Visitors to zoos are a source of potential stress to certain captive-housed animals. Much research has focused on Europe and America, whereas the effect of human audiences on the behaviour of captive animals in Chinese parks has so far not been investigated. Sika deer (Cervus nippon) housed in Zhu-Yu-Wan Park, Yangzhou City, Jiangsu Province, China, were studied to determine the effect of different visitor density levels on the animals’ activity. From June 21 to December 10, 2006, and again from February 21 to July 10, 2007, 21 subjects were observed for 10 h per week for a total of 44 weeks. Continuous focal animal sampling was used to quantify behaviours, and visitor density was recorded every minute. Friedman's tests were used to examine the effects of visitor density on the behaviour of sika deer. Results showed that high visitor density was significantly related to foraging, resting, watching and ‘non-visible’ behaviours. The findings demonstrate that high numbers of visitors have an effect on the welfare of sika deer.

The current study represents the second phase of developing the Yangtze Finless Porpoise Welfare Assessment Protocol (YFP-WAP), guided by the Five Domains model (FDM). Based on previously validated indicators, it aimed to create a scoring system to quantify welfare states. Application of the FDM grading system to the YFP-WAF revealed that indicators with higher scores influenced overall outcomes disproportionately, highlighting limitations in the original approach. As a result, a new scoring system was developed to ensure a more balanced contribution from all indicators across domains. The scoring system allows the separate quantification of welfare enhancement and compromise to prevent compensation between positive and negative experiences. It employs the sum of numerical values for each indicator, along with a percentage-based normalisation system to account for variations in indicator numbers across domains, ensuring balanced contributions to final welfare scores. In addition, a preliminary ‘Critical Scoring’ tool was created, which prioritises key indicators to identify urgent welfare issues before full assessment. Through the implementation of a standardised, transparent, and adaptable scoring method, the YFP-WAP aims to support individual-level welfare monitoring to improve the living conditions of captive porpoises and facilitate interventions for ex situ breeding programmes of YFP, and other closely related species. Despite challenges associated with fully capturing the complexity of welfare dynamics, this framework offers a practical and scientifically grounded approach for the assessment of the welfare of Yangtze finless porpoises (Neophocaena asiaeorientalis asiaeorientalis) under human care, that can also be applied or adapted to other cetacean species.

With the increasing number and diversity of reptile species kept in zoological facilities and households, their welfare in captivity warrants structured and consistent evaluation. However, focused research on reptile welfare remains limited within the broader field of animal welfare science. Recognising such a gap, this study adopts an evidence-informed approach to review existing literature and proposes two conceptual welfare assessment frameworks — one for zoo settings and another for private keeping. We first identify the intended audiences for each framework and discuss common challenges reptile caretakers may face when conducting welfare assessments in different contexts. The frameworks are grounded in established principles from the Five Domains model and the European Welfare Quality® protocol, incorporating both resource- and animal-based indicators under the domains of Environment, Nutrition, Physical Health, and Behaviour. The design rationale is also explained to support future refinement. Finally, these conceptual frameworks are intended as a foundation for the development and validation of adaptable tools, capable of guiding improved husbandry practices and resource allocation for better welfare outcomes across a broad range of reptile taxa.

Technological enrichment, such as motion sensors, touchscreens, and response-independent feeders, offer innovative ways to enhance animal welfare in captivity by promoting species-appropriate behaviours and cognitive stimulation. A scoping review of 22 publications comprising 25 studies identified various technologies, with computers being the most common, and sensory enrichment the most frequent type implemented. Positive or neutral welfare outcomes were common, though some negative effects were also reported. Primates and carnivores were the most frequently studied groups. Despite increasing research since 2012, gaps remain, including limited peer-reviewed studies and a need for standardised methodologies to better evaluate the impact of technological enrichment.

Zoos and aquaria have an ethical responsibility to ensure the welfare of the animals in their care. Developing and implementing an animal welfare strategy is central to fulfilling this obligation. An animal welfare strategy is a comprehensive framework that integrates animal welfare into all zoo operations, policies, and procedures, aiming to embed effective animal welfare practices across the entire organisation and extend these practices into the broader community. The strategy should reflect a clear ongoing commitment to animal welfare, incorporate the latest developments in animal welfare science, ensure an evidence-based approach, and be fully integrated into all policies and procedures. In addition, the strategy should provide a clear framework, measurable goals, and key performance indicators (KPIs), to ensure a structured, objective approach to animal welfare monitoring and enhancement. Creating a strategy involves nine key steps. Structuring the strategy around these steps through the lens of four primary domains: animal care; animal welfare assessment; communication; and evaluation, ensures a comprehensive institution-wide commitment to animal welfare. Once established, the strategy should be sufficiently flexible to ensure continued self-examination and improvement, and an ability to incorporate key insights from the rapidly developing field of animal welfare science. Implementing such a strategy requires sustained effort, strong leadership, and an organisational culture that supports shared values and continual improvement.

Given the difficulties of conducting regular endocrine and veterinary assessments of animals, behavioural observations are often the most commonly used tool to assess the welfare of animals in human care. Behavioural measures, inexpensive and convenient to collect, also have their challenges, such as ensuring the behaviours of interest are reliable indicators of an animal's internal state. Welfare assessments include both positive and negative indicators, and a commonly used indicator of negative welfare is self-directed behaviour (SDB). SDB has been described as a behavioural indicator of stress through observation and experimentation; however, this pattern is not universal despite assumptions otherwise. The purpose of this study was to experimentally evaluate the use of SDB as an indicator of negative welfare in mandrills (Mandrillus sphinx) with the goal of understanding the function of SDB in relation to stress. Using a touchscreen-mediated cognitive task, the mandrills were observed to self-scratch significantly more often during incorrect than correct trials; however, rates of SDB did not vary between increasingly difficult testing conditions. The mandrills had individual variation in their use of body-shakes and yawns under negative and positive conditions that mirror similar variation observed in other primates. This study provides experimental evidence that self-scratching in mandrills can be used as a behavioural indicator of anxiety and that welfare assessments for animals in human care need to account not only for species’ differences, but also for individual differences.

Animal welfare is important for the humane treatment of animals under our care. Zoos and rescue centres manage various charismatic animals, such as big cats, with limited resources. It is therefore essential for caretakers to understand the needs of an individual big cat to ensure its welfare. However, these needs may differ due to a big cat's personality, which may be identified by its coping style in a stressful situation. In addition, stress is one of the major factors affecting animal welfare. There is limited evidence showing strong associations between personality and stress physiology in big cats. This review focuses on the integration of personality and stress physiology of captive big cats, to highlight possible improvements in their husbandry. Our review identifies key factors that may influence big cat responses to stressors. These influencing factors include: i) social interactions; ii) environment; iii) life history and evolutionary traits; iv) genetics; and v) health. The first two factors are relatively well covered in the literature; however, the final three are potentially very promising avenues for future research to better understand how we can improve big cat welfare.

Cross-institutional studies that combine non-invasive physiological measures of stress responses and the assessment of individual differences in behaviour and temperament have great potential as tools for assessing the well-being of zoo animals and for identifying key environmental stimuli relevant to well-being. In addition, such studies allow comparison of animals under a wide variety of conditions and enable researchers to obtain sufficiently large samples sizes for statistical data analyses. Faecal corticoid measurements, a method recently developed to monitor adrenal activity in wildlife and domestic species, can be obtained non-invasively as part of the normal husbandry routine. While basic techniques still need improvement, and interpretation of the acquired measures can be challenging, assessment of faecal corticoid concentrations can provide a useful indicator of stress responses under a variety of captive conditions. Here we report on three studies that illustrate this approach and the results that can be obtained. An on-going study reveals significant differences in the pattern of variability of faecal corticoid concentrations between polar bears that are reported by keepers to perform stereotypic behaviour and those that do not. In another study, faecal corticoid measures indicated that stress responses to certain extraneous noises might interfere with the breeding of Hawaiian honeycreepers in captivity. In a study of clouded leopards, higher faecal corticoid concentrations were measured when cats were kept on public display or near potential predators compared to individuals maintained off exhibit or in the absence of visible predators. The findings of an on-going experimental study suggest a causal relationship between the provision of additional hiding spaces and a decline in faecal corticoid concentrations in clouded leopards.

Visitors to zoos can be a potential source of stress to captive-housed primates, resulting in increased abnormal behaviour and intra-group aggression. Finding a way to screen primates from human visitors may be one method of decreasing stress and enhancing animal welfare. For this study, the behaviour of six zoo-housed gorillas was studied for one month during standard housing conditions (control condition) and for a further month following the installation of a camouflage net barrier to the viewing area of the exhibit (barrier condition). Visitors’ (n = 200) perceptions of the animals and the exhibit were also recorded during each condition. The net barrier had a significant effect on some components of the gorillas’ behaviour. The gorillas exhibited significantly lower levels of conspecific-directed aggression and stereotypic behaviours during the barrier than the control condition. The net barrier also had a slight effect on visitors’ perceptions both of the animals and of their exhibit. The gorillas were considered to look more exciting and less aggressive during the barrier than the control condition. The exhibit was also considered to be more appropriate for visitors following the introduction of the camouflage netting. Overall, the addition of a screen such as camouflage netting could be considered a positive change, resulting in a reduction in those behaviours typically induced by large groups of visitors and an improvement in public perceptions of the animals and their environment.

Regurgitation and reingestion (R/R) of foodstuffs is a common abnormal behaviour in captive western lowland gorillas (Gorilla gorilla gorilla) and certain other non-human primates, but it is not part of their normal feeding mechanism. It is similar to a behavioural problem seen in humans, human rumination syndrome (HRS), which can occur in association with anxiety or a poor relationship with a caregiver. Patients with HRS often regurgitate stomach acid with the food matter which can result in clinical problems; until this study, it was not known if stomach acid is regurgitated by gorillas also. Thus, samples of regurgitated matter were collected opportunistically and non-invasively, and pH was measured using an electronic meter. Results were compared with the pH of samples of the original food eaten by the gorillas, and show that regurgitated food has significantly higher acidity than the originally-ingested meal. By comparison, samples of saliva were collected from gorillas opportunistically, in the absence of recent ingestion, and were found to be alkaline and, thus, saliva should not have contributed to the increased acidity of regurgitated matter. The results imply that stomach acid is being regurgitated, as in human patients with potentially-injurious rumination syndrome, and it is indicative of sub-optimal welfare. Causes and effects of R/R should be investigated further, to lead to potential treatment and prevention and to promote the welfare of captive gorillas.

Social Network Analysis (SNA) enables the fine scale of animal sociality and population structure to be quantified. SNA is widely applied to questions relating to behavioural ecology but has seen little use in the application to zoo animal management, despite its clear potential. Investment in social bonds between individuals positively affects health status, welfare state, long-term fitness and lifetime reproductive output. Such positive affective states can be maintained consistently within captive situations if more information is known about the social preferences of the individuals that are kept. Disruption to social bonds may lead to impoverished welfare and stress to individuals which have seen their social support compromised. The patterning of social relationships between individuals also influences how space is utilised and how animals interact with resources provided for them. With more detailed knowledge of the social structure of a group or population, social groupings (for example, for captive breeding) can be specifically designed to minimise social stress. Likewise, enhancing the chances of successful reproduction can be achieved if we understand the role that each individual within a network plays and how these roles may impact on the behaviour of others. This paper discusses key aspects of SNA applicable to zoo-based researchers wishing to investigate the social lives of zoo animals. We present a review of how SNA can be used to assess social behaviour and highlight directions for future research. Our aim is to stimulate new research to ultimately improve our understanding of reproductive success, decision-making, group leadership, animal health and enclosure use. We conclude that what can be learned about the dynamics of social zoo-housed species using SNA can directly impact on husbandry decisions and help underpin excellent standards of animal welfare.

Abnormal behaviour in captive animals is both pervasive and ambiguous. Although individual differences are central to the field of animal welfare, studies on abnormal behaviour predominantly employ quantitative, population-level approaches. For example, whereas previous studies on chimpanzee (Pan troglodytes) abnormal behaviour have reported significant variation between groups or individuals in the quantity (eg frequency and duration) of abnormal behaviour, much less is known about qualitative differences. Individual abnormal behavioural repertoires may be highly idiosyncratic, where certain behaviours are over-represented (ie individually specific abnormal behavioural ‘signatures’). The present study investigated qualitative individual variation in the abnormal behaviour of chimpanzees (n = 15) housed at Royal Burgers’ Zoo in Arnhem, The Netherlands. Substantial variation was found between individuals in the diversity (size and evenness) and overall composition of their abnormal behavioural repertoires. Factors including age, sex, and rank did not significantly account for dissimilarity of individuals’ abnormal behavioural repertoires, but kin dyads showed more similar abnormal behaviour than non-kin dyads. Further exploratory analyses examined whether individual variation in one abnormal behaviour (coprophagy) predicted variation in stress-related behaviour (self-scratching). This allowed us to tentatively conclude that there were also individual differences in the link between a given abnormal behaviour and the behavioural expression of stress. Qualitative individual variation in abnormal behaviour provides a novel angle to a literature traditionally focused on quantifying abnormal behaviour at the group- or species-level and may thus represent an important yet previously overlooked source of variation in the extent to which abnormal behaviour reflects the state of individual welfare.

While the zoological community strives to provide the best possible living environment for non-human animals, space limitations constrain where zoos can house particular species. Therefore, an individual may live in proximity to animals that impact its behaviour, physiology, reproductive function or overall welfare status. This article examines how solitary and social species living in managed settings are positively and negatively affected by conspecific neighbours. When making housing decisions, zoos should follow husbandry recommendations outlined by zoo associations, integrate natural history information and attempt to view the environment from the perspective of the species of interest. Furthermore, researchers can collect survey, behavioural and physiological data to examine how variables, such as density, distance between neighbours, the age/sex of conspecifics and types/amount of exposure to others influence welfare. Ultimately, zoos should consider the needs of individuals and investigate whether welfare can be enhanced by modifying enclosures, husbandry routines, enrichment schedules or access to conspecifics. A zoo's willingness to alter an animal's exposure to conspecifics may have a substantial impact on physical, mental and emotional health.

A comprehensive synopsis of the welfare of captive, wild (ie non-domesticated) animals in travelling circuses is missing. We examined circus animal welfare and, specifically, behaviour, health, living and travelling conditions. We compared the conditions of non-domesticated animals in circuses with their counterparts kept in zoos. Data on circus animals were very scarce; where data were absent, we inferred likely welfare implications based on zoo data. Circus animals spent the majority of the day confined, about 1-9% of the day performing/training and the remaining time in exercise pens. Exercise pens were significantly smaller than minimum zoo standards for outdoor enclosures. Behavioural budgets were restricted, with circus animals spending a great amount of time performing stereotypies, especially when shackled or confined in beast wagons. A higher degree of stereotyping in circuses may be indicative of poorer welfare. Inadequate diet and housing conditions, and the effects of repeated performances, can lead to significant health problems. Circus animals travel frequently and the associated forced movement, human handling, noise, trailer movement and confinement are important stressors. Although there is no conclusive evidence as to whether animals habituate to travel, confinement in beast wagons for long timeperiods is a definite welfare concern. Circuses have a limited ability to make improvements, such as increased space, environmental enrichment and appropriate social housing. Consequently, we argue that non-domesticated animals, suitable for circus life, should exhibit low space requirements, simple social structures, low cognitive function, non-specialist ecological requirements and an ability to be transported without adverse welfare effects. None of the commonest species exhibited by circuses, such as elephants and large felids, currently meet these criteria. We conclude that the species of non-domesticated animals commonly kept in circuses appear the least suited to a circus life.

To assess the validity of using wild behavioural data as a welfare indicator for zoo animals, the time budgets of 19 captive giraffe (Giraffa camelopardalis), from four zoos were compared with the time budgets of wild giraffe from Hwange National Park, Zimbabwe. Differences were shown to exist between the behaviour of wild and captive giraffe. However, only the duration of lying differed significantly across zoos. Correlations demonstrated that both enclosure size and feed restriction affected the locomotor activity of giraffe. An attempt to quantify observer influence upon the behaviour of wild giraffe was made. Different methods of observation were shown to significantly affect the time budget established. The extent to which wild giraffe behaviour can be used as a welfare indicator for captive conspecifics is discussed, as are the problems inherent in such a study. The difficulties in constructing an alternative welfare measure using prevalence to veterinary problems, are briefly considered. Methods by which captive giraffe welfare can be improved are discussed, particularly concerning the provision of browse to allow more natural feeding patterns to be established.

It is sometimes necessary to restrain kangaroos (Macropus spp) for veterinary treatment or in the course of scientific research, but the associated stresses may induce capture myopathy in wild kangaroos. Judicious use of injectable sedatives can reduce the risk of capture myopathy. Zoletil®, a proprietary mixture of tiletamine and zolazepam, is reported to have a wide safety margin, a small dose volume, and be quick acting for a range of animals. We investigated the dose-response relationship of Zoletil® in 26 western grey kangaroos (Macropus fuliginosus ocydromus). All kangaroos were recumbent within 5-10 min of intramuscular injection with mean (± SD) Zoletil® of 4.55 (± 0.98) mg kg−1. Mean (± SD) time to recovery varied between individuals, 2.07 (± 0.41) h over all occasions, and was independent of dose rate. For animals that were assessed on multiple occasions, mean (± SEM) time to recover was reduced from 2.25 (± 0.09) h on the first occasion to 2.15 (± 0.10) h on the second occasion and 1.81 (± 0.11) h on the third. Since kangaroos sedated with Zoletil® are vulnerable to predation and injury during recovery, we believe they should be supervised until they are able to fend for themselves.

As part of a translocation project, 28 Eurasian otters (Lutra lutra) were captured from the wild and transported to the Barcelona Zoo for veterinary evaluation, quarantine and intraperitoneal implantation of telemetry devices. Eleven animals were injected with the long-acting neuroleptic (LAN) perphenazine enanthate at the time of capture and the remaining animals served as a control group. During their time in captivity, which averaged 23 days, all of the animals were bled three times. Haematological and biochemical parameters were evaluated, including red blood cell count (RBC), haemoglobin (Hb), white blood cell count (WBC), blood urea, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (AP), lactate dehydrogenase (LDH), creatine kinase (CK), albumin, and serum cortisol. No significant differences were found between treated and control otters except for monocyte count, which was higher in treated animals. Time after capture had an effect on many parameters. RBC and Hb decreased at first and then increased, while WBC and segmented neutrophils decreased over time. Most of the biochemical parameters considered to vary in relation to stress, including AST, ALT, CK, AP and LDH, decreased over time, suggesting that the stress responses of the animals decreased throughout the period of captivity. However, no significant change in serum cortisol levels was noted. The lack of effect of perphenazine treatment on haematological parameters should encourage further research on other stress indicators applicable to wild animals, such as behaviour or faecal cortisol concentration. Finally, the results obtained in this study suggest that, when captive conditions are adequate, keeping wild-caught animals in human care for a period of time prior to their release into the wild can be beneficial. However, further studies taking into account other welfare indicators would be useful.

As zoos have evolved, conservation and conservation education have become primary tasks. To achieve the maximum educational impact, zoos are enriching animal habitats so that their occupants display a wide range of activities that are attractive to the visitor, and unattractive activities are eliminated and reduced. Because public perceptions of the attractiveness of animal behaviour may not coincide with welfare realities, there can be a tension between the requirements of desirable exhibits and those of maximally promoting animal welfare. Zoo animals differ from domesticated animals in human care in several respects. These differences are discussed and set in the context of the sometimes competing aims of enhancing welfare and promoting educational exhibits. An outline history of zoo enrichment programmes suggests that the subject is in need of systematization. The range of data available for improving zoo exhibit designs, and the lives of zoo animals, is reviewed. It is concluded that fundamental data on the environmental needs of many of the wild animals maintained in zoos are deficient in many important areas. Consequently, there is an urgent need to increase such research. Zoo habitats could be excellent places for such fundamental studies, which would feed back into field studies. At the same time, habitat enrichment in zoos cannot await such research and must proceed pragmatically using the range of insights described in this paper. In particular, functional substitution is advocated as a means of enrichment wherever this can be made acceptable to the broad public; its educational value in combatting naive anthropomorphism is stressed. Naturalism in enrichment is criticized as reinforcing anthropomorhisms, but is desirable for promoting global habitat conservation.

Animal welfare scientists actively seek reliable and practical metrics that can serve as indicators of animal welfare for use with agricultural, laboratory and zoo-housed animals. Behavioural diversity as a welfare concept originated from early welfare scientists linking poor animal welfare with a high proportion of time spent engaged in stereotyped behaviours and little expression of behaviours that would be expected under wild, or natural conditions. Recently, the concept of behavioural diversity as a welfare indicator has been widely adopted and is frequently quantified by the Shannon-Wiener Diversity Index (H-index). However, the H-Index is fraught with theoretical and mathematical limitations when applied to animal welfare. Four key problems with this metric are demonstrated: the metric's responsivity to the size of the behavioural repertoire and the underlying assumption that larger behavioural repertoires reflect better welfare, the sensitivity of the metric to arbitrary decisions about the resolution of behavioural categories, the fact that the calculation of the metric is agnostic to the valence of behaviours, and the metric's susceptibility to the common practice of excluding some behavioural categories. Moving forward, we recommend focusing on validated welfare measures that are sensitive to valence when evaluating animal welfare.