SAN DIEGO (FOX 5/KUSI) — A 10-year-old western lowland gorilla at the San Diego Zoo shattered a layer of protective glass in its habitat on Saturday, zoo officials confirmed.

According to a statement from the zoo, the event occurred on Oct. 11, when the gorilla, named Denny, broke through one of three layers of tempered glass that separates the animals from zoo guests in the gorilla forest habitat. Another gorilla was also present in the compound at the time.

“Denny was not injured,” the zoo noted. “Both gorillas will be cared for behind the scenes until the panel has been replaced.”

Zoo officials clarified that the glass panel comprises three protective layers, with only one being damaged. No guests or staff were injured during the incident.

The impact startled people who saw it happen.

“We were looking down at our cell phones and didn’t realize he had taken a running start, jumped and hurled himself into the glass. He struck it with his elbow or forearm, right in the glass directly in front of my face,” said Katya Sutil, who was celebrating her birthday at the zoo with her sister. “When it hit in front of me, I was so startled I fell back a few feet. When I looked up to see what had happened, I saw the gorilla staring directly at me, making eye contact, and then a giant crack… six feet. It was quite significant.”

A timeline for when the gorilla habitat will reopen to the public was not immediately provided.

“Honestly, the 20 minutes we were there, the gorillas were going back and forth, kind of taunting each other. One would charge the other and then disappear, then it would happen again,” Sutil explained. “So maybe there was tension between the two gorillas.”

Western lowland gorillas, such as Denny, are critically endangered species native to the forests of Central Africa. The San Diego Zoo is engaged in conservation efforts to protect these primates and their natural habitat.

For more information, visit sandiegozoowildlifealliance.org/species/gorilla.