‘Canary in a Coal Mine’: Definition, Meaning, and Examples

By Carly Forsaith, updated on September 22, 2022

If you've heard the phrase 'canary in a coal mine,' you might be confused about the meaning. What is a canary doing in a coal mine, anyway?

In today's article, we will explain the idiom's meaning, give you some example sentences on how to use it, and dive into a bit of history to understand where it comes from.

But first, let us summarize the meaning of 'canary in a coal mine.' The expression refers to something or someone who is an early indicator of impending danger. You can use it to describe a thing that is warning you of what's to come.

What is the Meaning of 'Canary in a Coal Mine'?

Idioms are a very useful part of language as they allow you to express yourself creatively. Often they use metaphors, so they can add a new dimension to the idea you are sharing by giving your listeners or readers an image to complement the words.

'Canary in a coal mine' is an idiom used to describe a person or thing that acts as a warning that trouble is on the way.

For example, in movies, when you see animals fleeing, they are the canary in a coal mine, and the only characters who don't flee along with the animals are the ones who specifically want to face the danger.

To understand the idiom further, see below for examples in a sentence.

Examples of 'Canary in a Coal Mine' in a Sentence

  • Melting icebergs are canaries in a coal mine for climate change.
  • The protest is a canary in a coal mine for the direction society's going in if nothing changes.
  • We have received numerous complaints about this lately - it may be the canary in a coal mine we were waiting for.
  • Smoke is very much the canary in a coal mine for a volcano.
  • Like canaries in a coal mine, the decline of the bee population is a predictor of the planet's health.
  • The documentary was a little shocking, but I think these types of media should be taken as canaries in a coal mine.
  • Like the warnings of canaries in a coal mine, the dog's barking woke me up in the middle of the night.

History of the Idiom

You might be wondering how this somewhat odd expression came about. Let's explore a little history.

In the early 1900s, after a deadly explosion in a coal mine, engineer John Scott Haldane came up with the idea that miners could take canaries down to the mines with them. Canaries are highly sensitive to carbon monoxide and other toxic gases, and as such, they would die before humans if the levels in the air were high.

In short, canaries were used as warning signs for the danger of toxic air, which explains why the idiom is used nowadays to warn of impending danger.

To Conclude

You should hopefully feel clearer on the meaning of the idiom now and somewhat more confident in your use of the idiom, too. Now, why not see if you can use it in a sentence yourself? Want to learn more about idioms and sayings? Then check out our new list of idioms and popular sayings to learn more.

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Written By:
Carly Forsaith
Carly Forsaith is one of the lead freelance writers for WritingTips.org. Carly is a copywriter who has been writing about the English language for over 3 years. Before that, she was a teacher in Thailand, helping people learn English as a second language. She is a total grammar nerd and spends her time spotting language errors on signs and on the internet.

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