A man who stepped over a barricade and entered a hippopotamus enclosure at the Los Angeles Zoo may face trespassing charges after he was filmed smacking one of the animals, CBS Los Angeles reported.

A viral video shared by several media outlets shows a man approach the hippo enclosure, step into it and creep over to two hippopotamuses calmly standing side by side. The man swiftly smacks one of the hippos on the backside then hops out of the enclosure.

It is unclear who took the original video, which one Twitter account called "Something to Laugh At" shared with the hashtags "dare devil" and "zoom challenge."

The hippos in the video are named Rosie and Mara, CBS Los Angeles reports. Rosie, who was slapped, does not appear to have much of a reaction to the man, but her mother, Mara, does look slightly startled.

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It is unclear if the man knew he was being filmed from afar. The Los Angeles Police Department is now reviewing the video after receiving a report of trespassing at the zoo, according to CBS Los Angeles.

After the incident, zoo officials posted "No Trespassing" signs around the zoo.

In a statement Monday, the zoo said it "would like to remind everyone that it is never acceptable for a guest to enter the habitat of any animal at the Zoo, excluding our staff-supervised animal encounters."

"It is a privilege to observe these rare and endangered species, but they are still wild animals and their space must be respected at all times," it said. "Our first priority is always to keep our guests, staff, and animals safe."