Unidirectional Airflow in the Lungs of Alligators

Abstract

Alligator Breath Birds have a unidirectional system of airflow within their lungs that has been attributed to the peculiarities of flight. However, Farmer and Sanders (p. 338 ) provide evidence that this unidirectional and more or less continuous flow of air also occurs through parts of the alligator lung; in contrast to the tidal, biphasic system in mammals. By analyzing lung and tracheal structures, the similarities of the alligator lungs were compared with those of birds. The data suggest that the unusual properties of bird lungs originated before the divergence of the alligator line from the dinosaur or avian line.