Video captured animals at the Texas Zoo reacting to the darkness during a total solar eclipse

The playful animals thought the day was over when the sky became dark

The animals at the Dallas Zoo were enjoying a playful day when the solar eclipse caused them to calm down.

Hundreds of guests visited the Texas attraction on Tuesday, April 8, to view the eclipse. Many were curious to see how various animals would react to totality, and researchers were on hand to document behavior at the Fort Worth Zoo, also in North Texas.

The researchers found that many animals immediately went back to their nighttime rituals and prepared to go to their evening enclosures, a marked difference from their playful behavior just moments before.

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Related: Must-see photos from today's incredible solar eclipse

Ahead of the eclipse, PEOPLE spoke with Erica Cartmill, a professor of anthropology, animal behavior and cognitive science at Indiana University, about how the event might affect animal behavior.

Cartmill acknowledged that it is difficult to predict behavior because solar eclipses “are such rare events, especially total eclipses.”

“There are not that many reports and not that many scientific studies about the behavior of animals during a solar eclipse,” she explained.

Cartmill said that based on her professional knowledge of animal behavior, she believes animals would likely respond to the total solar eclipse in one of two ways, if at all.

The most likely reactions “in order of frequency” are nocturnal behavior and signs of anxiety, said the professor.

“The most likely response is that the animals are starting their evening routine and exhibiting evening behavior,” Cartmill noted.

A solar eclipse is “like dropping a little piece of night in the middle of the day. So you could just pretend it's night,” she added.

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