The Unexpected Guest(s): How the Animals Reacted to the Zoo’s Closure and Reopening

June 3, 2021

For the first time in its 152-year history, Lincoln Park Zoo temporarily closed for an extended period. Since then, our concept of “normal” operations has completely changed. Due to the pandemic, the zoo closed to the public from March through June 2020 and again from January 2021 until late February this year.

As the City and State cautiously and gradually reopens, we are starting to get some of our old “normal” back. For the zoo, that means not only reopening zoo grounds and gardens like last summer, but reopening animal buildings as well. In late February 2021, the zoo welcomed back guests at reduced capacity, starting with a Members Weekend in which McCormick Bird House and Regenstein African Journey reopened for the first time since March 2020. Some of the most frequently asked questions from returning guests were: “Do you think the animals missed us?” or “Are the animals going to react differently to seeing visitors again”?

One of the primary aims of the Animal Welfare Science Program at Lincoln Park Zoo is to understand how animal welfare, or how animals “feel,” is affected by guests.

To answer this question, we turned to the information collected by volunteers in the zoo’s Animal Behavior Monitoring program. Since 2015, these volunteers have collected over 7,600 hours of data on more than 35 species using the Lincoln Park Zoo created app ZooMonitor. With ZooMonitor, the volunteers record how the animal is behaving and where the animal is located in their habitat. With this rich dataset, we are able to compare the behavior of animals when the zoo and buildings were closed to times when the zoo was open and guests were present. Looking at if and how the animals’ behavior changed in the presence or absence of guests helps provide clues to how they felt about guests nearby and insights on their individual welfare.

In total, we analyzed behavioral data of ten species as guests returned during Members Weekend and the weeks that followed: giraffes, klipspringers and pygmy hippos at Regenstein African Journey, American avocets, black-necked stilts, Guam kingfisher and Guam rail at McCormick Bird House, African penguins at Robert and Mayari Pritzker Penguin Cove, and cinerous vultures and snowy owls at Regenstein Birds of Prey.

Many species experience seasonal behavior changes, so to minimize seasonal discrepancies, zoo scientists focused on data collected during late winter-early spring timeframes. As animal welfare scientists, we were curious about if and how the animals’ behavior changed in the absence of visitors, and if and how they responded to the return of visitors. For the first question, we compared data collected in 2020 when the zoo was open to the same time in 2021 when the zoo was closed.

So how did the animals act when it was just them and essential staff at the zoo? While we did see some behavior changes in a few species during the zoo’s closure that suggested the animals were using their habitats with a bit less caution, such as increased visibility, and increased foraging, moving, and exploring, these changes were minimal (see left column in the chart below).

For our second question, “how did the animals’ behavior change when guests returned?”, we compared data collected before Members Weekend to data collected during and immediately following Members Weekend. The behavior the animals showed in response to guests returning differed by the species (see the right side of the chart below). Despite all these different reactions, we fortunately did not observe any concerning behaviors that would tell us the animals may be feeling stressed or fearful with the return of guests. Some animals have been very curious about guests, spending time at the front of their habitats in alert postures watching guests. Others showed no interest in guests but were generally more active in their habitat and with the groupmates, spending more time exploring, foraging, and moving around. This may reflect a general increase in arousal, or excitement, at the return of visitors. And finally, some species showed no major changes with guests present again.

A summary of the behavioral changes observed when the zoo closed and later when the zoo reopened.


While we as scientists would love to have simple answers, we rarely do! Additional context is needed to fully understand these changes in behavior. For one thing, behavior between species differs wildly, and a myriad of factors can impact their behavior, such as where they are in the food chain (a predator or prey species), if they are a solitary or social species, if they are most active in the daytime or the nighttime, to name a few. Just like humans, behavior between individuals of the same species can also vary depending on an individual’s own life experiences, if they are male or female, how old they are, and their personality. Complicating our interpretations even more, even though the zoo was closed to visitors, animal care staff continued to care for animals in ways that enhanced their welfare, for example by adding new perching, enrichment, and facilitating changes in social groups.

In our research, one pattern seems to hold true: how we care for the animals has a greater impact on animal behavior and welfare than the presence of guests. This is great news. Guest numbers could vary greatly depending on the season, weather, day of the week, and time of day; however, the care we provide the animals is something that is up to us, and decisions are made based on practice and science.

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