A 21-year-old man is undergoing a mental evaluation after climbing into the San Francisco Zoo's grizzly bear enclosure while the two bears were on display.
Police describe the man as a transient with a criminal record. He was arrested Saturday after he sneaked into the enclosure shortly before 5 p.m. Pacific time.
A zoo official says the man "froze" and that helped keep the bears calm. He says the bears approached the intruder "very cautiously." They also "sniffed his feet."
Zoo workers then secured the bears in their night den and the man was arrested without incident.
He's being evaluated at a San Francisco hospital. Police say he has a record for making threats and carrying a concealed weapon.