The world's largest, the emperor penguin,are having difficulty finding food and their homes are polluted and destroyed. Emperor penguins are birds but are considered marine animals because they live most of their lives in the water. The population of emperor penguins has decreased by 50% since 1950 because of habitat loss and pollution. Scientists point out that global warming and increasing shipping activities in Antarctica are directly responsible for the habitat loss and pollution. They are now included in the list of endangered animals.