Land of the giants - South America in the Early Cretaceous

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 animal

Argentinosaurus was not a solitary animal. It probably moved in herds of around 20, stripping vegetated areas of leaves, seed and fruit before moving on to find a new place to graze.

It's difficult to believe that any animal ever dared attack this gigantic creature. But one daring and vicious creature did. Argentinosaurus was stalked by a truly awesome predator called Giganotosaurus.

Big and mean

	Giganotosaurus hunted in packs of six or more

This distant relative of Allosaurus measured 14 metres (45 feet) in length and weighed around 6 to 8 tonnes. Its skull alone was over 1.6 metres long and lined with rows of needle-sharp teeth.

While it was not as gigantic as its prey, Giganotosaurus' overall size makes it the largest carnivore that has ever lived. South America in the Early Cretaceous was the stage for the ultimate hunt: the largest predator ever, stalking the largest prey of all time.

Giganotosaurus probably hunted Argentinosaurus in packs of six or more. They would have singled out individuals that were young, weak or isolated from the herd and pursued them relentlessly, perhaps taking turns to bite and weaken their prey until they were exhausted.

Thrill of the chase

Giganotosaurus had powerful jaws that would have inflicted traumatic damage on their unlucky victims.

When the time was right, the pack of Giganotosaurus went in for the kill, gorging themselves in a frenzied binge. After an Argentinosaurus steak, Giganotosaurus would not have needed to eat for weeks afterwards.

Fast-moving prey

The plains and valleys of South America in the Early Cretaceous were also home to Diplodocus-like dinosaurs called Andesaurus, which may also have been preyed upon by Giganotosaurus. Large, fast-moving dinosaurs called iguanodonts also fed on vegetation in the forests and woodland.

	Pteranodon- A large, graceful pterosaur that hunted fish.

Master of the skies

In the sky, Pteranodon used its membranous wings to soar on air currents called thermals. But these creatures were not quite masters of the skies. Pteranodon would have crossed flight paths with Ornithocheirus, the biggest flying animal of all time. Ornithocheirus boasted a wingspan of 40 feet, equivalent to that of a small aeroplane.

Ornithocheirus fed by swooping down over lakes, dipping its beak into the water and snatching fish with its razor sharp teeth.

This article was written to accompany the Walking with Dinosaurs special Land of the Giants.