When the Los Angeles Zoo was building its elaborate six-acre exhibit for Asian elephants, which opened a year ago, it included plenty of features to engage the animals -- waterfalls, mud holes, sandy hills.  On Tuesday,  a visitor decided to offer them one other feature -- herself.  A woman scaled a barrier and clambered through wire fencing  to get to the female elephants, Tina and Jewel.   Neither she nor the elephants were physically harmed.  The unsanctioned visitor reportedly later described herself as suffering from a mental illness.  She was taken to an area hospital for treatment.

A spokesman said the zoo had no plans to increase security.  That seems reasonable in this case.  A zoo visitor has to traverse an obstacle course of fences and ditches to get inside the enclosure for such an up-close and unauthorized meeting with the world's largest land mammals.

Most zoos generally have forbidding barriers of fencing and shrubbery and topography to prevent or, at least discourage, trespassing into exhibits.  But this incident, though rare, was another example of how visitors can be as dangerous as the wild animals they come to the zoo to see.   Even if it's physically possible to get into an enclosure, zoos rely on -- and rightly expect -- people to observe a certain decorum when they're visiting.  For instance, even if you can launch a chicken tender into an animal's exhibit, you shouldn't, because the zoo asks people not to feed the animals.  Nor should visitors scream at, pelt with food or otherwise harass the animals, and there is usually signage around a zoo stating as much.

Zoos spend a lot of time ensuring that animals don't breach the boundaries of their exhibits -- as in the tragic case of the Siberian tiger that bolted her enclosure at the San Francisco Zoo on Christmas Day in 2007, attacking three young men, one of them fatally. Zoo officials built higher walls around the big cat exhibits as a result.   But there were also reports that the young men taunted the tiger before she leaped from her enclosure.   A few months later, at the same zoo, a man was cited by police for misdemeanor animal taunting after he allegedly threw acorns at a rhinoceros.

Ultimately it's a zoo's responsibility to keep people and animals safe from each other -- but the thinking animals should always respect the boundaries of the other animals.

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 --Carla Hall

Photo: Jewel, left, and Tina, before the L.A. Zoo's Beastly Ball fundraiser in June. Credit: Al Seib / Los Angeles Times