Breathing in Birds and Crocodiles: What’s Different, What’s the Same, and Why Does It Matter?

At first glance, crocodiles and birds appear to be two very different groups of animals. Crocodiles tend to inhabit marshes and wetlands, while most birds tend to nest on dry land or in trees. Not only do they look very different, but while crocodiles walk on all fours and are excellent swimmers, most birds fly. Interestingly, researchers have found remarkable similarities in the way crocodiles and birds breathe! Different from how humans breathe, both birds and crocodiles have one-way air flow through their airways, meaning that air moves in a circular path into the lungs and back out. This article compares the structures of the respiratory systems in birds and crocodiles. We also examine how their respiratory systems are specialized for their unique environments and activities.