The San Francisco Zoo has closed its Lion House, an exhibit where the public can watch the big cats eat a meal, while officials investigate the mauling of a keeper by a Siberian tiger. The woman, who has worked at the zoo since 1997, was rushed into surgery Friday night to save her lacerated limb. Her family requested that her identity and condition not be released, zoo and San Francisco General Hospital officials said. The attack happened during a regular Friday afternoon public feeding, during which keepers typically deliver a meal of fortified horsemeat through a small metal slot. At least 50 visitors were in the Lion House when the 350-pound (157.5-kilogram) tiger, Tatiana, reached through her cage's iron bars and grabbed the keeper. Tyler Bridges and his 4-year-old daughter were in the Lion House and had just finished chatting with the keeper when the attack occurred as they were walking away. "She had just said, 'We feed them rabbits every Tuesday and Friday.' Fifteen seconds later, I hear her screaming," Bridges told the San Francisco Chronicle. "I see her with her back to us, facing the cage. Both of her hands were in front of her. Then somebody tried to pull her away from the tiger." Bridges, 46, said it was his daughter's first visit to San Francisco Zoo. "I picked up my daughter - she was very traumatized," Bridges said. "Some visitors were running out, zoo workers were running in. While we were heading out, I could still hear her screaming." While the Lion House is closed for the investigation, the public will be able to see the zoo's four lions and three tigers in the outdoor area of the exhibit, spokesman Paul Garcia said Saturday. The building will reopen when zoo officials think it is appropriate, he said. Tatiana arrived at the San Francisco Zoo from the Denver Zoo about a year ago, with zoo officials hoping she would mate with a 14-year-old male tiger. Tatiana has had no previous incidents of aggression against humans, said Ana Bowie, a Denver Zoo spokeswoman. The mauling was the first attack of its kind during a demonstration at the San Francisco Zoo's Lion House, Garcia said.