Emma Schachner documented that unidirectional breathing happens in monitor lizards

Emma Schachner and colleagues in Nature, documented for the first time that unidirectional, flow-through breathing previously only known in birds and crocodilians happens in monitor lizards. 

Some quick background: until the early 1970's, no-one was quite sure how birds breathed. Everyone knew that birds breathe, and that the air sacs had something to do with it, and that the bird lungs are set up as a series of tubes instead of a big array of little sacs, like ours, but the airflow patterns had not been worked out.

Then in a series of nifty experiments, Knut Schmidt-Nielsen and his students and colleagues showed that birds have unidirectional airflow through their lungs on both inspiration and expiration. Amazingly, there are no anatomical valves in the lungs or air sacs, and the complex flow patterns are all generated by aerodynamic valving. 

Source: Sauropod Vertebrate Picture of the Week on Tumblr.

Images by Emma Schachner