Dinosaurs' hollow bones may have given them the puff to lead active lifestyles. A fossil find shows that the group of dinosaurs that included Velociraptor and Tyrannosaurus rex probably used the same super-efficient respiratory system that birds have today.
The fossil, which is of a carnivorous dinosaur called Majungatholus atopus, shows that its bones included spaces for storing air. This would have allowed the species to have the quick metabolism necessary for an active predatory lifestyle.
Birds have fast metabolic rates thanks to their efficient way of extracting oxygen from the air. They have two lungs, as mammals do, but the airflow through them is controlled by a complex system of air sacs throughout the body. Most birds have nine such sacs, which also extend through their hollow bones.
Patrick O'Connor, of Ohio University in Athens, and Leon Claessens, of Harvard University in Cambridge, Massachusetts, compared the structure of air sacs in M. atopus's vertebrae to those in more than 200 living birds. The structures were very similar, they report in this week's Nature. ...