News about carbon monoxide is generally not very positive. This colourless, odourless gas is usually associated with incomplete combustion, exhaust fumes and tobacco smoke, and it can lead to asphyxiation. And yet there is a great deal of it in the blood of elephant seals!
The recorded levels in the blood of the northern elephant seal are comparable to that of heavy smokers (40 cigarettes a day). Are elephant seals puffing away while sunning on the beach? Of course not. The animals use carbon monoxide to protect their organs, according to a study published in the Journal of Experimental Biology. Elephant seals are predators. At the water’s surface they take a deep breath and then dive to depths of 300 to 800 metres. In order to conserve oxygen during these dives, circulation to less critical organs (kidneys, liver) is cut off. This ischemia is normally damaging to organs, as can be the resumption of the blood flow. Recent research has demonstrated, however, that low levels of carbon monoxide in the blood limit or prevent this damage. The researchers conclude that this is why elephant seals produce considerable levels of carbon monoxide.