Monster Mash: 8 Giant, Earth-Shaking, Prehistoric Beasts

Some of the coolest extinct animals are now the most mundane. A giant rodent the size of a small car is much more exciting than the one scurrying on the subway track. Prehistoric animals almost always seem to be larger than life, and a wonder to behold.

Gigantic Ground Sloth

(Images via mengualphelps, wikipedia, mentalfloss, wikipedia)

Megatherium are related to modern ground sloths, with one major difference: they were the size of elephants. These beasts would use their huge size to deter predators and get at low branches in trees. One of the largest land mammals of all time, Megatherium could weigh up to 8 tons.


(Images via bygonebeasts, intelligenttravelitsnature)

Indricotherium was the largest land mammal to roam the earth. 18 feet tall, 30 feet long, and weighing up to 20 tons, this animal was mind-bogglingly huge. While its gigantic girth would make it quite intimidating, this gentle giant was an herbivore, and would use its size to reach leaves and deter predators.

Giant Wombat

(Images via vivekgaurblog, 50birdsaustralianmuseumpbase)

Diprotodon was a terrifying, gigantic… wombat. These creatures are most closely related to the modern wombat and koala, but with a staggering size difference. Diprotodon could grow to weigh over 6,000 pounds.

Devil Toad

(Images via dinosaurs.about, nationalgeographic)

The Devil Frog was a beastly ancestor to the modern amphibian. They were 16 inches long and would weigh around 10 pounds.

Giant Rat

(Images via radatilly, projects.ajc, discovermagazine, cryptomundo)

The Capybara is the largest rodent in the world, but its size pales in comparison to the prehistoric giant rat, which could grow to be the size of a small car. Subsisting entirely on fruits and vegetables, it wasn’t quite as scary as the name “giant prehistoric rodent” suggests.

Short-faced Bear

(Images via edulifedeskslivescienceweb.mebear)

The short-faced bear (Arctodus Simus) would put the modern bear to shame. With a standing height of 13 feet and a whopping weight of up to 1,800 pounds, this beast was especially prolific in what is now California.

Demon Duck of Doom

(images via teara, tanystropheus)

The prehistoric Bullockornis, otherwise known as the Demon Duck of Doom (no joke!), stood over 8 feet tall and weighed over 550 pounds. To make this bird even scarier, paleontologists speculate that it was partly carnivorous.

Amphicoelias Fragillimus

(Images via prehistoricanimal, pravekysvet, svpowrealmagick)

Up to 200 feet long and weighing up to 135 tons, Amphicoelias Fragillimus was a giant among giants. This giant herbivore was arguably the largest creature to ever roam land.