By Romana Annette 05/05/2009
The penguin exhibit worked
fine for years at the Woodland Park Zoo in

One clever group of penguins
escaped from the New York City Zoo for a night on the town. It was decided to ship them back to
Antarctica, but they commandeered a freighter and ended up on the

Zoo officials suddenly
realized that they would have to redo the penguin exhibit to make sure that no
penguins could casually roam

The front part of the new exhibit has walls that no penguin can climb. The rear of the enclosure is more of a problem, so it was decided to protect it with an electric fence.

It first, it was believed that 10,000 volts would be enough, since this amount was enough to stop a Tyrannosaurus Rex. However, through trial and error, it was learned that only 15,000 volts would persuade penguins to turn back.