The Effects of Choice-Based Design and Management on the Behavior and Space Use of Zoo-Housed Amur Tigers (Panthera tigris altaica)

Effect of Feeding Environmental Enrichment on Lesser Anteaters' Behavior, Space Use and Food Selectivity

Studying behavioral response to management and housing conditions provides specific evidence to enhance animal welfare. Feeding environmental enrichment (FEE) is a powerful strategy to meet welfare challenges. Lesser anteaters' (Tamandua tetradactyla; n = 7) response to FEE was assessed by analyzing behavior and space use through focal sampling every 5 minutes/24 hours using cameras. Study 1 (S1): space use of enclosure zones (shelter = SZ, climbing structures = CSZ and ground = GZ) was characterized without FEE during 5 days using the modified Spread of Participation index (SPI). Study 2 (S2) used an ABA experimental design during 18 days (A=pre- and post-enrichment and B = enrichment). The FEE was applied in CSZ, the least utilized zone revealed in S1. S1: The lesser anteaters utilized the zones differently (modified SPI = 0.74 ± 0.02), and stayed mostly in the GZ. S2: An increment in feeding during FEE was detected, but it did not modify total activity, most natural behavior, repetitive locomotion or space use. The electivity index indicated that the routine diet was over-utilized and enrichment items were under-utilized. The provision of enrichment items created new foraging opportunities, improving the behavioral domain of animal welfare.

Using 3D Photogrammetry to Quantify Usable Space in Zoo-Housed Primate Habitats

Studies of zoo animal space use typically use ground-level measurements as a proxy for "usable space," but this method ignores above ground areas that are behaviorally relevant to arboreal species. Previous work has proposed different methods to calculate usable above ground space, but each has presented different limitations, ranging from the estimation of areas of dense complexity to the significant manual effort needed to physically measure spaces. To address these limitations, we tested a new, 3D photogrammetry-based method ("3DP method") for calculating usable space in the habitats of two zoo-housed primate species (crowned lemur [Eulemur coronatus], and Bornean orangutan [Pongo pygmaeus]). 3D photogrammetry generates a 3D point cloud and subsequent mesh, using physically captured images, with geometric, measurable properties. Our method was compared to a previously published method, based in SketchUp, ("MSU method") for both quantification of usable space (surface area, volume) and efficiency of model generation (active and passive work required). The 3DP method generated similar results for both usable surface area and volume for the crowned lemur habitat, while requiring 82% less active work from the user. Furthermore, the 3DP method was able to calculate usable space in a habitat (Bornean orangutan) that was 13,274% larger than the crowned lemur habitat, and substantially larger than any habitat where the MSU method has been applied in published work. Overall, the 3DP method decreased the ratio of active to passive work required for calculating usable space in zoo habitats with complex vertical space, and is flexible enough to be applied to habitats of varying sizes.

Social Relationships of Captive Bachelor Przewalski's Horses and Their Effect on Daily Activity and Space Use

Understanding social relationships in at-risk species held in captivity is vital for their welfare and potential reintroduction. In social species like the Przewalski's horse (Equus ferus przewalskii), daily time allocation and space use may be influenced by social structure and, in turn, reflect welfare. Here, we identify social relationships, time budgets, and spatial distribution of a group of nine older (aged 6-21 years) male Przewalski's horses living in a non-breeding (bachelor) group. We conducted our work at the Askania-Nova Biosphere Reserve, over 65 h of observation in summer, 2015. Horses formed stronger social bonds with individuals of similar gregariousness and dominance levels. Social-network analysis identified three distinct subgroups with significant differences in locomotion, social behaviour, and foraging. However, resting and vigilance behaviour remained similar across the subgroups. Behavioural synchrony across all activities was higher within subgroups than between. Space use was also affected by subgroup membership, with some horses overusing or underusing critical resource areas like hay and water. These findings suggest opportunities to improve welfare by adjusting space and resource distribution, particularly for more submissive individuals. Our approach may also aid in selecting reintroduction candidates by considering social characteristics alongside health, genetic, and other factors.

Tarantula welfare may be improved with greater environmental complexity: A preliminary behavioral study with Brazilian black tarantulas (Grammastola pulchra)

Increased environmental complexity has positive effects on the welfare status of vertebrates living in human care; however, this line of research has received little focus in invertebrates. Here we conducted a preliminary investigation of Brazilian black tarantula (Grammastola pulchra) behavior in relation to environmental complexity. Using a counterbalanced design, we housed tarantulas in both Standard and Complex environments. Complex housing was differentiated from Standard by being approximately six times larger and containing six times as many structural elements. We evaluated (1) how does tarantula behavior differ between these two housing conditions, (2) does housing affect tarantula behavior in a novel environment test, and (3) do tarantulas prefer one housing condition over the other? Activity budgets were approximately equivalent between the two housing conditions with inactivity accounting for nearly all observed behavior. Home ranges and core areas were 77% and 113% larger in the Complex housing condition. When in a novel environment, tarantulas had 150% greater odds of being active after living in the Complex condition. Interestingly, the tarantulas showed no clear preference for either environment in the preference test. Our preliminary results suggest tarantula welfare may be improved with greater environmental complexity as demonstrated through more neophilic response to novelty and greater home range and core area size when living in Complex housing. However, it is worth noting that broad patterns of behavior were similar, no clear preference in housing was identified, and our study sample size was limited. Further research is needed to better understand the behavior and welfare of tarantulas, but this study demonstrates how established methodologies used in the study of vertebrates can be readily applied to invertebrates.

An Analysis of Welfare Standards Within Tiger (Panthera tigris) Facilities in Thailand

In Thailand, tigers are more numerous in captivity than they are in the wild, with 51 facilities housing approximately 1962 tigers. As charismatic fauna, tigers are popular with tourists, and the majority of facilities offer a variety of entertainment activities with controversial reports towards the animals' welfare. The aim of this research was to investigate tiger welfare in Thai zoos to identify specific welfare issues. We assessed 34 tourism facilities holding tigers in Thailand in 2019 using a 25-point welfare assessment that utilizes the Five Domain model (incorporating all five domains: nutrition, physical environment, health, behavioural interactions and mental state). The mental domain score was derived from the scores of the other four domains. Additional data were collected from each facility, including the number of tigers, any colour variants, types of human interaction and admission cost. Welfare scores for each domain were calculated by totalling the scores per domain and dividing by the number of points allocated to that domain. A multiple regression was used to identify any significant predictors of mental domain score. The results revealed that the provision of a suitable physical environment scored the lowest, while nutrition scored the highest though this was still a low score overall. The multiple regression showed that 45.4% of the variance for the mental domain score was significantly affected by the number of colour variants housed and the types of human interaction available with facilities, with more of both these factors contributing to a more negative score. Our results demonstrate the need for urgent, comprehensive infrastructural, species-appropriate environment and design and animal management improvements to increase animal welfare. Informed institutional change toward the breeding and use of tigers for public interactions is also required. This is the first assessment completed of captive tiger welfare of tiger facilities in Thailand and shows that the welfare concerns encountered are within a high proportion (67%) of Thailand's facilities. This supports the need for the creation and enforcement of effective and clear captive wildlife operational standards to provide a sustained solution for captive tiger welfare and can provide a considered approach to ex-situ tiger management that, in conjunction with in-situ efforts, can improve much needed conservation efforts of this species.

Moving Toward Evidence-Based Care: Measuring Preferences in Zoo-Housed Aquatic Turtles Using 24-h Remote Monitoring

Providing evidence-based care to animals is a common goal in zoos and aquariums. However, there are many understudied species with a lack of information available, which may result in suboptimal care for individuals of these species. Using preference tests to ask individual animals what they want can be an effective means to enhance their care, and subsequently, their welfare. Using 24-h remote monitoring, we assessed substrate, enclosure feature, and lighting preferences of five aquatic turtles (two wood turtles, one Blanding's turtle, and two spotted turtles) that share an indoor enclosure at Lincoln Park Zoo. In addition, we compared enclosure feature and lighting preferences between winter and summer to determine whether the turtles had changing seasonal preferences despite being housed indoors. We found that the wood turtles and Blanding's turtle had substrate preferences, whereas the spotted turtles did not. In addition, we found that the turtles' enclosure feature preferences were consistent between winter and summer, but the amount of time spent on land, logs, and in water varied by individual. Finally, we found that the turtles utilized areas with ambient lighting more than areas with a heat lamp or UV lamp; this was consistent between winter and summer. The turtle preferences observed in this study can contribute to the development of care strategies that support their welfare and, in turn, may inspire similar preference studies at other institutions as we collectively advance toward providing animals of all taxonomic groups with evidence-based care.

Monitoring the world-oldest zoo-housed male giant panda (Ailuropoda melanoleuca): A case-study on pathway utilization

Habitat use monitoring is necessary for a comprehensive understanding of the biological and psychological requirements of animals under human care, facilitating improved exhibit designs and promoting animal welfare. Current studies focused on the space use of the exhibit while limited studies examined the pathway use of the zoo-housed animals. This study aimed to investigate the habitat use of An An, the world-oldest male giant panda (Ailuropoda melanoleuca) at Ocean Park Hong Kong using a pathway utilization monitoring method. The result showed uneven utilization of pathways favoring the upper area near his den over the lower area which required longer walking in the hilly exhibit. Moreover, the comparisons of walking directions showed a preference for gentle slopes during uphill movement and a favor for steep slopes during downhill movement. Our study also compared the walking distance between uphill and downhill movements and the results showed that An An walked longer distances heading upward than moving downward due to his choice of pathways. Our results are in line with the findings in the wild population, showing a preference for gentle slopes, especially in uphill movement. Our study demonstrated the value of the pathway monitoring technique. Due to its easy and time-effective use, this technique can be incorporated into the care teams' operation, providing valuable information on daily activity (e.g. accessing the walking ability of the aged animals by investigating the pathway use and walking distance) and habitat use. Consequently, the pathway monitoring technique can help improve exhibit designs promoting welfare.

Breaking the spell: Changes in the behavior of two zoo-kept tigers (Panthera tigris) after exposure to a distinct feast-and-fast feeding regime

The behavior of zoo carnivores has received intense attention due to their propensity for locomotor stereotypies. We observed two adult male tiger (Panthera tigris) siblings kept together for the duration of 104 days by round-the-clock video observation. The period consisted of three baseline periods with the zoo's regular feeding regime of five feeding days per week interrupted by two individual fasting days, with feeding occurring in the evening (B1-B3 of 14 days each). These periods were interrupted by two intervention periods (I1: randomized feeding times, 28 days; I2: gorge-feeding with three 10-day fasting periods, 34 days). As expected, day and night-time behavior was different, with the majority of sleep occurring at night. Pacing, which was mainly considered anticipatory, significantly decreased from 88 ± 132 min/day during B1 to 20 ± 33 min/day during B3. Pacing did not increase during the fasting days of I2. Over the course of whole study, lying time decreased and nonpacing locomotion increased. A major difference was observed between gorge-feeding and the subsequent first fasting days: during gorge-feeding, tigers spent a large part of the day feeding and locomoting (and less sleeping); on the subsequent day, they locomoted about 4.5 h less and slept about 4.3 h more. We suggest that interrupting routines by fasting periods of several days may be effective for reducing regular anticipatory behavior and creates an across-day structure that may correspond to the evolved psychological disposition of large carnivores.

The welfare problems of wide-ranging Carnivora reflect naturally itinerant lifestyles

Carnivora with naturally small home ranges readily adjust to the evolutionarily new environment of captivity, but wider-ranging species seem prone to stress. Understanding why would advance both collection planning and enclosure design. We therefore investigated which aspects of wide-ranging lifestyles are key. We identified eight correlates of home range size (reflecting energetic needs, movement, intra-specific interactions, and itinerant lifestyles). We systematically assessed whether these correlates predict welfare better than range size per se, using data on captive juvenile mortality (from 13 518 individuals across 42 species) and stereotypic route-tracing (456 individuals, 27 species). Naturally itinerant lifestyles (quantified via ratios of daily to annual travel distances) were found to confer risk, predicting greater captive juvenile losses and stereotypic time-budgets. This finding advances our understanding of the evolutionary basis for welfare problems in captive Carnivora, helping explain why naturally sedentary species (e.g. American mink) may breed even in intensive farm conditions, while others (e.g. polar bears, giant pandas) can struggle even in modern zoos and conservation breeding centres. Naturally itinerant lifestyles involve decision-making, and strategic shifts between locations, suggesting that supplying more novelty, cognitive challenge and/or opportunities for control will be effective ways to meet these animals' welfare needs in captivity.

Do zoo animals use off-exhibit areas to avoid noise? A case study exploring the influence of sound on the behavior, physiology, and space use of two pied tamarins (Saguinus bicolor)

Noise can be a known stressor but our understanding of its effects on animals living in zoo environments remains limited. Although exposure to loud, chronic noise may be expected to negatively impact welfare, providing access to quiet areas to escape loud noise may buffer these negative effects. In this study, we explored the benefits of access to quiet, off-exhibit areas for animals living in a chronically loud sound environment. Two pied tamarins (Saguinus bicolor) living near a large waterfall feature that emitted loud, chronic noise were experimentally exposed to varying sound levels during 2-week treatment conditions. Baseline conditions (waterfall feature on and access to quiet, off-exhibit areas), were followed by a Quiet sound condition (waterfall off), a Loud sound condition (waterfall on and a speaker in the off-exhibit area playing volume-matched white noise), and a final Baseline condition. During Baseline conditions, sound levels were greater than 10 dBA higher in the exhibit than in the off-exhibit area (i.e., roughly twice as loud). The number of visitor groups present during behavior observations were consistent throughout the study. Both tamarins modified their space use during treatment conditions. Under Baseline conditions, both individuals showed frequent usage of quiet, off-exhibit areas. During the Quiet and Loud conditions, where sound levels were generally consistent across spaces, both individuals used off-exhibit areas less and their use of exhibit and off-exhibit areas was not significantly different than would be expected by chance, given the size of the areas. Additional behavioral changes were minimal. No significant differences in fecal glucocorticoid metabolites were observed. Although the monkeys in this study appeared to avoid noise, the overall impact on welfare appeared to be minimal considering the limited behavioral and hormonal changes observed. This study highlights the potential benefits of off-exhibit spaces as a quiet refuge from noise in the zoo environment.

Applied behavior analysis and the zoo: Forthman and Ogden (1992) thirty years later

The field of applied behavior analysis has been directly involved in both research and applications of behavioral principles to improve the lives of captive zoo animals. Thirty years ago, Forthman and Ogden (1992) wrote one of the first papers documenting some of these efforts. Since that time, considerable work has been done using behavioral principles and procedures to guide zoo welfare efforts. The current paper reexamines and updates Forthman and Ogden's original points, with attention to the 5 categories they detailed: (a) promotion of species-typical behavior, (b) reintroduction and repatriation of endangered species, (c) animal handling, (d) pest control, and (e) animal performances. In addition, we outline 3 current and future directions for behavior analytic endeavors: (a) experimental analyses of behavior and the zoo, (b) applied behavior analysis and the zoo, and (c) single-case designs and the zoo. The goal is to provide a framework that can guide future behavioral research in zoos, as well as create applications based on these empirical evaluations.

Island Life: Use of Activity Budgets and Visibility to Evaluate a Multi-Species Within-Zoo Exhibit Move

Modern zoos strive to construct habitats which both enable and encourage animals to engage in species-specific behaviour, without compromising their visibility to visitors. Here, we present the findings of a within-zoo move to a custom-built exhibit (Islands at Chester Zoo, UK) with respect to the behaviour of four mammal species; the Sumatran orangutan (Pongo abelii), crested macaque (Macaca nigra), Malayan tapir (Tapirus indicus) and the Malayan sun bear (Helarctos malayanus). We used full activity budgets along with Compositional Data Analysis (CoDA) to gain insight into how the move to a more naturalistic exhibit influenced behaviour. Engagement in abnormal behaviour remained low during the study period for all four species, suggesting no adverse responses to the change in environment. Following the move, both the non-human primate species spent more time engaged in positive social interactions with conspecifics, highlighting the importance of social support during enclosure moves. Time spent visible to the public was largely unaffected by the enclosure move for the Sumatran orangutan, whilst the movement to a new environment increased visibility for the Malayan sun bear and decreased visibility for the crested macaque and Malayan tapir. We demonstrate the value of monitoring behaviour throughout the translocation of zoo-housed species and outline the positive behavioral impacts of providing individuals with naturalistic, species-appropriate environments.

Out of Sight, Out of Mind or Just Something in the Way? Visual Barriers Do Not Reduce Intraspecific Agonism in an All-Male Group of Nile Crocodiles (Crocodylus niloticus)

Simple Summary

The behavior of animals living in zoos and aquariums is influenced by the exhibits they live in, similar to how the behavior of animals in nature is influenced by the ecosystem they inhabit. In zoos and aquariums, changes in exhibit design can be implemented to modify the behavior of animals to ensure they are experiencing optimal welfare. Here, we evaluated if the addition of visual barriers—physical barriers placed at the surface of the water—reduce aggression amongst male Nile crocodiles living in a zoo. Both short- and long-term monitoring found that visual barriers did not reduce aggression within the group. While ineffective at reducing aggression, this study represents the first evaluation of exhibit design in relation to the behavior of a crocodilian species in a zoo or aquarium setting. As a commonly managed taxa in zoos and aquariums, it is imperative that their behavior and welfare are assessed systematically. We hope the methodologies and learnings from this study encourage future study of crocodilian behavior and welfare.

Abstract

Here, we evaluated if visual barriers could reduce intraspecific agonism in an all-male group of Nile crocodiles (Crocodylus niloticus) living in a zoo. Crocodiles were monitored for nearly 100 h, and four “hotspots” of aggression within their exhibit were identified. Within these four locations, visual barriers were placed at the surface of the water with the goal of reducing agonism by targeting sight lines associated with their species-typical minimum exposure posture, where crocodiles submerge their body but maintain facial sensory organs above the water line. Crocodile behavior was then monitored for 226 h, evaluating both short- and long-term effects of the visual barriers. In both observation periods, intraspecific agonism was unaffected by visual barriers. However, crocodiles were more likely to be on land and closer together, after the barriers were installed, showing the barriers affected nonagonistic behaviors. Monitoring of such unintended effects is significant to ensure no welfare concerns are created in any exhibit or husbandry modification attempt. Additionally, time of day and temperature were significant predictors of behavior, highlighting the importance of such factors in the analysis of reptilian behavior. While ineffective at reducing agonism, this is the first published study evaluating exhibit design and behavior of crocodilians in zoos and aquariums. The methodologies and findings here should provide useful information for future behavioral and welfare studies of this understudied taxa.