Earth's Oxygen Revolution
About 2.4 billion years ago, the "Great Oxidation Event" dramatically increased Earth's oxygen levels, making complex life possible.
Discover the fascinating creatures that once roamed our planet
Ordovician
Cameroceras was one of the largest animals of the Ordovician period and possibly the largest cephalopod ever! Living approximately 470-440 million years ago, this giant nautiloid had a straight, cone-shaped shell that may have ...
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Cretaceous
Bajadasaurus, meaning "downhill lizard," was one of the weirdest-looking dinosaurs ever discovered! Living during the Early Cretaceous period, about 140 million years ago in what is now Argentina, this ...
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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 ...
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March 23, 2026
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...
March 23, 2026
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...
March 23, 2026
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...
March 23, 2026
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...
March 23, 2026
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....
March 23, 2026
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...
March 23, 2026
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...
February 2, 2026
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...
February 2, 2026
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...
February 2, 2026
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...
February 2, 2026
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,...
February 2, 2026
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...
February 2, 2026
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...
February 2, 2026
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...
February 2, 2026
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...
About 2.4 billion years ago, the "Great Oxidation Event" dramatically increased Earth's oxygen levels, making complex life possible.
Argentinosaurus may have weighed up to 100 tons—as heavy as 14 elephants! Its thigh bone alone was taller than an adult human.
Woolly mammoths were still alive when the Egyptian pyramids were built! The last mammoths survived on Wrangel Island until about 1650 BCE—over 1,000 years after the Great Pyramid.
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!
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.
Scientists believe dinosaurs made closed-mouth sounds like cooing, booming, or growling—similar to crocodiles and ostriches today—not the dramatic roars from Jurassic Park!
Smilodon, the famous saber-toothed cat, had 28 cm (11-inch) fangs and lived throughout North and South America. Over 1,200 specimens have been found in the La Brea Tar Pits alone!
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.
Therizinosaurus had the longest claws of any animal ever—up to 1 meter (3.3 feet) long! Despite looking terrifying, this dinosaur was likely a plant-eater that used its claws for grabbing vegetation.
Real Velociraptors were only about 0.5 meters tall and weighed 15 kg—roughly the size of a turkey! The "raptors" in Jurassic Park were actually based on the larger Deinonychus.
The coelacanth was thought extinct for 65 million years—until one was caught in 1938! Called a "living fossil," it has barely changed in 400 million years and was like finding a living dinosaur.
Early whales like Ambulocetus had legs and could walk on land, showing the remarkable transition of mammals back to marine life.
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.
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.
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.
Horseshoe crabs have remained virtually unchanged for 450 million years—they existed before dinosaurs, survived all mass extinctions, and still live today! They're older than trees and sharks.
Dinosaur fossils have been found in Alaska and Antarctica! These polar dinosaurs survived months of darkness and near-freezing temperatures, possibly having feathers for warmth.
While many famous dinosaurs were enormous, the smallest known dinosaur was the Compsognathus, only about the size of a chicken!
SUE is the largest and most complete T-Rex ever found—90% of the skeleton! The Field Museum paid $8.4 million for SUE in 1997, the most ever paid for a fossil at auction.
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.
In 2005, scientist Mary Schweitzer discovered soft tissue, including flexible blood vessels, inside a 68-million-year-old T-Rex bone—a discovery that shocked the scientific world.
Despite their tiny appearance, T-Rex arms were incredibly strong—each could lift about 200 kg (440 lbs)! Scientists think they helped grip prey or push up from the ground.
Around 700 million years ago, Earth was almost completely covered in ice during the "Snowball Earth" period, with temperatures as low as -50°C.
Megalosaurus was the first dinosaur ever scientifically named, by William Buckland in 1824. The word "dinosaur" itself wasn't invented until 1842 by Richard Owen!