Lizard Has One-Way Breathing Hints at How Dinosaurs Breathed

Air flows only one way through its lungs—other than the American alligator, it’s the only other known reptile found to have this trait.

That’s surprising, because the unidirectional airflow of birds was thought to have evolved due to the high-oxygen demands of flight: Instead of being partially filled with stale, depleted air like human lungs, avian lungs contain air with a much higher average oxygen content and are much more efficient at getting oxygen to the blood.

So this method of breathing was generally considered to be unique to both warm-blooded animals and birds.

That changed in 2010, when Colleen Farmer of the University of Utah and colleagues found that alligators breathe one way.

Now, Emma Schachner, a postdoctoral researcher in Farmer’s lab, has added another species to that list.

“Finding this trait in a [cold-blooded] lizard means that warm-bloodedness and unidirectional airflow have no relationship whatsoever,” Schachner said.

As I Live and Breathe

When humans or other mammals breathe, the air flows through the same lung passages during both an inhale and an exhale. As we inhale, the air flows in through our nose and mouth and down through the windpipe, where it splits and flows into a bronchi, or passageway, that leads to each lung.

The airways divide and divide again, each time getting smaller and smaller. Eventually, the air makes it to tiny alveolar sacs, where oxygen travels from the air into the bloodstream.

courtesy: NGC

Tags: Ngc, Lizard