I've found that expression on a website, and I don't understand it.

At first I thought it was because the canary is yellow and the coal black... but it doesn't make much sense.

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    General Reference. I doubt they're still used in earnest anywhere today, but note that modern metaphorical usages will usually be intended to call attention to the fact that it's a sacrificial canary - if it actually does what it's there to do, it'll probably die on the job. Commented Feb 4, 2013 at 18:38
  • Putin was once asked if he could imagine his life without being a president, to which he replied that's it's actually quite a frequent question and "...it's like a canary in a coal mine, so to say. If a person is able to go back to live in a regular apartment instead of enjoying palace interiors, then I think that he didn't lose connection with the 'external world'." At least that's how they translated it. In fact, if directly translated from Russian, he said "it's like a litmus paper test", so I don't really know if these two expressions are interchangeable. (p.s. I'm not Putin's fan)
    – Arman
    Commented Sep 21, 2016 at 20:08

3 Answers 3


A canary in a coal mine is an advanced warning of some danger. The metaphor originates from the times when miners used to carry caged canaries while at work; if there was any methane or carbon monoxide in the mine, the canary would die before the levels of the gas reached those hazardous to humans.

See here.

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    I heard it was because the canary would sing desperately when gas reached dangerous levels, but perhaps my upbringing was more sheltered than yours. Commented Feb 4, 2013 at 15:56
  • @TimLymington I never heard that about the frantic singing; not in conjunction with carbon monoxide that is. But some birds start singing (to alert others) when they detect danger in the form of predators.
    – Mr Lister
    Commented Feb 4, 2013 at 16:30
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    @TimLymington Thanks for making it better, I shall now advocate the sheltered version... :)
    – varun
    Commented Dec 29, 2018 at 10:41

Miners used canaries to detect carbon monoxide and other gases in the mines. As long as the canaries continued to sing, the miners were safe. If the canary died, they'd evacuate the miners. I didn't see a reference included in your posting so lacking the context of the quote, I'd go out on a limb to say that what is meant is either literally a reference to that practice of gas detection or it is some sort of metaphor for some sort of early warning system as in the example below.

An example of how this expression can be used metaphorically, from wisegeek.com:

"Today, the practice of using a bird to test the air supply has become part of coal mining lore, but the ideology behind it has become a popular expression. The phrase "living like a canary in a coal mine" often refers to serving as a warning to others. The actual canary had little control over its fate, but it continued to sing anyway. In one sense, living this way indicates a willingness to experience life's dangers without compromise."


In case where a person is described as a canary in a coal mine, it usually means that they are being unwittingly used in some experiment. Like the first person to try to walk across a rickety rope bridge, or across a mine field. This is the same situation as what are called advance parties or scouts. The difference is that scouts are trained, equipped and aware of the risks. The 'canary' has no training, is not equipped, has no choice and may not realise that the task they are attempting is extremely high risk. You may want to compare this to 'cannon fodder'.


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