Page 28 - Dinosaur (DK Eyewitness Books)

Heads and brains

A ȥȪȯȰȴȢȶȳpȴ ȩȦȢȥ was built around a skull made up of separate
bones that slotted together to support the jaws and protect the brain.
There were holes for eyes, ears, nostrils, and jaw muscles, and often
extra holes that saved weight. Dinosaur heads came in a variety of
shapes and sizes. Some skulls were lightly built, with slender
bones. Other dinosaurs had heavy, solid-looking armored
skulls. Each skull enclosed a brain that was relatively
smaller and less complex than the brains of most
mammals. Some theropods had brains as large as
those in certain modern birds. These dinosaurs
may have had very keen senses and could probably
respond swiftly to their surroundings.

Naris (opening for nostril)

Orbit (opening
Ankylosaurus for eye)

ARMORED HEAD
Ankylosaurus would slowly forage on all fours
near ground level and was vulnerable to attacks
by theropods. But this plant-eater had a thick,
heavy, solidly built skull that protected its low,
broad head from bites during such attacks.
There were no windows in its skull like
those in many other dinosaurs. The only
openings were four small holes for the eyes
and nostrils. A relative of Ankylosaurus even Ankylosaurus
had bony eyelids that came down like skull
shutters to protect its eyes.
Naris (opening for nostril)

Slender rod
of bone Window

A SKULL WITH STRUTS
The skulls of some dinosaurs were delicately
built and the bones in the skulls were slender
rods, with the exception of those working
the jaws. This weight-saving design can
be seen in the skull of a Late Jurassic
sauropod called Camarasaurus, which
lived in western North America.
Having a light skull was more
important for this dinosaur than
protecting its skull, since it could
Camarasaurus hold its head above the reach of
predators and feed on high branches.
Camarasaurus skull

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