evolution
Horses Started Dog-Sized
The first horses (Eohippus) were only 30 cm tall—about the size of a fox! They had four toes and lived 55 million years ago. Horse evolution is one of the best-documented in paleontology.
Welcome to Prehistoric World
Discover the fascinating creatures that once roamed our planet
Featured Creatures
Featured Creatures
stegosaurus ungulatus
Jurassic
Stegosaurus ungulatus is a distinct species of the famous plated dinosaur that lived during the Late Jurassic period, approximately 155 to 150 million years ago in what is now North America. ...
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Dubreuillosaurus valesdunensis
Jurassic
Dubreuillosaurus was a coastal predator from the Middle Jurassic period, about 167 million years ago. Found in what is now Normandy, France, this unusual dinosaur had a ...
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Mosasaurus hoffmannii
Cretaceous
Mosasaurus was one of the most fearsome predators to ever rule the oceans—a giant marine reptile that dominated the seas during ...
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Latest Discoveries
May 16, 2026
Charnia
Proterozoic
Charnia is one of the most important fossils ever discovered! This mysterious frond-shaped organism lived during the Ediacaran period, approximately 575 to 555 million years ago, making it one of Earth's oldest known complex life forms. Charnia was the...
Location: England, Canada, Australia, Russia
Scientific Name: Charnia masoni
May 16, 2026
Tribrachidium
Proterozoic
Tribrachidium is one of the strangest creatures to ever exist! Living during the Ediacaran period about 558-555 million years ago, this bizarre disc-shaped organism had three-fold symmetry — a body plan found in no living animal today. It...
Location: Australia, Russia, Ukraine
Scientific Name: Tribrachidium heraldicum
May 16, 2026
Spriggina
Proterozoic
Spriggina is one of the most intriguing fossils from the Ediacaran period, living approximately 550-560 million years ago. With its distinctive horseshoe-shaped head and segmented body, it has sparked decades of debate about whether it represents...
Location: Australia
Scientific Name: Spriggina floundersi
May 16, 2026
Wiwaxia
Cambrian
Wiwaxia is one of the strangest creatures from the Cambrian Explosion, living approximately 508 million years ago. This bizarre armored slug-like animal was covered in overlapping scales and tall defensive spines, making...
Location: Canada (Burgess Shale), China
Scientific Name: Wiwaxia corrugata
May 16, 2026
Pikaia
Cambrian
Pikaia is one of the most important fossils ever discovered—it may be one of our earliest ancestors! This small, leaf-shaped swimmer lived approximately 508 million years ago during the Middle Cambrian period....
Location: Canada (Burgess Shale)
Scientific Name: Pikaia gracilens
May 16, 2026
Olenoides
Cambrian
Olenoides serratus is one of the most famous and scientifically important trilobites ever discovered! Living approximately 508 million years ago during the Middle Cambrian, this trilobite is celebrated for its exceptional...
Location: Canada (Burgess Shale), USA
Scientific Name: Olenoides serratus
May 16, 2026
Ottoia
Cambrian
Ottoia was a fearsome predatory worm that terrorized the Cambrian seafloor approximately 508 million years ago. As the most abundant worm in the famous Burgess Shale, this priapulid (penis worm) used its...
Location: Canada (Burgess Shale), USA (Utah)
Scientific Name: Ottoia prolifica
February 2, 2026
Dickinsonia
Proterozoic
Dickinsonia is one of the most mysterious and ancient creatures ever found! Living during the Ediacaran period about 558-555 million years ago, it was one of Earth's earliest complex life forms. This bizarre oval-shaped organism lived...
Location: Australia, Russia, Ukraine
Scientific Name: Dickinsonia costata
February 2, 2026
Orthoceras
Ordovician
Orthoceras was an ancient straight-shelled nautiloid—an early relative of today's squids and octopuses! Living from the Ordovician to Triassic periods (around 485-200 million years ago), these jet-propelled hunters had long, cone-shaped shells and were among the...
Location: Worldwide (Morocco, Sweden, North America)
Scientific Name: Orthoceras regulare
February 2, 2026
Birkenia
Silurian
Birkenia was a tiny jawless fish that swam in ancient Silurian seas about 430 million years ago! At only 10 cm (4 inches) long, this small but important fish was an anaspid—one of the early vertebrates that...
Location: Scotland, Norway
Scientific Name: Birkenia elegans
February 2, 2026
Tiktaalik
Devonian
Tiktaalik is one of the most important fossils ever discovered—a 375-million-year-old "fishapod" that shows the transition from fish to land animals! Found in the Canadian Arctic in 2004,...
Location: Arctic Canada (Ellesmere Island)
Scientific Name: Tiktaalik roseae
February 2, 2026
Phorusrhacos
Neogene
Phorusrhacos was one of the most terrifying "terror birds"—giant flightless predatory birds that ruled South America for millions of years! Standing 2.5 meters (8 feet) tall with a massive hooked beak, this apex...
Location: South America (Argentina)
Scientific Name: Phorusrhacos longissimus
February 2, 2026
Smilodon
Quaternary
Smilodon, the famous "saber-toothed cat," was one of the most iconic predators of the Ice Age! Living from about 2.5 million to 10,000 years ago, this powerful cat had enormous canine teeth that could...
Location: North and South America
Scientific Name: Smilodon fatalis
February 2, 2026
Woolly Rhinoceros
Quaternary
The Woolly Rhinoceros was a massive, shaggy beast that roamed the frozen steppes of Ice Age Europe and Asia! Living from about 350,000 to 10,000 years ago, this incredible animal was perfectly...
Location: Europe, Asia
Scientific Name: Coelodonta antiquitatis
February 2, 2026
Gorgonops
Permian
Gorgonops was one of the most fearsome predators of the Late Permian period, approximately 260-252 million years ago! Named after the Gorgons of Greek mythology (monsters with snakes for hair), this...
Location: South Africa
Scientific Name: Gorgonops torvus
Did You Know?
environment
The K-Pg extinction
The K-Pg extinction, caused by an asteroid impact 66 million years ago, wiped out 75% of species, including non-avian dinosaurs, due to climate shifts, wildfires, and tsunamis.
evolution
Megalodon: 7-Inch Teeth Monster
Megalodon's teeth could reach 7.5 inches (19 cm)—three times larger than great white shark teeth! This 20+ meter shark had the strongest bite of any animal ever: 182,000 Newtons.
dinosaur
Longest Dinosaur: 42 Meters!
Supersaurus may be the longest dinosaur ever at up to 42 meters (138 feet)—longer than three school buses! Its neck alone was over 15 meters, and its tail stretched 18+ meters.
evolution
Birds Are Living Dinosaurs
Modern birds are actually living theropod dinosaurs, having evolved from a group of dinosaurs called maniraptors.
discovery
Dinosaurs Were Caring Parents
Fossils show dinosaurs brooding their eggs like birds! A 70-million-year-old Oviraptor was found sitting on a nest of 24 eggs, proving dinosaurs were devoted parents who cared for their young.
dinosaur
T-Rex: Strongest Bite Ever on Land
T-Rex could bite with a force of up to 57,000 Newtons—like having a medium-sized elephant sit on you! This is the strongest bite force of any land animal that ever lived.
evolution
First Land Animals
Tiktaalik, living 375 million years ago, was one of the first vertebrates to venture onto land, with primitive lungs and leg-like fins.
environment
Earth's Oxygen Revolution
About 2.4 billion years ago, the "Great Oxidation Event" dramatically increased Earth's oxygen levels, making complex life possible.
discovery
Dinosaur Herding Started 193 Million Years Ago
The earliest evidence of herd behavior dates to 193 million years ago! Over 100 Mussaurus eggs and 80 skeletons were found together in Patagonia, showing complex social behavior.
environment
Oxygen Made Giant Insects Possible
During the Carboniferous period, oxygen levels reached 35% (vs 21% today). This allowed insects to grow huge—millipedes reached 2.5 meters (8 feet) long!
dinosaur
T-Rex vs Triceratops: Real Rivals
T-Rex and Triceratops actually lived at the same time and place! The Hell Creek Formation contains both—Triceratops makes up 40% of fossils there, T-Rex 24%. They definitely encountered each other.
discovery
Dinosaurs Got Cancer Too
Scientists diagnosed a 76-million-year-old Centrosaurus with bone cancer (osteosarcoma)—the same cancer that affects humans today! This shows cancer has been around for millions of years.
dinosaur
Spinosaurus: A Swimming Dinosaur
Spinosaurus had a paddle-like tail and dense bones for buoyancy—it was semi-aquatic! This 15-meter predator hunted fish in rivers like a giant crocodile-dinosaur hybrid.
dinosaur
T-Rex Teens Gained 45 lbs Per Week
During their teenage growth spurt, T-Rex gained 35-45 pounds PER WEEK until reaching adult size around age 20! Growth rings in SUE's bones revealed this incredible growth rate.
dinosaur
Dinosaur Eggs Were Surprisingly Small
Even the largest dinosaurs laid relatively small eggs—about the size of a football. If eggs were bigger, the shells would be too thick for babies to break out!
evolution
Tiny Mammals Lived With Dinosaurs
Small mammals existed for over 160 million years alongside dinosaurs! They were mostly nocturnal and mouse-sized, waiting in the shadows until the dinosaurs went extinct.
discovery
Dinosaurs Lived on Every Continent
Dinosaur fossils have been found on all seven continents, including Antarctica! When dinosaurs lived, Antarctica was much warmer and connected to other landmasses.
evolution
Crocodiles Outlived the Dinosaurs
Crocodilians have existed for over 200 million years, surviving the asteroid that killed the dinosaurs. They've barely changed because their design is nearly perfect for their lifestyle.
evolution
The First Eyes Appeared 540 Million Years Ago
The evolution of eyes triggered an "arms race" of evolution. Trilobites were among the first creatures with complex eyes, with some having over 15,000 lenses!
discovery
Amber: 230-Million-Year Time Capsules
The oldest creatures preserved in amber are 230 million years old! These tiny mites from Italy are 100 million years older than any other amber fossils, perfectly frozen in tree resin.
discovery
Dinosaurs Traveled in Herds
Trackway evidence proves many dinosaurs traveled in herds! Parallel footprints in Texas and Colorado show sauropods moving together, and the "Dinosaur Freeway" in Colorado stretches 40 miles.
environment
One Day Was Only 22 Hours Long
When dinosaurs roamed Earth, days were shorter! The Moon's gravity is slowly slowing Earth's rotation. 200 million years ago, a year had about 385 days.
discovery
Mary Anning: Fossil Hunting Pioneer
At just 12 years old, Mary Anning discovered the first complete Ichthyosaur fossil in 1811. She became one of history's greatest fossil hunters, despite never receiving formal credit in her time.