DescriptionBirdAirsacs.jpg English: Air-sacs of birds Date 1910 Source A history of birds Author William Plane Pycraft, 1868-1942...
DescriptionAirsacs-bird.jpg English: airsacs of a Common Kestrel (Falco tinnunculus) cervical air sac clavicular air sac cranial thoracal air sac caudal...
The primitive bird Archaeopteryx also had airsacs (Bonde and Christiansen, 2000). It is very likely that Deinonychosaurians had airsacs. We don't know...
