Wednesday, November 14, 2007

Dinosaurs

As carnivorous dinosaurs began to grow larger, faster, and became more adept at hunting, their prey began to develop defensive measures of their own. Here are three examples of the Thyreophora class: dinosaurs that developed thick armor to defend themselves from attack. They're huge, lumbering, slow-moving creatures which resemble modern cows. Unlike cows, these beasts could crush or impale with a swing of their heavy back or a swish of their tail.

Stegosaurus:

This is the most familiar of the Stegosauria, a group of dinosaurs that were characterized by a series of bony plates and spines extending along their backs. It could reach up to 30 feet (9 M) in length and weighed up to 2 tons. The impressive plates vary in size, with the largest just above the hip.
The plates were thin and blunt and would have offered little protection against an attack by a large meat-eater. They may have been used for warning off predators, or for recognition between members of a species. The heavy legs, curved back, and massive size suggest it was not capable of a quick getaway when under attack. Stegosaurus' best defense was probably to swing its powerful, spike-covered tail. In fact, scientists think Stegosaurus might have had a nerve bundle, or "second brain" in the tail, responsible for controlling reflexes in the rear portion of the body.

Ankylosaurus:
Spreading across the northern hemisphere alongside the great meat-eaters such as Tyrannosaurus Rex, the slow-moving Ankylosaurus would need heavy armor to protect themselves against such hunters. The armor consists of ovals of embedded bone supporting spiky horns. At the end of its tail was a bony club. There are no teeth at the front of the mouth, just a broad beak.
The Ankylosaurus' armor-covered head was very thick and often fossilized. As a result, the brain cavity is quite well known. The most highly developed part of the brain was for the sense of smell. It also had a maze of complicated nasal passages, which suggests this may have been the primary sense on which it relied.

Euoplocephalus:

From the same family as Ankylosaurus, this is one of the dinosaurs best known to science. There are more than 40 specimens known, including 15 skulls. It actually had armor-plated eyelids!
The back is covered with heavy, bony spikes fixed in leathery armor. At the end of the tail there was a heavy, spike-covered club used for defense, and possibly for occasional fights with other members of the species.
Occasional, because Euoplocephalus has never been found in groups, suggesting it was a solitary forager. The forelegs were used for digging roots and buried stems.

I post on dinos because they have universal interest. For yourself or as holidays gifts, check out National Geographic Dinosaurs, by Paul Barrett; and The Illustrated Encyclopedia of Dinosaurs, by Dougal Dixon.

3 comments:

Emile J. Walters said...

I like your little travels in the lost world of the Dinosaurs. May I however suggest you make a detour to the early years of the mammals? You will find the most extaordinary beasts out of some 30 - 40 million years ago :-)

Hansisgreat said...

Thanks for the suggestion, Emile. Posting on other types of animals is a possibility for the future.

I was very sorry to see you've decided to quit your own website. I'm a great admirer, and wish you the best for your future. If you ever miss blogging, I'd be thrilled to have you as a staff writer at Hansisgreat.

Good luck to you!

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