A zookeeper was in critical condition after he was attacked by a male Sumatran tiger at the San Antonio Zoo.

The keeper was attacked about 2:30 p.m. in a nonpublic area, said zoo spokeswoman Dawn Campos. The zoo, open every day of the year, was closed after the attack. Campos said it was expected to reopen on Sunday.

The zookeeper, who specializes in large cats, was flown to University Hospital, where he was in critical condition, a hospital spokeswoman said. She would not release any other information. Campos did not know the keeper's exact age, but said he was "in his 20s."

The tiger was 4-5 years old, Campos said, and one of two Sumatran tigers at the zoo. The other is female.

Campos said she did not know the extent of the zookeeper's injuries, but said, "He was very, very fortunate. He's going to be fine."