Hadrosaurs

These herbivores are also known as "duckbills," because of their toothless, ducklike bills. Hundreds of self-sharpening teeth arranged in rows lined the sides of the jaws. Hadrosaurs were bipedal. They held their bodies horizontally with their stiffened tails extended for balance. There are two main groups of hadrosaurs: hadrosaurines, with flat-topped skulls, and lambeo-saurines, with hollow Bony rods head crests. along spine<

Section of tightly packed hadrosaur teeth

Cross-section of hadrosaur jaw

Section of tightly packed hadrosaur teeth

Cross-section of hadrosaur jaw

Upper teeth slid outward

Lower teeth did not

Upper teeth slid outward

Lower teeth did not

Chewing action move

Hadrosaurs chewed food by grating the upper jaw teeth against the lower jaw teeth. The upper jaw was hinged so that when the jaws closed, the upper jaw would slide outward against the lower jaw.

Gryposaurus Skeleton

• The name hadrosaur means "bulky lizard."

• They ranged in length from 10 ft (3 m) to 49 ft (15 m).

• They are known as the duck-billed dinosaurs because of their long, flat snouts.

This Gryposaurus skeleton was found in Alberta, Canada.

Gryposaurus Like many hadrosaurs, Gryposaurus had a trellis of bony rods that stiffened the spine and tail. The deep tail would have been useful when swimming, and shows that hadrosaurs sometimes went into water. But they probably did this only when escaping from enemies.

Hadrosaurs
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