Birds and crocodiles are part of the spectacularly diverse group
of animals called the Archosauria, or archosaurs if you’re on
casual terms with them. Other (extinct) archosaurs include the
dinosaurs (non-avian), pterosaurs, and sundry wondrous other
beasts like aetosaurs and phytosaurs. Archosaurs have, and
presumably their common ancestor had, many specialized features
of their anatomy that are related to metabolism and locomotion.
That’s a big reason why, as a scientist, I love them. Yet the
bird lineage evolved its own extreme specializations, whereas in
some (but not all!) ways crocodilians stayed closer to the
ancestral state. Here is a great example of one of the major
categories of differences between living crocs and birds: the
proportions of the respiratory system, from freezer specimens
I’ve CT scanned with my former PhD student Vivian Allen, which
were part of a paper we published in Anatomical Record back in
2009. We scanned the thawed specimens with and without the lungs
inflated (croc results n