Page 43 - Dinosaur (DK Eyewitness Books)

TAILS HELD HIGH
Crisscrossing tendons stiffened the lower back and upper Stiffening tendon
tail of the hadrosaur (duck-billed dinosaur) Corythosaurus. Caudal vertebra
The vertical stiffening of the tail prevented it from (tail bone)
sagging. All hadrosaurs had stiff horizontal tails that
were held high. A stiffened tail was a feature that
hadrosaurs shared with most other kinds
of ornithischians, except stegosaurs.

Tail stiffeners
in Corythosaurus
Simple, rodlike vertebra
Ischium (hip bone)
THE LONGEST TAIL
Eighty caudal vertebrae formed the core of Diplodocus’s
incredibly slim and finely tapered tail—twice as many tail Tail bones become narrower
bones as some early sauropods possessed. At up to 43 ft toward the end
(13 m) from base to tip, this sauropod’s tail was perhaps the
longest of any dinosaur. When a herd of Diplodocus walked
together, the animals held their tails above the ground.
This counterbalanced their long necks and prevented the
members of the herd from stepping on one another’s tails.
Joint between tail bones

Flattened
chevron
Underside

DOUBLE BEAM
Chevron bones shaped like this one (seen from below)
earned Diplodocus its name, which means “double beam.”
These bones grew all along the tail’s underside. In the
middle region of the tail, they were short from top to
bottom but long from front to back. Each of these
chevrons looks a bit like two little beams stuck together.

Hips tilted back
REARING TO FEED
Barosaurus, Diplodocus, and some other sauropods could Tail used Raised forelimb
have used their tails as props if they reared on their as a prop
hind limbs to graze on leaves from treetops. The front
and rear projections of the “double beam” chevron
bones would have helped these sauropods to spread
the load pressing down on their tails. Chevrons might
also have served as tail skids and protected blood
vessels in the tail whenever it dragged on the
ground, though sauropods usually walked
with their tails held high.
Supporting
hind limb
Barosaurus

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