San Francisco ? A few penguins swimming leisurely at the San Francisco Zoo is nothing new. But dozens of them doing laps in unison for hours has zookeepers perplexed.

“We’ve lost complete control,” said Jane Tollini, the zoo’s penguin keeper. “It’s a free-for-all in here. After 18 years of doing this job, these birds are making mincemeat of me.”

It all started in November when six newcomer Magellannic penguins, formerly of Sea World in Aurora, Ohio, were brought in.

Since then the penguin pool at the San Francisco Zoo has been a daily frenzy of circle swimming by all of the 52 birds.

The penguins start swimming in circles early in the day and rarely stop until they stagger out of the pool at dusk.

Some penguin experts point to the highly social animals as being open to new ideas fostered by newcomers to the zoo’s so-called Penguin Island.

“Penguins are extraordinarily social birds,” said Christina Slager, associate curator at Monterey Bay Aquarium. “And they’re very, very inquisitive. If you combine those facts and put in a new stimulus, like the six new penguins, they have to check it out.”

The 52 penguins at the San Francisco Zoo have taken to doing laps in unison for hours, perplexing zookeepers. But penguin experts say the animals are just being social.