Mastodon

Mastodons are elephant-like creatures, the most well-known of which is the American mastodon. Though similar in appearance to woolly mammoths and elephants, they are found in a different family, the Mammutidae.

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Dinosaurs & Prehistoric Creatures

Acrocanthosaurus

Acrocanthosaurus was a large meat-eating dinosaur that had a prominent ridge along its neck and back. It lived in the Early Cretaceous Period.

Albertosaurus

Albertosaurus was a relative of Tyrannosaurus rex. It lived around 70 million years ago in what is now Canada. It was slimmer and smaller than its more famous cousin.

Allosaurus

Allosaurus (Al-loh-sore-us) lived in the Late Jurassic of North America, around 150 million years. It is the most common predator from the area known as the Morrison Formation.

Amargasaurus

This long-necked sauropod features long spines protruding from the back of its neck. It’s known from a nearly complete skeleton, missing only a few bones and most of the skull.

Ammonite

Ammonites are prehistoric molluscs related to octopuses and squids.

Ankylosaurus

Ankylosaurus was a large plant-eater from the Late Cretaceous period, around the end of the Age of Dinosaurs, 66 million years ago. It was covered in bony armor and spikes, with a fearsome club at the end of its tail.

Anzu wyliei

Anzu lived about 66 million years ago in what is now North and South Dakota. It is one of the most complete and well-known examples of an oviraptorosaur in the United States. Oviraptorosaurs were divided into two main groups: the early and more primitive protoarchaeopterygids, and the later caenagnathoids. Within the caenagnathoids are the oviraptorids which were limited to Asia, and the more widespread and larger caenagnathids, which includes Anzu wyliei.

Apatosaurus

One of the most well-known long-necked sauropod dinosaurs, this Jurassic plant-eater has a complicated history.

Archaeopteryx

Archaeopteryx, ancient wing, was the dinosaur-bird that lived in the Late Jurassic of Europe and is one of the most important fossils ever found. The first Archaeopteryx skeleton with feathers was found in 1861, and since then 6 – 7 skeletons have been recovered. The similarity to Compsognathus and other small theropods led to early specimens being classed as theropods until the feather impressions were recognized. The significant similarities between it and birds have heavily weighted current opinion in favor of Archaeopteryx being a bird rather than a non-avian theropod. As well as the features of the pelvis and limbs, the seventh skeleton contained a well-preserved skull which showed a unique combination of features supporting both the theropod origin of birds, and that Archaeopteryx is the most primitive bird yet found.

Austroraptor

Austroraptor was a large member of the dromaeosaur family, known for the large curved claw on each foot. Compared to other dromaeosaurs of similar size, Austroraptor had a more slender build.

Baryonyx

Baryonyx was a large meat-eating dinosaur from the Early Cretaceous Period. It was discovered in England and is notable for the large claws on each hand, as well as its long, crocodile-like snout.

Brachiosaurus

Brachiosaurus was one of the tallest long-necked dinosaurs. This ground-shaking herbivore occupied North America during the Late Jurassic, about 153 million years ago.

Camarasaurus

Camarasaurus (Cam-ah-rah-sore-us) lived during the Late Jurassic Period in North America, around 150 million years ago. It was the most common sauropod in North America. It shared the environment with Apatosaurus, Diplodocus, Stegosaurus and the main predator, Allosaurus.

Carcharodontosaurus

Carcharodontosaurus, named for the great white shark, Carcharodon, was a giant predator that lived in the Cenomanian age, which was the first part of the Late Cretaceous. Remains have been found in North Africa as well as Egypt to Niger.

Carnotaurus

Carnotaurus was a large predatory theropod dinosaur that lived in the Late Cretaceous of South America, about 70 million years ago. It is known for its distinctive horns that sprouted above its eyes.

Ceratosaurus

Ceratosaurus was a meat-eating dinosaur from the Late Jurassic Period, known for the nose horn on its face. It lived from around 160 million to 145 million years ago.

Citipati

Citipati was an oviraptorid, a group of bird-like theropod dinosaurs that had toothless beaks and often had crests like a cassowary on their heads. Citipati lived around 80 million years ago in what is now Mongolia, and is known from several nearly complete skeletons. Citipati’s remains are often used as a basis for the more popular – but less well-understood – dinosaur called Oviraptor, a close relative. Though Oviraptor means “egg thief”, several skeletons of Citipati have been found in a nesting position, showing that the eggs this dinosaur is believed to have stolen might have been its own eggs that it was nurturing.

Coelacanth

Coelacanths are a group of fish once thought to have become extinct millions of years ago, until living examples were found in the 1930s.

Coelophysis

Living over 200 million years ago in the Triassic Period, Coelophysis was an early meat-eating dinosaur that may have hunted in packs.

Concavenator

Concavenator was a medium-sized meat-eater that lived around 125 million years ago. It had a unique hump on its back.

Cryolophosaurus

Cryolophosaurus is a meat-eater from the early Jurassic Period, one of the few dinosaurs found in what is now Antarctica. It had a unique crest on its head.

Daeodon

Daeodon was a large, rhino-sized pig-like mammal known as an “entelodont”. It was formerly known as “Dinohyus” or “terrible pig”. Though entelodonts like Daeodon had pig-like physical characteristics, it’s not known if they were directly related to true pigs, and recent studies point to a closer relationship to hippos and whales than to pigs.

Daspletosaurus

Daspletosaurus was a relative of Tyrannosaurus Rex. It lived about 10 million years earlier than its larger cousin, and like T. Rex, it was an apex predator that preyed upon other dinosaurs.

Deinocheirus

Deinocheirus means “Terrible Claw”, because for a long time, the only known remains of this dinosaur were its huge hands and arms, which ended in massive claws. It wasn’t until almost 50 years after its initial discovery that more complete finds helped paint an accurate picture of this amazing dinosaur.

Deinonychus

Deinonychus (Dye-NON-ick-us) lived during the Early Cretaceous Period, from 115 to 108 million years ago. It lived in what is now North America. It was a fast, effective predator with an enlarged, curved claw on the second toe of each foot. It was closely related to Velociraptor.

Diabloceratops

Diabloceratops lived in the Late Cretaceous Period, around 80 million years ago. It gets its name from the two devil-like large horns atop its frill.

Dilophosaurus

Dilophosaurus was one of the earliest large meat-eating dinosaurs, living during the Early Jurassic Period almost 190 million years ago.

Dimetrodon

This popular sail-backed prehistoric creature is often incorrectly included amongst the dinosaurs, though it actually lived long before the dinosaurs existed, and is more closely related to mammals than dinosaurs.

Dimorphodon

A flying pterosaur from the Early Jurassic Period (195 million years ago), Dimorphodon is known for its large and unusual skull.

Diplodocus

Diplodocus lived in the Jurassic Period, around 150 million years ago. It was considered the longest dinosaur known, until skeletons of larger long-necked sauropods were discovered.

Doedicurus

Doedicurus clavicaudatus, pestle tail, was a prehistoric glyptodont with a mace-like clubbed tail. Doedicurus lived during the Pleistocene until the end of the last glacial period, some 11,000 years ago. It lived in North and South America and was the largest known glyptodont. Glyptodonts were heavily armored cingulate xenarthrans related to modern armadillos that evolved during the Miocene in South America. The extinction of the glyptodonts coincided with the arrival of early humans in the Americas and evidence suggests that these humans made use of the animal's armored shells.

Dracorex

Dracorex was discovered in 2006. It is now believed to be a growth stage of Pachycephalosaurus.

Dunkleosteus

Dunkleosteus was a large prehistoric fish that lived over 350 million years ago.

Edmontosaurus

Edmontosaurus (Edd-mont-oh-sore-us) lived during the Late Cretaceous Period, right up until the extinction event that killed almost all of the dinosaurs. It lived in what is now North America. It was a large hadrosaur, or duck-billed dinosaur.

Elasmosaurus

Elasmosaurus was a prehistoric marine reptile with an amazingly long neck.

Estemmenosuchus

This prehistoric creature's head was covered in unique horn-like structures. It lived over 260 million years ago!

Giant Sloth

This giant ground sloth from South America lived in the Pliocene and Pleistocene. It is one of the largest mammals to have ever lived, with a size exceeded only by Mammoths and some giant rhinos. Ground Sloths are xenarthrans, a distinct group of South American mammals that includes the living anteaters, tree sloths, and armadillos and the extinct megafauna, glyptodonts, and pampatheres. It had a close relative, Eremotherium, that migrated to North America during the Great American Interchange when the land bridge connected the continents.

Giganotosaurus

Giganotosaurus was one of the largest meat-eating theropod dinosaurs ever discovered. It could grow over 40 feet long!

Hyaenodon

Hyaenodons, despite their similar names, were not related to present-day hyenas. They also weren’t particularly hyena-like in their appearance or behavior, which likely bore a closer resemblance to modern-day wolves. Hyaenodons were widespread apex predators in their time, and the largest of these was Hyaenodon Gigas.

Ichthyosaurus

Ichthyosaurus (Ick-thee-oh-sore-us) lived during the Late Triassic and Early Jurassic Periods, around 200 million years ago. It looked like a dolphin, with a sleek body, long snout, and fins. However, it was a reptile that had become completely adapted to aquatic life.

Iguanodon

Iguanodon was a plant-eating dinosaur that lived in the Early Cretaceous around 125 million years ago. It had a unique thumb spike on each hand.

Kaprosuchus

Kaprosuchus was a crocodile relative from the Middle Cretaceous Period (around 100 million years ago) with tusks resembling that of a boar.

Kentrosaurus

Kentrosaurus was a relative of Stegosaurus with rows of spines down its back. It lived in the Jurassic Period around 150 million years ago.

Kronosaurus

A giant seagoing predator, Kronosaurus was named for a titan of Ancient Greek mythology.

Liopleurodon

Liopleurodon was a predatory prehistoric marine reptile that lived in the Jurassic Period, around 160 million years ago.

Macrauchenia

This prehistoric mammal lived in South America from 7 million years ago to around 10,000 years ago.

Majungasaurus

Majungasaurus was a meat-eating dinosaur from the Late Cretaceous Period. It lived right up until the end of the age of dinosaurs, about 66 million years ago, in what is now Madagascar, off the coast of Africa. Majungasaurus was a relative of Carnotaurus, another meat-eating dinosaur from Argentina.

Malawisaurus

Malawisaurus was a long-necked sauropod dinosaur named after the area where its remains were found in Africa. It lived in the Early Cretaceous Period, specially the Aptian Age, between 125 and 113 million years ago.

Masiakasaurus

Masiakasaurus, Vicious Lizard, lived in the Late Cretaceous of Madagascar. It is the best known of the Noasaurs that filled the small and medium-sized predators in Africa and South America.

Megacerops

Megacerops was a Brontohere, which means “thunder beast”. This family contained the largest land animals during the Eocene epoch. Though they possessed large bony protrusions on their snouts, they were not closely related to the rhinoceros they resembled.

Megalodon

Megalodon was a massive shark that lived millions of years ago that is believed to have grown longer than 50 feet in length!

Megalosaurus

One of the first dinosaur fossils to be named scientifically, Megalosaurus was a large meat eater from the Jurassic Period, 166 million years ago.

Microraptor

Microraptor was an interesting dinosaur that lived 120 years ago. It had wing-like feathers not only on its front legs, but its rear legs as well!

Monolophosaurus

Monolophosaurus was a meat-eater known for the large crest covering much of the top of its snout. It lived during the Jurassic Period, around 165 million years ago.

Mosasaurus

Mosasaurus was a marine reptile that lived up until 66 million years ago. It could grow to over 40 feet long.

Nanotyrannus

Nanotyrannus was originally thought to be a much smaller cousin of Tyrannosaurus rex, though now most paleontologists agree it was a younger version of T. rex.

Nanuqsaurus

Nanuqsaurus lived during the Late Cretaceous Period around 70 million years ago, in what is now Alaska. Though it was not as consistently cold there as it is today, Nanuqsaurus still likely faced climate extremes that were much more severe than those of most other dinosaurs.

Pachycephalosaurus

Pachycephalosaurus (Pack-ee-seff-ah-low-oh-sore-us) lived during the Late Cretaceous Period, right up until the extinction event that killed almost all of the dinosaurs. It lived in what is now North America. The main distinguishing feature of this two-legged plant-eater was its thick, domed skull, which may have been used in combat between individuals to impress a potential mate.

Parasaurolophus

Parasaurolophus was a duck-billed plant-eating dinosaur known for the large tube-shaped crest on its head. It lived in the Late Cretaceous Period, about 75 million years ago.

Patagotitan

Patagotitan (Pa-TAH-go-TIE-tin) was a giant long-necked sauropod that lived in what is now Patagonia, Argentina, around 100 million years ago. It was one of the largest dinosaurs ever and one of the largest animals to ever walk the Earth.

Postosuchus

Postosuchus was a large predator that prowled North America at the beginning of the age of the dinosaurs, approximately 210 million years ago. It was not a dinosaur, but a type of reptile called a rauisuchid. Postosuchus was the largest predator in its ecosystem.

Prestosuchus

Prestosuchus looks like a dinosaur, but it was actually an early ancestor of crocodiles that lived during the Triassic Period, around 240 million years ago. Its remains were discovered in what is now Brazil in South America. It was related to other early crocodile relatives like Postosuchus.

Psittacosaurus

Psittacosaurus was an early ceratopsian, the same group that would later produce large horned dinosaurs like Triceratops. A Psittacosaurus fossil in China was found with a row of quill-like bristles running down its tail.

Pteranodon

Pteranodon was a winged pterosaur that lived in the Late Cretaceous of North America around the western interior seaway that divided North America. Pterosaurs were not dinosaurs, but they were related to them, as both belonged to a group called archosaurs. Pteranodon was a close relative of the nyctosaurs, one of the two groups of pterosaurs that lasted until extinction at the end of the Mesozoic around 66 million years ago. Pteranodon is often called “pterodactyl” incorrectly. There is no actual pterosaur named “pterodactyl”; the closest is a very small pterosaur known as “Pterodactylus” which is very different from Pteranodon.

Qianzhousaurus

Qianzhousaurus (Chee-ann-joe-sore-us) lived during the Late Cretaceous Period, right up until the end of the Age of Dinosaurs, around 66 million years ago. The remains of this T. rex relative were found in what is now China, near the city of Ganzhou.

Quetzalcoatlus

One of the largest pterosaurs of all time, this prehistoric flying reptile had a wingspan of nearly 40 feet!

Regaliceratops

Regaliceratops is a relative of Triceratops that lived in the Late Cretaceous Period, very close to the end of what is known as the “Age of Dinosaurs”. This ceratopsian (horned dinosaur) is notable for its crown-shaped frill that gives it its name.

Rhamphorhynchus

Rhamphorhynchus was a flying reptile called a pterosaur that lived around 150 million years ago during the Late Jurassic Period.

Saltasaurus

Saltasaurus was small for a sauropod (long-necked dinosaur), but still reached a respectable length of nearly 30 feet long. It lived in the Late Cretaceous, around 70 million years ago, and had a rotund body covered in bony osteoderms.

Sarcosuchus

Sarcosuchus (Sar-koh-sook-uss) lived during the Early Cretaceous Period, around 112 million years ago, in what is now South America and Africa. It was a huge relative of crocodiles, and one of the largest croc-like animals to ever live.

Sauropelta

Sauropelta, lizard shield, was an Early Cretaceous armored dinosaur that may be a predecessor to the later and more heavily armored ankylosaurids. The preceding Late Jurassic fauna is replaced with fauna of dromaeosaurs, ornithopods, and nodosaurs like Sauropelta.

Shringasaurus

Shringasaurus (Shreen-guh-sore-us) was a prehistoric reptile living in the Middle Triassic Period, around 240 million years ago, in what is now India. It had two large distinctive horns on its head, like the ceratopsian dinosaurs that would appear millions of years later.

Smilodon

Often called the “sabre-toothed tiger” or “saber-toothed cat”, Smilodon wasn’t actually a close relation of modern tigers, or today’s cats in general. While in the feline family, it belonged to a now extinct subgroup called Machairodonts.

Spinosaurus

Spinosaurus (Spine-oh-sore-us) lived in the Early Cretaceous Period in Africa. Spinosaurus was one of the largest predatory dinosaurs ever known and may have grown to over 50 feet long. It is known for the large dorsal spines on its back, which may have formed a large sail or hump. For a long time, Spinosaurus was only known from a few remains, but recent finds have allowed scientists to get a better idea of this unique theropod dinosaur.

Stegosaurus

Stegosaurus (Steg-oh-sore-us) lived in the Late Jurassic of North America. It is the most common ornithscian (bird-hipped) dinosaur from the Morrison Formation, an area in the western United States that has yielded a large number of dinosaur fossils.

Stegouros

Stegouros was an ankylosaurian (armored) dinosaur from the Late Cretaceous with a very unique spiked tail.

Stygimoloch

Stygimoloch was discovered in 1983. It is now thought to be a growth stage of Pachycephalosaurus.

Styracosaurus

Styracosaurus was a ceratopsian dinosaur from the Late Cretaceous Period, around 75 million years ago. It lived in what is now Alberta, Canada and is known for the long spikes on its large shield-like head frill.

Suchomimus

Suchomimus was a large meat-eating dinosaur from the Early Cretaceous Period around 110 million years ago. It was found in Africa, and was related to Baryonyx and Spinosaurus.

Tapejara (Tupandactylus)

Tapejara lived in Brazil around 112 million years ago during the Cretaceous Period. Like many other Cretaceous pterosaurs, it had a distinctive head crest.

Therizinosaurus

An unusual dinosaur with a long neck and a stocky body, Therizinosaurus’s most notable feature was its extremely long claws.

Triceratops

The most popular and well known of the horned dinosaurs, and one of the most recognizable of all the dinosaurs, Triceratops remains a favorite of kids and adults alike!

Tylosaurus

Tylosaurus was a marine reptile called a mosasaur, thought to be closely related to modern day monitor lizards.

Tyrannosaurus Rex

One of the most well-known and popular dinosaurs of all time, Tyrannosaurus Rex was a large meat-eating dinosaur that lived right up until the end of the Cretaceous Period, 66 million years ago. It has captivated dinosaur fans young and old alike for over a century.

Uintatherium

Uintatherium was a large, rhinoceros-like plant-eating mammal that lived during the Eocene epoch roughly 40 million years ago. The most striking feature of these beasts were the six bony knobs on their unusual skulls.

Utahraptor

Utahraptor was a giant dromaeosaur, related to Deinonychus and Velociraptor. Like it’s relatives, it had a large curved claw on each foot, and likely had feathers.

Vagaceratops

Vagaceratops was a horned dinosaur that lived 76 million years ago during the Late Cretaceous Period. It had a unique frill with a flattened top edge lined with downward curving spikes.

Velociraptor

This relatively small predatory dinosaur became massively popular after a larger, more monstrous version was featured as the star dinosaur of the Jurassic Park film franchise.

Woolly Mammoth

Massive, thick-furred elephant relatives, mammoths once walked the frozen plains of the Pleistocene Epoch, where they were hunted by early humans.

Woolly Rhinoceros

The Woolly Rhinoceros lived from three and a half million years ago up until about 10,000 years ago, and was depicted by early humans in cave paintings. Unlike most rhinos of today, it was covered in shaggy fur to protect it from the harsh cold climate it lived in.

Yutyrannus

Yutyrannus huali, feathered tyrant, lived in Early Cretaceous Liaoning China. It was a medium-size non-tyrannosaurid tyrannosauroid and the largest feathered theropod known to date. The other known tyrannosauroids from this time are small predators, so the size indicates that the lineage history is more complex than previously thought.

Zuul

Zuul was an armored ankylosaur, and one the most complete ankylosaurs discovered in North America.