During the dog days of last summer, when the New York City tabloids needed a breather from O.J. Simpson, Newsday discovered Gus the Neurotic Bear. He wasn’t too hard to find. A 700-pound polar bear, he lives in the Central Park Zoo, sharing a large slate-gray quarry of rock, both real and fake, with Lily and Ida. The females do what you might expect of bears in sticky 97-degree heat: roll on their backs to scratch fleas, pee in the stream, sit and watch the passing crowd in the windows of their habitat. But, in a deep pool, Gus swims short laps like a bear possessed. He surfaces with a neck like a giant fur buoy and falls into a back stroke to the other side, pauses, and dives back along the bottom with bubbles trailing by his whiskers. He repeats the same motions for hours on end, down to the way his tongue flicks across his back lips.