Hi,i want to ask something stupid.does crocodilian has porous bones and kinda hollow like bird does?i just wondering since they are both an archosaus,although i presume crocs have solid and heavy bone like most of aquatic animals isn't it?thanks

Hi Evan!

You are correct that crocodilian and birds are both archosaurs, but having hollowing bones is not what defines the group. Archosaurs are defined by having teeth set in sockets (even if birds eventually lost their teeth), certain holes in the skull and jawbones, and a specific ridge on the femur bone. Hollow bones first evolved in Theropoda, the group of meat-eating dinosuars including animals like Tyrannosaurs rex and Velociraptor. Birds are also theropods, and the hollow bones certainly helped them be light enough to evolve the ability to fly. Fortunately crocodiles can't fly, because that would be terrifying.

Last edited by Ryan Haupt (15th Feb 2016 22:40:54)