Authorities did not believe more people were attacked, but they wanted to inspect the area in the daylight. Zoo officials were still uncertain how long the Siberian tiger, the same one that mauled a zookeeper last year, was loose before being shot dead.
The three men who were attacked Tuesday while visiting the zoo were in their 20s, police spokesman Steve Mannina said. The attack occurred just after the 5 p.m. closing time, on the east end of the 125-acre grounds.
They suffered "pretty aggressive bite marks," Mannina said.
The zoo was to be closed Wednesday.
The two injured men were listed in stable condition at San Francisco General Hospital. Dr. John Brown, an emergency room physician, told ABC's "Good Morning America" on Wednesday they suffered deep bites and claw cuts to their heads, necks, arms and hands.
"These injuries are severe injuries, but they are very treatable," Brown said, "and these two gentlemen seem to be in good health, so I think they have a good chance."
The Siberian tiger, named Tatiana, was the same giant cat that attacked a zookeeper just about a year ago during a public feeding, said Robert Jenkins, the zoo's director of animal care and conservation.
The approximately 300-pound female did not leave through an open door, Jenkins said. But he could not explain how it escaped
- the tiger's enclosure is surrounded by a 15-foot-wide moat and 20-foot-high walls.
"There was no way out through the door," Jenkins said. "The animal appears to have climbed or otherwise leaped out of the enclosure."
The first attack happened right outside the Siberian's enclosure - the victim died at the scene. A group of four officers came across his body when they made their way into the dark zoo grounds, Mannina said.
The second victim was about 300 yards away, in front of the Terrace Cafe. The man was sitting on the ground, blood running from gashes in his head and Tatiana sitting next to him.
The cat attacked the man again, Mannina said. The officers approaching the tiger with their handguns. Tatiana moved in their direction and several of the officers fired, killing the animal.