Blog: Who gives a hoot about sound in the zoo?

The BIAZA Sound Focus Group, part of the Research Committee, on this often overlooked area of zoo study:

Sound is one of the least studied aspects of the zoo environment, but it has important implications for animals and visitors.

We often think of noise disturbance from visitors and special events when considering sound in the zoo, but a huge range of sources can contribute to the zoo sound environment. This includes continuous sound sources (e.g., heating, ventilation and air conditioning (HVAC) units and life-support systems), intermittent noise sources from humans (e.g., construction, maintenance and husbandry), human voices, and animals’ vocalizations. As a result, the zoo soundscape is unique among both urban and rural environments due to the varied sources of sound and the presence of geographically diverse species. Despite this, a recent study published in 2020 in JZAR by Binding et al. found that non-visitor noise was one of the least well-studied aspects of the zoo environment.

Sound in the zoo is most often considered for its effects on animals’ behaviour. Whilst we may be interested in noise associated with specific events, such as construction or evening opening hours, day-to-day noise sources can also impact animals in the zoo. Noise disturbance can cause shifts in behaviour, such as altered activity budgets (e.g., reduced time spent foraging or enclosure usage), or physiological responses. Sound is important to monitor and mitigate if needed as, outside of the zoo, noise exposure has been linked to a number of potential problems, including reduced communication efficiency, hearing loss, altered development trajectories, and reduced reproductive success.  

It is essential to consider species biology when examining the potential impact of sound on animals. Many species have hearing ranges different to our own, and so may be affected by noises that humans are unable to perceive, such as ultrasound (above human hearing range) and infrasound (below human hearing range). Individual animals may also differ in their noise tolerance, meaning that responses to noise disturbance are likely to vary by species and individual.

As well as its potential impacts, sound can also be a useful tool in the zoo and beyond. Animal vocalizations are incredibly varied among species and individuals and are produced in a wide range of situations. These vocalizations often provide information about the caller, such as age, sex, and social status. Bioacoustic monitoring, which uses animals’ sound to infer species distributions, abundance, and behaviours, is a common tool used in wildlife conservation. Within the zoo, we can support this work by helping to develop monitoring technology, for example by creating reference recordings or determining specific technical information. In addition to its importance for in-country conservation programmes, bioacoustic monitoring may also prove useful for studying animals in the zoo to help ensure the best care. Animals often produce different vocalizations in different situations. As a result, these vocalizations could be used for monitoring species in the zoo by providing information on activity, emotional status, and reproductive status.

The sound environment in zoos can also impact visitors’ experience and well-being. Zoos are an important green space, especially in areas where other green spaces may be restricted, and can promote connection with nature.  Although less frequently considered, the zoo soundscape can contribute to these outcomes. Early studies suggest that use of ecologically relevant sounds enhanced visitors’ experience in the zoo, improved learning, and resulted in increased positive emotions towards animals in the zoo. More recent studies have added to these findings, reporting that interacting with the zoo soundscape can enhance engagement with the zoo and its animals, resulting in a greater appreciation of the zoo environment.

Due to recent technological advances, there is now a wide range of equipment to measure sound in the zoo, from traditional decibel meters to high-specification autonomous recording units, each with their own advantages and disadvantages. In addition to using human ears to listen attentively, there are a broad range of tools and techniques we can use to measure sound beyond traditional decibel levels, including the exploration of narrow frequency bands and acoustic indices. Getting started with sound monitoring programmes may seem daunting to those who are new to the field. However, the recently formed BIAZA Sound Focus Group is on hand to provide guidance and information for all things sound!

Rebecca Lewis, Chester Zoo & BIAZA Sound Focus Group

To get in touch with the Focus Group, contact [email protected] 

All blogs reflect the views of their author and are not a reflection of BIAZA's positions. 

Binding, S., Farmer, H., Krusin, L., & Cronin, K. (2020). Status of animal welfare research in zoos and aquariums: Where are we, where to next?. Journal of Zoo and Aquarium Research, 8(3), 166-174.

Briefer, E. F. (2012). Vocal expression of emotions in mammals: mechanisms of production and evidence. Journal of Zoology, 288(1), 1-20.

Clark, F. E., & Dunn, J. C. (2022). From Soundwave to Soundscape: A Guide to Acoustic Research in Captive Animal Environments. Frontiers in Veterinary Science, 9, 889117.

Kight, Caitlin R., and John P. Swaddle. "How and why environmental noise impacts animals: an integrative, mechanistic review." Ecology letters 14.10 (2011): 1052-1061.

Kight, C. R., Saha, M. S., & Swaddle, J. P. (2012). Anthropogenic noise is associated with reductions in the productivity of breeding Eastern Bluebirds (Sialia sialis). Ecological Applications, 22(7), 1989-1996.

Lewis, R. N., Williams, L. J., & Gilman, R. T. (2021). The uses and implications of avian vocalizations for conservation planning. Conservation Biology, 35(1), 50-63.

Ogden, J. J., Lindburg, D. G., & Maple, T. L. (1993). The effects of ecologically‐relevant sounds on zoo visitors. Curator: The Museum Journal, 36(2), 147-156.

Powell, D. M., Carlstead, K., Tarou, L. R., Brown, J. L., & Monfort, S. L. (2006). Effects of construction noise on behavior and cortisol levels in a pair of captive giant pandas (Ailuropoda melanoleuca). Zoo Biology: Published in affiliation with the American Zoo and Aquarium Association, 25(5), 391-408.

Rice, T., Reed, A., Badman-King, A., Hurn, S., & Rose, P. (2021). Listening to the zoo: challenging zoo visiting conventions. Ethnos, 1-20

Schneiderová, I., & Vodička, R. (2021). Bioacoustics as a tool to monitor the estrus cycle in a female slow loris (Nycticebus sp.). Zoo Biology, 40(6), 575-583.

Steinbrecher, F., Dunn, J. C., Price, E. C., Buck, L. H., Wascher, C. A., & Clark, F. E. (2023). The effect of anthropogenic noise on foraging and vigilance in zoo-housed pied-tamarins. Applied Animal Behaviour Science, 105989.

Teixeira, D., Maron, M., & van Rensburg, B. J. (2019). Bioacoustic monitoring of animal vocal behavior for conservation. Conservation Science and Practice, 1(8), e72.

Wark, J. D., Schook, M. W., Dennis, P. M., & Lukas, K. E. (2023). 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). American Journal of Primatology, 85(3), e23421.

https://www.wwf.org.uk/sites/default/files/2019-04/Acousticmonitoring-WWF-guidelines.pdf