Original: A black panther isn't a new animal — it's a very dark leopard or jaguar. They are super rare!
Corrected (singular): A black panther isn't a different animal. It's a very dark leopard or jaguar. It is very rare.
Corrected (plural): Black panthers aren't a different kind of animal. They are very dark leopards or jaguars. They are very rare.
Why these changes?
- "Isn't a new animal" → "isn't a different animal" or "isn't a different kind of animal" is a bit clearer.
- Keep the same number (singular or plural) for the whole idea. If you start with "A black panther" (singular), use "it" and "it is". If you talk about them in general, start with "Black panthers" (plural) and use "they" and "they are."
- "Super rare" is okay for talking with kids, but "very rare" is a standard grammar choice.
Pick the version you like: the singular one talks about one black panther, the plural one talks about black panthers in general. Both are correct.