Looking inside owls To get a glimpse of the owl's blood vessels when their necks were turning, the duo injected dye into the blood vessels of a dozen dead owls and used a CT scan to visualize the shimmering fluid spreading throughout the birds' arteries like blood, said Fabian de Kok-Mercado, who performed the work while getting a master's in medical illustration at Johns Hopkins. (He is now an illustrator at the Howard Hughes Medical Institute in Chevy Chase, Md.) The researchers then twisted the dead owls' heads to see what happened. [Video: Watch the owls' necks twist.]
After creating the CT scan images, the researchers injected a plastic-like substance into the veins of dead snowy, barred and great horned owls and dissected the animals, drawing the routes and locations of the vessels.
They found a number of previously undiscovered and unique traits, de Kok-Mercado told OurAmazingPlanet. For one, the owls' neck bones, or vertebrae, contain holes that are much larger than those found in other birds or humans. In humans, the hole in the vertebra is about the same size as the artery, but in owls the hole is about 10 times larger than the artery, according to the study, published today (Jan. 31) in the journal Science. These holes, or canals, likely hold air sacks meant to cushion the twisting motion of the head, de Kok-Mercado said.