turtles, and its effect on welfare improvement during captivity/rehabilitation and on survival after release into nature. Technologies such as satellite tags are an important means to determine rehabilitation success and survival of injured individuals from endangered species after release into the wild, as they allow tracking and monitoring of such individuals, and determine their location in areas used by their natural populations for feeding or breeding.

Overlooked and Under-Studied: A Review of Evidence-Based Enrichment in Varanidae

Enrichment has become a key aspect of captive husbandry practices as a means of improving animal welfare by increasing environmental stimuli. However, the enrichment methods that are most effective varies both between and within species, and thus evaluation underpins successful enrichment programs. Enrichment methods are typically based upon previously reported successes and those primarily with mammals, with one of the main goals of enrichment research being to facilitate predictions about which methods may be most effective for a particular species. Yet, despite growing evidence that enrichment is beneficial for reptiles, there is limited research on enrichment for Varanidae, a group of lizards known as monitor lizards. As a result, it can be difficult for keepers to implement effective enrichment programs as time is a large limiting factor. In order for appropriate and novel enrichment methods to be created, it is necessary to understand a species’ natural ecology, abilities, and how they perceive the world around them. This is more difficult for non-mammalian species as the human-centered lens can be a hinderance, and thus reptile enrichment research is slow and lagging behind that of higher vertebrates. This review discusses the physiological, cognitive, and behavioral abilities of Varanidae to suggest enrichment methods that may be most effective.

Artificial Termite-Fishing Tasks as Enrichment for Sanctuary-Housed Chimpanzees: Behavioral Effects and Impact on Welfare

Simple Summary

The welfare of captive animals is nowadays a topic of major concern. In order to express their natural behavioral repertoires, however, animals require complex environments and stimuli which are difficult to reproduce in captivity. To overcome this, environmental enrichment is considered one of the most successful tools to increase behavioral opportunities and enhance animal welfare. In this study, we explored whether providing an artificial termite-fishing task, and whether participation in this task, predicted changes in the solitary and social behavior of sanctuary-housed chimpanzees (Pan troglodytes). We compared chimpanzee behavior when the enrichment was presented to different periods without enrichment. We found that the presence of the enrichment predicted an increase in tool use and feeding behavior and a decrease in inactivity, especially for those chimpanzees with higher participation. However, we did not detect significant changes in abnormal or self-directed behaviors. Furthermore, we found no variation in affiliation- or aggression-related behaviors, but social proximity increased in chimpanzees that participated more. Our results support previous studies demonstrating that artificial termite-fishing promotes species-typical behaviors in captive chimpanzees with no major effects on social activities.

Abstract

Artificial termite-fishing tasks are a common enrichment for captive great apes, promoting species-typical behaviors. Nonetheless, whether these activities are linked to changes in other behaviors and whether these changes persist over time has seldom been investigated. We assessed whether the use of an artificial termite-fishing task was linked to changes in the solitary behavior and social dynamics in two groups of sanctuary-housed chimpanzees (Pan troglodytes). Specifically, we compared chimpanzee behavior during eight enrichment sessions distributed over a two-month period, with similar periods before and after the introduction of the enrichment. Data were collected from combined interval and continuous sampling methods and were analyzed using generalized linear mixed models. We found that participation increased across sessions and that both enrichment and participation predicted an increase in tool use and feeding and a decrease in inactivity, which were all maintained throughout the sessions. Furthermore, participation was positively associated with social proximity, revealing a gathering effect of the task. However, neither enrichment nor participation were linked to changes in abnormal, self-directed, affiliation-related or aggression-related behaviors. Overall, our results support the hypothesis that artificial termite-fishing is a suitable enrichment for captive chimpanzees, maintaining the subjects’ interest and promoting species-typical behaviors, with no negative effects on social activities.

In search of the optimal enrichment program for zoo-housed animals

Zoo-housed animals are regularly exposed to new forms of environmental enrichment to make their lives less predictable. However, providing new enrichment can have unpredictable effects. We evaluated the effectiveness of two enrichment regimes: (1) providing only new enrichments - "Novelty" and (2) only familiar enrichments - "Familiar." In this case study, enrichment efficacy was assessed using activity budget analysis and novel object tests. The subjects were two focal animals: the golden jackal (Canis aureus) and the European badger (Meles meles). Our results suggest that both assessment methods provided similar conclusions about the animal's welfare. The "Familiar" treatment significantly increased activity and decreased abnormal behavior in the jackal's activity budget, who avoided novel objects in her baseline novel object test. The Novelty treatment resulted in the growth of time the jackal spent in the moat instead of the main enclosure, and an increase in avoidance and abnormal behaviors. In contrast, the badger demonstrated a high intensity of exploratory behavior in the baseline novel object test, and both regimes led to an increase in the activity budget of the badger. We propose that a stable, but complex enrichment can be an effective robust tool to increase animal welfare, but its efficacy depends on the novelty preference of individual animals. A novel object test can be a rapid tool to assess individual animals' novelty preferences, and this information may help to choose optimal enrichment regimes for individual animals.

The Effect of Enrichment Filling and Engagement Time on Regurgitation and Reingestion Behaviour in Three Zoo-Housed Orangutans

Regurgitation and reingestion (R/R) is a prevalent, abnormal behaviour observed in captive great apes. R/R may be related to animal welfare and while less R/R appears to occur when apes are provided with browse and continuous foraging opportunities, the aetiology of the behaviour (e.g., foraging time or taste characteristics such as sweetness) is not well understood. This study aimed to determine how environmental enrichment may affect R/R in three zoo-housed, adult orangutans. Over eight weeks, nine fillable enrichment items were provided twice to each orangutan–once with a sweet filling and once with a savoury filling. Enrichment engagement time and R/R behaviour were monitored for 1-h after the item was provided. Individual differences were found in R/R occurrence. One individual was more likely to perform R/R when given enrichment with a sweet filling (p < 0.05), and a second was more likely to R/R with savoury filled enrichment (p < 0.05). R/R behaviour from the third orangutan was unaffected by enrichment filling (p > 0.05), however he engaged longer with savoury filled enrichment, compared to sweet (p < 0.05). No relationship was found between engagement time and amount of R/R behaviour, for any of the orangutans (p > 0.05). While these results should not be generalized without a larger study, they do suggest that diet and enrichment qualities may play a role in the performance of R/R, and individual variation should not be overlooked when considering causation.

Motion Illusions as Environmental Enrichment for Zoo Animals: A Preliminary Investigation on Lions (Panthera leo)

Investigating perceptual and cognitive abilities of zoo animals might help to improve their husbandry and enrich their daily life with new stimuli. Developing new environmental enrichment programs and devices is hence necessary to promote species-specific behaviors that need to be maintained in controlled environments. As far as we are aware, no study has ever tested the potential benefits of motion illusions as visual enrichment for zoo animals. Starting from a recent study showing that domestic cats are spontaneously attracted by a well-known motion illusion, the Rotating Snake (RS) illusion, we studied whether this illusion could be used as a visual enrichment for big cats. We observed the spontaneous behavior of three lionesses when three different visual stimuli were placed in their environment: the RS illusion and two control stimuli. The study involved two different periods: the baseline and the RS period, in which the visual stimuli were provided to the lionesses. To assess whether the lionesses were specifically attracted by the RS illusion, we collected data on the number of interactions with the stimuli, as well as on the total time spent interacting with them. To investigate the effect of the illusion on the animals' welfare, individual and social behaviors were studied, and compared between the two periods. The results showed that two lionesses out of three interacted more with the RS stimulus than with the two control stimuli. The fact that the lionesses seemed to be more inclined to interact with the RS stimulus indirectly suggests the intriguing possibility that they were attracted by the illusory motion. Moreover, behavioral changes between the two periods were reported for one of the lionesses, highlighting a reduction in self-directed behaviors and an increase in attentive behaviors, and suggesting positive welfare implications. Thus, behavioral observations made before and during the presentation of the stimuli showed that our visual enrichment actually provided positive effects in lionesses. These results call for the development of future studies on the use of visual illusions in the enrichment programs of zoo animals.

Behavioral Epigenetics: Perspectives Based on Experience-Dependent Epigenetic Inheritance

Epigenetic regulation plays an important role in gene regulation, and epigenetic markers such as DNA methylation and histone modifications are generally described as switches that regulate gene expression. Behavioral epigenetics is defined as the study of how epigenetic alterations induced by experience and environmental stress may affect animal behavior. It studies epigenetic alterations due to environmental enrichment. Generally, molecular processes underlying epigenetic regulation in behavioral epigenetics include DNA methylation, post-translational histone modifications, noncoding RNA activity, and other unknown molecular processes. Whether the inheritance of epigenetic features will occur is a crucial question. In general, the mechanism underlying inheritance can be explained by two main phenomena: Germline-mediated epigenetic inheritance and interact epigenetic inheritance of somatic cells through germline. In this review, we focus on examining behavioral epigenetics based on its possible modes of inheritance and discuss the considerations in the research of epigenetic transgenerational inheritance.