Are ミツバチ and イルカ more frequently written in katakana?

Question

I was looking through a list of words that normally are written in kana, instead of their kanji. Two caught my attention because the list has them written in katakana, instead of hiragana. But, as neither are 外来語, writing them in katakana seems strange.

When given no context, is it true that both "honey bee" and "dolphin" are written in katakana (instead of hiragana)?

(Note: I do not care about any theory as to "why" they are exceptions. Simply, when there is no context and they are just words in a list, should both be written in katakana?)

Here is the full list of animals written in kana, instead of kanji:

あかんぼう　baby, infant
イルカ　　　dolphin
うさぎ　　　a rabbit
かたつむり　snail
きつね　　　a fox
くらげ　　　a jellyfish
とら　　　　tiger
とんぼ　　　dragon fly
ばら　　　　rose
ミツバチ　　honey bee
やまあらし　porcupine
やもめ　　　a widow
りす　　　　a squirrel

Answer 1

When given no context, is it true that both "honey bee" and "dolphin" are written in katakana (instead of hiragana)?

Yes, but using hiragana is perfectly acceptable.

Names of species is one area where katakana is very often used, but there seem to be no rule to tell which is more widely used to write a specific name. In the examples you mentioned above, ウサギ，カタツムリ， etc. are equally common, and I can't really say which (katakana vs. hiragana) is more common. I feel イルカ is more often seen than いるか, but I wouldn't find it odd if I see いるか without context. (There are contexts where one is probably preferred over the other, but I think this is out of topic for this question).

The common custom to write names of species (plants, animals, insects..) seems to have derived from the convention of academic fields.

Several informations that might interest you:

• Japanese wikipedia encourages to use katakana in titles of articles of species.
• 現代日本語書き言葉における非外来語のカタカナ表記事情 (pdf) (Frequency of Katakana Representation for Japanese Non-loan Words as Observed in the BCCWJ Corpus), found under the National Institute for Japanese Language and Linguistics , deals with similar question. While neither みつばち nor イルカ is observed in the article, it mentions the plant/animal names as a more-likely-to-be-written-in-katakana words.
• The Balanced Corpus of Contemporary Written Japanese may be good for individual research.

Answer 2

I wholeheartedly agree with @Ian's answer. There's absolutely no reason why "honey bee" should have been written in katakana, and "snail" not. In fact, in the BCCWJ mentioned in @Yosh's answer, writing "snail" in katakana is more popular by roughly the same margin:

みつばち 70 results
ミツバチ 212 results

かたつむり 77 results
カタツムリ 194 results

("dolphin" is hard to get numbers for, because いるか appears so often as part of ～ているか, which might be a reason to choose katakana in this case. This argument doesn't hold for みつばち, though!)

But that's not the only thing that's wrong with that list. The "baby, infant" entry is rarely written in kana, but practically always in kanji:

赤ん坊 1252 results
あかんぼう 17 results

Another misleading entry:

寡婦 304 results
やもめ 61 results

So, the list you're looking at is

• inconsistent in its choice of kana syllabary,
• provides misleading information of what words really are written more frequently in kana, and
• includes obscure words, like "porcupine", at the expense of more obvious choices, like "candle":

ろうそく 296 results
ロウソク 158 results
ローソク 158 results
蝋燭 48 results

Anyway, all in all, I think you need a better list.

Answer 3

I'm in the translation industry and in my experience if given a list such as yours with no context there is no particular reason those words need to be written in katakana. The English is also inconsistent. Some words are arbitrarily preceded with "a". I think the katakana usage here is the same thing.

I hope this helps

Answer 4

Both words you mentioned have Kanji.

海豚｛いるか} - dolphin

蜜蜂{みつばち} - honey bee

Most biological terms are written in Katakana in everyday language (places like aquariums and TV spots). However it is also not uncommon to see them written as Kanji in biological or science texts.

Other examples include...

-海豹{あざらし} (アザラシ) >[Earless Seal]

-海驢{あしか} (アシカ) >[Eared Seal]

-膃肭臍{おっとせい} (オットセイ) >[Fur Seal]

-蜻蛉{とんぼ} (トンボ) >[Dragonfly]

-水黽{あめんぼ} (アメンボ) >[Water Strider]

EDIT: The list you provide I have usually seen as the following.

赤ん坊(a baby is an animal?)、イルカ、うさぎ・ウサギ、蝸牛、狐、くらげ・クラゲ、トラ、トンボ、バラ、ミツバチ、山荒、寡婦（a widow is an animal?）、リス

Depending on where you are usually depends on how they are written. A children's science/biology centre will usually feature all names in ひらがな as some 小学生 aged children have not yet learned カタカナ. However family aquariums and zoos usually feature the 漢字 and カタカナ readings ie. 北極熊{ホッキョクグマ}.

Without knowing more about your list and the person who wrote it, it is somewhat difficult to know why they chose to put all except 2 items as hiragana. The choice whether to use ひらがな or カタカナ (or even Kanji) readings when referring to various animals is largely a stylistic choice by the author as both ひらがな and カタカナ can be read and understood interchangeably in this context. To cover all your bases (aand make it easier to search for), you could always have a third column in your database for カタカナ readings (instead of just ひらかな).

Some sources:

http://en.wiktionary.org/wiki/%E6%B5%B7%E8%B1%9A http://detail.chiebukuro.yahoo.co.jp/qa/question_detail/q1319142318