Why are pygmy hippos so small? And 6 other pygmy hippo facts

A baby pygmy hippo at a Thailand zoo has become an internet sensation, thanks to a social media-savvy zookeeper and a 24-hour livestream. Unlike baby Moo Deng (whose name was selected by fans and roughly translates to "meatball"), wild pygmy hippos are camera shy, living a reclusive and nocturnal life in swampy forests in West Africa.

Like pygmy hippos, many species require healthy forests and freshwater to thrive. WWF works to prevent deforestation and protect rivers globally.

Read on to learn more about these endangered animals.

Where do pygmy hippos live?

Related to the common river hippo found in East Africa, the pygmy hippo is found only in West Africa. Most live in Liberia, with smaller populations in Sierra Leone, Guinea, and Côte d'Ivoire.

How many pygmy hippos are there?

Fewer than 2,500 individuals are thought to exist in the wild. The species has been greatly impacted by deforestation from logging, mining, and agricultural expansion, and from poaching. As a result, their numbers continue to decrease, unfortunately.

Why are pygmy hippos so hard to see in the wild?

Besides there being so few of them, pygmy hippos live a solitary, secretive life along rivers and in swamps. They don't vocalize much, and they're only active at night. Because of that, scientists haven't been able to observe them much in the wild; most research is done at zoos, like the one where Moo Deng was born in July 2024.

What do they eat?

Pygmy hippos have four stomach chambers and spend a lot of time filling them—at least six hours a day, according to footage recorded on camera traps. They are herbivores, feeding on grasses, roots, stems and leaves of young trees, fruits, and other vegetation.

Why are they so small?

"Small" is a relative term—adult pygmy hippos weigh around 550 pounds, the same as domestic pigs and male lions. If you compare them to a standard-size hippo, however, they are about one-tenth the size. Interestingly, research in the past decade theorizes that pygmy hippos and hippos are most closely related to whales and dolphins—way bigger beasts!

Can they run fast?

Despite stubby legs and bulky bodies, pygmy hippos can move it—18 mph on average, which is comparable to humans and lizards. Their East African cousins are of course faster, clocking speeds of up to 30 mph.

Why are pygmy hippos so shiny?

You'd think that gloss comes from wallowing in water all day. Nope. All over their skin, pygmy hippos have tiny mucus glands that excrete a pink goo, keeping them hydrated and protected from the sun. Their skin is actually greenish-black, but the mucus gives them a rosy glow.

Learn more about WWF's work on wildlife conservation.