The fossil record is rich in fascinating creatures.
In fact, Earth’s fauna was richer in the prehistoric past than its current condition.
Interestingly, despite our best efforts, we only know a small percentage of animals that have lived throughout geologic history.
That’s because only a small percentage of animal remains are preserved in the fossil record.
Land animals are even less likely to be preserved as fossils, which means a huge percentage of terrestrial species are yet to be discovered.
For many species, their current form differs considerably from what their ancient ancestors looked like.
Some prehistoric animals also have no living relatives, meaning we cannot be entirely sure what they look like.
It’s all part of an intriguing tapestry of ancient life forms that everyone needs to know in order to fully appreciate how far life on Earth has come.
In this article, we list 25 prehistoric animals that have occupied Earth’s terrestrial ecosystem throughout geologic history.
25. Arthropleura
| Name | Arthropleura |
| Name Meaning | “Jointed ribs” |
| Pronunciation | Ar-thro-PLOOR-uh |
| Era | Paleozoic—Late Carboniferous |
| Classification | Diplopoda, Arthropleurida, Arthropleuridae |
| Diet | Herbivorous |
| Length | 2.5 meters (8.2 feet) |
| Location | North America and Europe |
The Arthropleura was a giant millipede that grew to a length of up to eight feet and had more than 700 legs.
It is considered one of the largest terrestrial invertebrates to have ever lived.
Arthropleura lived during the Carboniferous Period about 300 million years ago.
Scientists are unsure what this giant critter ate, but it was most likely a herbivore.
Like modern arthropods, the Arthropleura molted periodically as it grew.
Numerous molting shells of this giant arthropod have been found across North America and Europe, and they’re the only evidence of its existence preserved in the fossil record.
24. Brontosaurus
| Name | Brontosaurus |
| Name Meaning | “Thunder lizard” |
| Pronunciation | BRON-toh-SAWR-us |
| Era | Mesozoic—Late Jurassic |
| Classification | Dinosauria, Saurischia, Sauropoda |
| Diet | Herbivorous |
| Height | 7–9 meters (23–30 feet) |
| Length | 21–22 meters (69–72 feet) |
| Weight | 15–17 metric tons (33,000-34,000 pounds) |
| Location | North America (United States) |
Brontosaurus was a long-necked sauropod dinosaur that lived in North America about 150 million years ago during the Jurassic Period.
With a length of about 80 feet and weight of up to 30 tons, it is commonly featured on the list of largest dinosaurs ever discovered.
In addition to being massive, the long tail of the Brontosaurus ends in a muscular whip-like structure that was probably used to defend itself against predators.
23. Dimetrodon
| Name | Dimetrodon |
| Name Meaning | “Two measures of teeth” |
| Pronunciation | Die-met-ro-don |
| Era | Paleozoic—Permian |
| Classification | Synapsida, Pelycosauria, Sphenacodontidae |
| Diet | Carnivorous |
| Height | 4 to 5 meters (13 to 16.5 feet) |
| Length | 3–4.5 meters (10–15 feet) |
| Weight | 28–250 kg (62–551 pounds) |
| Location | North America and Europe |
This sail-backed synapsid is often mistaken for a dinosaur.
But it lived during the Permian Period, several million years before the dinosaurs first evolved.
Dimetrodon could grow up to 30 feet long and weighed up to 1,000 pounds.
Although it had a sprawling posture and generally reptile-like appearance, the Dimetrodon was more related to mammals than reptiles.
Dimetrodon was an adaptable terrestrial predator, but it was also capable of wading in muddy waters to catch prey.
22. Aepyornis
| Name | Aepyornis |
| Name Meaning | “High bird or tall bird” |
| Pronunciation | Ay-pee-or-nis |
| Era | Cenozoic—Tertiary |
| Classification | Aves, Palaeognathae, Aepyornithiformes |
| Diet | Herbivorous |
| Height | 3–4 meters (10–13 feet) |
| Weight | 275–1,000 kilograms (610–2,200 pounds) |
| Location | Madagascar |
More commonly referred to as elephant bird, Aepyornis is considered the largest bird to have ever lived.
This massive bird weighed about 275 to 1,000 kilograms (610–2,200 pounds) and was up to nine feet tall.
It lived on the Island of Madagascar until the 16th or 17th century, when human activities on the Island drove the large bird to extinction.
Like most big birds, the Aepyornis was flightless, and it survived on a diet made up predominantly of plant materials.
21. Mastodon
| Name | Mastodon |
| Pronunciation | MAS-tuh-don |
| Era | Cenozoic—Tertiary |
| Classification | Mammalia, Proboscidea, Mammutidae |
| Diet | Herbivorous |
| Height | 8–10 feet at the shoulder (2.4–3 meters) |
| Length | 10–13 feet (3–4 meters) |
| Weight | 4,500–11,000 kilograms (9,920–24,250 pounds) |
| Location | North and Central America, Eurasia, and Africa |
This elephant-like mammal lived in North America, Europe, and Asia during the Pleistocene Epoch.
It was alive from two million years till about 10,000 years ago.
Mastodons were similar in size to modern elephants, with an average height of up to 13 feet and a weight of about 10 tons.
Like their modern relatives, mastodons were herbivores with a diet of leaves, twigs, and fruits.
They were hairy, with a thick undercoat of wood, which helped to protect them against predators.
20. Stegosaurus
| Name | Stegosaurus |
| Name Meaning | “Roof lizard” |
| Pronunciation | steg-uh-SAWR-us |
| Era | Mesozoic – Late Jurassic |
| Classification | Dinosauria, Ornithischia & Stegosauria |
| Diet | Herbivorous |
| Height | 4 to 5 meters (13 to 16.5 feet) |
| Length | 9 to 10 meters (30 to 33 feet) |
| Weight | 3.5–5 metric tons (7,716–11,023 lbs) |
| Location | North America (United States) |
Stegosaurus is arguably one of the most recognizable dinosaurs.
It was a massive herbivore that lived during the Late Jurassic Period about 150 million years ago.
It grew to a length of about 30 feet and weighed up to nine tons.
But the most distinctive feature of this dinosaur was the rows of bony kite-shaped plates on its back and the spikes on its tail.
The backplates probably were for thermoregulation, while the tail spikes (also known as thagomizers) served the purpose of defending the dinosaur against predators.
19. Andrewsarchus
| Name | Andrewsarchus |
| Name Meaning | “Named after Roy Chapman Andrews and “archus” meaning “ruler” or “monarch.”” |
| Pronunciation | An-droo-sar-kus |
| Era | Cenozoic—Paleogene |
| Classification | Mammalia, Artiodactyla, Andrewsarchidae |
| Diet | Carnivorous |
| Height | 1.8 meters (6 feet) |
| Length | 4.8-5.5 meters (16-18 feet) |
| Weight | 500-1000 kilograms (1,100-2,200 pounds) |
| Location | Mongolia and China (Asia) |
The Andrewsarchus is considered one of the largest carnivorous land mammals to have ever lived.
This large mammal was around 45 to 34 million years ago during the Paleogene Period.
It probably preyed on other large mammals in its ecosystem, including the ancestors of rhinoceroses and elephants.
A relative of modern whales and hippos, Andrewsarchus lived in desert to semi-arid ecosystems in parts of present-day Mongolia.
18. Plateosaurus
| Name | Plateosaurus |
| Pronunciation | PLAT-ee-oh-SAW-rus |
| Era | Mesozoic—Late Triassic |
| Classification | Dinosauria, Saurischia, Sauropodomorpha |
| Diet | Herbivorous |
| Height | 2.4–3 meters (8–10 feet) |
| Length | 4.8–10 meters (16–33 feet) |
| Weight | 600–4,000 kilograms (1,300–8,800 lb) |
| Location | Germany and Switzerland (Europe) |
Before sauropods became the massive quadrupedal beasts that we are familiar with, they were the first bipedal herbivores.
The Plateosaurus is a classic example that demonstrates this.
It was a basal sauropod that lived during the Triassic Period about 210 million years ago.
Although smaller than the sauropods that would evolve later in the Jurassic and Cretaceous, the Plateosaurus was still one of the largest terrestrial animals of its time, growing to an average length of about 20 feet.
17. Triceratops
| Name | Triceratops |
| Name Meaning | “Three-horned face” |
| Pronunciation | Trih-SAIR-uh-tops |
| Era | Mesozoic – Late Cretaceous |
| Classification | Dinosauria, Ornithischia, & Ceratopsia |
| Diet | Herbivorous |
| Height | 2.3 meters (7.5 feet) |
| Length | 9 meters (30 feet) |
| Weight | 5 to 9 tons (10,000–18,000 lbs) |
| Location | USA & Canada (North America) |
The Triceratops is one of the most famous dinosaurs ever discovered, thanks to its distinctive appearance.
It was a ceratopsian dinosaur—a family of plant-eating dinosaurs known for their distinctive frills and facial horns.
Triceratops had three prominent horns on its head and a large frill at the back of its head.
These head adornments probably helped to protect the dinosaur from predators and were also used for mating rituals.
Triceratops lived in the Late Cretaceous Period, which means it was alive during the last few million years of the dinosaurs.
16. Therizinosaurus
| Name | Therizinosaurus |
| Name Meaning | “Scythe Lizard” |
| Pronunciation | Theri-zino-sore-us |
| Era | Mesozoic – Late Cretaceous |
| Classification | Dinosauria, Saurischia & Theropoda |
| Diet | Herbivorous |
| Height | 4-5 meters (13-16 feet) |
| Length | 9-10 meters (30-33 feet) |
| Weight | 3-5 tons (3.3-5.5 short tons) |
| Location | Mongolia (Asia) |
The Therizinosaurus was a massive dinosaur with three-foot-long claws.
The claw bones of this dinosaur are the largest of any land animal, giving it a truly menacing appearance.
The dinosaur itself was about 33 feet long and weighed up to five tons.
Despite the fierce claws, the Therizinosaurus was probably a herbivore.
The claws were mainly used for tearing down plant materials but would have been effective for self-defense, too, if the dinosaur ever got cornered.
15. Megalania
| Name | Megalania |
| Name Meaning | “Great wanderer” |
| Pronunciation | MEG-uh-LAY-nee-uh |
| Era | Cenozoic—Quaternary |
| Classification | Reptilia, Squamata, Varanidae |
| Diet | Carnivorous |
| Length | 3–7 meters (10–23 feet) |
| Weight | 97–1,940 kilograms (214–4,277 pounds) |
| Location | Australia |
The Megalania is an extinct monitor lizard that lived in Australia during the Pleistocene Epoch.
It was the apex predator on the continent and considered the largest lizard that has ever lived.
The 23-foot lizard preyed on Australia’s megafauna, which included large terrestrial animals like the Diptrodon.
In addition to a massive jaw lined with rows of serrated teeth, experts think the Megalania was probably venomous like many species of monitor lizards today.
The Megalania went extinct 50,000 years ago, which means it probably lived alongside early humans on the continent before its extinction.
14. Thylacoleo
| Name | Thylacoleo |
| Name Meaning | “Pouch lion” |
| Pronunciation | THIGH-lah-co-LEE-oh |
| Era | Cenozoic—Quaternary |
| Classification | Mammalia, Diprotodontia, Thylacoleonidae |
| Diet | Carnivorous |
| Height | 75 centimeters (30 inches) |
| Length | 150 centimeters (59 inches) |
| Weight | 90-160 kilograms (198–352 pounds) |
| Location | Australia |
Although it is commonly referred to as the marsupial lion, Thylacoleo was not a lion at all.
Instead, it is more closely related to marsupials like kangaroos and wombats.
It did have a cat-like appearance and was about the same size as modern lions.
Thylacoleo is the largest carnivorous land mammal known from Australia.
It had one of the most powerful bites of any animal in its weight class.
13. Repenomamus
| Name | Repenomamus |
| Pronunciation | Rep-en-oh-MAY-mus |
| Era | Mesozoic—Early Cretaceous |
| Classification | Mammalia, Theria, Gobiconodontidae |
| Diet | Carnivorous |
| Height | 1–2 feet (30–60 centimeters) |
| Length | 3–4 feet (1–1.2 meters) |
| Weight | 4–11 kilograms (9–22 pounds) |
| Location | China and Mongolia (Asia) |
Mammals were around during the age of dinosaurs (the Mesozoic Era), but most of them were small, rodent-sized creatures.
The Repenomamus was exceptional because it was larger than most of the other mammals of its day.
It lived during the Cretaceous Period about 125 million years ago.
Repenomamus was a badger-sized mammal and weighed up to 25 pounds on average.
It was a prolific carnivore and one of the few mammals known to have preyed on dinosaurs.
Fragments of a juvenile Psittacosaurus were found in the gut content of the Rapenomamus.
12. Megantereon
| Name | Megantereon |
| Pronunciation | MEG-an-TAY-ree-on |
| Era | Cenozoic—Quaternary |
| Classification | Mammalia, Carnivora, Felidae |
| Diet | Carnivorous |
| Height | 72 centimeters (28 inches) |
| Length | 1.5–2 meters (5–6.5 feet) |
| Weight | 90–150 kilograms (200–330 pounds) |
| Location | Africa, Europe, and Asia |
The saber-toothed tigers were among the most notable prehistoric mammalian carnivores.
The most intriguing aspect of their appearance was their long, dagger-like teeth, which gave them their nickname.
Megantereon was one of the most well-known members of this group.
It lived during the Pleistocene Epoch, predating more popular saber-toothed cats like the Smilodon.
Megantereon was built like modern jaguars but had a bulkier appearance.
Megantereon hunted prey by leaping on them from high trees and inflicting deep, fatal wounds with its extra-long canines.
11. Glyptodon
| Name | Glyptodon |
| Pronunciation | GLIP-toh-don |
| Era | Cenozoic—Quaternary |
| Classification | Mammalia, Cingulata, Chlamyphoridae |
| Diet | Herbivorous |
| Height | 1.2–1.5 meters (4–5 feet) |
| Length | 3–4 meters (10–13 feet) |
| Weight | 1,500–2,000 kilograms (3,300–4,400 pounds) |
| Location | South America |
Imagine an enormous armadillo-like creature the size of a small car- that’s the Glyptodon.
This prehistoric mammal was covered in a hard, protective shell similar to present-day armadillos, which served a similar purpose of protecting it from prey.
The Glyptodon also had a massive tail club that was useful for defense.
Glyptodon was alive during the Pleistocene Epoch in North and South America, from three million years to about 11,000 years ago.
10. Darwinus
| Name | Darwinus |
| Pronunciation | dar-win-hus |
| Era | Cenozoic—Paleogene |
| Classification | Mammalia, Primates, Adapidae |
| Diet | Herbivorous |
| Length | 58 centimeters (23 inches) |
| Location | Germany (Europe) |
A relative of modern lemurs and galagos, this strepsirrhine primate lived during the Middle Eocene Epoch about 47 million years ago.
Only one fossil of the Darwinus has ever been found.
The individual fossil nicknamed Ida was discovered in Germany in 1983.
But it was not officially named or described until 2007 because it was kept secret by a private collector who purchased it shortly after it was found.
Darwinus is one of the oldest primate fossils ever discovered.
9. Stagonolepis
| Name | Stagonolepis |
| Pronunciation | Stag-oh-NOH-lep-is |
| Era | Mesozoic—Late Triassic |
| Classification | Reptilia, Aetosauria, Stagonolepididae |
| Diet | Herbivorous |
| Length | 10–13 feet (3–4 meters) |
| Weight | 280 kilograms (620 pounds) |
| Location | North America, Europe, and Africa |
Stagonolepis was a crocodile-like reptile that lived during the Late Triassic Period.
It was an aetosaur, a group of heavily armored reptiles whose existence predates the crocodiles.
They were the most abundant land vertebrates before the dinosaurs took over.
Stagonolepis was a 10-foot-long quadrupedal herbivore that survived on a diet of horsetails, cycads, and ferns that were abundant in its ecosystem.
The morphology of its limbs suggests that it was probably capable of digging the substrate in search of food.
8. Lisowicia
| Name | Lisowicia |
| Pronunciation | Li-soh-VEE-see-uh |
| Era | Mesozoic—Late Triassic to Early Jurassic |
| Classification | Synapsida, Therapsida, Stahleckeriidae |
| Diet | Herbivorous |
| Height | 2.5 meters (8.5 feet) |
| Length | 4.5–6 meters (15–20 feet) |
| Weight | 8000kg (9 tons) |
| Location | Poland (Europe) |
Lisowicia was a massive synapsid that lived during the Late Triassic, about 210 million years ago.
It is the largest non-mammalian synapsid ever discovered, with a size that rivaled that of modern elephants.
Unlike the other synapsids (and other animals of the Triassic) with a sprawling posture, Lisowicia is one of the first animals with an upright posture.
Its limbs were held directly under its body like that of the dinosaurs and living mammals.
It was a herbivore that survived on a diet of soft vegetation and conifers.
7. Proganochelys
| Name | Proganochelys |
| Pronunciation | Proh-gan-oh-KEE-lees |
| Era | Mesozoic—Late Triassic to Early Jurassic |
| Classification | Reptilia, Pantestudines, Testudinata |
| Diet | Herbivorous |
| Length | 2–3 feet (0.6–0.9 meters) |
| Weight | 20–30 kilograms (44–66 pounds) |
| Location | Germany and Thailand (Europe) |
Like their reptilian relatives, turtles have been around since the early years of the Mesozoic and the Proganochelys is one of the oldest forms of this unique group of reptiles.
Proganochelys lived as far back as the Triassic Period, about 210 million years ago.
This means it is one of the oldest stem turtle species to have ever lived.
It had fully developed shells and a beak.
The most prominent difference between the Proganochelys and living turtles is their spiked tail club, which they use to defend themselves from predators.
6. Tsaidamotherium
| Name | Tsaidamotherium |
| Pronunciation | TIE-dah-moe-THEE-ree-um. |
| Era | Cenozoic—Tertiary |
| Classification | Mammalia, Artiodactyla, Bovidae |
| Diet | Herbivorous |
| Length | 3 meters (10 feet) |
| Weight | 200 kilograms (440 pounds) |
| Location | China (Asia) |
Tsaidamotherium was an odd-looking relative of modern-day bovines such as the giraffe and okapi.
It looked morphologically similar to a modern musk ox but had several striking features.
The most notable one was the large cylindrical horn that sits right at the center of its forehead.
It also had a smaller horn right next to the main horn.
Tsaidamotherium lived during the Late Miocene in parts of Northwestern China.
5. Megatherium
| Name | Megatherium |
| Name Meaning | “Great beast” |
| Pronunciation | Meg-uh-theer-ee-uhm |
| Era | Cenozoic—Quaternary |
| Classification | Mammalia, Pilosa, Megatheridae |
| Diet | Herbivorous |
| Height | 2.1 meters (6 feet 11 inches) |
| Length | 6 meters (20 feet) |
| Weight | 4 tons (8,800 pounds) |
| Location | South America and North America |
The Megatherium was an elephant-sized version of modern-day sloths.
It lived in South America from the Early Miocene to the Pleistocene Epoch and was one of the largest land animals on the continent throughout this period.
It was up to 20 feet long with a shoulder height of up to six feet on average.
Megatherium had a robust muscular build.
Experts think it was capable of rearing up its upper body to assume a bipedal posture to access plants that were beyond the reach of other herbivores.
4. Smilodon
| Name | Smilodon |
| Name Meaning | “Knife tooth” |
| Pronunciation | SMY-lo-don |
| Era | Cenozoic—Quaternary |
| Classification | Mammalia, Carnivora, Felidae |
| Diet | Carnivorous |
| Height | 1 meter (3.3 feet) |
| Length | 1.5–2.5 meters (5–8 feet) |
| Weight | 160–280 kilograms (350–620 pounds) |
| Location | North America and South America |
The Smilodon is arguably the most famous saber-toothed cat.
This lion-sized predator is known for its long, serrated canine teeth that could deliver powerful bone-crushing bites.
Smilodon prowled the forests of North and South America during the Pleistocene Epoch and was alive until about 11,000 years ago.
It was an apex predator that hunted large American megafauna such as giant bison, horses, and camels.
3. Brachiosaurus
| Name | Brachiosaurus |
| Name Meaning | “Arm Lizard” |
| Pronunciation | Brak-ee-oh-SAWR-uhs |
| Era | Mesozoic – Late Jurassic |
| Classification | Dinosauria, Saurischia & Sauropoda |
| Diet | Herbivorous |
| Height | 12-13 meters (39-43 feet) |
| Length | 18 to 22 meters (59 and 72 feet) |
| Weight | 28 to 56 tons (61,000–120,000lbs) |
| Location | USA (North America) |
This colossal, long-necked dinosaur lived about 150 million years ago during the Jurassic Period.
It was a sauropod with an estimated body length of up to 72 feet.
Brachiosaurus is known for its disproportionately long neck, which made it possible to browse vegetation high above the ground.
Fossils of the Brachiosaurus were discovered in the 1900s.
It was considered the largest land animal for several years until the discovery of larger sauropods much later in the 20th century.
It is still one of the largest animals to have ever lived.
2. Velociraptor
| Name | Velociraptor |
| Name Meaning | “Swift plunderer” |
| Pronunciation | Vuh-LOS-uh-rap-tor |
| Era | Mesozoic – Late Cretaceous |
| Classification | Dinosauria, Saurischia, Theropoda |
| Diet | Carnivorous |
| Height | 0.6 meters (2 feet) |
| Length | 1.8 meters (6 feet) |
| Weight | 15-20 kilograms (33-44 pounds) |
| Location | Mongolia and China (Asia) |
The Velociraptor is often depicted in movies and other pop-culture materials as an oversized killing machine.
But the real Velociraptor was probably just about the same size as a turkey.
It was about 6.8 feet long and 1.6 feet tall at the hips.
It was an intelligent predator with sharp claws that were effective for slashing at prey.
Velociraptor lived in Asia about 75 million years ago during the Cretaceous Period.
1. Tyrannosaurus rex
| Name | Tyrannosaurus |
| Name Meaning | “Tyrant lizard” |
| Pronunciation | Tie-RAN-oh-SAWR-uhs |
| Era | Mesozoic – Late Cretaceous |
| Classification | Dinosauria, Saurischia, Theropoda |
| Diet | Carnivorous |
| Height | 4–6 meters (13–20 feet) |
| Length | 12–15 meters (40–50 feet) |
| Weight | 5–8 tons (11,000–18,000 lbs) |
| Location | United States and Canada (North America) |
No list of prehistoric terrestrial animals is complete without mentioning the “tyrant king of dinosaurs.”
The Tyrannosaurus is one of the most recognizable prehistoric animals thanks to its abundant representation in pop culture.
The T-rex was the apex predator of Late Cretaceous North America.
The dinosaur is known for its imposing size and powerful jaws, effective for taking down some of the largest prey animals on the North American continent during the last few million years of the Cretaceous.
Sources
- https://en.wikipedia.org/wiki/Aepyornis#
- https://en.wikipedia.org/wiki/Mastodon
- https://www.amnh.org/explore/news-blogs/on-exhibit-posts/andrewsarchus
- https://www.cs.mcgill.ca/~rwest/wikispeedia/wpcd/wp/t/Triceratops.htm
- https://australian.museum/learn/animals/mammals/thylacoleo-carnifex/
- https://en.wikipedia.org/wiki/Megantereon
- https://en.wikipedia.org/wiki/Glyptodon
- https://www.livescience.com/5419-ancient-human-ancestor-ida-discovered.html
- https://en.wikipedia.org/wiki/Proganochelys
- https://www.britannica.com/animal/Megatherium
- https://ucmp.berkeley.edu/diapsids/saurischia/dromaeosauridae.html
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