Page 30 - Dinosaur (DK Eyewitness Books)

Horns and head crests 7+5((ʜ+251(' )$&(
Two brow horns 3½ ft (1 m) long and a short
nose horn earned Triceratops its name, which
means “three-horned face.” Males probably
flaunted horns at one another threateningly
TȩȦ ȴȬȶȭȭȴ Ȱȧ ȮȢȯȺ ȥȪȯȰȴȢȶȳȴ had bumps, horns, or head and sometimes had actual clashes. The bony
shield at the back of the head saved their
crests. The dinosaurs probably used these either for display—to necks from injury. Fossil skulls show
signs of bone that regrew
scare a rival or impress a mate—or to act as signals that helped after damage.
other dinosaurs to spot fellow members of their species from a
distance. Head crests
that were made of thin,
fragile bone would have
been used only for display. Long brow horn
But skulls with sturdy bumps
and horns could have served as
weapons of attack or defense. Thickened
skulls seemed to have been made for butting
heads with rivals, and long horns for jabbing, or
shoving, if the horns of two rivals were to interlock. But
perhaps the most effective use of bumps, crests, and horns
was to frighten off enemies or predators.

Small nose
$ 7+,&. 126( horn
Instead of the sharp nose horn of most large
plant-eating ceratopsians, Pachyrhinosaurus
(“thick-nosed lizard”) grew a bony lump
that was broad and flattish. The lump
developed as a thick mass of spongy
outgrowth from bones that roofed the
nose. The lumps in some individuals
dipped in the middle, while those in
others bulged. Perhaps males grew
one kind and females the other.
Rival males very likely met
bump to bump and pushed
until the weaker male gave
way. Like other ceratopsians,
Pachyrhinosaurus lived in the
western part of North America
late in the Cretaceous Period.

Helmet-shaped
skull roof

Narrow beak

7+,&.ʜ+($'(' READY TO FIGHT
Pachycephalosaurs (“thick-headed lizards”) Every fall, rival male deer size each
such as Stegoceras had immensely thick other up, parading their antlers in an
skull roofs. These might have functioned openly threatening posture. If two stags
as crash helmets to protect the brains when seem evenly matched, both will lock antlers
rival males bashed heads together. Or perhaps and try to shove each other backward. The
males dominated their rivals by brandishing winner earns the right to mate with many
their domes in a display of threat. Many females. Jousting in this way, large deer
animals today use horns or fangs in this with dangerous headgear show how some
way, instead of risking injury by fighting. horned dinosaurs might have behaved.

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