What Is The Biggest Dinosaur That Ever Lived?
Edition 2026-10
Nobody knows for sure, and that is the interesting part.
The short answer
Nobody knows for sure, because the biggest dinosaurs are known from only a few bones. The heaviest we know of were long-necked sauropods from Argentina such as Argentinosaurus and Patagotitan, estimated at somewhere around 50 to 80 tonnes and more than 30 meters long: longer than two school buses.
The Long Answer
Size estimates come from the bones that survive. For the giants, that is often a few vertebrae, a leg bone and some ribs, so scientists scale up from relatives they know better. Different methods give different answers, which is why the numbers below are ranges.
The Heaviest
Argentinosaurus and Patagotitan, both titanosaurs from Argentina, are the leading candidates. Patagotitan is known from several skeletons: it was about 31 to 37 meters long and weighed about 50 to 70 tonnes. The Field Museum's cast of it is 37 meters long. Argentinosaurus is estimated at about 65 to 75 tonnes, though some scientists say more.
The Tallest
Brachiosaurus stood about 12 meters tall with its neck raised, more than twice as tall as a giraffe.
The Biggest Hunter
Tyrannosaurus rex was about 12 meters long and weighed about 5 to 9 tonnes. It had about 60 teeth, some up to 20 centimeters long.
For scale: a big US school bus is up to about 12 meters (40 feet) long.
Sources
- Carballido et al. 2017, Patagotitan
- Paul 2019, titanosaur masses (Annals of Carnegie Museum)
- Field Museum: Maximo the titanosaur
- Blue Bird: school bus specifications
- Natural History Museum, London: Tyrannosaurus
- Field Museum: SUE the T. rex
- Encyclopaedia Britannica: Brachiosaurus
- Natural History Museum, London: When did dinosaurs live?
- Natural History Museum, London: What are dinosaurs?
- Natural History Museum, London: Stegosaurus
- Natural History Museum, London: How dinosaurs got their name
- San Diego Zoo: Giraffe
- Natural History Museum, London: Velociraptor
- American Museum of Natural History: Velociraptor
- Cornell Lab of Ornithology: Wild Turkey
It is on the poster
Dinosaur Poster
Dinosaurs, with their names big enough to read.
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