If you were to step into a time machine and head back to the age of the dinosaurs, you might find it a little hard to catch your breath. Back then, the Earth’s atmosphere contained much less oxygen than it does today. So how did dinosaurs manage to lead such active lives?
Researchers at Manchester University think they have the answer: dinosaurs had highly efficient bird-like lungs that enabled them to thrive in the harsh conditions.
Crocodilians share a common ancestor with dinosaurs, and birds are dinosaurs’ modern-day descendants. It was thought that some dinosaurs would have smooth reptilian-like lungs while others would have more complicated bird-like lungs. To test this, the team used CT scans to look at the lung cavities of four species of modern crocodilians and 29 bird species, and compared their structure with 16 different dinosaur species.
They found that all of the dinosaurs had bird-like lungs, as well as having vertebrae and skeletal structures that were more similar in shape to birds than reptiles.
“If even the very first dinosaurs to evolve had bird-like lungs, this would go some way to explaining why dinosaurs became the dominant animal species of their time,” said Prof Bill Sellers, who took part in the study. “Other animal groups simply may not have had lungs as well suited to extracting oxygen from the air. That simple evolutionary difference may have let dinosaurs rule.”