Alligator Lungs

A new understanding of how alligators breathe informs what we think about dinosaur physiology. It has been know for some time now that birds have a unique unidirectional method of breathing. They inhale through their mouths or nostrils like us, but what happens next is different. Our lungs expand and contract with a single opening the way a balloon inflates or deflates. Birds lungs once they take in air move it through unidirectional tubes. There is no reversing of air flow.

It has been assumed that birds developed this trait in response to the aerobic demands of flying. The recent study of alligator lungs indicates that the trait probably appeared in an earlier ancestor from which both birds and alligators evolved. That indicates that dinosaurs likely had unidirectional lungs, since it is thought they also developed from the same predecessor as birds and alligators. Lungs are soft tissue, so they are not well preserved in the fossil record. Scientists would not previously had evidence about unidirectional lungs for dinosaurs.

Click here to read original abstract about alligator lungs.