Within minutes, several visitors had placed bouquets and other mementos at a makeshift shrine just inside the zoo's entrance.
A zoo spokeswoman said memorials would be welcomed both for Carlos Sousa Jr., the 17-year-old from San Jose who died, and for Tatiana, the 4-year-old Siberian tiger who was shot by police after mauling Sousa and his two friends, who survived.
"Tatiana was always friendly," said Susan Pettit, a Santa Clara homemaker who gingerly set down photographs, a stuffed animal and flowers in the tiger's memory. "I never saw her act aggressively even once."
"The big cats were like my own kids," added Pettit, who has visited the zoo once a week for three years. "I loved them all."
Police are investigating what prompted Tatiana to vault over the 12 1/2 -foot barrier around her enclosure.
Mark Geragos, an attorney for the two brothers who survived the attack, has denied speculation that the victims provoked the animal.
A report in the San Francisco Chronicle on Thursday quoted a visitor who said she saw a group of young men taunting lions the afternoon of the attack.
Jennifer Miller told the newspaper that she later recognized Sousa from newspaper photographs as being part of the group, although she said she did not see him participate in the teasing.
Sgt. Steve Mannina, a San Francisco police spokesman, confirmed that the department had twice talked with Miller, but would not say whether her account had been corroborated or disclose any details of what she had told investigators.
Miller said there were four young men at the big-cat grottoes, but only Sousa and his friends, Paul Dhaliwal, 19, and Kulbir Dhaliwal, 23, have been publicly identified.
Mannina also confirmed that a vodka bottle was found in the car that Sousa and his friends drove to the zoo. He said the results of toxicology tests will not be released before the investigation is completed.
Exactly how and why Tatiana escaped are still matters of speculation. Mannina said no slingshots, laser pointers, BB guns or other devices were found, despite at least one published report to the contrary.
"We don't believe those things were involved," he said.
At the zoo Thursday, workers were tearing into the top of the big-cat walls with jackhammers, preparing to install glass panels that will raise their height to 19 feet.
The big cats are being kept indoors and won't be on view to the public until work on the outdoor enclosures is complete.
Shirley Hardy of nearby Pacifica was among the morning's first visitors. She said she wanted to bring family members to the zoo the day after Christmas but was thwarted by its sudden shutdown.
Hardy, a school district payroll technician and frequent zoo patron, said she sees people trying to get the animals' attention from time to time, and even admitted occasionally mugging for the monkeys.
"Maybe we'll all learn to be more respectful," she said. "Maybe it's a lesson all around."