A gorilla escaped his enclosure Friday at a South Carolina zoo and injured a worker before returning to his holding area on his own about five minutes later.

The food service worker, an employee of Aramark Corp., was treated at a hospital and released, said company spokesman Dan Smith. Aramark runs the cafeterias at the Riverbanks Zoo and Garden. Smith declined to identify the worker or talk about the person's injuries.

The zoo was packed with day care groups and visitors, who were ushered to indoor exhibits or outside the gates for about 45 minutes after the gorilla escaped, spokeswoman Lindsay Burke said.

The gorilla got out about a half-hour after the zoo's 9 a.m. opening and returned to the gated sleeping area connected to his outdoor enclosure, which is separated from the public by different barriers in different spots, including mesh and plexiglass.

A second of three gorillas in the exhibit also went into the sleeping area when the escaped animal returned, but it took 40 minutes to coax a third male into the holding area, Burke said.

Burke said officials were unsure which of the zoo's three western lowland gorillas got free. Early reports blamed a 16-year-old male named Mike. Also in the exhibit are 24-year-old Chaka and 15-year-old Kimya.

Teresa Todd, the owner of Cayce Gymnastics, had a group of 10 children ready to enter when the zoo was locked down.

She considered returning home but, like most visitors, said they were unphased.

"We had fun. It's been a good day," Todd said.