Featured Creature: Hippopotamus

Photo by Cassandre Crawford

Which creature is a land animal closely related to marine mammals, has a portable pharmacy, and recently celebrated a holiday?


Photo by Cassandre Crawford

River Horse

Hippos are often described as large water pigs or cows, due to their appearance and water-loving nature. But their namesake, hippopotamus, comes from the Ancient Greek term for ‘river horse.’ Despite all these links to land mammals, their closest living relatives are ocean dwellers – specifically, cetaceans (such as whales and dolphins). We have made a few mistakes while attempting to categorize hippos, but these misnomers can serve as a lesson: creatures are more than what meets the eye.

Photo from Facts Just for Kids

CVS who?

Hippopotamuses have fragile skin. If they spend too much time out in the sun, their skin cracks and becomes vulnerable to infection. For a creature that lives in hot sub-saharan Africa, the sun is a real problem – but one that they’re ready for.

Hippos create and sweat out an oily red liquid, that can appear like blood, to prevent their skin from getting dry. This liquid also acts as a sunblock, and is believed to have antibiotic properties. A moisturizer, sunscreen, and medicine all in one – these creatures have an entire built-in pharmacy!

Photo from Fine Art America

Land Cetacean

To remain cool throughout the day, hippos spend most of their time in water bodies. Since their eyes, nose, and ears are on the top of their head, they can easily submerge the rest of their body while keeping these body parts dry. Their submerged jaws can sense vibrations in the water, so they are able to stay updated on current events above and below the water’s surface all at once. 

Hippos can hold their breath for about five minutes. When they go underwater, their nostrils and ears fold shut to prevent water from getting into their bodies. Coming up to breathe is instinctual.  Even hippos sleeping underwater will rise for a breath without waking up. They spend so much time in the water, and yet they never actually swim.

Hippo legs are made of extremely dense bones, and that bone material prevents them from floating. Since they can’t float, hippos don’t swim – they sink. Thanks to their large size, this isn’t a huge deal since a grown hippopotamus can comfortably stand in a river or lake while peeping at the water’s surface. To move around, hippos push off from the riverbed and glide until they sink again, then push off again if needed. At night, they move away from the river and forage for grass on land. 

Photo from TreeHugger


Hippopotamuses were once found throughout more than half of the African continent. Unfortunately, due to habitat loss and poaching, the remaining hippo populations only live in protected areas in East African countries. To help hippos, you can support organizations like The Turgwe Hippo Trust as they protect and rehabilitate hippo habitat. 

Helping hippos benefits other creatures, too. Hippo bodies create microhabitats for small organisms. By walking along river beds, hippos promote the cycling of nutrients and, as a result, maintain a healthy habitat for fish. 

If you didn’t get a chance to celebrate World Hippo Day on February 15th, you can share this Featured Creature and celebrate now!

By Tania Roa