Page 129 - Prehistoric Animals

Stig-O-Sorus

Stegosaurus

What is a Dinosaur ?
Known as a Dinosaur

Stegosaurus (Roof lizard) is a genus of herbivorous* ar-
moured dinosaurs. It roamed the earth in the Late Jurassic, around
155 to 145 million years ago. It was on average 9 metres in length
and 4 metres in height and weighed in around 6 tonnes. It was
named by, Othniel Charles Marsh in 1877, and to date, there are on-
ly three species recognized, S. stenops, S. ungulatus and S. sul-
catus, though there are many still waiting for confirmation.

Stegosaurus was a large quadruped**. With hindlimbs much
longer then its forelimbs this gave its back an arched appearance.
At the end of its long tail were four 3ft long defensive spikes
(Thagomizer***). It’s believed Stegosaurus would have held its tail
high while browsing as a warning to any would be predators. It had
a relatively short neck that supported, in relation to it huge body, a
very small head. Its mouth was small, and like many herbivores
lacked any biting force, like the brutal biting force of a carnivore.
However, its mouth was lined with sharp teeth more than adequate
for taring and chewing small twigs and vegetation.

One of the more notable and controversial feature of Stego-
saurus are the large plates running down its back. These large trian-
gular plates protrude from its back to a height of 2ft and are roughly
2ft long. They are controversial because no one can work out what
purpose they serve. They are attached to the skin and not to the
bones of the body and have large blood vessels running through
them. To add to the confusion, each species has its own plates all a
different size and shape to the others. Although there are many the-
ories banded about as to the purpose of these plates one explana-
tion is slowly gaining acceptance; that Stegosaurus uses them not
only to identify its own species, but also as a thermal regulator to
help cool its body in the hot humid weather.

There is no concrete reason that can explain the disappear-
ance of Stegosaurus. But a testament to its intelligence is the fact it
successfully survived on this planet for millions of years. Maybe this
gentle giant had just reached the end of its evolutionary cycle, and
couldn’t adapt in a world that is constantly changing.
*Herbivorous (Wikipedia)
A herbivore is an animal anatomically and physiologically adapted to eating
plant material.
** It walked on all fours.
***Thagomizer (Wikipedia)
is the distinctive arrangement of four spikes on the tails of stegosaurian dino-
saurs. These spikes are believed to have been a defensive measure against predators.