A polar bear, its fur stained with algae, stands in its cage at Higashiyama Zoo in Nagoya, central Japan, Saturday, Sept. 6, 2008. Three polar bears at the zoo changed their colors in July after swimming in a pond with an overgrowth of algae, prompting many questions from visitors concerned about whether the animals are sick or carrying mold, a zoo official said. (AP Photo/Kyodo News, Shuzo Shikano) ** JAPAN OUT, MANDATORY CREDIT, FOR COMMERCIAL USE ONLY IN NORTH AMERICA **