Dragons & Dinosaurs

To make matters worse, Apatosaurus lost its head. Honestly. Because the original skeleton was found without a head, no one was sure what Apatosaurus's skull looked like. For nearly 100 years, models and drawings in museums all over the world showed it with no head, or the wrong head. Finally, the skull was located in a museum basement, and Apatosaurus could once again hold its head up proudly.

Or maybe not. Recent evidence indicates that Apatosaurus and other dinosaurs with long, elegant necks may not have been able to lift their heads far off the ground. For many years, experts believed that these vegetarian dinosaurs reached their necks into the treetops to dine, like giraffes. Recently, however, computer modeling has revealed that the positioning of their neck bones would have prevented them from raising their heads any higher than about 12 feet. While it may have been able to rear up on its hind legs to snag treetop treats, more often Apatosaurus probably reached its long neck across creeks or other obstacles as it grazed for food along the ground.

Listening to the Bones

Computers have become a valuable tool to help paleontologists picture dinosaurs better. Scientists can now even hear what dinosaurs might have sounded like. Consider Parasaurolophus, an oddlooking fellow. A large, bony crest extended from the top of its head back over its shoulders. Handsome, perhaps, but what did the crest do? Some scientists think it may have been a weapon or even a snorkel, but no evidence supports these ideas. How about a trombone? When a nearly complete Parasaurolophus skull was found in New Mexico, computer scientists and paleontologists joined forces to see if the head crest might actually have been a noisemaker. They took scans of the inside of the crest with special imaging equipment so that they wouldn't have to break it open. Then they used the scans to model a three-dimensional image of the crest. They found that it was filled with a complicated series of hollow tubes and chambers. When the computer created the sounds made by blowing air through the crest, the scientists heard an eerie, deep rumbling tone. Were the scientists hearing a sound not made on earth for 65 million years.

Who can know?

Snorkel? Weapon? Noisemaker? Parasaurolophuss curious crest has scientists guessing.

* To hear a dino roar, go to http://museums.state.nm .us/nmmnh/p3_staff_res_ sounds.html.

* To see computer images of dinos in motion, go to http://nationalgeographic .com/dinorama/sauro/html or http://palaeo.gly.bris.ac.uk /dinosaur/animation, html.