Gorilla at Buffalo Zoo Slips Through Unlocked Door, Bites Keeper

March 19, 2012 Updated Mar 19, 2012 at 9:02 PM EDT

By Kyla Igoe

March 19, 2012 Updated Mar 19, 2012 at 9:02 PM EDT

Buffalo, NY (WKBW) -An unlocked door within the Buffalo Zoo is to blame for a 400-pound Silverback Gorilla to leave its designated area.

Just before 11a.m. Monday, Koga, a 24-year-old Silverback male gorilla, accessed the animal keeper aisle, and bit a keeper. The animal keeper aisle is located in a secure non-public area behind the gorilla exhibit.

The keeper, described by staff members as experienced, was bit in the hand and leg by the animal. The employee then locked herself in one of the holding cages with two other gorillas to help protect herself. According to officials, the keeper notified the animal escape team and protocols were in place and followed. Visitors were also taken to designated areas as a precaution. The Buffalo SWAT Team was also called.

"We had the best possible scenario because the personnel did their jobs and contained this to the smallest area possible," said Buffalo SWAT Commander Mark Maraschiello.

The gorilla was shot with a tranquilizer dart and subdued within 15 minutes. Koga is currently off exhibit. The zoo was able to re-open 2 hours later. Zoo officials say they do not know why that secure door was left unlocked and the zoo has now launched an investigation. Officials say human error could be a possibility.