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The pulmonary air sac systems of dinosaurs and birds exhibit striking similarities. Download this image.
April 30, 2010

Pulmonary air-sac systems of dinosaurs and birds exhibit striking similarities

The pulmonary air-sac systems of dinosaurs and birds exhibit striking similarities, including predicted regions air of sac integration into the skeleton. The air sacs act like bellows to move air through the rigid lungs.

Theories about animals' relatedness were first proposed in the late 19th century but soon fell out of favor. Evidence gathered over the past 30 years, however, has breathed new life into the hypothesis.

The work of two National Science Foundation-supported researchers makes clear the unique pulmonary system of birds, which has fixed lungs and air sacs that penetrate the skeleton, has an older history than previously realized. It also dispels the theory that predatory dinosaurs had lungs similar to living reptiles, like crocodiles.

This image accompanied NSF press release, "Study Documents Bird-like Breathing Systems in Long-extinct Dinosaurs."

Credit: Nicolle Rager Fuller, National Science Foundation


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