Documenting Aggression, Dominance and the Impacts of Visitor Interaction on Galápagos Tortoises (Chelonoidis nigra) in a Zoo Setting

The Impacts of Evening Events in Zoos: A Christmas Event at Knowsley Safari

It is important to examine the animal welfare implications of all aspects of zoo operations, including out-of-hours public events. Research to date has indicated variable responses across species and event types. The current research aimed to understand and quantify the impact of a Christmas lights event. Four species of ungulates: Rothschild giraffe (Giraffa camelopardalis rothschildi; n = 2) in one exhibit and capybara (Hydrochoerus hydrochaeris; n = 4), lowland tapir (Tapirus terrestris; n = 3) and vicuña (Lama vicugna; n = 5) in a mixed species exhibit were observed. Data were collected from 16:00–20:00 between 28 October 2021 and 11 January 2022. The event ran from mid-November to the end of December 2021. Five-minute behavioural observations were undertaken once per hour using instantaneous scan sampling with a one-minute inter-scan interval. A further six days of 12 h observations were conducted to enable a more detailed investigation post-event. Data collected were compared on non-event and event days using Mann–Whitney U tests (event vs. non-event) and Kruskal–Wallis tests (pre-event, event, post-event periods). Kruskal–Wallis tests and one-way ANOVAs were undertaken to compare behaviours during three time periods (12:00–16:00, 16:00–20:00, 20:00–00:00) over 12 h. Mixed behavioural responses were seen across the study species. Capybara spent more time in their house from 16:00–20:00 on event nights compared to non-event nights (p < 0.001) and tapir only engaged in vigilant behaviour from 16:00–20:00 when the event was held, (p = 0.044). There were no differences in frequency of behaviour between pre-event, event, and post-event observation periods, with the exception of capybara, who spent more time OOS in the pre-event period than during (p < 0.001) or after the event (p < 0.001). The results of the project, undertaken as part of an evidence-based management programme, highlighted that the event did not have any overtly negative impacts on the ungulates studied. Except for the giraffe, all individuals had free access to inside and outside environments, and it is believed this choice enabled animals to be active in managing their response to the event. It is recommended that future work observe animals over 24 h to understand whether events lead to behavioural changes the day after events or if animals reverted to normal activity once the event ended.

Behavioural Impact of Captive Management Changes in Three Species of Testudinidae

Reptile behaviour and welfare are understudied in comparison with mammals. In this study, behavioural data on three species (Astrochelys radiata, Stigmochelys pardalis, Aldabrachelys gigantea) of tortoises were recorded before and after an environmental change which was anticipated to be positive in nature. The environmental changes differed for each population, but included a substantial increase in enclosure size, the addition of substrate material, and a change in handling procedure. A tortoise-specific ethogram was created to standardise data collection. Focal behaviour sampling was used to collect behavioural data. Changes in the duration of performance of co-occupant interaction and object interaction in the leopard (Stigmochelys pardalis) and Aldabra (Aldabrachelys gigantea) tortoises were observed following the environmental changes. The Shannon–Weiner diversity index did not yield a significant increase after the changes but had a numerical increase which was relatively greater for the leopard tortoise group, which had experienced the greatest environmental change. The leopard tortoises also demonstrated changes in a greater number of behaviours compared to the other species, and this was sustained over the study period. However, this included a behaviour indicative of negative affect: aggression. Whilst we are unable to conclude that welfare was improved by the management changes, there are suggestions that behavioural diversity increased, and some promotion of positive social behaviours occurred.

An Improvement in Enclosure Design Can Positively Impact Welfare, Reduce Aggressiveness and Stabilise Hierarchy in Captive Galapagos Giant Tortoises

The interest in the welfare of zoo animals, from both the public and the scientific community, has long been biased towards mammals. However, growing evidence of the complex behavioural repertoires of less charismatic animals, such as reptiles, reveals the necessity to better comply with their welfare needs in captivity. Here, we present the effects of an enclosure change towards a more natural habitat in captive Galapagos tortoises (Chelonoidis spp.) held at ZSL London Zoo. Using behavioural observations, we found that the tortoises habituated to their new enclosure in six days. This represents the first quantification of habituation latency to a new enclosure in a reptile model to our knowledge—which is important information to adapt policies governing animal moves. The tortoises expressed time budgets more similar to those of wild individuals after their transition to the new enclosure. Interestingly, the hierarchy between the individuals was inverted and more stable after this change in environment. The tortoises interacted less often, which led to a decrease in the frequency of agonistic encounters. We also found that higher ambient sound volume was associated with increased likelihood of interactions turning into fights. Taken together, our results demonstrate the potential of appropriate enclosure design to improve reptile welfare.

Evaluating the Effect of Visitor Presence on Nile Crocodile (Crocodylus niloticus) Behavior

Visitor presence has been shown to affect the behavior of animals in zoos. However, studies to date have not included a wide range of taxonomic groupings, and thus, the effect is poorly understood for many species. Here, we compared the behavior of Nile crocodiles (Crocodylus niloticus) in the presence and absence of visitors for the first time. Data were collected at Disney’s Animal Kingdom® over two months during normal operating conditions and during the same two months the following year when the park was closed due to the COVID-19 pandemic, totaling 158 observation hours. Significant differences in crocodile behavior were observed between park operating conditions; however, the direction of change varied by behavior and average differences were generally small. In addition, we found that time of day, temperature and month significantly affected behavior, often with greater magnitude than visitor presence. This highlights the importance of accounting for environmental variables when evaluating and interpreting the behavior, and ultimately welfare, of reptiles in zoos. Collectively, the data suggest the overall effect of visitors on crocodile behavior was small and neutral from a welfare perspective. This study highlights the importance of taxonomic diversity in studying the visitor effect.

Widespread Behavioral Responses by Mammals and Fish to Zoo Visitors Highlight Differences between Individual Animals

The impact that humans have on zoo animals can vary based on the species of animal, exhibit design, and individual differences in behavioral responses. We independently analyzed data from 10 never-published studies that examined the impact of zoo visitors on zoo animal behavior. Of the 16 species studied, 90.9% of the mammal species and 60.0% of the fish species demonstrated a change in at least one behavior based on zoo visitor abundance or visitor behavior (e.g., noise, solicitation of interactions from zoo animals). In addition, behavioral changes associated with zoo visitors were present in animals housed in exhibits where there was direct contact with zoo visitors, as well as in exhibits where there was indirect contact and no direct contact. Individuals often varied in their behavioral responses, and some individuals appeared to seek out interactions with visitors. Our findings demonstrate that short-term research projects can provide valuable insight into individual animal-level and species-level responses to visitor abundance and visitor behavior in the zoo setting. We recommend that behavioral assessments focus on the analysis of behaviors of individual animals whenever possible, and we recommend that exhibits provide areas that allow for animals to retreat from the public view.