Mining foreman R. Thornburg shows a small cage with a canary used for testing carbon monoxide gas in 1928. George McCaa, U.S. Bureau of Mines Never mind the gas—it was automation that got them in the ...

Canaries, which are popular as pets due to their beautiful singing, have been used as 'coal mine canaries' to detect toxic gases in coal mines, taking advantage of the fact that their barking stops ...