Featured Research

from universities, journals, and other organizations

Dinosaurs Were Airheads, CT Scans Reveal

Date:
December 9, 2008
Source:
Ohio University
Summary:
Paleontologists have long known that dinosaurs had tiny brains, but they had no idea the beasts were such airheads. Scientists suggest that newly discovered large air spaces helped lighten the load of the head, making it about 18 percent lighter than it would have been without all the air. That savings in weight could have allowed the predators to put on more bone-crushing muscle or even to take larger prey.

Compared to brainy humans, dinosaurs were airheads. The head of Tyrannosaurus rex was filled with sinuses that lightened the head while enhancing its strength.
Credit: Art by Lawrence Witmer/Ryan Ridgely

Paleontologists have long known that dinosaurs had tiny brains, but they had no idea the beasts were such airheads.

A new study by Ohio University researchers Lawrence Witmer and Ryan Ridgely found that dinosaurs had more air cavities in their heads than expected. By using CT scans, the scientists were able to develop 3-D images of the dinosaur skulls that show a clearer picture of the physiology of the airways.

“I’ve been looking at sinuses for a long time, and indeed people would kid me about studying nothing—looking at the empty spaces in the skull. But what’s emerged is that these air spaces have certain properties and functions,” said Witmer, Chang Professor of Paleontology in Ohio University’s College of Osteopathic Medicine.

Witmer and Ridgely examined skulls from two predators, Tyrannosaurus rex and Majungasaurus, and two ankylosaurian dinosaurs, Panoplosaurus and Euoplocephalus, both plant eaters with armored bodies and short snouts. For comparison, the scientists also studied scans of crocodiles and ostriches, which are modern day relatives of dinosaurs, as well as humans.

The analysis of the predatory dinosaurs revealed large olfactory areas, an arching airway that went from the nostrils to the throat, and many sinuses—the same cavities that give us sinus headaches. Overall, the amount of air space was much greater than the brain cavity.

The CT scans also allowed Witmer and Ridgely to calculate the volume of the bone, air space, muscle and other soft tissues to make an accurate estimate of how much these heads weighed when the animals were alive. A fully fleshed-out T. rex head, for example, weighed more than 1,100 pounds.

“That’s more than the combined weight of the whole starting lineup of the Cleveland Cavaliers,” Witmer said.

Witmer suggests that the air spaces helped lighten the load of the head, making it about 18 percent lighter than it would have been without all the air. That savings in weight could have allowed the predators to put on more bone-crushing muscle or even to take larger prey.

These sinus cavities also may have played a biomechanical role by making the bones hollow, similar to the hollow beams used in construction — both are incredibly strong but don’t weigh as much their solid counterparts. A light but strong skull enabled these predators to move their heads more quickly and helped them hold their large heads up on cantilevered necks, explained Witmer, who published the findings in a recent issue of The Anatomical Record.

Though most researchers have assumed that the nasal passages in armored dinosaurs would mimic the simple airways of the predators, Witmer and Ridgely found that these spaces actually were convoluted and complex. The passages were twisted and corkscrewed in the beasts’ snouts and didn’t funnel directly to the lungs or air pockets.

“Not only do these guys have nasal cavities like crazy straws, they also have highly vascular snouts. The nasal passages run right next to large blood vessels, and so there’s the potential for heat transfer. As the animal breathes in, the air passed over the moist surfaces and cooled the blood, and the blood simultaneously warmed the inspired air,” said Witmer, whose research is funded by the National Science Foundation. “These are the same kinds of physiological mechanisms we find all the time in warm-blooded animals today.”

These twisty nasal passages also acted as resonating chambers that affected how the ankylosaurs vocalized. The complex airways would have been somewhat different in each animal and might have given the dinosaurs subtle differences in their voices.

“It’s possible that these armored dinosaurs could recognize individuals based on the voice,” said Witmer, who noted that his research team’s studies of the inner ear revealed a hearing organ that probably had the capability to discriminate these subtle vocal nuances.

Though Witmer found few similarities between the dinosaur and human sinuses—our brain cavities take up much more space relative to our sinuses— the scientist did find a resemblance between the air spaces of the crocodiles and ostriches and the ancient beasts under study.

“Extra air space turns out to be a family characteristic,” he said, “but the sinuses may be performing different roles in different species. Scientists have tended to focus on things such as bones and muscle, and ignored these air spaces. If we’re going to decipher the mysteries of these extinct animals, maybe we need to figure out just why it is that these guys were such airheads.”


Story Source:

The above story is based on materials provided by Ohio University. Note: Materials may be edited for content and length.


Cite This Page:

Ohio University. "Dinosaurs Were Airheads, CT Scans Reveal." ScienceDaily. ScienceDaily, 9 December 2008. <www.sciencedaily.com/releases/2008/12/081208114300.htm>.
Ohio University. (2008, December 9). Dinosaurs Were Airheads, CT Scans Reveal. ScienceDaily. Retrieved September 17, 2014 from www.sciencedaily.com/releases/2008/12/081208114300.htm
Ohio University. "Dinosaurs Were Airheads, CT Scans Reveal." ScienceDaily. www.sciencedaily.com/releases/2008/12/081208114300.htm (accessed September 17, 2014).

Share This



More Fossils & Ruins News

Wednesday, September 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Researchers Explore Shipwrecks Off Calif. Coast

Researchers Explore Shipwrecks Off Calif. Coast

AP (Sep. 16, 2014) — Federal researchers are exploring more than a dozen underwater sites where they believe ships sank in the treacherous waters west of San Francisco in the decades following the Gold Rush. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Museum Traces Fragments of Star-Spangled Banner

Museum Traces Fragments of Star-Spangled Banner

AP (Sep. 12, 2014) — As the Star-Spangled Banner celebrates its bicentennial, Smithsonian curators are still uncovering fragments of the original flag that inspired Francis Scott Key's poem. (Sept. 12) Video provided by AP
Powered by NewsLook.com
Spinosaurus Could Be First Semi-Aquatic Dinosaur

Spinosaurus Could Be First Semi-Aquatic Dinosaur

Newsy (Sep. 11, 2014) — New research has shown that the Spinosaurus, the largest carnivorous dinosaur, might have been just as well suited for life in the water as on land. Video provided by Newsy
Powered by NewsLook.com
Meet Spinosaurus, the First-Known Water Dinosaur

Meet Spinosaurus, the First-Known Water Dinosaur

AFP (Sep. 11, 2014) — Spinosaurus aegyptiacus was adapted for both land and water, and an exhibit featuring a life-sized model, based on new fossils unearthed in eastern Morocco, opens at the National Geographic Museum in Washington on Friday. Duration: 01:02 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

      Technology News



      Save/Print:
      Share:  

      Free Subscriptions


      Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

      Get Social & Mobile


      Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

      Have Feedback?


      Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
      Mobile iPhone Android Web
      Follow Facebook Twitter Google+
      Subscribe RSS Feeds Email Newsletters
      Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins