|
Pachycephalosaurus: The
Biggest Bonehead
 Pachycephalosaurus
(Greek for "thick-headed lizard"), plant-eating, birdlike,
beaked dinosaur that lived in North America in the late Cretaceous Period
(about 97 million to 65 million years before present). A member of the
suborder Pachycephalosauria, order Ornithischia, this bipedal (standing on
two legs) dinosaur grew to a length of 8 m (27 ft), making it much larger
than other dinosaurs in its suborder.
Pachycephalosaurus
had a 25 cm (10 in) thick, bony, domed head with a crown of spikes and
bumps. The thickness of the skull left little space for a brain, which was
very small for the size of the head. Because of its durability, the skull
has been better preserved than any other part of the skeleton.
Its
small leaf-shaped teeth were not designed to grind plants efficiently,
so much of the breakdown of plant material is thought to have occurred
in a large fermenting gut, similar to that of cows, or in a gizzard, as
used by some birds.
The bodies of Pachycephalosaurus were
designed like battering rams—the spine could lock rigidly to withstand
the force of impact. Their thick skull may
have allowed it to butt heads with other Pachycephalosaurus
dinosaurs without injuring its brain; these dinosaurs also may have
fought by ramming their heads into the soft bellies of other dinosaurs.
|
