History and fact about dinosaurs

Dive into these quick facts about dinosaurs for kids of all ages. Find out why the dinosaur had sharp teeth, where the name “tyrannosaurus” comes from, and more!

Basic facts about dinosaurs
Dinosaurs are a group of reptiles that lived on Earth for about 245 million years.
In 1842, the English naturalist Sir Richard Owen coined the term Dinosauria, which derives from the Greek words deinos, which means “frighteningly great”, and sauros, which means “lizard”.
Dinosaur fossils are found on all seven continents.
All non-avian dinosaurs became extinct about 66 million years ago.
There are approximately 700 known species of extinct dinosaurs.
Modern birds are a type of dinosaur because they share a common ancestor with non-avian dinosaurs.
Glenn Rose Dinosaur Track
Paleontologists are like investigators examining evidence of extinct animals left behind. These dinosaur-shaped clues have been found in fossils — the ancient remains of an organism, such as a tooth, bone or shell — or evidence of animal activity, such as footprints and trails.

Everything we know about non-avian dinosaurs is based on fossils, which include bones, teeth, footprints, tracks, eggs, and skin impressions. For centuries, people all over the world have discovered amazing fossilized bones and footprints. The early finds were inspired by legends and fairy tales, where people imagined that these bones belonged to giants or huge monsters.

Barnum Brown, who began his career at the American Museum of Natural History in 1897, is considered by some to be one of the greatest dinosaur hunters of the late 19th and early 20th centuries. He began his career at the American Museum of Natural History in 1897. Many of his greatest discoveries, including the first dinosaur specimens ever found, are on display in the museum’s dinosaur halls.

CT Dinosaur GIF
Today, in addition to patience and sharp observation skills, paleontologists use new techniques to solve unanswered questions about dinosaurs and other fossils. Advanced imaging technology, such as computed tomography, allows paleontologists to see the 3D structure of fossils, often without having to remove the matrix.

Paleontologists integrate biomechanics research, and apply principles of physics and engineering to reconstruct the biological motions of non-avian dinosaurs. Information from fossil bones combined with observations of both movement and muscles of living animal species helps scientists model how non-avian dinosaurs moved.

Age of the dinosaurs
Stegosaurus Fossil in the Museum
The oldest known dinosaurs appeared during the Triassic period (approximately 250 to 200 million). Dinosaurs evolved into a very diverse group of animals with a wide range of physical traits, including modern birds.

Contrary to what many people think, not all dinosaurs lived during the same geological period. Stegosaurus, for example, lived during the late Jurassic period, about 150 million years ago. Tyrannosaurus rex lived during the late Cretaceous period, about 72 million years ago. Stegosaurus became extinct for 66 million years before the dinosaur walked on Earth.

During the Mesozoic Era (a period of more than 180 million years that included the Triassic, Jurassic, and Cretaceous periods), a type of non-avian dinosaur evolved into a type of avian dinosaur. This bird dinosaur is the first bird and predecessor of all birds. Every non-avian dinosaur became extinct 66 million years ago.

There are several theories as to what may have contributed to the mass extinction of the non-avian dinosaurs and other species at the end of the Cretaceous period. Sure enough, a massive asteroid or comet hit Earth during this time, causing a major shift in Earth’s climate. Some scientists believe that this effect had dire consequences for life on Earth. But other factors, including changing sea levels and widespread volcanic activity, may also have played an important role in this mass extinction.

Dinosaur fossils and fossilization
Protoceratops fossil skulls
Paleontologists use fossil evidence preserved in ancient rocks to discover how extinct animals lived and behaved.
In most cases, the fossilized bone is actually a rock made of minerals, with no trace of the original bone material.
The discovery of dinosaur eggs and nests provided evidence of the behavior of some dinosaurs.
By comparing the skulls of Protoceratops of different ages (as pictured above), paleontologists can draw conclusions about how some dinosaurs grew.
To discover how living things lived in the past, paleontologists search for evidence preserved in ancient rocks — fossilized bones, teeth, eggs, footprints, tooth marks, leaves, and even the dung of ancient organisms.
Jaws, teeth, and fossilized dung provide important clues about what non-avian dinosaurs ate.
A series of fossilized footprints, called tracks, reveal some intriguing clues about dinosaur behavior and movement.
Until recently it was believed that feathers are unique to birds. However, recent discoveries have revealed evidence of non-avian feathered dinosaurs.
Paleontologists searching for dinosaur fossils begin their work by scanning areas to find sedimentary rocks from the Mesozoic period. Finding the right niche requires experience and a keen eye.

Fieldwork is only a small part of what paleontologists do. They also work in the lab, examining specimens they found as well as fossils collected years ago. They spend a lot of time classifying specimens, examining their properties, and determining their biological relationships.

Teeth, footprints and feathers
A close-up view of the teeth of a Tyrannosaurus Rex dinosaur model on display in the museum.
Most theropod dinosaurs, such as Tyrannosaurus, had pointed, slightly curved back, and serrated teeth. Sharp points pierced the flesh, and serrations helped slice it by picking up and tearing muscle fibers. Meat eaters did not cut or grind their food. Swallow whole.

Plant-eating dinosaurs had teeth of various shapes designed for their own diets. For example, Triceratops had hundreds of teeth that formed a solid “wall” with sharp edges. The teeth were used to cut plants. Other plant eaters, such as Anatotitan, had wide, flat teeth that they used to grind tough plants. Long-necked dinosaurs, such as Diplodocus, had long, pencil-like teeth, which they used to shovel leaves off twigs. These dinosaurs swallowed the leaves whole. They also swallowed small stones, called gastric stones, that likely crush food in their stomachs, just as modern birds, such as parrots and chickens, do today.

From the individual footprint, scientists can estimate the height of the dinosaur that made it. A rough estimate of stem length is obtained by multiplying the print length by four.

The fingerprint can also provide clues about what kind of dinosaur it was. The three-toed imprint with sharp claws means that the imprinter was most likely a theropod – usually a carnivore. A three-toed print with rounded fingers likely belonged to an ornithopod – a herbivore. Pairs of asymmetrical prints were most likely the work of four-legged, long-necked, long-tailed dinosaurs called sauropods, another group of herbivores.

Modern birds, or avian dinosaurs, have skeletal features that are nearly identical to some non-avian dinosaurs.

Feathers evolved before flight and may have served as insulation to keep dinosaurs warm, or for display as a way to attract friends.

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