The Impact of COVID-19 Zoo Closures on Behavioural and Physiological Parameters of Welfare in Primates

Abstract

Primates are some of the most cognitively advanced species held in zoos, and their interactions with visitors are complex. The COVID-19 pandemic provided a unique opportunity to understand the impact of zoo visitors on animals, in comparison to “empty zoos”. This study sought to understand the impact of facility closures and subsequent reopenings on behavioural and physiological parameters of welfare in four primate species housed in the UK: bonobos (Pan paniscus) (n = 8), chimpanzees (Pan troglodytes) (n = 11), and western lowland gorillas (Gorilla gorilla gorilla) (n = 6) held at Twycross Zoo (TZ); and olive baboons (Papio anubis) (n = 192) held at Knowsley Safari (KS). Behavioural data were collected from April–September 2020 (KS) and November 2020–January 2021 (TZ). Faecal samples were collected during morning checks from October–November (TZ) and July–November 2020 (KS). Faecal glucocorticoid metabolites (FGMs) were measured using ELISA kits. Statistical analysis for behavioural observations was undertaken using general linear models. Enclosure usage was assessed using t-tests and Mann–Whitney U-tests as appropriate. Bonobos and gorillas spent less time alone when facilities were open to the public (p = 0.004, p = 0.02 respectively). Gorillas spent less time resting when the facility was open to the public (p = 0.04), and chimpanzees engaged in more feeding (p = 0.02) and engagement with enrichment (p = 0.03) when the zoo was open to the public than when it was closed. Olive baboons performed less sexual and dominance behaviour and approached visitor cars more frequently when the safari park was opened to the public than they did the ranger’s vehicle during closure periods. There were no significant changes in physiological parameters for any of the study species. The results suggest variable impacts of the zoo closures on zoo-housed primates. We recommend future work that seeks to understand the impact of individual-level differences on “visitor effects” and that differences between animal experiences in zoos and safari parks are further explored in a range of species.

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

“…Similar changes to enclosure use have been observed in some species when zoological facilities opened after the COVID-19 facility closures [39,40]. However, behavioural changes did not always correspond with increased cortisol, which suggested animals were behaviourally controlling their stress levels caused by the changing environmental situations [13,15]. This research further supports the importance of enabling animals to make choices within their environments.…”

“…Furthermore, zoo species are used to the presence of humans. Recent research during the COVID-19 pandemic has suggested that they are habituated to these environments and can control their own experiences through modified behaviour in the presence and absence of zoo visitors [15].…”

“…When conducted in person or via camera feeds, behavioural observations have the added benefit of enabling facilities to find out 'instantly' the impacts of evening events and act accordingly to support good animal welfare. However, assessment of physiological measures, principally analysis of faecal glucocorticoid metabolites (FGMs), has indicated that animals are less affected by the presence of visitors than their behaviour signifies [13][14][15], which may also explain the range of behaviour changes during evening events, with animals adapting to reduce the impacts of stressors related to evening events. Several behavioural changes have been observed within primate species.…”

The Impact of Visitors on Non-Primate Species in Zoos: A Quantitative Review

“…However, many animal species within zoos have been born and raised in zoos, and so have likely become habituated to the presence of humans [ 45 ]. Zoo animals also show adaptability to the changing conditions of visitors in zoos [ 15 ]. Despite this, some of the species in this study matched with the predictions made by Queiroz & Young [ 39 ].…”

“…Zoo visitors are also drawn to active animals [ 5 , 11 ] and active animals will increase visitor dwell time at enclosures [ 12 ]. Studies have reported changes in primate behaviour in response to visitors, with visitors being recognised as a stimulant for some primates [ 13 , 14 , 15 ] but a negative stressor for others [ 16 , 17 , 18 ].…”