Penguins have lowest blood oxygen levels ever recorded

A new study suggests that emperor penguins may have a supercharged form of a blood protein that allows them to dive underwater for more than 20 minutes on a single breath.

The research showed that penguins in Antarctica return from long fishing excursions under the sea ice with the lowest blood oxygen levels ever recorded in wild animals.

With such depleted reserves, experts say, other creatures would black out and suffer tissue damage.

The finding suggests that emperors—the largest of all penguin species—may have a hyped-up version of hemoglobin, the blood protein that carries oxygen from the lungs to the body.