Most dinosaurs were herbivores, which mean that they ate plants.
The biggest carnivores were Theropods from the Cretaceous period. An example is Tyrannosaurus Rex.
From dinosaur fossils found throughout the world, scientists have gained evidence about when dinosaurs lived, what they ate and how large they grew. Dinosaurs lived during the Mesozoic era, from 245 million to 65 million years ago. The Mesozoic era is divided into three periods: Triassic, Jurassic, and Cretaceous.
English Paleontologist Richard Owen first named dinosaurs in an article he wrote in 1842. The name comes from the Greek words “deinos” (meaning terrible, fearsome or formidable) and “sauros’ (meaning lizard).
The biggest dinosaurs were over 100 feet long and 50 feet tall. The Sauropod was the largest dinosaur. The smallest dinosaurs were the size of a chicken and were called mussaurus, or mouse lizard.
Because the Earth has changed dramatically in the last 65 million years, dinosaur fossils are found in all sorts of places. A fossilized seashore with dinosaur tracks, for example, may have been tossed by geologic forces to form the nearly-vertical side of a cliff, making it look as if the dinosaur had been running up the cliff.
Dinosaurs had relatively lightweight, flexible skulls with lots of holes. These holes had several purposes. They cut down on the weight of the skulls so that they were not too heavy, and they helped carnivores keep bones from breaking while eating a squirming meal. Ceratopsians, like Triceratops, are the exception; they had very large solidly built skulls. Their complex, lightweight construction makes it extremely hard to find complete dinosaur skulls now. They break up easily during the fossilization process.
The Ruyang or Huanghetitan ruyangensis may have been a new discovery for paleontologists in China, but the residents of Shaping Village had used its fossil bones for decades in traditional medicines. The community believed that the bones belonged to a flying dragon and had healing properties. Because of this, paleontologists have only been able to recover 40 percent of its remains.
While the Tyrannosaurus Rex may not have had much brain power, its jaw packed a powerful punch – 10,000 newtons of punch to be exact. The specially strengthened nose structure allowed it to capture prey and combat other dinosaurs using bone splintering, crushing bites.
Many believe the myth that the Tyrannosaurus Rex had puny, useless arms. However, its heavy bone structure and large areas for muscle attachment actually indicates a very strong system. Its biceps alone could lift 439 pounds!
Tyrannosaurs Rex had teeth that were seven inches long! Sauropods had teeth that were not very good for chewing, so they ate stones, which ground up the food in their stomachs. The Stegosaurus had the smallest brain of any dinosaur. Its brain weighed only 2.5 ounces.
Paleontologists are generally unable to determine whether dinosaur fossils are male or female. However, they do know that one T-Rex fossil is definitely female; her femur contained a medullar bone, which is a special inner layer previously only found in ovulating female birds like chickens.
Today, more than 1,000 different dinosaur species have been identified and named. However, this is a relatively small number compared to the 10,000 bird species and 5,400 mammal species that have been identified to date. Paleontologists believe that there are many more dinosaur species to be discovered.
Dinosaurs are some of the largest animals to have walked the Earth – the Brachiosaurus weighed up to 80 tons. However, the blue whale that swims in today’s oceans is the largest animal known to man.
Dinosaur eggs from the period closest to the extinction have shown large amounts of strontium, manganese zinc, copper, lead, cobalt, nickel and vanadium than those from earlier periods. These elements could produce developmental defects and result in fewer healthy specimens hatched with each successive generation.
Only about 3 percent of dinosaur fossils found are from meat eaters.
At present over 700 different species of dinosaurs have been identified and named. However, paleontologists believe that there are many more new and different dinosaur species still to be discovered.