It"s World Hippo Day, time to celebrate one of Earth"s heaviest land animals! These African herbivores are scattered across the continent south of the Sahara Desert but, despite their wide range, hippos are listed as a vulnerable species due to habitat loss. While they spend their lives in and around water, hippos aren"t good swimmers and can"t float. They move about in deep water by bouncing off the bottom. Hippos can live up to 40 years in the wild and possess the largest mouth of any land animal in the world, so smiling for the camera comes naturally.