I began to wonder if hippos and horses are related due to the word “hippology” which can be broken down into its Greek and Latin origins to mean “the study of the horse”. So if “hippo” means horse, then where did the hippopotamus come from?
Well, as it turns out, their name means “river horse”. I get that they seem like the laziest animal lounging around in water all day letting birds pick their teeth but they look nothing like a horse. In fact, they are not even related to the equid family. Hippos are related to whales and dolphins. At least there is a water connection there.
The horse’s closest family relatives, however, are rhinos and tapirs. Really? Talk about dysfunctional family gatherings! It would include grumpy rhinos, timid tapirs and know-it-all horses. The link that holds them all together is their toes and eating habits. Horses, rhinos and tapirs belong to the odd-toed ungulate group and they either browse (eat trees and bushes) or graze (eat grass). On the mammal family tree equids, rhinos and tapirs are in the Perissodactyla order together.
If you look at the tapir as an evolutionary link to the horse, the connection is easier to believe. A tapir sort of looks like a rhino who has lost all his cool rhino stuff. He does not have the armor and the impalement gear on the face. In fact, I wonder if tapirs are related at all to Gonzo from The Muppets? The tapir also resembles the horse’s oldest relative, the Eohippus.
The small-as-a-fox Eohippus made its entrance into the world about 50 million years ago. He went from being a forest dwelling, five-toed little critter to the horse we know and love today. Not all at once though. There were many other forms of modern horse-like equids in between. It would be easy to see that maybe, with the rhino horns, a unicorn came out of this family line. Right?
So the next time you are out with your horse and he huffs and snorts, think about their relative the rhino because they make those sounds too!