Penguins Continue Diving Long After Running out of Oxygen

Breathing heavily at the edge of an ice hole, an Antarctic emperor penguin prepares to dive. Taking a last gulp of air, the bird descends and may not emerge again for another 20 minutes. The penguin initially carries sufficient oxygen in three stores — the blood, lungs and myoglobin in muscle — to sustain aerobic metabolism. However, around 5.6 minutes after leaving the surface, lactate begins appearing in the penguin’s blood and the bird crosses the so-called ‘aerobic dive limit’, switching to anaerobic metabolism in some tissues. So what triggers this transition?

An Emperor penguin dives into the water. (Credit: Photo by Glenn Grant, National Science Foundation / U.S. Antarctic Program Photo Library)

Read More>>

Comments are closed.

%d bloggers like this: