Heaviest dinosaur
Argentinosaurus huinculensis
60–124 tonne(s)/metric ton(s)
Not Applicable ()

The largest living creature to ever walk the Earth was the sauropod dinosaur Argentinosaurus huinculensis, which lived in what is now South America roughly 97–93.5 million years ago (in the Late Cretaceous period). Argentinosaurus – which was part of a subgroup called the titanosaurs – is estimated to have weighed somewhere between 60 and 124 tonnes (132,277–273,373 lb), with most palaeontologists favouring the lower reaches of this range (between 60 and 90 tonnes). Estimates of the animal's length are similarly varied, with figures ranging from 30 to 40 metres (98–131 ft). Even by the most conservative estimates, however, Argentinosaurus dwarfs any living land animal, weighing around 10 times more than an adult African elephant.

Argentinosarus was a herbivore, similar in appearance and behaviour to the better-known diplodocus and apatosaurus, with a long neck and tail that extended a far beyond its sturdy four-legged body.

The reason for the variation in size estimates is the fragmentary nature of the fossil remains found so far. Argentinosaurus is known only from a few fossil bones, including nine vertebrae (most of which are incomplete), a partial femur and fibula, and some sections of ribs. This makes it impossible to be certain exactly how the dinosaur was proportioned. Existing estimates have been made by essentially scaling up the known proportions of more complete sauropod skeletons to match the size of the bones that have been found.