Effects of a recurring late-night event on the behavior and welfare of a population of zoo-housed gorillas

Promoting Good Nonhuman Primate Welfare outside Regular Working Hours

Promoting good primate welfare outside of daylight hours is an important task. The responsibility to provide a complex environment and environmental enrichment is an essential element of primate wellbeing programs that should be approached from a 24-h perspective and planned according to the species and individual needs, including giving animals the ability to interact with and control their environment during hours when animal care staff are not present. One must be aware, however, that their needs may differ at night-time from their care needs during the day when staff are present. Assessing welfare and providing enrichment during times when staff are not on hand can be achieved through the use of a variety of technologies, such as night-view cameras, animal-centred technologies, and data loggers. This paper will address the relevant topics concerning the care and welfare of primates during off-hours, and the use of related technologies to facilitate and assess wellbeing at these times.

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.

The Benefits and Challenges of Conducting Primate Research in Different Settings

Internationally, primate research takes place in laboratories, zoos, sanctuaries, and the wild. All of these settings present unique advantages and challenges in terms of methodology, translatability, animal welfare, and ethics. In this novel commentary, we explore the scientific and ethical benefits and drawbacks of conducting non-invasive psychological research with primates in each setting. We also suggest ways to overcome some of the barriers. We argue that while there may be greater experimental control in laboratory-based research, settings that more closely mirror primates' natural habitats are generally better suited to meet their specialized needs. More naturalistic research settings, including field studies, may also circumvent some ethical concerns associated with research in captivity, and yield more ecologically valid data.

Dither: A unifying model of the effects of visitor numbers on zoo animal behavior

Interest in the impact of human presence on the behavior and well-being of zoo and aquarium animals is increasing. Previous work has conceptualized the presence of zoo visitors as having one of three impacts on the behavior of animals in zoos: positive, negative, or neutral. Research suggests the same species may exhibit all three responses under different conditions, calling into question whether the positive/negative/neutral framework is the most useful way of considering visitor impact on animal behavior. Here we present a model of visitor effects that unifies these three predictions. Our model suggests that zoo-goers may provide a "dither effect" for some animals living in zoos. We posit animals may show nonlinear behavioral responses over a range of visitor densities, effectively exhibiting changes in both comfortable and anxiety-like behaviors under different levels of human presence. We tested this model during two COVID-19 related closures at the San Francisco Zoo, studying seven species for evidence of nonlinear relationships between visitor numbers and animal behavior. Our results support the dither effect acting in several species observed.

Is Chimpanzee (Pan troglodytes) Wounding Frequency Affected by the Presence Versus Absence of Visitors? A Multi-Institutional Study

Visitor effect studies have had inconsistent results, due in part to the inability to control for all confounding variables such as time of day, seasonal weather patterns, and so forth. This study represents the first instance where chimpanzee (Pan troglodytes) wounding frequencies were investigated across extensive time periods in the presence and complete absence of visitors, thus eliminating many visitor-related variables. Additional variables were eliminated through the zoo selection process, based on institutional responses to a 29-question survey, providing a novel approach to the question of visitor effects. The aim of this study was to determine if visitors were associated with a change in chimpanzee wound event frequencies across four 51-day time conditions, three of which occurred prior to the COVID-19 pandemic, and one during the first wave of pandemic-related zoo closures. We analyzed the archival records of 21 chimpanzees housed at three U.S. zoos. Due to the small number of wound events across all study windows, frequencies of “no wound” events were analyzed. A chi-square goodness of fit test was performed to determine whether the frequency of “no wound” events was equal between the “open” and “closed” trials. Results indicate that the frequencies did not differ, suggesting that chimpanzee welfare, as it relates to wounding, may not be adversely affected by zoo visitors.

From Soundwave to Soundscape: A Guide to Acoustic Research in Captive Animal Environments

Sound is a complex feature of all environments, but captive animals' soundscapes (acoustic scenes) have been studied far less than those of wild animals. Furthermore, research across farms, laboratories, pet shelters, and zoos tends to focus on just one aspect of environmental sound measurement: its pressure level or intensity (in decibels). We review the state of the art of captive animal acoustic research and contrast this to the wild, highlighting new opportunities for the former to learn from the latter. We begin with a primer on sound, aimed at captive researchers and animal caregivers with an interest (rather than specific expertise) in acoustics. Then, we summarize animal acoustic research broadly split into measuring sound from animals, or their environment. We guide readers from soundwave to soundscape and through the burgeoning field of conservation technology, which offers new methods to capture multiple features of complex, gestalt soundscapes. Our review ends with suggestions for future research, and a practical guide to sound measurement in captive environments.

Preliminary investigation of the effects of a concert on the behavior of zoo animals

To increase visitor footfall and engagement, zoos may host public events that may extend outside typical opening hours. With plans to hold a 2‐day concert at Tayto Park, Ireland, this study aimed to identify the behavioral response to the music event of a selected group of species in the zoo. Twenty‐two species were observed across three phases of the event (pre‐, during, and post event). Specific behaviors of interest were categorized as active, resting, asleep, abnormal, and out of sight, with repeated observations being made at each enclosure during each phase. Alongside these behavioral data, sound pressure levels (SPLs) were concurrently recorded at the observation locations in terms of both dB(A) and dB(C). The median dB(C) levels during the event were found to be significantly higher (mdn = 64.5 dB) when compared with both pre‐event (mdn = 60.7 dB) and postevent phases (mdn = 59.4 dB), while dB(A) levels were only significantly higher during the event (51.7 dB) when compared with the pre‐event phase (mdn = 49.8 dB). We found some species‐specific behavioral changes (mainly associated with active and resting behaviors) correlated with increased SPLs and/or event itself. However, the behavioral responses varied between species and there were numerous species that did not respond with any change in behavior to the increased SPLs or the event itself. This variation in response across species reinforces the need for monitoring of behavioral changes as well as consideration of their natural behavioral ecology when implementing appropriate mitigation strategies. Further research should be encouraged to provide an evidence‐based assessment of how music events may affect animal welfare and behavior and to test the efficacy of mitigation strategies that are implemented to safeguard animal welfare.

We found several species expressed behavioral changes that correlated with increased noise and/or other aspects of a public event. The nature of these responses varied across species. Many species did not show any change in behavior during the event.

Habitual resting/active periods may have changed due to extended opening hours. The onset of sleep behavior in vultures occurred later during the event compared with the pre‐event phase. Porcupines emerged from their dens later during the event compared to pre‐ or postevent phases.

Predetermined maximum sound pressure limits for animal enclosures were not exceeded, confirming that precautionary measures, that is, soundproofing, location, stage position, and other mitigations, provided effective control of noise propagation in the zoo.

The effects of Zoo Lights on animal welfare: A case study of great Indian hornbills at Denver Zoo

Popular evening events, such as Zoo Lights, increase the exposure of animals in managed care to stressors such as artificial light and noise, which may alter their behavior and negatively affect animal well-being. The pair of great Indian hornbills (Buceros bicornis) at Denver Zoo provided an opportunity to study the impacts of these stressors because their exhibit was open every evening during Zoo Lights 2017. We expected the hornbills to display increased aggressive behaviors during Zoo Lights due to more exposure to stressors compared to the periods before and after the holiday event. Alternatively, if behavioral changes were associated with hornbills' breeding season which runs from December-March, we expected the hornbills to engage in more affiliative behaviors, and to increase conspecific and nest proximity, during and after Zoo Lights compared to before it due to the onset and progression of the breeding season. The hornbills did not engage in significantly more aggressive behavior during Zoo Lights than before or after it. By contrast, the hornbills engaged in significantly more affiliative behaviors and increased conspecific proximity during and after Zoo Lights compared to before the event. These results are consistent with the timing of the hornbills' breeding season and not with the increased exposure to stressors during Zoo Lights. This case study provides an early step in assessing the impact of Zoo Lights on animals whose exhibits are part of these holiday events. Studies like this will help inform best practices for Zoo Lights events such that they are positive experiences for the zoo, visitors, and animals.

Activity Budget Comparisons Using Long-Term Observations of a Group of Bottlenose Dolphins (Tursiops truncatus) under Human Care: Implications for Animal Welfare

Simple Summary

Behavioral observations are widely considered easy-to-apply and straightforward animal welfare measures for animals under human care. In the present behavioral study, the activity budgets of a group of bottlenose dolphins are analyzed for nine different observation periods over five years. For some of the time periods, some extraordinary events took place, such as construction work. Our results show that activity budgets are significantly impacted by individual factors (e.g., age) and external factors (e.g., group composition). Furthermore, the presence of construction noise significantly affects the occurrence of other behaviors (fast swimming), as well as the dolphins’ performance during daily training sessions. We find that behavioral monitoring is an essential tool for assessing and ascertaining how the welfare of dolphins under human care can be improved, especially if used together with other measures, such as keeper ratings or health assessments.

Abstract

Zoos and aquaria must provide optimal husbandry conditions and the highest welfare standards for their animals. How the welfare state of an animal or a group of animals can be precisely assessed is currently under debate, and new approaches are necessary to reliably evaluate changes in welfare. One particular measure that is easily applicable is behavioral observations. However, for dolphins and other cetaceans under human care, reliable behavior-based measures are rare. Using long-term observations of a group of bottlenose dolphins, we investigate how their activity budgets and different behaviors changed over time and are impacted by construction noise. Additionally, we investigate whether behavioral differences are also reflected in changes in the dolphins’ performance during daily training sessions. Our results show that construction noise significantly alters the dolphins’ behavior. Play behavior decreases during construction periods; most importantly, the frequency of fast swimming activities significantly increased, and at the same time, a decrease in training performance is found. Additionally, inter- and intraindividual behavioral differences are attributed to factors, such as age or weaning. Significant changes in a dolphin’s activity budget can also pose potential welfare concerns. Thus, this study highlights the importance of regularly assessing and analyzing the behavior of dolphins under human care. Behavioral observations are essential welfare indicators and can—when complemented with other measures, such as assessment of training performance—provide zoo staff with important information about each individual’s state of welfare.

Effects of Nearby Construction Work on the Behavior of Asiatic Lions (Panthera leo persica)

In order to be successful and have high standards of animal welfare, modern zoos strive to regularly modify, improve, and build animal enclosures and visitor areas. However, these periods of development could result in temporary durations of sub-optimal welfare for animals housed nearby. In this study, we monitored the behavior of three Asiatic lions (Panthera leo persica) prior to, during, and following a period of construction on a nearby building. Our results provide evidence that welfare may have been temporarily reduced during the construction period. Compared to the pre-construction period, the male exhibited an increase in pacing behavior and all three lions reduced the time they spent resting. We infer that the most significant negative stimulus related to the construction was sound and/or ground vibrations, as a physical barrier ruled out stress from visual stimuli. The behavioral response to the construction work was relatively short-lived and no long-term changes were observed one year on. This research highlights the importance of measuring animal behavior around events outside routine husbandry, and considering animal welfare on an individual basis. Finally, this work adds to the body of literature surrounding the impacts of construction on animal wellbeing and outlines some suggestions for potential mitigation.

A Preliminary Study Investigating the Impact of Musical Concerts on the Behavior of Captive Fiordland Penguins (Eudyptes pachyrhynchus) and Collared Peccaries (Pecari tajacu)

Simple Summary

Understanding the effects that human environments have on captive zoo animals is key when developing management procedures that foster good captive animal health and welfare. Through analysis of behavioural time budgets of Fiordland penguins and collared peccaries (solitary- and group-housed), we found that species’ behaviours and exhibit use altered when musical concerts were held at Melbourne Zoo. Fiordland penguins increased the use of a nest and pool and spent less time preening and interacting with the habitat on concert days compared to days when there was no concert. The solitary-housed peccary rested more and used the back and front of the exhibit more on concert days compared to days where there was no concert, while four group-housed peccaries rested more and were more vigilant on concert days. There were many time points when animal location and behaviour were unknown, which were related to concert days, highlighting the importance of monitoring the whole exhibit—or at least preferred habitats—when assessing potential stressors on behaviour. It is difficult to ascertain whether observed behavioural changes were indicative of stress or behavioural flexibility that allowed animals to cope; however, this research generates hypotheses for future investigations to better manage captive Fiordland penguins and collared peccaries on event days.

Abstract

Captive animal welfare is important for establishments that exhibit species for education, conservation, and research. However, captive animals are often exposed to a number of potential stressors, such as visitors and anthropogenic noise. We aimed to identify the impact of a concert series on the behaviour of Fiordland penguins (Eudyptes pachyrhynchus; n = 2), and solitary- (n = 1) or group- (n = 4)-housed collared peccaries (Pecari tajacu). Animal behaviour, visitor density, and visitor behaviour was monitored pre-concert (afternoons; 16:00–19:00), during the concert (evenings; 19:00–21:00), and post-concert (nights; 21:00–00:00) on concert days (penguin n = 7 days; peccary n = 8 days) and in the same periods on days when there was no concert (penguin n = 8 days; peccary n = 6 days). Fiordland penguins spent more time surface swimming and diving in the pool on concert afternoons and evenings (all p < 0.001), more time in the nest on concert nights (p < 0.001), preened less on concert afternoons and nights (p = 0.019), and engaged with their habitat less on concert evenings and nights (p = 0.002) compared to these periods on days without a concert. The group-housed peccaries slept more in the afternoon and evening (p ≤ 0.01) and were more vigilant at night (p = 0.009) on concert days compared to no-concert days. The solitary-housed peccary slept more on concert nights (p = 0.035), rested more frequently across all time periods on concert days (p < 0.001), and used the front of the enclosure more across all concert time periods (p < 0.001) compared to no-concert days. We provide evidence that behaviour was altered on event days; however, we cannot determine the nature of these changes. Further research is needed to understand the impact of music concerts on zoo animal welfare.