Species’ or Species’s – What’s the Difference?

Understanding when to use species’ vs. species’s is a common grammar challenge, but it’s easier to navigate once you grasp the basics. The key difference lies in whether you’re following Chicago or AP style—Chicago prefers species’s for singular possessives and species’ for plural, while AP style simplifies it by using species’ for both.

 So, why does something as simple as an apostrophe cause so much confusion? This small punctuation mark can change the meaning of your writing. 

What’s the Difference?

The difference between species’ and species’s lies in their possessive forms.

• Species’ is the plural possessive form. It refers to something that belongs to multiple species.
• Species’s is the singular possessive form. It refers to something that belongs to one species.

However, the complication arises because some style guides allow species’ for both singular and plural possessives. For example, the AP Stylebook allows species’ for both cases, while the Chicago Manual of Style prefers species’s for singular possessive.

Consider the following examples:

• “The species’ survival depends on conservation efforts.” (Multiple species)
• “The species’s habitat is shrinking due to deforestation.” (One species)

Understanding these distinctions is crucial for clear and professional writing.

Understanding Species’ or Species’s

English grammar rules for possessive forms have changed over time. Traditionally, singular nouns take an apostrophe + s (‘s), while plural nouns ending in s take only an apostrophe. However, some words—like species—don’t change between singular and plural, making possessive forms confusing.

To make things more complicated, style guides differ on the best approach.

• The Chicago Manual of Style (CMOS) suggests using species’s for singular possessive.
• The AP Stylebook suggests species’ for both singular and plural possessive.

This inconsistency means that both forms are grammatically acceptable, but you should follow the style guide that suits your writing context.

What Does Possessive Mean?

A possessive noun shows ownership or association. In English, most singular nouns form possessives by adding ‘s, while plural nouns ending in s take just an apostrophe. However, some irregular nouns, like species, make things tricky.

Singular Possessive – Species’s or Species’?

What Is Singular Possessive?

A singular possessive noun shows that one person, place, or thing owns something.

• Example: “The dog’s leash” means that one dog owns the leash.

For the word species, the singular possessive can be written in two ways, depending on the style guide you follow.

Singular Possessive for Species

Since species does not change in its singular and plural form, its singular possessive can be written as either species’s or species’.

• CMOS (Chicago Manual of Style): Species’s (preferred for singular possessive)
• AP Stylebook: Species’ (used for both singular and plural possessive)

Examples:

• “This species’s habitat is being destroyed by climate change.” (Chicago Style)
• “This species’ habitat is being restored by conservationists.” (AP Style)

Table Singular Possessive Forms

Style Guide	Singular Possessive Form
Chicago Manual of Style (CMOS)	species’s
AP Stylebook	species’

Plural Possessive – Species’

What Is Plural Possessive?

A plural possessive shows that multiple people, places, or things own something.

• Example: “The dogs’ bones” means the bones belong to multiple dogs.

Plural Possessive for Species

When referring to something belonging to multiple species, the correct form is always species’.

Examples:

• “The species’ survival mechanisms vary across ecosystems.”
• “The species’ adaptations help them thrive in different habitats.”

Since species already ends in ‘s’, we simply add an apostrophe to form the plural possessive.

Table Plural Possessive Forms

Style Guide	Plural Possessive Form
Chicago Manual of Style (CMOS)	species’
AP Stylebook	species’

Understanding Species (Plural and Singular)

Species (Plural and Singular) Explained

One reason species’ and species’s confuse people is that species is both singular and plural.

• Singular: “This species is endangered.”
• Plural: “These species are found in tropical forests.”

Because the word doesn’t change between singular and plural, you must determine its meaning from context.

Examples of Species’ (Plural Possessive)

Here are some examples where species’ is used as a plural possessive:

• “The species’ natural habitats are being destroyed.”
• “Scientists study the species’ behavior patterns.”
• “Different species’ instincts help them survive.”
• “The species’ breeding cycles vary by climate.”
• “Conservationists are focused on the species’ protection efforts.”

Examples of Species’s (Singular Possessive) – Less Common

Although species’s is correct in Chicago Style, it is less common in everyday usage. Here are some examples:

• “The species’s unique adaptations allow it to live in cold climates.”
• “A species’s survival depends on its ability to find food.”
• “This species’s natural predators include large cats and birds of prey.”
• “The species’s diet consists mainly of rodents.”
• “This species’s habitat is shrinking due to deforestation.”

Everyday Usage

10 Examples of Species’ in Sentences

1. The species’ characteristics help them adapt to their environment.
2. The species’ instincts vary between predators and prey.
3. The species’ migration routes are changing due to climate change.
4. The species’ reproductive cycles depend on temperature.
5. The species’ survival relies on biodiversity.
6. The species’ natural habitats are under threat.
7. The species’ food sources are declining.
8. The species’ behaviors differ depending on their ecosystem.
9. The species’ natural predators include larger mammals.
10. The species’ conservation efforts require funding.

10 Examples of Species’s in Sentences

1. The species’s habitat is in danger due to pollution.
2. The species’s ability to camouflage helps it escape predators.
3. The species’s diet consists mainly of small mammals.
4. The species’s migration path covers thousands of miles.
5. The species’s survival depends on conservation efforts.
6. The species’s reproduction rate is slow.
7. The species’s role in the ecosystem is crucial.
8. The species’s instincts allow it to hunt effectively.
9. The species’s natural enemies include larger predators.
10. The species’s genetic diversity helps it adapt.

Examples of Using Species’ vs. Species’s,

#	Example Sentence	Correct Form
1	The species’ diet is high in fiber.	species’
2	The species’s behavior changes with the seasons.	species’s
3	The species’ natural habitat is endangered.	species’
4	The species’s migration patterns vary.	species’s
5	The species’ genetic makeup is complex.	species’
6	The species’s survival depends on climate change.	species’s
7	The species’ extinction is imminent.	species’
8	The species’s adaptation to the environment is remarkable.	species’s
9	The species’ mating rituals are fascinating.	species’
10	The species’s diet varies depending on the region.	species’s
11	The species’ population has declined rapidly.	species’
12	The species’s unique traits help it survive harsh conditions.	species’s
13	The species’ behavior is studied by researchers.	species’
14	The species’s reproduction rate is low.	species’s
15	The species’ migration route is crucial for survival.	species’
16	The species’s offspring are protected by the adults.	species’s
17	The species’ numbers have increased due to conservation efforts.	species’
18	The species’s territorial behavior is linked to survival.	species’s
19	The species’ role in the ecosystem is vital.	species’
20	The species’s interaction with humans has been controversial.	species’s
21	The species’ survival is at risk due to deforestation.	species’
22	The species’s migration path is long and treacherous.	species’s
23	The species’ territorial disputes are common.	species’
24	The species’s feeding habits are still being researched.	species’s
25	The species’ predators are increasingly scarce.	species’
26	The species’s behavior during mating season is interesting.	species’s
27	The species’ populations are scattered across continents.	species’
28	The species’s conservation status is critical.	species’s
29	The species’ ecosystem contributes to global biodiversity.	species’
30	The species’s habitat destruction is a serious concern.	species’s

Tips for Remembering

It can be tricky to remember when to use species’ or species’s, but with a few simple memory tricks, you can master their usage.

1. Think About the Number of Species

• If you’re talking about one species, use species’s (Chicago Manual of Style) or species’ (AP Style).
• If you’re talking about multiple species, always use species’.

Example

• One species: “The species’s diet is primarily herbivorous.” (Chicago) / “The species’ diet is primarily herbivorous.” (AP)
• Multiple species: “The species’ diets vary depending on their habitats.”

2. Remember That AP Style is Simpler

If you follow the AP Stylebook, things are easier because you use species’ for both singular and plural possessives. This avoids the need for an extra “s” after the apostrophe.

• One species: “The species’ migration pattern is studied by scientists.”
• Multiple species: “The species’ behaviors are influenced by climate change.”

3. Use Context Clues

Since species remains the same in singular and plural, look at the rest of the sentence for context.

• If the verb is singular (is, has, feeds), it’s referring to one species.
• If the verb is plural (are, have, feed), it’s referring to multiple species.

Example

• One species: “The species’ natural predator is the hawk.” (singular verb: “is”)
• Multiple species: “The species’ natural predators are diverse.” (plural verb: “are”)

4. Check the Style Guide Requirements

If you’re writing for academia, publishing, or journalism, follow the preferred style guide:

• Chicago Manual of Style → Use species’s for singular possessive and species’ for plural possessive.
• AP Stylebook → Use species’ for both singular and plural possessives.

By keeping these rules in mind, you’ll avoid confusion and use the correct possessive form with confidence.

Common Mistakes and How to Avoid Them

Even experienced writers make mistakes when using species’ and species’s. Here are some common errors and how to fix them:

Mistake #1 Using an Apostrophe for a Plural Species

❌ “Many specie’s are facing extinction.” (Incorrect)
✅ “Many species are facing extinction.” (Correct)

Mistake #2 Using the Wrong Possessive Form

❌ “The species’s migration routes change with the seasons.” (Incorrect in AP Style)
✅ “The species’ migration routes change with the seasons.” (Correct in AP Style)
✅ “The species’s migration routes change with the seasons.” (Correct in Chicago Style)

Mistake #3 Misidentifying Singular vs. Plural

❌ “This species are difficult to track.” (Incorrect—species is singular here)
✅ “This species is difficult to track.” (Correct)

Deep Dive: Why Do Different Style Guides Disagree?

The difference between species’ and species’s comes from historical changes in English grammar rules. Traditionally, singular possessives always took an apostrophe + s (‘s), while plural possessives only took an apostrophe (‘).

However, since species already ends in “s”, some grammarians argued that adding another “s” after the apostrophe looked awkward. This led to two different schools of thought:

• The Chicago Manual of Style kept the traditional rule: species’s for singular possessive and species’ for plural possessive.
• The AP Stylebook opted for simplicity, making species’ the standard possessive form for both singular and plural.

Neither approach is more correct than the other—it all depends on which style guide you follow.

Final Thoughts

Mastering the difference between species’ and species’s may seem tricky at first, but by keeping a few simple rules in mind, you can confidently use the correct form. Whether you’re following the Chicago Manual of Style, which differentiates between singular and plural possessives, or the AP Stylebook, which simplifies things by using species’ for both, understanding the context is key.

Pay attention to whether you’re discussing one species or many, and use context clues like verb agreement to help guide your choice. With practice, these rules will become second nature, making your writing more polished and precise.

 FAQs

1. Is species’ or species’s correct?

Both are correct, depending on the style guide:

• Species’s is the singular possessive form in Chicago Style.
• Species’ is used for plural possessive in both Chicago and AP Style.
• AP Style allows species’ for singular possessive as well.

2. Can I use species’ for both singular and plural possessives?

Yes, but only if you’re following the AP Stylebook, which recommends species’ for both cases.

3. Why does the word species stay the same in singular and plural?

The word species is an irregular noun that doesn’t change between singular and plural. It follows a pattern similar to deer, sheep, and fish.

4. How do I know if species is singular or plural in a sentence?

Check the verb that follows:

• If the verb is singular (is, has, depends), then species is singular.
• If the verb is plural (are, have, depend), then species is plural.

Example:

• Singular: “This species is endangered.”
• Plural: “These species are endangered.”