"Obviously, there will be disciplinary action," Zoo Director Randy Wisthoff said. "We will sit down with everybody and go over the protocols. They've worked so far. If we identify something that needs to be modified, changed or rethought, we are fully prepared to do that once we understand exactly what happened."
The two adult male gorillas, which weigh more than 400 pounds each, got out of their interior cages Sunday afternoon and moved around the zookeeper area for 3 hours, officials said. The two zookeepers made their way into the outdoor exhibit where a third keeper gave them a ladder so they could climb to safety.
Zoo visitors were temporarily moved into enclosed areas while zookeepers assessed the situation, The Kansas City (Mo.) Star reported.
After about 45 minutes, employees determined the public was not at risk and allowed people to leave.
The Africa area of the zoo where the western lowland gorillas live, however, was shut down for the rest of the day as a precaution.
Zookeepers said they first used special treats such as marshmallows to try to lure the gorillas back into their enclosure. Eventually, the staff resorted to spraying the gorillas with hoses and that worked.
Julie Neemeyer, the zoo's director of marketing, said the two gorillas got into an area that allowed them to view female gorillas -- a compound from which they are normally separated.
"They were posturing for the females," Neemeyer said. "They were doing what male gorillas do."