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.
Discover the fascinating creatures that once roamed our planet
Quaternary
Megalania, meaning "great roamer," was the largest land lizard to ever exist—a giant monitor lizard that terrorized Australia during the Pleistocene Epoch. Living from about 1.6 million to 40,000 years ago, this massive ...
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Cretaceous
Pteranodon is probably the most famous pterosaur of all time—and one of the most recognizable prehistoric creatures! Living approximately 86-84 million years ago during the ...
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Jurassic
Brachiosaurus, meaning "arm lizard," was one of the most magnificent dinosaurs ever to walk the Earth. Living during the Late Jurassic period (154-150 million ...
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August 16, 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...
August 16, 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...
August 16, 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...
August 16, 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...
August 16, 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....
August 16, 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...
August 16, 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...
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.
Hadrosaurs had the most complex teeth ever—up to 300 teeth per jaw arranged in "dental batteries." These constantly replaced themselves and could grind the toughest plants.
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.
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.
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!
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.
Sharks have been swimming in Earth's oceans for about 450 million years—that's 100 million years before the first trees appeared! They survived all five mass extinctions.
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.
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!
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.
Modern birds are actually living theropod dinosaurs, having evolved from a group of dinosaurs called maniraptors.
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.
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!
Scientists study fossilized dinosaur poop (coprolites) to learn what they ate! A 2024 study of 500+ coprolites showed early dinosaurs were "opportunistic" eaters—they ate everything.
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.
The blue whale is the largest animal EVER—bigger than any dinosaur! At 200 tons, it weighs twice as much as the largest dinosaurs. Some dinosaurs were longer, but none were heavier.
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.
About 2.4 billion years ago, the "Great Oxidation Event" dramatically increased Earth's oxygen levels, making complex life possible.
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.
During the Cretaceous, sea levels were 150-200 meters higher than today. About 30% of today's land was underwater, and there was no ice at the poles!
Quetzalcoatlus had a wingspan of 10-11 meters—longer than a school bus! This pterosaur was as tall as a giraffe when standing and could fly at 80 mph for days.
The Permian-Triassic extinction event, known as "The Great Dying," wiped out about 95% of marine species and 70% of land species.
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.
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!