…Amazing Animal Books
101 Facts… Dinosaurs!
Over 101 cool facts in this web-book about some of the most awe-inspiring animals that have ever existed.
Dinosaurs went extinct millions of years ago, yet continue to amaze and intrigue today. These giant reptiles have been depicted in various books and films, sometimes as fearsome creatures and sometimes as friendly, adorable ones. While there are hundreds of species, there are a handful that stand out because of their size and their unique features. According to scientists, there are hundreds more waiting to be discovered.
The name dinosaur means ‘terrible lizard’. Dinosaurs, however, are not lizards, but indeed a distinct group of reptiles.
Dinosaurs first appeared in the Triassic period, roughly 231 million years ago, and were the most common animals on land from the Jurassic period to the Cretaceous period, roughly 150 million years.
One of a dinosaur’s most distinguishing features is its ability to stand erect, whether on two legs or four, unlike lizards and crocodiles, who stand with their legs sprawled.
Allosaurus fragilis skeleton mounted in the lobby of the San Diego Natural History Museum.
Dinosaurs that walked on their hind feet are called bipedal dinosaurs, while those who walked on all fours were called quadrupedal dinosaurs. Some dinosaurs were both bipedal and quadrupedal.
The collective term for dinosaurs with long necks, long tails, and thick legs is sauropods. Sauropods are some of the largest animals to have ever lived.
Sauropod – Apatosaurus louisae at the Carnegie Museum by tadekk
Dinosaurs that walked on two legs and were primarily meat-eaters are called theropods.
Theropods are believed to be the ancestors of modern birds.
Irritator challengeri (theropod) by Kabacchi
Dinosaurs that walked on two legs and had bird-like feet and beaks are called ornithopods. They started out small, but evolved to up to fifty feet tall and were known for their amazing speed.
The study of dinosaur fossils is called paleontology. Paleontology literally means ‘the study of ancient life’.
There are two types of dinosaur fossils – body fossils consist of bones and shells, and trace fossils are tracks, burrows, and nests.
Tyrannosaurus rex at Palais de la Découverte, Paris by David Monniaux
Dinosaur fossils have been found on every continent.
The most dinosaur fossils have been discovered in the United States.
Megalosaurus by LadyofHats Mariana Ruiz
Over 700 different species and sub-species of dinosaurs have been discovered so far.
The Iguanodon was the first dinosaur to be discovered, but the Megalosaurus was the first dinosaur to be named and described in detail.
All dinosaurs built nests and laid eggs.
Female dinosaurs grew a special type of bone called the medullar bone in order to lay eggs.
Theropods laid elongated eggs, while sauropods and ornithopods laid round eggs.
Clutch of round eggs named “Oolithes spheroides” by Gerbil
The largest number of dinosaur eggs ever found in a single nest is twenty-four.
The first dinosaur eggs were discovered in 1869 in France and belonged to the Hypselosaurus. The eggs were one foot long and ten inches wide.
The largest dinosaur egg was two feet in diameter.
Segnosaurus nest at Dinosaurland, Lyme Regis, England by Ballista
The smallest dinosaur eggs ever found were Mussaurus eggs – they measured only one inch across.
Some scientists believe that female sauropods laid eggs through a tube like some of today’s turtles, in order to prevent the eggs from breaking – otherwise they would drop from a height of about eight feet!
The name Tyrannosaurus Rex means ‘king tyrant lizard’.
Tyrannosaurus rex by myfavoritedinosaur.com and LadyofHats
The most complete Tyrannosaurus Rex skeleton ever found measured 12.3 meters (forty feet) long and up to four meters (thirteen feet) tall at the hips.
Sue, the most complete fossil skeleton of a Tyrannosaurus Rex specimen ever found. Photo by Connie Ma
More than thirty T.Rex specimens have been discovered, some of which consist of complete skeletons.
The largest known T. Rex skull measured five feet long.
Tyrannosaurus skull on display at the University of California, Berkeley by EncycloPetey
The arm of a T. Rex measured only one meter (3.3 feet) long, which is relatively very short. They were very strong, and would have been able to lift a weight of up to 199 kg (439 pounds).
Tyrannosaurus arm at the National Museum of Natural History, Washington, D.C. by Postdlf
Studies suggest that the T. Rex had the greatest bite force of all animals that ever lived, about three times the bite force of a great white shark.
The largest dinosaur tooth ever found was a T. Rex tooth measuring thirty cm (twelve inches) long from the root to the tip.
A T. Rex could swallow up to 500 pounds of meat in one bite.
Much like many of today’s birds, the T. Rex ate stones to help it digest its food.
Young T. Rex dinosaurs weighed about 1,800 kg (4000 pounds) until they turned fourteen, at which point they started gaining weight dramatically – about 600 kg (1,300 pounds) a year until they turned eighteen, when their growth slowed down again.
T. Rex and Human by P. Jaworski
The average lifespan of a T. Rex was believed to be twenty-four to thirty years.
A T. Rex’s vision is believed to have been thirteen times sharper than a human’s.
The Triceratops, a three-horned plant-eating dinosaur, is the most well-known of all horned dinosaurs.
It is unclear what the Triceratops used its horns for. Some scientists believe that these horns were used to defend against predators, particularly the T. Rex, while others suggest that they were used more to beat other males to get a mate, much like a deer’s antlers are used.
Triceratops from the Late Cretaceous of North America by Nobu Tamura
Triceratops measured 7.9 tonine9 m (twenty-six to 29.5 feet) long and about three m (9.8 feet) in height.
Triceratops had one of the largest skulls of all land dinosaurs, measuring 2.5 m (eight feet) across.
Reconstruction of a Triceratops skeleton at the Senckenberg Museum in Frankfurt, photo by Eva Kröcher
Each of a Triceratops’ horns measured about three feet long.
The Triceratops had as many as 800 teeth.
Triceratops – Jura Park Baltow by Alina Zienowicz
The first Triceratops fossil was discovered in 1887.
Based on skeletons found, the Diplodocus was the longest dinosaur to have lived, measuring thirty-three m (108 feet) long. Roughly twenty feet of this was the Diplodocus’ neck.
Rather than holding their heads up high, it is believed that Diplodocuses held their necks horizontally or level to the ground.
Diplodocus size comparison by Dropzink
The Diplodocus had only one claw, located on one of its front toes, the function of which is yet unknown.
Diplodocus skeletons are the most commonly displayed sauropod bones, with many mounted skeletons having been donated by American businessman Andrew Carnegie during the beginning of the twentieth century.
Panoramic view of Diplodocus Carnegii by Javier Conles
Diplodocuses are believed to have lived for more than 100 years.
The first Diplodocus fossil was found in 1877.
Diplodocus at the Carnegie Museum of Natural History, Pittsburgh by ScottRobertAnselmo
The name Diplodocus means ‘double beam,’ referring to the two beams on its back which helped support the weight of its neck and tail.
The name Stegosaurus means ‘roof lizard’. This dinosaur is best known for its tail spikes and the plates on its back.
Stegosaurus had seventeen plates on their back and four to ten spikes on its tail.
The Stegosaurus was roughly nine meters (thirty feet) long and four meters (thirteen feet) tall.
Stegosaurus size comparison by Piotr Jaworski
The brain of a Stegosaurus weighed only eighty grams, which is far lighter than the human brain and was even small for this dinosaur. For this reason, many believe that the Stegosaurus was unlikely to be the smartest of dinosaurs.
However, some studies suggest that the Stegosaurus had two brains, a second one in its tail that was roughly twenty times larger than the one in its skull.
The Stegosaurus was named by Othniel Charles Marsh in 1877.
Reconstruction of a Stegosaurus skeleton at the Senckenberg Museum in Frankfurt, photo by EvaK
The largest Stegosaurus plates ever found measured two feet wide and two feet tall.
The Stegosaurus’ tail spikes are called thagomizers. Whether or not these spikes were used as weapons or had some other purpose remains unknown.
Stegosaurus tail spikes measured two to three feet long.
Model of stegosaurus in Baltow Jurassic Park by Jakub Hałun
The Stegosaurus had a low bite force -less than half that of a Labrador Retriever!
The Velociraptor was a medium-sized dinosaur that walked on two feet and had curved claws. Its largest claw measured 2.6 inches long and is believed to have been used to deliver fatal blows to its prey.
The Velociraptor measured two m (6.8 feet) long.
Velociraptor at Wyoming Dinosaur Center, photo by Ben Townsend
The Velociraptor is believed to have lived seventy-five to seventy-one million years ago.
The first Velociraptor fossil was found by Peter Kaisen in Mongolia in 1923.
The name Velociraptor means ‘swift robber’.
In spite of their portrayal in Jurassic Park, there is no evidence that Velociraptors lived in packs or that they were smart.
Size comparison of Utahraptor ostrommaysorum (orange), Deinonychus antirhhopus (green), and Velociraptor mongoliensis (blue), with a human. Image by Matt Martyniuk
The Deinonychus is the larger and more fearsome cousin of the Velociraptor. It could grow up to eleven feet long.
The name Deinonychus means ‘terrible claw’, referring to the large, sickle-shaped claws on the second toe of its hind feet.
The first Deinonychus fossils were discovered by Barnum Brown in Billings, Montana in 1931.
Deinonychus antirrhopus skeleton, Philadelphia Academy of Natural Sciences by Bearerofthecup
Despite its size, the bite force of the Deinonychus is believed to have been only fifteen percent of the American alligator.
The Ankylosaurus was an armored dinosaur with a clubbed tail which it could swing to break bones.
Ankylosaurus lived roughly sixty-six million years ago and were among the last dinosaurs to appear.
Possible appearance of an Ankylosaurus by Mariana Ruiz Villarreal (LadyofHats)
The Ankylosaurus’ eyelids were made of bone.
A complete Ankylosaurus skeleton is yet to be found, but based on fossil remains, it is estimated to be twenty-six to thirty feet long.
Estimated size of Ankylosaurus compared to a human by Conty
The largest Ankylosaurus skull discovered measured 64.5 cm (25.4 inches) long.
The name Parasaurolophus means ‘near crested lizard’.
The Parasaurolophus was a plant-eating dinosaur that could walk on either two or four feet. It is best known for the long, hollow crest on its head.
Sketch of hadrosaurid parasaurolophus by Tim Bekaert
The Parasaurolophus was discovered in 1922 by William Parks.
The Parasaurolophus is estimated to have been 9.5 m (thirty-one feet) long.
Size comparison between Parasaurolophus and human by Dropzink
The function of the Parasaurolophus’ crest remains unknown, though some scientists believe that it was used for communication, or to help regulate the dinosaur’s temperature.
The Parasaurolophus belongs to the family of dinosaurs known as hadrosaurs, or duck-billed dinosaurs. They did not exactly have duck bills, but the structure of their heads is similar to those of modern ducks.
The Iguanodon was a bulky plant-eating dinosaur that could walk on both two feet and four feet. They were about thirty-three feet long and weighed more than three tons.
The name Iguanodon means ‘iguana teeth’. This refers to the fact that the Iguanodon’s teeth are similar to the modern iguana’s, but much larger.
Fossil of Iguanodon by Ghedoghedo
One of the Iguanodon’s most distinct features is its thumb spike, which could have been used to fend off predators and break seeds and fruits open.
Iguanodon scale by Dinoguy2
Aladar, the main character in the Disney film ‘Dinosaur,’ is an Iguanodon.
The event which led to the extinction of most dinosaurs is called the Cretaceous – Paleogene extinction event.
Dinosaurs went extinct roughly sixty-six million years ago.
Painting by Donald E. Davis shows asteroid hitting seas off the Yucatan Peninsula
Apart from dinosaurs, it is estimated that the Cretaceous – Paleogene extinction event wiped out 75% of all plant and animal species on earth.
The Cretaceous – Paleogene extinction event is widely believed to have been triggered by a massive comet.
Dinosaurs were not the first reptiles on earth.
The Royal Belgian Institute of Natural Science in Brussels has the largest dinosaur hall in the world.
The Field Museum in Chicago is home to the world’s largest T. Rex skeleton – it has been named Sue!
The Troodon is said to be the most intelligent dinosaur, about as intelligent as the modern possum.
Head and neck of troodon sculpture, from the Natural History Museum, London, photo by Ballista
The Micropachycephalosaurus, which means ‘tiny thick-headed lizard’ is the dinosaur with the longest name.
The Brachiosaurus, a dinosaur with a long neck held high, is said to be the tallest dinosaur that ever lived, measuring about fifty feet tall, or as tall as three giraffes.
Size comparison of brachiosaurus and human by Marmelad
The name Oviraptor means ‘egg stealer,’ referring to the belief that Oviraptors mainly ate the eggs of other dinosaurs. There is no concrete evidence, however, to support this belief.
Ornithomimids were the fastest dinosaurs, believed to have been able to run at sixty kilometers (thirty-seven miles) per hour. They looked just like ostriches with toothless beaks and slender necks.
Pterodactyls are not dinosaurs. Rather, they belonged to a group of flying reptiles that lived before the dinosaurs, known as pterosaurs.
Plesiosaurs, large aquatic reptiles with flippers, are not dinosaurs, either. Rather, they are ancient marine reptiles that first appeared in the early Jurassic period. They were the largest marine predators to have ever lived.
Plesiosaur skeleton of Meyerasaurus in the Stuttgart Museum by Ra’ike
Many dinosaurs were warm-blooded, they could keep themselves warm, as opposed to today’s reptiles that are cold-blooded and have to use the sun to warm them.
Most dinosaurs had light, flexible skulls. Unfortunately, that means they broke easily. For this reason, completely intact dinosaur skulls have never been found. In fact, many dinosaur skeletons that have been found lack the skull.
There were more plant-eating dinosaurs than meat-eating dinosaurs.
Close up of “Sue” T-Rex replica skull at the Field Museum of Natural History in Chicago by ScottRobertAnselmo
Photo01 Allosaurus fragilis skeleton mounted in the lobby of the San Diego Natural History Museum. cc1.0
Photo02 Sauropod – Apatosaurus louisae at the Carnegie Museum by tadekk
Photo03 Irritator challengeri (a theropod) by Kabacchi www.flickr.com/photos/[email protected]/3559066934/ cc2.0
Photo04 Tyrannosaurus rex at Palais de la Découverte, Paris by David Monniaux cc2.0
Photo05 Megalosaurus is a genus of large meat-eating theropod dinosaurs of the Jurassic Period from what is now southern England by LadyofHats Mariana Ruiz cc1.0
Photo06 Clutch of round eggs named “Oolithes spheroides” by Gerbil cc3.0
Photo07 Segnosaurus nest at Dinosaurland, Lyme Regis, England by Ballista cc3.0
Photo08 Colored image of a Tyrannosaurus rex by myfavoritedinosaur.com and LadyofHats cc3.0
Photo09 Sue, the most complete fossil skeleton of a Tyrannosaurus Rex specimen ever found. Photo by Connie Ma www.flickr.com/photos/ironypoisoning/7532869012/ cc2.0
Photo10 Tyrannosaurus skull on display at the University of California, Berkeley by EncycloPetey cc3.0
Photo11 Tyrannosaurus arm at the National Museum of Natural History, Washington, D.C. by Postdlf
Photo12 T. Rex vs Human by P. Jaworski cc3.0
Photo13 Triceratops from the Late Cretaceous of North America, pencil drawing by Nobu Tamura (spinops.blogspot.co.uk/) CC3.0
Photo14 Reconstruction of a Triceratops skeleton in the Senckenberg Museum in Frankfurt, photo by Eva Kröcher (Eva K.) cc1.2
Photo15 Triceratops – Jura Park Baltow by Alina Zienowicz cc3.0
Photo16 Diplodocus size comparison by Dropzink cc3.0
Photo17 Panoramic view of Diplodocus Carnegii by Javier Conles cc3.0
Photo18 Diplodocus skeletal mount at the Carnegie Museum of Natural History, Pittsburgh by ScottRobertAnselmo cc3.0
Photo19 Stegosaurus size comparison by Piotr Jaworski cc3.0
Photo20 Reconstruction of a Stegosaurus skeleton in the Senckenberg Museum in Frankfurt, photo by EvaK cc3.0
Photo21 Model of stegosaurus in Baltow Jurassic Park by Jakub Hałun cc3.0
Photo22 Velociraptor at Wyoming Dinosaur Center, photo by Ben Townsend
Photo23 Size comparison of Utahraptor ostrommaysorum (orange), Deinonychus antirhhopus (green), and Velociraptor mongoliensis (blue), with a human. Based on the largest described specimens by Matt Martyniuk cc3.0
Photo24 Deinonychus antirrhopus skeleton, Philadelphia Academy of Natural Sciences by Bearerofthecup cc1.0
Photo25 Possible appearance of an Ankylosaurus by Mariana Ruiz Villarreal (LadyofHats) cc1.0
Photo26 Estimated size of Ankylosaurus compared to a human by Conty cc3.0
Photo27 Sketch of the hadrosaurid Parasaurolophus by Tim Bekaert cc1.0
Photo28 Size comparison between Parasaurolophus and human by Dropzink cc2.5
Photo29 Fossil of Iguanodon by Ghedoghedo cc3.0
Photo30 Iguanodon scale by Dinoguy2 cc3.0
Photo31 Painting by Donald E. Davis shows asteroid hitting seas off the Yucatan Peninsula Donald E. Davis for NASA
Photo32Head and neck of troodon sculpture, from the Natural History Museum, London, photo by Ballista cc3.0
Photo33 Size comparison of brachiosaurus and human by Marmelad cc2.5
Photo34 Plesiosaur skeleton of Meyerasaurus in the Stuttgart Museum by Ra’ike cc3.0
Photo35 Close up of “Sue” T-Rex replica skull at the Field Museum of Natural History in Chicago by ScottRobertAnselmo cc3.0