A myriad of exotic species are housed in zoos and aquariums (hereafter “zoos”) around the world with birds and fish being the most species-diverse of the taxonomic groups currently held (Rose et al., 2019).
Husbandry and management are becoming more species-specific with a strong foundation of evidence from scientific research, information from natural history and behavioural ecology from the wild. Therefore, the welfare states and associated quality of life experiences of animals managed under human care in zoos are improving, and consequently the key aims of the modern zoo – education, conservation, research and recreation – are better supported and realised (Rose, 2018, 2021).
The “visitor effect” is the term used to describe potential positive (eg enriching), negative (eg fearful) or neutral (eg ignored) effects of zoo visitors on animal behaviour and welfare (Hosey, 2000)
In spite of these evidence-based approaches and improvements to welfare monitoring and care, there are still challenges in the way wild animals are displayed to human visitors, and some of these challenges come from the visitors themselves. Conflicts between visitors’ desire for close contact with the animals they are observing and their desire to see animals behaving naturally can be a trial for the zoo to manage while ensuring that animal welfare remains good and that visitors are satisfied (Fernandez et al., 2009).
The “visitor effect” is the term used to describe potential positive (eg enriching), negative (eg fearful) or neutral (eg ignored) effects of zoo visitors on animal behaviour and welfare (Hosey, 2000).
Assessing and monitoring stress
Zookeepers, curators and vets can assess stress, including the potential or actual stressors, to the animals involved by observing behaviour and their enclosure usage; reviewing the density levels and frequency of visitors at the enclosure; and planning husbandry and enclosure design accordingly. Figure 1 identifies areas of zoo management and species husbandry that should be evaluated to determine the potential impacts of visitors on the well-being of the zoo’s inhabitants.
Some things to consider when monitoring potential visitor effects and their impacts on animal behaviour and welfare might be: can the animal remove itself from public view? Where are visitors likely to gather and does this impact on how animals use their resources? Is access to resources (foraging sites or resting areas) compromised by the proximity of the viewing public at the enclosure?
As an example, enclosure usage of captive flamingos gives a clear indicator of their comfort within an enclosure (Rose et al., 2014). Except when birds naturally clump together for nesting in one specific enclosure area, a contented flock of flamingos will be spread out around the enclosure, using the available space widely. A flamingo flock that is unsettled will spend most of its time close together in the same area of the enclosure.
Zoo staff can monitor this and then review the birds’ behaviour according to different levels of visitation. Data from this monitoring can then provide evidence for enacting the aspects of enclosure modification which promote positive behaviours in the animals and reduce any negative influences of visitor presence (Figure 2). Modifications could include:
- Changes to where resources are provided, moving them towards areas where the animals are more comfortable using them
- Placing visual barriers and hides to give the animals a choice of being visible or not
- Alterations to visitor flow at the enclosure to minimise crowding or undue noise from visitor presence near specific sections of the exhibit
- Changes to the furnishings and/or structure within the enclosure to provide shelter and refuge
A behavioural perspective on the “visitor effect”
From a behavioural perspective, activities that promote positive welfare states, ie those that are associated with good psychological and physical heath, or activities that suggest a degree of autonomy over the animal’s situation, where the animal has choice and control over what it is doing, can be measured alongside visitor presence.
Individuals will differ in their behavioural responses to visitors as well as to the daily husbandry of the zoo, so it is important to consider species’ ecology and behavioural needs when designing an enclosure for said species in the zoo. It is also important to have knowledge of and consider the individual personality and characteristics (eg bold, shy) when evaluating the influence of visitors on each animal’s welfare.
If the animal performs behaviours associated with positive welfare states irrespective of visitor presence, then the zoo’s husbandry protocol and the design of the enclosure are likely to be biologically relevant and suitable for the species. Figure 3 provides examples of enclosure usage and some of the behaviours which are associated with good welfare.
During COVID-19 closures
Species differences are apparent in how they respond to visitor presence. After the enforced closure of zoos due to the COVID-19 pandemic in 2020, many species experienced an environment with a very limited presence of people.
Research on captive amphibians by Boultwood et al. (2021) demonstrated that the visibility of different species of frog changed in the presence of visitors. Notably, the species with bright patterns and colours warning of toxicity were more likely to be active and visible to the visiting public compared to cryptic species which became more visible during a period without visitation and also took a longer time to readjust to visitors coming back into the collection. The visitor effect is also influenced by weather, climate and season. Research on both mammals (Goodenough et al., 2019) and birds (Rose et al., 2020) has demonstrated that the visitor effect is complicated by seasonal and temporal conditions. Animals may be less active or have a less wide enclosure usage when more people are around because of hotter weather, causing them to seek shade or use only one or two valued resources, and do so more frequently.
Measuring the impact of visitors on animal behaviour in the zoo must be recorded alongside the environmental conditions and keeper presence at both the species and individual levels (Figure 3). Such data provides a holistic view of the animal’s life in the zoo.
Developing enclosures to be more naturalistic not only benefits the animals’ behaviour patterns and attainment of good welfare states, but also can positively impact the messages that visitors take away from their experiences of the species in the zoo (Lukas and Ross, 2014).
Ultimately, understanding the animals’ responses to visitors and how the visitors are perceiving the animals’ well-being strengthens the value of the zoo’s living collection and its overall impact on society.