Around 100 million years ago, South America was home to the biggest dinosaur that has ever walked the Earth. Argentinosaurus may have stood as tall as 21 metres (70 feet) and measured an enormous 35 metres (115 feet) in length. At this size, Argentinosaurus probably shook the ground as it moved. Palaeontologists estimate that it may have weighed as much as 75 to 100 tonnes. Social animalArgentinosaurus was not a solitary animal. It probably moved in herds of around 20, stripping vegetated areas