When we think of hippos, we tend to conjure up images of enormous, lazy, lumbering creatures that lounge in rivers. Most people also know that they weigh up to three tons and that they reside in Africa, but there is more to them than just these basics. Here are 15 lesser-known facts about hippos that might just surprise you.

1. They’re not all that nice

As much as we’d hope they’d be friendly giants, they are far from it. Hippos are very aggressive and often times you’ll see deep scars and cuts on their skin from fights with other hippos. Some male hippos have killed off younger ones so they can mate with the mother. If you don’t believe us, just ask Paul Templer — the man who was swallowed whole by a hippo and survived to tell his story.

2. They’re good climbers

No, you won’t find them looking down at you from a tree (they’re too heavy for that), but hippos can definitely climb over fences, rocks, and other hippos. But hey! That’s pretty good considering they weigh more than three tons!

3. They’re incredibly immune to disease

Hippos are immune to many diseases that plague sub-Saharan Africa, which has led them to last longer than other species.

4. They were once called “River Horses”

Hippopotamus comes from the Greek word “hippo” which means “horse,” so there you go (can you hear the voice of the father in ‘My Big Fat Greek Wedding’ here?).

5. There are only two species of hippopotamus

There are 10,000 bird species in the world, 350 breeds of horse, and more than 3,000 snake species scattered across the globe. But hippos? Just two. Only two. The cute pygmy hippo (pictured above) is a dwarf version of its bigger, fatter cousin, the standard hippopotamus.

6. They cannot sweat

They don’t have sweat glands, so they can bask in the sun all day without sweltering. The downside is that prolonged exposure to the sun can cause blistering in their skin (hence why they spend so much time in the water).

7. They are active at night

To avoid the sun ruining their sensitive skin, hippos lounge in the water during the day. But when night falls, they get active on land to scavenge for grass.

8. They’re herbivores

Considering their size, you’d think hippos would eat cheetahs for breakfast. But no, their main diet is grass. However, some people have reported witnessing hippos in cannibalistic acts when they fight over mates or territory.

 9. They live up to 45 years

Yes, humans can outlive hippos, unlike the tortoises of the Galapagos. A good way to tell when a hippo is old is by its teeth. They grow continuously throughout a hippo’s life, so the longer the teeth are, the older the hippo is (as seen above).

10. They’re rapidly declining in population

Okay they’re not falling off cliffs or waterfalls — rather humans are their main downfall, and poaching is a big cause of their decline. Many Africans hunt them for their ivory, hides, and meat. Whether they taste like chicken or not is unclear.

11. They’re closely related to dolphins and whales

Who knew they would be so closely related to dolphins and whales? You’d expect them to be cousins of the rhinoceros or maybe elephant — but no, it’s Flipper.

12. They use echolocation

They can hear underwater and are easily tipped off by any unwanted predators. When they sense danger, they will let out a loud roar and echolocate your socks off!

13. They can go three weeks without eating

What? You mean they’re not hungry hungry hippos? Despite their enormous size, they can go for up to three weeks without eating (and remember they eat only grass).

14. They can be very loud

If you should ever want to go deaf, just spend some time with a pod of hippos. Hippos’ vocal cords are so powerful that they can produce sounds up to 115 decibels (as loud as a Whitesnake concert).

15. They submerge themselves in water to lighten the load

While hippos do spend time in the water to cool off, they also love water because of its buoyancy, which counteracts their enormous bulk. They are also excellent swimmers.

Related content on AFKTravel:

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This article was originally published on October 28, 2014.

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