According to information from the Antarctica government, the Emperor penguin is capable of a 22-minute underwater stay, up to a depth of 984 feet. The length of a typical stay is three to six minutes.
Live Science reports that penguins have special probes that monitor oxygen levels when diving on a single breath of air. In 2011, a study was published in the "Journal of Experimental Biology" concerning the other ways in which penguins manage oxygen levels while diving. In one method, penguins allow the muscles to function on their own and divert oxygen to the brain and heart. Alternatively, to avoid fatigue and prolong dive time, their bodies periodically deliver oxygen to the muscles.