The hippo plural can seem confusing because English has more than one accepted form. If you are writing about several of these large semi-aquatic mammals, you can use hippos, hippopotamuses, or hippopotami, depending on the context.

For standard modern English, hippopotamuses is the safest full plural form. Hippos is a common informal shortening, while hippopotami is a traditional plural that is still accepted. This guide explains when to use each form and gives simple examples to make the choice easy.

What Is the Plural of Hippo?

The plural of hippo is hippos.

“Hippo” is already a shortened form of hippopotamus, so it follows the ordinary English plural pattern by adding -s.

For everyday conversation, hippos is perfectly natural. If you are writing a formal article or explaining the full noun, hippopotamuses is usually the clearest choice.

Hippo vs. Hippopotamus

A hippo is simply the shortened form of hippopotamus. Both refer to the same animal.

The difference is mainly one of style and length:

• Hippo — shorter, casual, and widely used.
• Hippopotamus — the complete noun.
• Hippos — the plural of hippo.
• Hippopotamuses — the regular plural of hippopotamus.
• Hippopotami — an alternative traditional plural.

You might use “hippo” in everyday conversation, while “hippopotamus” may be more appropriate when introducing the animal in formal writing.

Is “Hippos” the Correct Plural?

Yes. Hippos is the standard plural of the shortened noun hippo.

For example:

The hippos spent most of the afternoon in the water.

Because hippo functions as an ordinary English noun, adding -s creates its plural naturally.

There is no need to change “hippo” to “hippi” or another unusual form. The simple plural is hippos.

What Is the Plural of Hippopotamus?

The full noun hippopotamus has two established plural forms:

• hippopotamuses
• hippopotami

Both are used in English. However, hippopotamuses is generally the more familiar choice in modern everyday writing. The supplied reference also identifies it as the more common modern plural.

So if you are unsure which one to use, hippopotamuses is a straightforward choice.

Why Are There Two Plurals of Hippopotamus?

The two forms exist because English has borrowed words from other languages and sometimes retains older plural patterns alongside regular English ones.

Hippopotami follows a classical plural pattern associated with words ending in -us. English also applies its own regular plural system, producing hippopotamuses.

This is not unusual in English. Borrowed words can develop more than one accepted plural as speakers adapt them to ordinary English grammar.

The important point is that you do not need to treat one of these forms as automatically incorrect.

Hippopotamuses vs. Hippopotami

The difference is mainly in form and usage rather than meaning. Both refer to more than one hippopotamus.

For a general audience, hippopotamuses is usually the least confusing full form.

Hippopotami may sound more traditional because of its classical ending, but that does not make it the only correct option.

If you enjoy learning tricky English word forms, [ Syllabuses or Syllabi: 7 Clear Examples] can help you explore another commonly confused plural.

Examples of the Hippo Plural in Sentences

Seeing the forms in context makes the distinction easier.

Using “hippos”

• The hippos gathered near the river.
• We watched several hippos from a safe distance.
• The documentary showed how hippos behave in the wild.

Using “hippopotamuses”

• The wildlife park is home to several hippopotamuses.
• Researchers observed the hippopotamuses near the water.
• The children learned interesting facts about hippopotamuses.

Using “hippopotami”

• Several hippopotami were recorded during the observation.
• The researchers documented a group of hippopotami near the river.

All three forms can be understood correctly, but their style differs.

When Should You Use “Hippos”?

Choose hippos when the tone is casual, conversational, or aimed at a general audience.

It is especially natural in:

• Everyday speech
• Children’s writing
• Informal articles
• Captions
• Conversations
• General-interest content

For example:

We saw two hippos at the zoo.

There is nothing grammatically wrong with this sentence. In fact, “hippos” is often the most natural way to refer to several animals in ordinary conversation.

When Should You Use “Hippopotamuses”?

Use hippopotamuses when you want the complete noun rather than its shortened form.

It works well in:

• Formal writing
• Educational content
• Articles
• Reports
• Explanations
• General informational writing

For example:

The study examined the behaviour of hippopotamuses near freshwater habitats.

If your goal is to use the full and straightforward modern plural, hippopotamuses is a reliable option.

Is “Hippopotami” Wrong?

No. Hippopotami is an accepted plural form of hippopotamus. The existence of the more regular hippopotamuses does not make hippopotami incorrect.

However, the two forms are not equally common in every situation. Modern English commonly uses hippopotamuses, while hippopotami has a more traditional or classical feel.

If you are writing for readers who simply want the most familiar modern form, hippopotamuses is likely to be easier to understand.

Common Mistakes With the Hippo Plural

Several mistakes can happen when people try to pluralize hippo or hippopotamus.

Using “hippi”

“Hippo” does not become hippi in standard English. The correct plural is hippos.

Assuming only “hippopotami” is correct

The classical-looking ending can make hippopotami seem like the only proper answer, but hippopotamuses is also correct.

Assuming “hippopotamuses” is wrong

The regular -es ending is a valid English plural formation, and it is widely used in modern English.

Confusing the shortened and full forms

Remember that hippos is the plural of hippo, while hippopotamuses and hippopotami are plural forms of hippopotamus.

Quick Answer: What Is the Hippo Plural?

If you only need the answer quickly:

The plural of “hippo” is “hippos.”

If you mean the full word hippopotamus, the accepted plurals are hippopotamuses and hippopotami.

For modern general writing, you can remember it this way:

• One hippo
• Two hippos
• One hippopotamus
• Two hippopotamuses
• Hippopotami is also accepted

Frequently Asked Questions

What is the plural of hippo?

The plural of hippo is hippos.

What is the plural of hippopotamus?

The plural can be hippopotamuses or hippopotami. Hippopotamuses is commonly used in modern English.

Is hippos grammatically correct?

Yes. Hippos is the regular plural of the shortened noun hippo.

Is hippopotami correct?

Yes. Hippopotami is an accepted plural of hippopotamus.

Which is more common, hippopotamuses or hippopotami?

Hippopotamuses is generally more common in modern English usage than hippopotami.

Can I use hippos in formal writing?

You can, but hippopotamuses may be preferable when you want the complete, more formal noun.

Conclusion

The hippo plural is simple: hippos. When you use the full word hippopotamus, both hippopotamuses and hippopotami are accepted plural forms.

For most modern writing, hippopotamuses is the clearest full plural, while hippos is natural for everyday use. Hippopotami remains a valid alternative, particularly when a traditional or classical form is appropriate.