The Story of the Real Canary in the Coal Mine
Used until 1986, the humble canary was an important part of British mining history, By: KAt Eschmer, Smithsonian Magazine, Deember, 2016

The idea of using canaries is credited to John Scott Haldane, known to some as “the father of oxygen therapy.” His research on carbon monoxide led him to recommend using the birds, writes Esther Inglis-Arkell for Gizmodo. He suggested using a sentinel species: an animal more sensitive to the colorless, odorless carbon monoxide and other poisonous gases than humans. If the animal became ill or died, that would give miners a warning to evacuate.

Why was a canary Haldane’s suggested solution? Canaries, like other birds, are good early detectors of carbon monoxide because they’re vulnerable to airborne poisons, Inglis-Arkell writes. Because they need such immense quantities of oxygen to enable them to fly and fly to heights that would make people altitude sick, their anatomy allows them to get a dose of oxygen when they inhale and another when they exhale, by holding air in extra sacs, he writes.

Click here to read this interesting article from The Smithsonian Magazine on some amazing mining histoy.