It's wintertime and the king penguins at a zoo in northern Japan are putting on weight. But the keepers there have a solution: exercise. Authorities at Asahiyama Zoo are taking the penguins on 500-yard walks on the snowy grounds twice a day, said zoo spokesman Tetsuo Yamazaki. "Just like in humans ... the fat accumulates during the winter months, and the blood-sugar level rises," Yamazaki explained from the zoo, 570 miles northwest of Tokyo. The zoo's 15 king penguins aren't exactly obese. Penguin winter weight varies from 33 pounds to 40 pounds, said zoo official Kazunobu Maru. So far, only...