It isn't hard to imagine the world full of dinosaurs, even though these extinct animals haven't walked the earth for millions of years. Learn all about dinosaurs, including early dinosaur discoveries, dinosaur fossils, and dinosaur extinction.

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Thescelosaurus was one of the last hypsilopbodontid dinosaurs. It is known from the end of the Late Cretaceous of Montana in the United States is and Alberta and Saskatchewan in Canada. Learn more about the Thescelosaurus.


The first two Torosaurus specimens were a pair of skulls found in Wyoming in 1891 by John Bell Hatcher. They were described by Othniel Marsh later that same year. These two skulls were named Torosaurus latus and Torosaurus gladius.


Triceratops is one of the most spectacular and well known of all dinosaurs. It lived to the end of the Cretaceous. Triceratops was the largest of the ceratopsians. Learn more about the Triceratops and other Late Cretaceous dinosaurs.


Troodon was described in 1856 by Joseph Leidy on the basis of a single small tooth. It was one of the first North American dinosaurs described. Learn more about the Troodon and other Late Cretaceous dinosaurs.


Tylocephale is one of a group of new dome-headed dinosaurs discovered by the Joint Polish-Mongolian Paleontological Expeditions to the Gobi Desert. Learn more about the Tylocephale and other Late Cretaceous dinosaurs.


Even today, 90 years after it was discovered by Barnum Brown in the Hell Creek Formation of Montana, Tyrannosaurus rex remains the largest known predator to have walked the earth. Learn about Tyrannosaurus, Late Cretaceous dinosaurs and dinosaurs of all eras.


The most amazing find in Mongolia may be the discovery of the skeletons of the small theropod Velociraptor ("speedy predator") with its right arm clamped firmly in the beak of the small ceratopsian Protoceratops. Learn about Velociraptor, Late Cretaceous dinosaurs and dinosaurs of all eras.

Types of Dinosaurs

Types of dinosaurs include the lizard-hipped dinosaurs and the bird-hipped divisions of dinosaurs. Both of these types of dinosaurs probably shared a common ancestor during the Middle Triassic. How else are these dinosaurs related?

Dinosaur Bones

Dinosaur bones are all we have to study what these animals looked like and how they lived. Some of the most important dinosaur bones that paleontologists study come from the skull. Why is the skull so important?

Triassic and Early Jurassic Periods

The Triassic and early Jurassic periods were the time periods in which dinosaurs first appeared. It was also the time where all of the land on Earth was joined together in a single land mass. What types of dinosaurs lived during this time?


Anchisaurus was one of the first North American dinosaurs described. The first skeleton was found in 1818 and was originally mistake for human fossils. What did this early dinosaur look like and how did it live?


Barapasaurus is named for a word meaning "big leg" in a local dialect in central India. This large dinosaur was a herbivore with large flat teeth that are ideal for cutting or crushing vegetation. What did this dinosaur look like?


One of the most unusual predators is that of Coelophysis. It was only slightly larger than a turkey and had a long slender tail and a mouth full of knife-edged teeth. What was this dinosaur's behavior like?


Often called the terror of the Early Jurassic, the Dilophosaurus was a fast and agile dinosaur with extremely powerful neck and jaw muscles. It also had two crests on its head that may have been used for displaying the animal's social position.


Euskelosaurus was a sauropod of spectacular proportions. It measured about 33 feet in length. Little is known about this dinosaur because the head, hands and feet are unknown. What exactly is known about this giant dinosaur?


The Herrerasaurus was a large dinosaur that weighed about 400 pounds and was about 10 feet long. It survived on a diet of small animals which it most likely caught by ambush and surprise. What else is known about this dinosaur?


Heterodontosaurus is a small plant eating dinosaur that most likely walked on its hind legs. An unusual feature on this dinosaur is a pair of tusks that probably helped with eating. What else do we know about this tiny dinosaur?


Lesothosaurus was a dinosaur that measured about three and a half feet in length and was build for running. It had hollow bones and hollow spaces in the skull. What was this dinosaur's behavior like?


Lufengosaurus was a sauropod that measured about 20 feet in length and was a close relative of Plateosaurus. There are complete skeletons of this dinosaur, but it has not been fully described. What else is known about this dinosaur?


Massospondylus was a medium-size prosauropod that lived in what is now modern-day North America and Africa. Its proportions suggest that it probably was able to stand up on its hind legs. What else is known about this dinosaur?


Mussaurus was a sauropod of modest proportions. This animal is important in that it may help explain the relationship between prosauropods and sauropods. It is thought that the Mussaurus serves as a sort of missing link between the two.


Riojasaurus was a quadrupedal dinosaur that could not rear up on its hind legs like some of its relatives. It was a large dinosaur that measured about 33 feet in length. What are some of the other dinosaurs the Riojasaurus is related to?


Scelidosaurus was discovered in the 19th century. At the time, it was one of the most complete dinosaur skeletons ever found. It was a heavily built plant eating dinosaur that grew to around 13 feet in length.


Scutellosaurus was a very unusual dinosaur because it was a two-legged dinosaur that had armor. Most armored dinosaurs walked on all fours. Many scientists believe this dinosaur to be the ancestor of later larger armored dinosaurs.


Sellosaurus was a sauropod of modest proportions. It was around 10 feet high and lived during the late Triassic Period. The sellosaurus lived in what is now modern day Germany. What else do we know about this dinosaur?