Length: 33 ft. Weight: 3-4 tons Period: Cretaceous

The giant tyrannosaur stalked closer and closer.  Ready for the attack, she crept up quietly on the grazing duckbill, totally unsuspected.  Then, a bugling cry sounded the alarm!  The startled duckbill fled her hungry jaws, all thanks to the alarm cry of a watchful Parasaurolophus.

Parasaurolophus Physique
Characteristics of the Crest
The Hadrosaurs
How Do We Know That? 
Mesozoic Timeline

Parasaurolophus lived 65 million to 76 million years ago, at the end of the Cretaceous period.  One of the duck-billed dinosaurs, Parasaurolophus roamed North America.

Parasaurolophus Physique   
Parasaurolophus could stand on its long hind legs, but it leaned down on its shorter forearms to graze.  It lived on a diet of pine needles, leaves and twigs.  This rough vegetation was snapped up in the dinosaur’s toothless beak and then ground up by its many rows of cheek teeth. 

This dinosaur often grew to be 33 feet long (10 meters) and 16 feet tall (5 meters).  Parasaurolophus reached weights of 3 to 4 tons (2.7 to 3.6 tonnes).  A thick, pointy tail provided balance when Parasaurolophus ran.
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Characteristics of the Crest   
Parasaurolophus had a long, hollow, bony crest on its head.  Bigger than the rest of the skull, the crest sloped backward from Parasaurolophus’ forehead.  The crest could be 6 feet long (1.82 meters).  The dinosaur’s nostrils extended through the crest in tubes that may have been used to make foghorn-like sounds.  Parasaurolophus may also have had an advanced sense of smell.
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The Hadrosaurs   
Parasaurolophus belonged to a family of dinosaurs called hadrosaurs.  Large herds of hadrosaurs were once so plentiful that scientists now refer to these dinosaurs as the “cows of the Cretaceous.”  Because of their most common characteristic, a beak similar to that of a modern duck, hadrosaurs are also known as duck-billed dinosaurs.  Hadrosaurs’ bills were generally toothless, but these plant-eating dinosaurs did have hundreds of cheek teeth to grind up their food. 

Hadrosaurs were large dinosaurs, usually from 13 to 49 feet (4 to 14.9 meters) in length.  They walked on all fours but could run on two legs, using a stiff tail for balance.  Variations in skull shape divide the hadrosaurs into two main subgroups.  The hadrosaurines had flat skulls with bumps of solid bone on the snouts.  The lambeosaurines (including Parasaurolophus) had skulls with long, hollow bony crests.
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How Do We Know That?   
Parasaurolophus skulls discovered in Canada, the United States, and Mexico have led scientists to believe that the dinosaur’s gender was indicated by crest shape.  A medium-length, curved crest indicated an adult female Parasaurolophus.  Adult males had long, curved crests.  Parasaurolophus juveniles had short, straight crests.
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Mesozoic Timeline

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