Anthropogenic noise is a recognized global pollutant, affecting a wide range of nonhuman animals. However, most research considers only whether noise pollution has an impact, ignoring that individuals within a species or population exhibit substantial variation in responses to stress. Here, we first outline how intrinsic characteristics (e.g., body size, condition, sex, and personality) and extrinsic factors (e.g., environmental context, repeated exposure, prior experience, and multiple stressors) can affect responses to environmental stressors. We then present the results of a systematic search of the anthropogenic-noise literature, identifying articles that investigated intraspecific variation in the responses of nonhuman animals to noise. This reveals that fewer than 10% of articles (51 of 589) examining impacts of noise test experimentally for intraspecific variation in responses; of those that do, more than 75% report significant effects. We assess these existing studies to determine the current scope of research and findings to-date, and to provide suggestions for good practice in the design, implementation, and reporting of robust experiments in this field. We close by explaining how understanding intraspecific variation in responses to anthropogenic noise is crucial for improving how we manage captive animals, monitor wild populations, model species responses, and mitigate effects of noise pollution on wildlife. Our aim is to stimulate greater knowledge and more effective management of the harmful consequences of this global pollutant.

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Causes and consequences of intraspecific variation in animal responses to anthropogenic noise

There is a growing interest and need for zoos to develop and implement welfare assessment tools that are practical to use and provide meaningful results that can inform management decisions. This paper presents a process that was developed to support this type of evidence-based management in zoo animal welfare. The process is configured to facilitate institutional risk assessment, using an adapted version of the Five Domains Model for animal welfare assessment. It is designed to systematically analyse information gathered from zoo personnel in order to highlight areas of welfare risk, as well as areas that are performing well and areas requiring further investigation. A trial was conducted on three zoos over three years. Results of the trial suggest the process developed is practical and effective in identifying areas of welfare risk in a wide range of species in a zoo setting. It represents a further step towards achieving high-level animal welfare in zoos by integrating animal welfare as an institutional priority. The more zoos that employ such strategies, the greater the ability of the sector to advance the welfare of the animals in their care.

/pdf/an-animal-welfare-risk-assessment-process-for-zoos-51eyqm3h85.pdf

An Animal Welfare Risk Assessment Process for Zoos.

Measuring welfare in captive flamingos: Activity patterns and exhibit usage in zoo-housed birds

We provide an initial insight into the occurrence and characteristics of animal-visitor interactions (AVIs) involving captive wild animals within zoos and aquaria. Using information provided online via official public websites of modern zoos and aquaria, we found that AVIs were provided by the majority of facilities. Our study revealed that a variety of AVI types were being offered. Globally, petting captive wild animals was the most prevalent AVI type advertised (n = 1241 observations, 43% (534) of facilities) and Mammalia was the most advertised taxonomic class (n = 5142; 53% (2739)). We found certain AVI types that were more commonly offered than predicted. These were opportunities to: (1) Hand feed captive wild animals in Asia, North America and Oceania; (2) ride wild animals in Europe and North America; (3) walk with or swim through wild animal enclosures in Asia; and (4) walk with wild animals in Asia and Europe. Given the global prevalence of AVIs in modern zoos and aquaria, and an apparent lack of animal welfare focused research, we provide recommendations to help effectively balance and manage captive wild animal welfare with other primary interconnected goals.

https://www.mdpi.com/2076-2615/9/6/332/pdf

A Global Review of Animal-Visitor Interactions in Modern Zoos and Aquariums and Their Implications for Wild Animal Welfare.

In the zoo environment, anthropogenic noise is common as sound levels fluctuate due to visitors, construction, habitat design, and special events. In this study, changes in the mood of three species of zoo-housed primates in response to a loud annual event were evaluated with the response-slowing paradigm. In this paradigm, animals experiencing anxiety slow responses on simple cognitive tasks when emotional content is displayed. Following a previously validated approach, we measured latencies to touch potentially threatening (conspecific faces with directed gaze) and non-threatening (conspecific faces with averted gaze) images overlaid on a grey square, relative to neutral control images (grey squares only) on a touchscreen. In Experiment 1, four Japanese macaques (Macaca fuscata) were tested in two conditions: during a baseline (non-stressful) period and opportunistically during three days during which loud jets frequently flew overhead. Results indicated a significant effect of condition, with an increase in latency to touch images of conspecific faces relative to control images during the days of the loud event. In Experiment 2, chimpanzees (Pan troglodytes, n = 4) and western lowland gorillas (Gorilla gorilla gorilla, n = 2) were tested during the same loud event following a similar methodology. The results revealed subtle changes across conditions; however, this was likely driven by the apes increasing their response speed to face stimuli relative to control stimuli over time (habituation). These findings suggest that the macaques, but not the apes, underwent detectable affective changes during the loud event. With additional development, this relatively simple paradigm may be an effective and feasible way to evaluate real-time changes in the mood of zoo-housed animals.

Sandra Quadros

Papers

Zoo visitor effect on mammal behaviour: does noise matter?