Pierre, a venerable 25 years old jackass penguin, 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 California Academy of Sciences penguin tank and ended up shivering on the sidelines while his 19 peers played in the water.

Staff at Oceanic Worldwide, a supplier of dive gear based in San Leandro, were enthusiastic about making a real penguin suit for Pierre.

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. With his plumage restored, Pierre is being weaned off the suit, taking more and more dips in the buff.