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Until as recently as 1987, British coal pits employed caged canaries as sentinels that alerted miners to the presence of poisonous gases. Being more sensitive to them than we are, the birds would get distressed before the gases reached levels that are dangerous to humans, giving the miners time to evacuate and avoid suffocation.
According to new research, the sense of smell is the canary in the coalmine of human health. A study published today in the open access journal PLOS ONE, shows that losing one’s sense of smell strongly predicts death within five years, suggesting that the nose knows when death is imminent, and that smell may serve as a bellwether for the overall state of the body, or as a marker for exposure to environmental toxins.