Why are canaries being used in the coal mine to detect toxic gases leakage? Why not other animals like cats, mice or other birds?

Guddy22

they used canaries, because canaries tend to sing a lot and therefore not only give a visible cue (when the gases kill them) but also an audible cue Nov 29 09, 3:27 AM

looney_tunes

More importantly, canaries are extremely sensitive to the presence of toxic gases such as those found in coal mines, and will die before the level becomes dangerous for humans, providing advance warning of the danger form undetectable (to human senses) gases. http://en.wikipedia.org/wiki/Animal_sentinels Nov 29 09, 3:44 AM

crotalus77

Interestingly, modern day H2S monitors tend to be yellow in honor of their feathered predecessors. http://www.canarysense.com/index.php?page=hydrogen_sulfide_h2s_gas_detector Nov 29 09, 8:55 AM

Baloo55th

H2S is rarely dangerous in mines, and is fairly easy to detect with your own nose - the danger toxic is CO. However, in most mines, methane and CO2 are more of a hazard. CO2 is not toxic as such, but too large a proportion of it in the air can cause suffocation. Canaries would keel over well before humans, and thus would be used for detecting black damp (atmosphere consisting of CO2 and nitrogen with less than the safe proportion of O2). They would also keel over for CO. However, they would not detect a near explosive proportion of fire damp (methane) in the air. The modern safety lamp can detect all the problems. Black damp puts the flame down at first, then out. (Time to beat a swift retreat...) If the flame is brighter than usual, this indicates fire damp. The methane passes through the gauze of the lamp and burns, but the flame will not pass out through the gauze. (Also time for a very swift retreat, but without making any sparks or switching anything electric on or off.) http://www.therhondda.co.uk/gases/mine_gases.html I say most mines in connection with fire damp. Some, like those in the Forest of Dean, have no methane. They used to light large fires down in the mines there to bring a draught of fresh air through, and in the olden days carried a candle in something like a tobacco pipe to see their way. You wouldn't dare do that in most places. (Source: going down Hopewell Pit.) Nov 29 09, 11:19 AM

Baloo55th

Missed out: Why canaries? Birds in general have a need for a higher oxygen component in the air they breathe. Even if they are just sat in a cage they are still built to take in high levels of O2. Hence, they pass out before we do. http://en.wikipedia.org/wiki/Bird_anatomy Canaries were being bred in quantity from the 1600s on. As guddy22 says, they sing a lot. This would serve two functions: an audible warning (or rather, a silent warning...), and companionship for the miners down in their dark holes. Ever been down a mine with no lights on? I have. That's real dark. http://en.wikipedia.org/wiki/Domestic_Canary Nov 29 09, 11:30 AM