Snakes! Word/Reading Choice -- 蛇: へび vs じゃ vs くちなわ


蛇

I'm wondering what the difference in usage between へび, じゃ, and くちなわ is to
reference snakes/serpents. Is one more common than the other? Is one more
casual or more literary? For example, "snake" comes up in casual conversation
more often than the word "serpent"; can the same be said for へび, じゃ, or くちなわ?




If you just see the kanji 蛇, you would normally read it as へび. That's the
basic word for 'snake'. You can forget about the word くちなわ for the most part;
it's an old word for snake (said to come from their resemblance to a rotten
rope), but へび is the usual word today. Likewise, if you want to talk about
snakes in conversation, just say へび.

There are other readings, but they're not usually used as independent words.
The _on_ readings じゃ and だ appear when this character is used as part of
compound words:

  * 蛇口{じゃぐち} 'faucet'
  * 蛇足{だそく} 'superfluous/unnecessary [thing]'
  * 蛇行{だこう} 'meandering; wandering' 
  * 長蛇{ちょうだ}の列{れつ} 'long line' (or 'long queue' in BrE)

But if you just see 蛇 by itself, you wouldn't normally read it じゃ or だ. You
may run into these as independent words from time to time, as in 夏目漱石's
[虞美人草](https://www.aozora.gr.jp/cards/000148/files/761_14485.html), but this
is an unusual stylistic choice, and I would usually expect there to be
furigana in cases like these.

One exception might be in set phrases or proverbs:

  * [蛇{じゃ}の道{みち}は蛇{へび}](http://kotowaza-allguide.com/si/jyanomichiwahebi.html) (or 蛇の道は蛇が知{し}る)  
'Set a thief to catch a thief'  
(lit. 'The track of a snake can only be recognized by another snake')

But I don't think these exceptions will be especially common.

You should also be aware of 大蛇, which can be read two ways. It can be read
だいじゃ 'great serpent' as a regular word, but especially in fiction or
mythology, it often represents おろち; please see
[ヤマタノオロチ](https://en.wikipedia.org/wiki/Yamata_no_Orochi) on Wikipedia for
more information.




If you just see the kanji 蛇, you would normally read it as へび. That's the
basic word for 'snake'. You can forget about the word くちなわ for the most part;
it's an old word for snake (said to come from their resemblance to a rotten
rope), but へび is the usual word today. Likewise, if you want to talk about
snakes in conversation, just say へび.

There are other readings, but they're not usually used as independent words.
The _on_ readings じゃ and だ appear when this character is used as part of
compound words:

  * 蛇口{じゃぐち} 'faucet'
  * 蛇足{だそく} 'superfluous/unnecessary [thing]'
  * 蛇行{だこう} 'meandering; wandering' 
  * 長蛇{ちょうだ}の列{れつ} 'long line' (or 'long queue' in BrE)

But if you just see 蛇 by itself, you wouldn't normally read it じゃ or だ. You
may run into these as independent words from time to time, as in 夏目漱石's
[虞美人草](https://www.aozora.gr.jp/cards/000148/files/761_14485.html), but this
is an unusual stylistic choice, and I would usually expect there to be
furigana in cases like these.

One exception might be in set phrases or proverbs:

  * [蛇{じゃ}の道{みち}は蛇{へび}](http://kotowaza-allguide.com/si/jyanomichiwahebi.html) (or 蛇の道は蛇が知{し}る)  
'Set a thief to catch a thief'  
(lit. 'The track of a snake can only be recognized by another snake')

But I don't think these exceptions will be especially common.

You should also be aware of 大蛇, which can be read two ways. It can be read
だいじゃ 'great serpent' as a regular word, but especially in fiction or
mythology, it often represents おろち; please see
[ヤマタノオロチ](https://en.wikipedia.org/wiki/Yamata_no_Orochi) on Wikipedia for
more information.

