From River Giants to Pygmy Fighters: 10 Must-Know Hippo Facts

Is anything cuter than a baby hippo? Fans of Thailand’s Khoa Kheow Open Zoo don’t think so. The zoo recently held a four-day festival dedicated to their most famous resident: a pygmy hippo named Moo Deng. The festivities celebrated Moo’s first birthday, welcoming more than 12,000 visitors on opening day alone. In honor of the little one’s birthday, the zoo sponsored fund raising events like memorabilia auctions. Moo Deng, the adorable social media star, has helped raise awareness for hippo conservation while bringing joy to the masses.

The hippopotamus is a semiaquatic mammal. It is native to sub-Saharan Africa and is one of the largest land mammals in the world, weighing between 2,200 and 9,900 pounds. This mammal inhabits lakes, rivers, and mangrove swamps. The hippopotamus, alongside the pygmy hippopotamus (a small hippopotamid native to West Africa), is an extant species in the Hippopotamidae family.

Hippos are considered one of the most dangerous animal species in the world. They are unpredictable and may become highly aggressive if someone trespasses into their habitat. Since spotting a hippopotamus is difficult and dangerous, we’re here to tell you some incredible facts about them that will make you feel like you’ve seen one in real life!

This post was updated on July 15, 2025 to include information on Thailand’s Moo Deng.

1. The Hippopotamus is Related to Cetaceans

Scientists have found that hippopotamuses are the closest living terrestrial relatives to cetaceans. Whales, porpoises, and dolphins are members of the suborder Cetacea. It is believed that they had a common ancestor around 55 million years ago.

2. The Hippopotamus Has an Enormous Head

At first glance, you might not notice how big the head of a hippopotamus is. But what if we told you that it makes up around one-third of the hippopotamus’s body weight? Each of its tusks weighs up to approximately 6.6 pounds. Even more, the animal can open its mouth to 150 degrees.

3. The Hippopotamus Spends Most of Its Life Underwater

The hippopotamus does not sweat. You might be wondering how this is related to living underwater, right? Here’s the connection: because it cannot sweat, the hippopotamus’s skin quickly becomes dry above the water. The body secretes an oily substance that keeps the skin moisturized, prevents sunburn, and has anti-bacterial properties.

Sometimes this substance is called “blood sweat” because it makes the hippo look reddish, as if it’s covered in blood. But, as already mentioned, it’s neither sweat nor blood. This substance becomes red-orange a few minutes after secretion and, in the end, has a brown color. Despite this incredible plus, the hippopotamus still spends around 16 hours a day underwater.

4. Hippos Can Neither Swim Nor Breathe Underwater

Although they spend most of their lives underwater, hippos do not swim in the traditional sense; instead, they move through water by pushing off the bottom and walking or bounding along riverbeds. They have developed an automatic system that allows them to raise their heads above the water to breathe. Hippos surface above the water every four to five minutes to take a breath. They can do this even while sleeping, thanks to this automatic reflex. Young hippos can only hold their breath underwater for up to five minutes, so they resurface every four to five minutes.

5. The Hippopotamus is One of the Deadliest Animals in the World

Around 500 people die every year in Africa because of hippopotamus attacks. They are very aggressive and unpredictable, so people are advised to take great care if they somehow end up in an area close to hippos.

In 2014, twelve children and one adult were killed by a hippopotamus while crossing the Niger River on a boat. The hippo flipped the boat and killed everyone. Crushing a human being is a piece of cake for its sharp teeth.

A study conducted at Arche Hospital in Burundi presents 11 cases of hippo bites that appeared over one year at the emergency department. While none of the patients died, most of them became permanently disabled. The study shows that a hippo bite should be treated as a major trauma because it’s highly life-threatening.

6. Hippos Eat More Than 60 Pounds of Food a Night

Due to their vast size, hippos consume a lot of food. In fact, they can consume up to 60 pounds of food in one night. After 16 hours underwater, they get out and start looking for food. They spend the remaining hours on land grazing.

7. Hippos Also Have Predators

While hippos are considered one of the most dangerous animal species on Earth, there are still some animals that can kill them. Animals such as Nile crocodiles, lions, and spotted hyenas can occasionally prey on young or weak hippos.

8. Hippos Don’t Develop Social Bonds

The hippopotamus is not a social animal and does not develop social bonds. An exception is the relationship between mothers and their young. Male hippos are highly territorial in water, aggressively defending stretches of river or lake, while females and young are less territorial.

9. The Oldest Hippo in the World Lived 65 Years

The hippopotamus has an average lifespan of 40 to 50 years. However, two known hippos in the world lived much beyond that number. The first one is Donna the hippo, who lived at the Mesker Park Zoo in Evansville, Indiana, United States. She died in 2012 when she was 61 years old.

The other oldest hippo lived in Manila Zoo, the Philippines, and was called Bertha. Bertha had been living in the zoo since 1959, when it opened its doors, and died in 2017 when she was around 65 years old.

10. The Hippopotamus Has a Great Significance in the Worldwide Culture

If you do some research, you’ll find that hippos are an essential cultural reference worldwide. For example, Egyptian mythology portrays the god Set as having the form of a red hippopotamus while fighting Horus. The hippopotamus is also a central theme in African folktales. Even though it hasn’t been as popular in Europe because it’s not a common animal on the continent, there’s still an iconic oil painting signed by Peter Paul Rubens called “The Hippopotamus and Crocodile Hunt.”

T. S. Eliot wrote a famous poem in which the hippopotamus plays a pivotal role. It’s entitled “The Hippopotamus” and is a comparison between a hippopotamus and the Catholic Church.

Hippos have essential roles in movies, too:

• The ballerina hippo in the Disney film “Fantasia.”

• The movie “Hugo the Hippo” follows Hugo’s journey as he escapes from Zanzibar.

• Gloria’s character in the “Madagascar” movie is a hippo.

The post From River Giants to Pygmy Fighters: 10 Must-Know Hippo Facts appeared first on A-Z Animals.