Friedman recalls several instances where his office was called to deal with deer that crossed the Golden Gate Bridge and were running through the Presidio. Any manner of large snakes have been corralled in recent years by Animal Control officers and -- this one is fantastic -- a congregation of albino rabbits a group of stoners out by Candlestick Park assumed were hallucinations turned out to be quite real. Astoundingly, the stoners managed to call Animal Control.
San Francisco, incidentally, is more restrictive of what sort of animals you are allowed to house as pets than neighboring cities (Police Code Section 486 clearly states that it "shall be unlawful to feed or offer food to any Red Masked Parakeet in any park of the City and County of San Francisco." You've been warned!).
Boa constrictors, and other exotic reptiles legal in the East Bay, are not permitted here. Rabbits and chicks can be sold as pets in San Mateo -- but not here (this is to stave off Easter novelty animals being abandoned in city parks).
If you're feeding rabbits and chicks to your boa in San Francisco -- you're busted. If you're feeding the snake monkeys -- you're a dead man.