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!
Discover the fascinating creatures that once roamed our planet
Permian
Dimetrodon, meaning "two measures of teeth," is one of the most misunderstood prehistoric creatures ever! With its dramatic back sail, it looks like a dinosaur—but it isn't one at all! Living during ...
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Jurassic
Cryolophosaurus, meaning "frozen crested lizard," was a large predatory dinosaur that lived in Antarctica approximately 194 million years ago during the Early Jurassic. Famous for its ...
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Jurassic
Ceratosaurus dentisulcatus is a smaller species of the famous horned dinosaur Ceratosaurus, living approximately 150-145 million years ago during the Late Jurassic. While its larger cousin ...
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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...
February 2, 2026
Triassic
Postosuchus was one of the top predators of the Late Triassic, approximately 228-202 million years ago! This massive archosaur was not a dinosaur, but it filled the same ecological role as large theropods would later. At up to 5...
February 2, 2026
Triassic
Tanystropheus is one of the strangest reptiles ever discovered! Living during the Middle Triassic, approximately 242-235 million years ago, this bizarre creature had a neck that was longer than its body and tail combined! At up to 6 meters long, with a 3-meter...
February 2, 2026
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 reached 6 to 9 meters (20-30 feet) in length. It was...
February 2, 2026
Carboniferous
Meganeura was a giant dragonfly-like insect that ruled the skies during the Carboniferous period, approximately 300 million years ago! With a wingspan of up to 70 cm (28 inches)—about the size of a modern hawk—it was one of the...
February 2, 2026
Carboniferous
Arthropleura was the largest land invertebrate ever to exist! This giant millipede-like creature lived during the Carboniferous period, approximately 300 million years ago, and could grow up to 2.6 meters (8.5 feet) long—longer than most humans are tall! Despite its...
February 2, 2026
Cambrian
Hallucigenia is one of the most bizarre creatures ever discovered! This tiny Cambrian animal was so strange that scientists couldn't figure out which end was up—or even which...
February 2, 2026
Silurian
Eurypterus remipes is the most famous of the "sea scorpions" and the official state fossil of New York! This remarkable arthropod lived approximately 410 million years ago during the Silurian period, swimming through the shallow, brackish waters that once...
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 fossils have been found in Alaska and Antarctica! These polar dinosaurs survived months of darkness and near-freezing temperatures, possibly having feathers for warmth.
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.
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.
About 335 million years ago, all continents were joined into one supercontinent called Pangaea. You could have walked from Antarctica to the Arctic!
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.
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.
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!
Argentinosaurus may have weighed up to 100 tons—as heavy as 14 elephants! Its thigh bone alone was taller than an adult human.
Early whales like Ambulocetus had legs and could walk on land, showing the remarkable transition of mammals back to marine life.
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.
About 2.4 billion years ago, the "Great Oxidation Event" dramatically increased Earth's oxygen levels, making complex life possible.
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.
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.
The Ordovician-Silurian extinction, around 445 million years ago, was caused by a rapid ice age and fluctuating sea levels, eliminating nearly 85% of marine species.
While many famous dinosaurs were enormous, the smallest known dinosaur was the Compsognathus, only about the size of a chicken!
The Chicxulub crater in Mexico is 200 km (124 miles) wide—created by an asteroid 10-15 km across traveling at 20 km/second. The impact released energy equal to 4.5 billion atomic bombs!
Tiktaalik, living 375 million years ago, was one of the first vertebrates to venture onto land, with primitive lungs and leg-like fins.
Thousands of dinosaur trackways have been found on every continent! Some tracks in Colorado show dinosaurs walking together in herds, and some footprints are over a meter wide.
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.
Ornithomimus and Gallimimus were the speed champions, reaching up to 70 km/h (43 mph)—faster than a horse! Their ostrich-like build was perfect for running.
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!
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.