How do I say "cat"? And do I use kanji, hiragana, katakana or rōmaji?

Question

猫, ねこ, ネコ, neko

Which of these means "cat"? Is it all of them? Which situation do I use each of these in?

Answer 1

Firstly, r­ōmaji is not used to write Japanese. (The only Latin letters you find in Japanese text are abbreviations, like CD, OL, TPP, etc.)

Now, the question reduces to whether all of 猫, ねこ and ネコ can be used to say "cat". And the answer is "yes!".

Especially for plants and animals, it's often not so easy to decide which is the most natural choice in a given context (and the choice varies from person to person).

But in the case of "cat", the kanji 猫 has been a jōyō kanji since 1981, and is by a large margin the most common way of writing "cat" (data from the Balanced Corpus of Contemporary Written Japanese, via http://nlb.ninjal.ac.jp)

猫　     6171 results (82%)
ネコ     1340 results (18%)
ねこ       54 results  (1%)

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For more info about the difference between kanji, katakana & hiragana for plants or animals see the following questions:

• How to know when I should use katakana form words referring to animals, lesser creatures, or other organisms?
• Why are katakana preferred over hiragana or kanji sometimes?
• Are ミツバチ and イルカ more frequently written in katakana?
• Why are the names of plants and animals often written in katakana?
• Octopus kanji: 章魚 vs 蛸 vs 鮹
• Writing キリン vs 麒麟 (Giraffe vs Qilin)

Answer 2

1. カタカナ is most commonly used to write words from a foreign language.
2. And, there is no strict rule to determine whether to write in 漢字 or in ひらがな.

These are the most important rules.

However, names of animals and plants are a little bit special. In the context of natural science, katakana is used to write them. This is because it is easier to distinguish names of species from the other parts of sentences. http://ikimonotuusin.com/doc/289.htm

So,

ネコ: in academic context. When you want to mention the species.

猫 or ねこ: in more general context. There is not much difference between 漢字 and ひらがな. ひらがな is softer.

Well, they are not that strict.