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Prehistoric Animals

Dinosaurs weren't the only prehistoric animals roaming the earth tens of millions of years ago. Here are profiles of the other prehistoric animals of the Mesozoic and Cenozoic Eras, including mammals, fish, sharks, birds, amphibians, and non-dinosaur reptiles.
  1. Prehistoric Animal Facts (20)
  2. Prehistoric Mammals A to Z (279)
  3. Tetrapods and Amphibians A to Z (110)
  4. The Cenozoic Era (9)
  5. The Paleozoic Era (7)

Vertebrate Animal Evolution
Vertebrate animals have come a long way since their tiny, translucent ancestors swam the world's seas over 500 million years ago. Here's a detailed chronological list of the major vertebrate animal groups, ranging from fish and amphibians to reptiles and mammals (including human beings).

10 Missing Links in Vertebrate Evolution
The phrase "missing link" is a bit misleading: most of the transitional forms in vertebrate evolution aren't missing, but have been conclusively identified in the fossil record, and it's impossible to pick out a single, definitive "missing link" from the broad continuum of evolution. That said, here are the 10 most important missing links in...

The First Animals of Their Kind
Have you ever wondered about the identity of the first dinosaur, or the first bird, or the first shark? Here's a list of important "firsts" in the animal kingdom.

How Big Were Prehistoric Animals?
It's one thing to know that a dinosaur was 40 feet long and weighed seven tons, and another to grasp just how enormous that was compared to the average full-grown human. This photo gallery will show you just how enormous some prehistoric animals were!

10 Animals That Grew to Dinosaur-Like Sizes
The Greek prefix "dino" (meaning "great" or "terrible") is extremely versatile--it can be attached to just about any kind of creature, as demonstrated by these examples.

10 Giant Mammals that Succeeded the Dinosaurs
The mammals of the Mesozoic Era were small, quivering creatures that kept well out of the way of dinosaurs by living high up in trees--but not so their successors of the Cenozoic, which were free to evolve into giant sizes and fill the ecological niches left open by the extinction of the dinosaurs. Here's a list of the 10 most notable giant...

Prehistoric Dogs
Most people know only the end of the story of dog evolution--when wolves were domesticated by early humans. The fact is, though, that prehistoric dogs roamed the plains of North America for tens of millions of years before humans appeared on the scene.

The First Mammals
It's not quite true that mammals succeeded the dinosaurs--they lived right alongside these lumbering beasts, in small, quivering, furry form, all through the Mesozoic Era. Here's a look at the evolution, anatomy and survival strategies of the earliest mammals.

Prehistoric Fish
The first vertebrate animals on the planet, prehistoric fish lay at the root of hundreds of millions of years of evolution. Here's everything you need to know about the evolution (and extinction) of prehistoric fish.

Prehistoric Sharks
Sharks are among the most successful vertebrates on earth; the first species evolved about 420 million years ago and their descendants have survived down to the present day. Here's everything you need to know about the behavior and evolution of prehistoric sharks.

Prehistoric Megafauna
It seems that every type of animal on earth grew to giant sizes two, 20, or even 40 million years ago--witness the Giant Wombat, the Giant Beaver and the Giant Sloth, to name just three. Here's everything you need to know about the megafauna that prospered after the age of dinosaurs.

Prehistoric Amphibians
During the Carboniferous period, over 300 million years ago, the first tetrapods evolved features that allowed them to prosper on land as well as in water--and for tens of millions of years, these prehistoric amphibians were the dominant terrestrial animals on earth.

Prehistoric Primates
The first ancestral primates appeared on earth around the time the dinosaurs went extinct--and diversified, over the next 65 million years, into monkeys, lemurs, great apes and human beings. Here's everything you need to know about primate evolution.

10 Extinct Lions and Tigers - 10 Lions and Tigers that Have Gone Extinct in...
Few creatures on earth are as threatened by extinction today as the big cats--lions, tigers and cheetahs. In fact, the past 10,000 years have witnessed the demise of no less than ten species and subspecies of big cats, as well as one tiger-like marsupial. Here are the 10 most notable big cats that have gone extinct in historical times.

The First Tetrapods
400 million years ago, give or take a few million years, a brave fish climbed out of the water and onto dry land, armed with primitive lungs and four stumpy limbs. Here's what we know about the first tetrapods that blazed the trail for the earth's land-dwelling animals.

Prehistoric Whales
It may be hard to believe, but modern whales evolved from terrestrial, dog-sized mammals that roamed central Asia about 50 million years ago. Here's the story of cetacean evolution, along with profiles of a dozen prehistoric species.

Prehistoric Snakes
The origin of snakes is shrouded in mystery: the first, fragmentary forms appeared about 150 million years ago, but it's unclear whether they evolved from land- or water-dwelling ancestors. Here's everything we currently know about snake evolution.

Prehistoric Horses
Horses have come a long way since their tiny, ferret-sized ancestors prowled the woodlands of North America, 10 million years after the extinction of the dinosaurs. Here's a look at horse evolution, along with profiles of various important genera.

Prehistoric Elephants
Modern elephants belong to a long and distinguished evolutionary line that dates back 60 million years, to shortly after the extinction of the dinosaurs. Here's a history of prehistoric pachyderms, along with profiles of various extinct species.

Marsupial Evolution
How is it that marsupials evolved well over 100 million years ago, but today are mostly restricted to the continent of Australia? Here's the story of marsupial evolution, along with a list of notable prehistoric marsupial species.

10 Facts About Titanoboa
Titanoboa was the biggest prehistoric snake that ever lived, measuring almost 50 feet from head to tail and weighing over a ton. Here are ten facts you may (or may not) have known about Titanoboa.

The 10 Deadliest Prehistoric Mammals
Today, there are very few mammals alive on earth that can kill you with one well-aimed bite or swipe of its paw--but that wasn't the case millions of years ago, when the earth was ruled by giant cats, hyenas, and rhinoceroses. Here's our list of the 10 deadliest prehistoric mammals.

10 Facts About the Tasmanian Tiger
The Tasmanian Tiger wasn't really a tiger, but a dog-like marsupial that went extinct in the 20th century. Here are 10 facts you may or may not have known about this striped predator.

The 10 Deadliest Marine Reptiles
Until the K/T Extinction, 65 million years ago, the deadliest creatures in the sea weren't sharks, but marine reptiles like pliosaurs, plesiosaurs and mosasaurs. Here's our list of the 10 deadliest marine reptiles of the Mesozoic Era.

Saber-Toothed Cats
They weren't technically tigers, but saber-toothed cats were every bit as dangerous to the grazing mammals (and early hominids) of their day. Here's a look at saber-tooth evolution and lifestyles, as well as profiles of the most important genera.

Prehistoric Turtles
Turtles and tortoises branched off from the mainstream of reptile evolution hundreds of millions of years ago, and have persisted down to the present day with the same basic body plan. Here's everything you need to know about testudine evolution.

10 "Terrible" Prehistoric Animals
The Greek root "dino" means "terrible" or "fearsome," but not all prehistoric animals with "dino" in their names were equally awe-inspiring. Here's a list of 10 more-or-less "terrible" extinct animals.

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