Giants of deep time
15 Prehistoric Giants: Some of the Largest Animals by Group
Meet giant dinosaurs, fishes, marine reptiles, mammals and arthropods. Discover how long necks, enormous wings and different ways of feeding produced very different kinds of giants.
Explore the animals 15 ↘
How this list was selected
A selection of unusually large members of different animal groups, arranged as a journey from dinosaurs to oceans, land mammals and flight. This is not a single size ranking: body mass, body length and wingspan answer different questions. Arthropleura was a millipede relative, not an insect. Modern blue whales are outside this extinct-animal selection.
In this guide 15
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15 atlas records
About 96–92 million years ago
Argentinosaurus
Argentinosaurus huinculensis
A handful of colossal vertebrae and limb bones indicate one of the largest land animals known.
South America · Present-day Argentina
About 154–152 million years ago
Diplodocus
Diplodocus carnegii
A whip-like tail balanced an extremely long neck on this lightly built giant.
Western North America
About 77 million years ago
Dreadnoughtus
Dreadnoughtus schrani
A relatively complete skeleton makes this giant titanosaur unusually measurable.
Floodplain woodland · Patagonia, Argentina
About 154–150 million years ago
Brachiosaurus
Brachiosaurus altithorax
Long forelimbs lifted its shoulders and neck toward the Jurassic canopy.
Western North America
About 23–3.6 million years ago
Megalodon
Otodus megalodon
Its hand-sized teeth belonged to a giant shark specialized in hunting marine mammals.
Warm oceans worldwide
About 165–155 million years ago
Leedsichthys
Leedsichthys problematicus
This giant bony fish opened a broad mouth and strained plankton through dense gill rakers, much like a whale shark.
Warm Jurassic oceans · Europe and South America
About 237–227 million years ago
Shonisaurus
Shonisaurus popularis
This roughly fifteen-meter ichthyosaur had a long narrow snout and four flippers.
Eastern Panthalassa · Present-day Nevada
About 82–66 million years ago
Mosasaurus
Mosasaurus hoffmannii
A giant marine lizard propelled by a deep tail fin patrolled Late Cretaceous seas.
Europe · North America · Open oceans
About 41–34 million years ago
Basilosaurus
Basilosaurus isis
This long-bodied early whale still carried tiny external hind limbs.
Tethys Sea · North American coasts
About 34–23 million years ago
Paraceratherium
Paraceratherium transouralicum
The largest known land mammal was a hornless rhinoceros relative built to browse high foliage.
Central Asia
About 400,000–4,000 years ago
Woolly Mammoth
Mammuthus primigenius
They lived not on endless ice, but in a wind-shaped grassland ecosystem.
Northern Eurasia · North America
About 400,000–10,000 years ago
Giant Ground Sloth
Megatherium americanum
Standing on its hind legs, this elephant-sized sloth could reach high branches with huge claws.
South American grasslands and woodlands
About 60–58 million years ago
Titanoboa
Titanoboa cerrejonensis
The largest known snake moved through hot tropical swamps after the dinosaurs vanished.
Northern South America · Present-day Colombia
About 68–66 million years ago
Quetzalcoatlus
Quetzalcoatlus northropi
One of the largest known flying animals stood as tall as a giraffe on the ground.
Inland wetlands of North America
About 345–290 million years ago
Arthropleura
Arthropleura armata
This many-segmented arthropod grew longer than a person in coal-swamp forests.
Tropical forests of Europe · North America
