Page 32 - Dinosaur (DK Eyewitness Books)

Senses and communication

Long, tubelike crest
made of nose bones
DȪȯȰȴȢȶȳȴ ȥȦȱȦȯȥȦȥ Ȱȯ sight, smell, taste,
hearing, balance, and touch to tell them
CALLING OUT
Parasaurolophus tooted how to find food and mates, and to
like a trombone by forcing air detect danger. Because organs like eyes
out through its hollow head crest.
Other members of its herd standing and nostrils seldom fossilize, anatomists
some distance away could hear and (experts in anatomy) cannot examine a
respond—like other hadrosaurs,
Parasaurolophus had a good sense of dinosaur’s sense organs directly to judge
hearing. Hadrosaurs without head how well they worked. But there are clues
crests probably called by blowing
up skin flaps on their faces, much in parts of a dinosaur’s skull. For instance,
as frogs can produce loud croaks holes for the eyes help to tell us their size
by inflating their throat pouches.
and the way they faced, and the shape of
a braincase in a skull may show that the
brain it contained had large, complex
Eye facing right
areas dealing with hearing and smell.
Anatomists studying these clues find
that many dinosaurs had senses
as acute as those of many
animals living today.

Gallimimus Troodon

SIDE VISION EYES FORWARD
Like a horse, the ostrichlike dinosaur Troodon had large, forward-facing
Gallimimus had an eye on each side of eyes, so both could see and focus
its head—one looked left and the other looked on the same thing at once, such as
right. Each eye saw things the other could not. baby hadrosaur prey. This is called
This is called monocular vision. Between them, binocular vision. The eyes produced
the two eyes could spot a predator creeping up a three-dimensional image of the
behind. This gave Gallimimus time to dash away prey in Troodon’s brain and enabled
before being caught. Speed was this toothless the theropod to judge the distance
theropod’s best defense, but its life depended between itself and its victim. This
on eyes that served as an early warning system. helped turkey-sized Troodon
to stalk and seize its prey.
Narrow field of
overlapping vision Field of vision
of right eye
Field of vision of left eye
Wide field of
overlapping vision
SEEING THINGS
These illustrations show
the tops of the heads of
Gallimimus and Troodon.
The areas in blue indicate
how much of the world
around was visible to each.
Gallimimus had a much
wider field of vision than Field of
Troodon, but Troodon vision Field of vision
could judge distance in of left eye of right eye
the overlapping field of
vision directly in front.
Gallimimus’s field of vision Troodon’s field of vision

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