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Dinosaurs were giant reptiles that lived a long time ago, around 65 million years. Some of them were carnivores and ate flesh, while others were herbivores and ate plants. Most dinosaurs were huge, about 10-100 feet tall, and around 50,000 lbs! Some dinosaurs were the size of chickens.
When and where did dinosaurs live?
Dinosaurs lived throughout the Mesozoic Era, which began 245 million years ago and lasted for 180 million years. It is sometimes called the "Age of Reptiles" The era is dived into three periods: Triassic - 245 to 208 million years ago, Jurassic - 208 t 146 million years ago, and Cretaceous - 146 to 65 million years ago. They lived all over the world.
Species
There were many different species of dinosaurs. There were flyers, swimmers, and land walkers. One of the flyers was the Pterosaur. A swimming dinosaur is the Plesiosaurus. Some of the land walkers were Brontosaurus, Brachiosaurus, Tyrannosaurus Rex, Velociraptor, and many more.
Pterosaur
There were 2 kinds of Pterosaur, a meat eater, and a plant eater. The way to tell which is which is by looking at there head. If their head has a long piece on the back of the head, it's a plant eater, if not, it's a carnivore. The Pterosaur looked like birds without feathers. This dinosaur lived in the Triassic period.
Plesiosaurus
Plesiosaurus was rather quite big. It had a long neck, a small tail, and flippers, kind of like an under water Brontosaurus. Some people think that there is a Loch Ness monster in the lake Loch Ness in Scotland. If there is, scientists say that it would be the remains of Plesiosaurus.
Brontosaurus, Brachiosaurus
The names Brontosaurus and Brachiosaurus mean thunder lizard. They are called that because when they walked it sounded like thunder. Brontosaurus and Brachiosaurus are like giant giraffes, except with a longer tail and different colors. These 2 dinosaurs had long necks, so that they could reach the leaves at the tops of trees. They lived in the Jurassic period.
Tyrannosaurus Rex
Another name for Tyrannosaurus Rex is T-Rex. T-Rex means king. This dinosaur was known as the king because he was so big and ate others. T-Rex looked like a big Iguana that stood on 2 legs and had 2 small, stubby claws on each hand. T-Rex lived in the Cretaceous period. The teeth of the Tyrannosaurus Rex were just as long as pencils and even sharper.
Velociraptor
The Velociraptor was extremely fast: 60-70 mile per hour if it is in the open. They are also really great jumpers. They can jump just as a deer or a kangaroo. Velociraptors were like miniature T-Rexes, but with more claws. This dinosaur lived during the Cretaceous period. Velociraptors name means bird of prey. These fantastic dinosaurs were pack hunters.
Defenses
These dinosaurs needed to protect themselves against enemies, so they each have their own way of defending themselves. Brontosaurus and Brachiosaurus both had their nose above their eyes, so all they had to do was go under water. Ankylosaurus had the most amazing defense, a club tail and heavily plated armor with spikes on its back. You can probably guess what a Triceratops would do. Because Triceratops live in packs, these plant eating animals would form a circle with the babies in the middle, and have the adults facing outward with their big strong horns.
Did dinosaurs live with humans?
Absolutely not! After the dinosaurs died out, it took 65 million years for humans to evolve. But, during this time there were small mammals taking the dinosaurs place, such as the Wooly Mammoth, and the Saber Tooth Tiger. These creatures lived in the era known as the Ice Age. Soon after humans arrived, scientists found out that modern day birds are in fact the descendants of dinosaurs.
Why did dinosaurs become extinct?
There are many theories, but here is one that might really be true. Scientists have found an impact crater and think that the way the dinosaurs died was from a giant meteor hitting the earth, making a huge amount of dust get into the air, blocking the sunlight, and stopping the plants from growing. When the plants stopped growing and died out, the plant eaters had nothing to eat, so they died out, then the meat eaters and egg eaters (example: Struthiomimus) died out because there weren't anymore dinosaurs to eat.
Dinosaur fossils embedded in stone Buy this Giclee Print at AllPosters.com |
Fossils
Fossils are the remains of plants and animals that have been preserved for thousands or millions of years, usually as a stone. They might be the remains of living things, like bones, shells, eggs, seeds, etc. Or they might just be footprints or scratch marks.
How do fossils form?
When creatures die, its non-bone parts rot away, and their bones sink into the mud or land over millions of years. If the bones do sink into the mud, they may eventually turn into stone. When a shellfish dies and sinks to the bottom, its shell will get buried in the mud. Over millions of years, water flowing through the ground eventually dissolves the shell, but minerals in the water fill up its place, making a perfect fossil.
Record Breakers
Biggest
Many of the dinosaurs were huge, but the largest were the plant eating sauropods. Sauropods had long necks for browsing the trees. The biggest may have been the Brachiosaurus. Brachiosaurus was at least 14 meters tall and 25 meters long, which is 4 times as tall as an elephant and 6 times as long!
Smallest
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The smallest known dinosaur was the Compsonnathus. It was about the size of a chicken and weighed around 6.5 pounds. It had a long tail, moved quickly on 2 legs, and ate meat. This dinosaur lived in the Jurassic period.
Fastest
The fastest dinosaur was the Velociraptor. It could run just as fast as a cheetah if it's in the open. The way they hunted is by having its target only see 1 Velociraptor, while 2 more of them get on different sides and then attack.
Smartest
Troodon is the smartest dinosaur known to man. It had the largest brain-to-body ratio out of all known dinosaurs. It is believed to be as intelligent as modern day birds, and they're pretty stupid. Troodon was a meat eater, and was about 6 feet tall. It lived during the Cretaceous period.
Dumbest
The brain of a Stegosaurus was the size of a walnut. If brain-to-body ratio indicates intelligence, then this 3-ton herbivore wasn't a mental giant. The Stegosaurus was around in the Jurassic period, and its name means "Plated Lizard". Stegosaurus was the biggest plated dinosaur, and it had 2 pairs of dangerous spikes on its tail.
Best defense
The defense of the Ankylosaurus was really good. It had the most heavily plated armor of all dinosaurs, with bony plates, sharp spikes lining its entire back, even on its eyelids. Its tail had a thick bone at the end, which was used as a club to smack enemies. Ankylosaurus lived in the Cretaceous period.
What is the oldest creature species on earth?
The oldest species that is still living are the sharks. Sharks are even older than the dinosaurs! They have been around for an extremely long time. Sharks continually replace lost teeth. A shark can grow 24,000 teeth in a lifetime, and can live 50 years. The largest shark is the whale shark, which can grow up to 50 feet long, and weigh several tons.
