This is a much better shot of Triceratops which is easy to recognize because of it's head. Triceratops is Greek for "three-horned face," but this dinosaur had only two real horns, the third much shorter "horn" on its snout was made from a different material. It's skull was one third the length of its entire body and can grow to 7 feet long. It is believed that fully grown Triceratops were about 26 feet long, 10 feet in height, and weighed anywhere between 6 to 12 tons.

Triceratops had anywhere between 400 and 800 teeth although only a small percentage of these were in use at any one time as they were constantly replaced throughout its lifetime. Their diet consisted of plants and grass's unlike some of his cousins that ate meat. Triceratops lived about 65 million years ago and was one of the last dinosaurs standing.
 

Mamenchisaurus (pronounced 'Ma-man-chee-sore-uss') was a long necked, long-tailed, plant eating dinosaur. Mamenchisaurus means 'Mamenchi (China) lizard)' and had the longest neck of any known dinosaur except the newly found Sauroposeidon. His neck alone is about 46 feet long, overall length is 70 to 80 feet long and weighed roughly 12 tons. It had 19 vertebrae in its neck, more than any other known dinosaur had.

The long neck may have been used to poke into forests to get foliage that was otherwise unavailable to smaller dinosaurs. Many paleontologists believe that it used its massive neck to eat foliage on the ground. They believe that Mamenchisaurus would have swung its neck in a giant arc, eating everything it could eat. Then it would have taken a step forward, and started the process over again. Mamenchisaurus lived during the late Jurassic Period, from about 156 million to 145 million years ago. He was a sauropod, whose intelligence (as measured by its relative brain to body weight, or EQ) was among the lowest of the dinosaurs.
 

Tyrannosaurus Rex was the king of the dinosaurs and was very big and very dangerous. The name Tyrannosaurus Rex means; Tyranno meaning 'tyrant', sauros meaning 'lizard' and Rex meaning 'king'. Here you see a trio of them, all at different ages. The smallest is 2 years old, 11 feet long and is the youngest known T. Rex fossil in the world. To his right is a 20 feet long, 13 year old weighing about 4,000 pounds. The oldest at 17 years old, 34 feet long and weighed nearly 7,000 pounds. All three fossils were found in the badlands of Montana.
 

No one knows why T. Rex's arms were so short. Did they use their small arms to push itself off the ground after restful naps, or to clasp struggling prey close to its chest? Or is it possible that this predator's arms were completely useless and would have disappeared entirely (as happened with snakes) after another few million years of evolution? No one knows but it looks to me they didn't do enough bench press and did way to much stepper  :-]

Based on the size and shape of its olfactory lobes (nostrils), T. Rex seems to have had a very sensitive nose, which would have helped it to hone in on living or dead and rotting prey. The females were believed to be larger than the males and weighed more by a few thousand pounds based on the size of existing fossils and the shapes of their hips.
 

Tyrannosaurus Rex had an incredibly powerful bite and enormous teeth with knifelike serrations. Scientists determined that T. Rex chomped on its prey with anywhere from 1,500 to 3,000 pounds of force, comparable to a modern alligator. But more recent studies put that figure in the 5,000 pound range. For comparison the average adult human can bite with a force of about 175 pounds. A bite that powerful may have been capable of shearing off a Triceratops' horns.

As you can see I was having fun with this picture.
 

It's hard to tell a dinosaur's life span from its fossil remains, but based on an analysis of existing specimens, experts speculate that Tyrannosaurus Rex may have lived as long as 30 years. And since this dinosaur was on top of the food chain, it was most likely killed by old age, disease, or hunger rather than attacks by another dinosaur. It's estimated that T. Rex could gain at mid spurt about 1,500 pounds in a year.
 

Camptosaurus was a plant eating dinosaur of the Late Jurassic period where most were large. Camptosaurus was an exception, it reached an adult weight of no more than 1,000 pounds. Camptosaurus means 'flexible lizard' and stood around five feet tall at the hips. Some paleontologists compare Camptosaurus with a deer in today's forests. Camptosaurus browsed on low vegetation and the chisel-like teeth on the sides of its jaws were strong and well suited for crushing tough plants. Instead of front teeth for nipping, the fronts of both jaws were covered with a beak.

Using its tail as a counterweight, Camptosaurus was able to balance on its hind legs, leaving its arms for feeding and other tasks, such as self defense. Fossilized tracks show evidence that Camptosaurus also walked on all fours at times.
 

Stegosaurus is an armored dinosaur covered with 17 bony plates that were embedded in its back which ran along its back and tail in two rows, and the plates alternated in alignment. The largest of these triangular plates was about 2.5 feet tall and just as long. Stegosaurus also had spikes at the end of its flexible tail that could be used as weapons. The name Stegosaurus means Roofed Lizard or Plated Lizard.

Stegosaurus was 26-30 feet long long, 9 feet tall at the hips and weighed about 7000 pounds. They were about the size of a bus but had unusually small brains, only about the size of a walnut. They were plant eaters but also ate rocks to help mash up the tough vegetable matter in its enormous stomach, of which it would have had to eat hundreds of pounds a day. This one was found in Utah and it's around 150 million years old.