Study: Predatory dinosaurs had birdlike pulmonary system

What could the fierce dinosaur Tyrannosaurus rex and a modern songbird such as the sparrow possibly have in common? Their pulmonary systems may have been more similar than scientists previously thought, according to new research from Harvard University and Ohio University.

Though some scientists have proposed that predatory dinosaurs had lungs similar to crocodiles and other reptiles, a new study published in this week’s issue of the journal Nature suggests the ancient beasts boasted a much bigger, more complex system of air sacs similar to that in today’s birds. The finding is one of several studies in recent years to paint a new, more avianlike portrait of meat-eaters such as T. rex: The creatures may have had feathers, incubated their eggs, grown quickly, and perhaps even breathed like birds.

“This paper shows that predatory dinosaurs had a pulmonary system with the potential to support elevated rates of metabolism, higher than what we typically associate with ‘cold-blooded’ reptiles,” said co-author Leon P.A.M. Claessens, who received a Ph.D. from Harvard in organismic and evolutionary biology last month and will join the faculty at the College of the Holy Cross in Worcester, Mass., this fall. “The pulmonary system of meat-eating dinosaurs such as T. rex in fact shares many structural similarities with that of modern birds, which, from an engineering point of view, may possess the most efficient respiratory system of any living vertebrate inhabiting the land or sky.”