Heads

Crests, frills, horns, and spikes adorned the heads of many dinosaurs. These decorations helped dinosaurs identify one another and were sometimes used for signaling. In a competition for territory, or control of a herd, the dinosaur with the most spectacular head might well have been the winner. Horned herbivores may have used their weapon for defense against hungry carnivores.
BIRD BEAK
Gallimimus ate plants, insects, and lizards with its long, toothless beak. Itslarge-eyed skull looks very much like that of a big bird.
HEAD CREST
Oviraptors may have used their head crest to signal to one another. Although toothless, their beaked jawsmay have been powerful enough to crush shellfish. HORNS AND FRILLS The ceratopsian group of dinosaurs had heads with a variety of frills and horns. These plant eaters probably used such decorations to frighten off attackers or to attract a mate.
STRONG SKULL
The massive head of Albertosaurus was built for strength. It could withstand the shock as Albertosaurus crashed, open-mouthed, into its prey. Huge jaws carried the deadly sharp teeth, and spaces in the skull left room for bulging muscles.
NOISY CRESTS
Corythosaurus carried a plate of bone high on its head which formed a crest. Males and females probably had different-sized crests for recognizing each other. The crests also had tubes inside them with which Corythosaurus was able to make sounds.