Pierre, a venerable 25-year-old, was going bald, which left him with an embarrassingly exposed, pale pink behind.

Unlike marine mammals, which have a layer of blubber to keep them warm, penguins rely on their waterproof feathers.

Without them, Pierre was unwilling to plunge into the academy's penguin tank and ended up shivering on the sidelines while his 19 peers played in the water.

"He was cold, he would shake," senior aquatic biologist at the academy Pam Schaller said.

The biologists were concerned that the other penguins would reject Pierre in his new duds, but they accepted his sleek new look.

Pierre was outfitted with the suit about six weeks ago. Since then he has gained weight, grown back feathers on his hind parts and is again acting like his feisty, alpha-male self.