Elephant seals and heavy smokers might have more in common that anyone ever would have suspected. According to a new study published in the Journal of Experimental Biology, the massive marine mammals contain surprisingly high levels of carbon monoxide in their blood -- similar to the amount that humans who smoke two packs of cigarettes per day have in their blood. Although carbon monoxide is commonly known as a "silent killer" (because the odorless, colorless gas is fatal in high enough blood concentrations), researchers found that for elephant seals, high levels of carbon monoxide could be a good thing.
"Elephant seals will shut off blood to specific organs and tissues as they are diving," the study's lead researcher, Michael Tift, told Live Science. "Recently, we found that low levels of carbon monoxide can be therapeutic in treating certain conditions where blood has been shut off to muscles." Tift and his colleagues suspect that elephant seals, who are incredible and frequent divers, might rely on carbon monoxide to prevent injuries from reperfusion, when blood and oxygen return to muscles after periods of deprivation.