Visitors at the San Diego Zoo were startled when a western lowland gorilla damaged a tempered glass panel in the park’s gorilla forest habitat on Saturday. The animal, a 10-year-old male named Denny, struck one of the viewing windows while people were nearby. The section contains three laminated layers and staff reported a single layer was cracked.

Zoo officials reported Denny was not injured and that the gorillas would be cared for behind the scenes until the damaged panel is replaced. Park staff moved the animals off public display while maintenance plans are put in place. The institution has not released further details about the circumstances that led to the incident.

San Diego State University anthropology professor Dr. Erin Riley offered a few possible explanations for the behavior seen at the exhibit. “Gorillas, particularly males, will often do what we call ‘charging displays,’ as a kind of an act of like showing off,” said Riley. Her point was that displays can appear alarming but may be part of normal primate behavior.

“What I don’t know, of course, since I wasn’t there, is whether or not there was something that kind of provoked that display behavior. One of the things that gorillas actually don’t like is to be stared at directly in the eyes, and that’s not something that zoo visitors always understand.”

Riley also noted that not every dramatic movement is aggressive and play can be misread. Denny could have also been having fun and playing around, Dr. Riley told CBS 8 San Diego. Still, she warned that if the animal’s attention is fixed on the glass, an intense crowd or direct eye contact may make him uneasy.

“Given that it was directed towards the window, which is where the visitors are, I don’t know if they were feeling threatened, if there were a lot of people there at the time that made Denny feel a little bit threatened,” said Riley.:

The zoo’s immediate messaging has focused on safety and animal care rather than speculation about motives. Repairs to replace the cracked laminate are planned, and staff are prioritizing the animals’ well-being while the work is completed. No timeline for the repair has been announced publicly.

The incident highlighted how close encounters behind glass can test exhibit design and visitor expectations. Those laminated viewing panels are designed to absorb impact and protect both guests and animals, but a cracked layer shows how much force a large primate can exert at close range. Exactly what triggered the action remains undetermined pending any internal review.

Officials reiterated that no one was hurt during the episode and that animal care professionals are managing the group away from public view. The zoo said it will return the gorillas to the exhibit only after crews confirm the area is safe and the panel is properly replaced. For now, staff are handling repairs and animal care out of sight while they assess the next steps.

Glass viewing areas are intended to give visitors a close, unobstructed look at large primates while maintaining protection for both sides. That proximity can make ordinary behaviors look startling because the natural buffer between people and animals is removed. Facilities try to balance guest experience with animal welfare through design and staff oversight.

The zoo says it will share updates as repairs progress. Right now the animals are being cared for away from public view.