Have you ever wondered what the plural of hippopotamus is? If so, you’re not alone. This word tends to confuse many English learners and even native speakers. Some people say hippopotamuses, others say hippopotami, and occasionally, you might even hear hippopotamus being used as both singular and plural.

That’s a lot of hippos to keep track of! But don’t worry. In this guide, we’ll explore the plural of hippopotamus step by step. We’ll look at where the word comes from, what forms are correct, which ones are most common, and how to use them in real-life sentences. By the end, you’ll be able to talk about more than one hippopotamus with complete confidence.

Let’s dive in just like a hippo splashing into a river.

What Does the Word Hippopotamus Mean?

Before we talk about plurals, let’s first understand the word itself.

The word hippopotamus comes from Greek. It combines two parts:

• hippos = horse
• potamos = river

So the word hippopotamus literally means “river horse.” It makes sense, doesn’t it? These massive animals spend much of their time in rivers and lakes, and they’re as strong as horses.

In short: a hippopotamus is a large, mostly plant-eating mammal found in Africa, known for spending lots of time in water.

What Is the Plural of Hippopotamus?

Here’s the big question: what’s the correct plural of hippopotamus?

The good news is that there are actually two accepted forms:

1. Hippopotamuses
2. Hippopotami

Both are considered correct, but they’re used in slightly different ways.

• Hippopotamuses is the standard plural in modern English. It follows the usual English rule of adding -es to a word that ends in “-us.”
• Hippopotami comes from Latin-style pluralization, where words ending in “-us” often change to “-i.”

So, if you’re writing a school essay, a report, or just talking with friends, hippopotamuses is the safer, more common choice. But if you want to sound a little more classical or old-fashioned, you can also use hippopotami.

Why Are There Two Plurals?

This is where things get interesting. English is a language that borrows from many others Latin, Greek, French, and more. Because hippopotamus has Greek roots but entered English through Latin, people sometimes apply Latin rules to it.

• In Latin, many words ending in -us change to -i in the plural (like cactus → cacti).
• In English, however, we usually just add -es (like bus → buses).

That’s why both hippopotamuses and hippopotami exist side by side.

Which Plural Should You Use?

If you’re unsure which form to pick, here’s a simple guide:

• Use hippopotamuses in everyday conversation, modern writing, and academic work.
• Use hippopotami if you’re feeling fancy, classical, or playful.

Most dictionaries today list hippopotamuses as the preferred plural, with hippopotami as an alternative.

So, if you’re in doubt, go with hippopotamuses. It’s correct, clear, and widely recognized.

Is Hippopotamus Ever Used as Both Singular and Plural?

Yes, sometimes! Like many animal names, the word hippopotamus can occasionally stay the same in singular and plural form.

For example:

• “The hippopotamus is a dangerous animal.” (singular)
• “The hippopotamus are found near rivers and lakes.” (plural though less common)

This is not the standard plural form, but it does appear in scientific writing or older texts. However, if you’re learning English or want to sound natural, it’s better to stick with hippopotamuses.

Example Sentences with Hippopotamuses

Let’s practice using the word in real sentences. Notice how it works in everyday English.

• “We saw three hippopotamuses resting by the riverbank.”
• “The zoo has two new hippopotamuses in the African exhibit.”
• “Did you know that hippopotamuses are the third-largest land mammals?”
• “In the wild, hippopotamuses spend most of the day in water to stay cool.”

Example Sentences with Hippopotami

Here are examples with the alternative plural, hippopotami:

• “The explorers wrote about herds of hippopotami in their journals.”
• “In old books, you may find the word hippopotami instead of hippopotamuses.”
• “The river was crowded with hippopotami, all peeking their heads above the water.”

Comparing with Other Similar Words

To make things easier, let’s compare hippopotamus with other tricky words ending in -us:

• Octopus → octopuses (common) or octopi (less common)
• Cactus → cactuses (common) or cacti (scientific/Latin)
• Fungus → fungi (scientific) or funguses (less common)
• Syllabus → syllabi or syllabuses

Do you see the pattern? Many words borrowed from Latin or Greek can have two plurals: one that follows English rules (-es) and one that follows classical rules (-i).

Fun Facts About Hippopotamuses

Learning about words is fun, but let’s also enjoy some facts about the animals themselves:

• A group of hippopotamuses is called a bloat or a pod. How funny is that? Imagine saying, “Look at that bloat of hippos!”
• Hippopotamuses can weigh up to 3,000 kilograms (over 6,000 pounds).
• Despite their size, they can run surprisingly fast on land up to 30 km/h (about 19 mph).
• Hippos are considered one of the most dangerous animals in Africa, even though they mainly eat plants.
• The word hippopotamus has been in the English language since the late 14th century.

Common Mistakes to Avoid

When using the plural of hippopotamus, here are a few things to watch out for:

1. Don’t say hippopotamusses (with double “s”). The correct spelling is hippopotamuses.
2. Don’t mix forms, like hippopotami’s for plural. If you need possession, just say:
   • “The hippopotamuses’ habitat is shrinking.”
   • “The hippopotami’s behavior has been studied for centuries.”
3. Don’t assume that hippopotami is the only “correct” form. It’s acceptable, but not the most common.

Simple Definition Recap

• Singular: hippopotamus = one animal
• Plural: hippopotamuses (standard), hippopotami (less common, classical)

Tips for Remembering the Plural

Here are some quick memory tricks:

• If you’re ever unsure, add -es: hippopotamus → hippopotamuses.
• Remember that hippopotami is like cacti: both are Latin-style plurals.
• Think: “When in doubt, use the longer form hippopotamuses.”

Extra: Using Hippo as a Short Form

In everyday speech, people often shorten hippopotamus to hippo. And the plural? Simply add -s:

• One hippo → two hippos

This is very common in casual conversation:

• “The kids loved watching the hippos at the zoo.”
• “We saw a family of hippos playing in the water.”

So, if hippopotamuses feels too long, you can always stick with hippos.

Conclusion

So, what have we learned today? The plural of hippopotamus can be either hippopotamuses or hippopotami. Both are correct, but hippopotamuses is the standard, modern choice that most people use. If you want to keep it short and simple, you can also just say hippos.

Remember:

• Hippopotamus = one
• Hippopotamuses = many (common, modern)
• Hippopotami = many (classical, less common)
• Hippos = everyday, casual

The next time you’re talking about these amazing river horses, you’ll know exactly which word to use. And now, if anyone asks, “What’s the plural of hippopotamus?” you’ll be the expert with a clear, confident answer.

Just be careful if you ever see one in real life they may look friendly, but those hippopotamuses (or hippopotami!) are far from cuddly.