Did The Pandemic Lockdowns Affect The Welfare of The Sumatran Orangutans (Pongo abelii) At The Toronto Zoo?

The COVID-19 pandemic led to unprecedented lockdowns with rippling impacts on the lives of humans and animals alike. Fortunately, these lockdowns also presented the opportunity to study the relationship of visitor presence with the welfare of zoo-housed animals as natural experiments. The reduction of visitor counts to zero for several consecutive months allowed researchers to study visitor effects on welfare measures and address the confounding variables associated with the time of the day. The purpose of this thesis was to study how the welfare measures of the Toronto Zoo Sumatran orangutans (Pongo abelii) changed when visitors were reintroduced after the lockdowns were lifted. I compared behavioural and physiological measures of stress between the lockdown and visitor introduction phases. Specifically, I studied changes in aversive behaviour by measuring the equality of physical enclosure space use, as well as changes in behavioural indicators of arousal (self-directed behaviours, agonistic behaviours, and object-directed displacement) and a physiological indicator of arousal (fecal consistency) as visitors were reintroduced to the orangutan pavilion. I found that the orangutans did not change their space use when visitors were introduced. In fact, the orangutans hid less when visitors were introduced than during the lockdown. This suggests that visitor presence was not aversive to these orangutans. Foraging and inactivity levels did not change across the phases of the study. Behavioural indicators of arousal also did not change when visitors were introduced. Fecal consistency did not change across the study. However, the presence of conspecifics and keepers strongly affected the behaviours of the orangutans. The results are congruent with studies that found that the pandemic lockdown measures did not negatively affect the welfare of a variety of species.