The American lion was one of the largest cats of Ice Age North America. It was not a dinosaur, and it was not exactly the same as a modern African lion. Scientists call it Panthera atrox and study its bones, teeth, and La Brea Tar Pits fossils to understand how it hunted and lived.

Castoroides was a giant extinct beaver from Ice Age North America. It was not a dinosaur, and it was much larger than modern beavers. Castoroides lived near lakes, wetlands, and waterways, but scientists are cautious about saying it built dams like modern beavers because the evidence is not clear.

The cave bear was a large Ice Age bear that lived in Europe and western Asia. It was not a dinosaur, and it was not the same as a modern brown bear. Cave bears are famous because many of their bones were found in caves, where they likely hibernated during cold seasons.

The cave lion was a large extinct cat from the Ice Age. It was not a dinosaur and was not the same as a modern lion, though it was closely related. Cave lions lived across cold northern landscapes, hunted large prey, appeared in ancient art, and even left frozen cub fossils in Siberia.

The dire wolf was an extinct Ice Age predator from the Americas. It looked wolf-like, but new research shows it was not just a bigger gray wolf. Dire wolves had strong jaws, powerful teeth, and many fossils at La Brea Tar Pits, where they are one of the most famous Ice Age mammals.

Doedicurus was a giant armored mammal from South America. It was not a dinosaur, and it was not an ankylosaur, even though its heavy tail club can look a little dinosaur-like. Doedicurus was a glyptodont, an extinct armadillo relative with a huge shell and a powerful clubbed tail.

Elasmotherium was a giant extinct rhinoceros relative from Ice Age Eurasia. It was not a dinosaur and not a horse, even though its nickname, the Siberian unicorn, sounds magical. Scientists think it lived on open grasslands and may have survived until less than 40,000 years ago.

Genyornis was a giant extinct flightless bird from Pleistocene Australia. It was not a dinosaur and not an emu, though it lived in the same country as modern emus. Genyornis newtoni was the last known mihirung, or thunder bird, and may have stood over 2 metres tall before disappearing around 45,000 to 50,000 years ago.

Giant ground sloths were extinct mammals related to modern sloths. They were not dinosaurs, and they did not live in trees like today’s small sloths. Different kinds lived in North and South America, from forest browsers such as Megalonyx to enormous South American forms such as Megatherium.

Gigantopithecus was a giant extinct ape from Pleistocene southern China. It was not a dinosaur, gorilla, or Bigfoot, though it may have been the largest primate ever known. Scientists mostly know it from jaws and thousands of teeth, so its full body is reconstructed carefully from clues rather than a complete skeleton.

Glyptodon was a giant armored mammal from South America. It was not a dinosaur, and it was not a turtle, even though its huge bony shell can make people think of one. Glyptodon was a glyptodont, a large extinct armadillo relative with a domed carapace made from many bony plates.

Homotherium was an extinct scimitar-toothed cat that lived in parts of Africa, Eurasia, and the Americas. It was not a dinosaur and not the same as Smilodon. Homotherium had shorter, flatter saber teeth, long legs, and a body that may have been better for moving through open habitats.

The Irish elk was a giant extinct deer from the Ice Age. It was not a dinosaur, and despite its name, it was not a true elk like the North American elk. Male Irish elk are famous for enormous antlers that could spread wider than a small car.

Litopterna was an extinct order of native South American hoofed mammals. They were not dinosaurs, horses, camels, or llamas, although some looked a bit like familiar hoofed animals. Litopterns evolved in South America after the dinosaurs, spread into many shapes, and included long-necked Macrauchenia, one of the last members of the group.

Macrauchenia was a strange extinct South American mammal from the Ice Age. It was not a dinosaur, camel, llama, or horse, even though its long neck and body can look camel-like. Macrauchenia belonged to Litopterna, a vanished group of native South American hoofed mammals, and its nostrils sat high on the skull in a way that still makes scientists debate its face.

Mastodons were extinct elephant relatives that lived in North America during the Ice Age. They were not dinosaurs, and they were not the same as mammoths. Mastodons had tusks, trunks, heavy bodies, and bumpy cone-shaped molars suited for browsing leaves, twigs, and forest plants.

Megalania, also called Varanus priscus, was a giant extinct monitor lizard from Pleistocene Australia. It was not a dinosaur and not a crocodile. It was a huge reptile related to modern monitor lizards, and many scientists consider it the largest land-dwelling lizard known from fossils.

Megaloceros was a genus of giant deer from the Ice Age. Its most famous species, Megaloceros giganteus, is often called the Irish elk or giant deer, but it was not a true modern elk. Male Megaloceros are famous for enormous antlers that spread wider than almost any deer antlers known.

Megatherium was a giant ground sloth from South America. It was not a dinosaur, and it was not a tree sloth like the small sloths alive today. Megatherium was an enormous Ice Age mammal with huge claws, a strong tail, and a body built for walking on the ground and reaching plants.

Meiolania was a giant extinct horned turtle from Australasia. It was not a dinosaur and not a tortoise you would want to bump into. Meiolania had a big shell, strange horns on its skull, and an armored tail with a club-like end, making it one of the most spectacular turtle-shaped tanks in prehistory.

Mihirung is a name used for Australia’s extinct giant flightless birds in the family Dromornithidae. It is more of a group name than one single animal, so this page covers the thunder birds as a group. Some mihirungs were taller than people, and Dromornis stirtoni may have been one of the heaviest birds ever known.

Notoungulates were an extinct order of native South American hoofed mammals. They were not dinosaurs and not the same as modern horses, cows, rhinos, or deer. The group was amazingly diverse, with tiny rabbit-like forms, sheep-like grazers, and huge rhino-like plant eaters such as Toxodon.

Palaeoloxodon was an extinct genus of elephants that included the famous straight-tusked elephants. It was not a dinosaur and not a woolly mammoth, though it lived during the Ice Age alongside many other giant mammals. Some Palaeoloxodon species were enormous forest elephants, while island species became tiny dwarf elephants.

Palorchestes was an unusual extinct Australian marsupial often nicknamed the marsupial tapir. It was not a real tapir and not a dinosaur. Its skull suggests it may have had a short trunk-like snout, and its powerful forelimbs and large claws may have helped it pull down branches or dig for roots.

Procoptodon was a giant extinct short-faced kangaroo from Pleistocene Australia. It was not a dinosaur and not a normal modern kangaroo. The best-known species, Procoptodon goliah, was the largest kangaroo known to science, with a short flat face, powerful legs, long clawed fingers, and unusual single-toed feet.

The short-faced bear was a giant Ice Age bear from North America. It was not a dinosaur, and it was not just a bigger version of a modern grizzly. Scientists study its bones, teeth, caves, and chemistry clues to understand whether it hunted, scavenged, ate plants, or did a mix of all three.

Smilodon was a powerful saber-toothed cat from the Ice Age. It was not a dinosaur and not a true tiger, even though people often call it the saber-toothed tiger. Smilodon had huge upper canine teeth, strong front legs, and fossils famous from places such as La Brea Tar Pits.

Stegodon was an extinct elephant relative that lived across Africa and Asia for millions of years. It was not a dinosaur and not exactly a modern elephant, though it was part of the proboscidean family tree. Stegodon is famous for its ridged molars, long tusks, giant mainland species, and dwarf island species such as Stegodon florensis on Flores.

The steppe bison was an extinct Ice Age bison that lived across Eurasia and North America. It was not a dinosaur, but a hoofed mammal related to modern bison. Steppe bison had large horns, a heavy body, and lived in open mammoth-steppe habitats with mammoths, horses, wolves, and big cats.

Teratornis was a giant extinct flying bird from the Ice Age. It was not a dinosaur and not a pterosaur. The best-known species, Teratornis merriami, looked a bit like a huge condor with a hooked beak, broad wings, and strong soaring skills. Many fossils have been found at the La Brea Tar Pits in Los Angeles.

Thylacoleo was an extinct Australian marsupial often called the marsupial lion. It was not a real lion and not a dinosaur. The best-known species, Thylacoleo carnifex, was Australia's largest known mammalian carnivore and may have ambushed big Pleistocene animals with powerful forelimbs, sharp claws, and slicing teeth.

Titanis was a giant extinct flightless bird from North America. It was not a dinosaur and not an ostrich. Titanis walleri belonged to the terror bird family, a group that began in South America, and it became the only confirmed terror bird known from North America after moving north during the Great American Biotic Interchange.

Toxodon was a huge extinct South American mammal from the Ice Age. It was not a dinosaur, rhinoceros, or hippopotamus, even though its heavy body can look rhino-like in drawings. Toxodon belonged to Notoungulata, a vanished group of native South American hoofed mammals, and it became famous after Charles Darwin collected its fossils.

Wonambi was a giant extinct snake from ancient Australia. It was not a dinosaur and not a python, even though it lived in Australia and looked snake-like in a familiar way. Wonambi belonged to an old snake family called Madtsoiidae and was a powerful constrictor that lived during the Pliocene and Pleistocene.

The woolly mammoth was an Ice Age elephant relative with long shaggy hair, a thick fat layer, small ears, a trunk, and huge curved tusks. It lived in cold northern habitats across Eurasia and North America. The last woolly mammoths survived on islands until about 4,000 years ago.

The woolly rhinoceros was an extinct Ice Age mammal with thick fur, a large front horn, a smaller nose horn, and a sturdy body built for cold open habitats. It lived across northern Eurasia in steppe-tundra landscapes with mammoths, bison, reindeer, and other Ice Age animals.

Zygomaturus was a giant extinct marsupial from ancient Australia. It was not a dinosaur and not a rhinoceros, though people sometimes compare its bulky body with a hippo or rhino. Zygomaturus trilobus was a large plant-eater related to Diprotodon, wombats, and other diprotodontid marsupials.