Plural of Species
“Species” is invariant in form. One biological species is “a species,” and more than one are “species.” Number is shown by determiners, quantities, context, and agreement rather than by changing the spelling. “Specie” is a different word and is not the biological singular of “species.”
The plural of “species” is “species”: singular and plural have the same spelling.
Key details
Choose the right form
| Meaning / situation | Form / construction | Decision |
|---|---|---|
| one kind / biological category | a species / one species | Singular. |
| more than one | species | Same-form plural. |
Quick tests
Plural-choice test
Are you referring to more than one species?
If yes: Use “species,” with plural context or agreement.
If no: Use “a species” or “one species” for singular.
Caveat: Because the noun is invariant, surrounding grammar carries the number information.
Examples
This species is found only on the island.
Singular is shown by agreement and context.
Several species are threatened.
Plural keeps the same noun form.
The survey identified one new species.
“One” marks singular number.
Further guidance
Core difference
Use “species” for both singular and plural.
Fast Test
Look at determiners, quantities, agreement, and context to determine number.
Usage Boundary
Do not create “specieses” or use “specie” as the ordinary biological singular.
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
- SPECIES | English meaning - Cambridge Dictionary (opens in a new tab)Cambridge University Press · Cambridge records species as both singular and plural.