The Oakland Zoo is now reviewing cell phone video showing a visitor climbing over the outer wall by the tigers' pen.
A family at the zoo on Sunday took video of a man who climbed the wooden barrier that separates guests from the wire fence, then scrambled back when a tiger approached.
The family posted the video online for a community bulletin board. The family told NBC Bay Area by phone they are upset the man's actions seemed to encourage some children there to do the same thing.
Zoo officials said they are reviewing the video.
"Now that we know that happened, we can definitely take it into consideration," said Erin Harrison with the Oakland Zoo. "We feel our barriers are great, but we can always review that and see if there's more we can do to communicate to the public."
The visitors who took the video said the man claimed later he was retrieving glasses, but they said they did not see him do that. Zoo visitors on Monday said, regardless, it is not a good excuse to climb over the barrier.
"If we're going to jump the fence and break the rules like that, then we're sending the wrong message to the families and the children," said Dan Dagg, a Clayton resident who visited the zoo on Monday.
The zoo points it is well within the set safety standards. Zoo officials also said while they appreciate the public posting videos, they want visitors to report violations directly to authorities.