Page 38 - Dinosaur (DK Eyewitness Books)

Long and short necks

Cervical vertebra
(neck bone)
SȢȶȳȰȱȰȥȴ ȩȢȥ ȵȩȦ ȭȰȯȨȦȴȵ ȯȦȤȬȴ of all dinosaurs—some more
than five times as long as a giraffe’s. Prosauropods and sauropods
were the first animals that could graze on treetop leaves while
standing on the ground. In contrast, most armored, plated, and
horned dinosaurs had short, strong necks, and generally fed
on vegetation near the ground. The length of a plant-eating
dinosaur’s neck determined which levels of vegetation it
could browse. Theropods had a muscular S-shaped neck, like
a bird’s. Large meat-eaters, such as Tyrannosaurus, had massive Mandible
(lower jaw)
necks, while smaller theropods, such as Velociraptor, had slim necks
that uncoiled like springs when attacking prey.

Muscles running BRACED FOR HEADY HEIGHTS
along the topside Powerful neck muscles lifted Brachiosaurus’s head
of the neck raised and a strong heart pumped blood up to its brain. This
the head
sauropod’s neck was supported at the base in the same
way that the movable jib (projecting arm) of a crane is
supported by a tower and base. Raising the heavy load of
the head and neck would have been difficult for Brachiosaurus
due to the effects of gravity. This is why all sauropod necks
needed bracing, which came from the muscles, tendons, and
the cablelike ligament above the neck bones. Maybe bracing
was also helped by ribs that grew back from each neck bone
to overlap the bone behind. Bracing strengthened sauropod
necks so that they could function as flexible rods.

Head lifted to about 42 ft
(13 m) above ground

Crane with movable jib

JURASSIC GIANTS
A Brachiosaurus herd would have
wandered through riverside forests
of conifers, cycads, and ferns. The
great sauropods lowered their necks
to drink and lifted them to feed.
The herds would feed first on
leaves growing lower down and
then graze through foliage at the
treetops. To reach that height,
these gigantic creatures might
have had to raise their heads
to the height of a four-story
office building.