Hippopotamus mother and baby, Chobe National Park, Botswana

© jacobeukman/Getty Image

World Hippo Day, a giant celebration. World Hippo Day

It’s time to celebrate one of earth’s heaviest land animals on World Hippo Day! These African herbivores are scattered across the continent below the Sahara Desert, but despite their wide range are listed as a vulnerable species due to a loss of habitat. While they spend their lives in and around water, hippos can’t swim or float. To breathe, they push off the ground underwater, a behavior they can do even while asleep. 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.