Carcharodontosaurus’s South American cousin, Giganotosaurus (“GIG-a-NOTE-o-SORE-uss”) was another beast to rival T-rex for size. Depending on the specimen, it is thought to have been slightly smaller than Carcharodontosaurus, but longer, taller and more slender than T-rex. It was the fastest of the three, besting the others by at least 16 kilometres (ten miles) per hour, perhaps thanks to its superior balance.
It had a very large skull but, like Carcharodontosaurus, it was more neurologically primitive than T-rex; its brain was a puny half the size of T-rex’s. Still, evidence suggests it had a keen sense of smell, which coupled with its athletic prowess and eight-ton bulk made it a formidable foe.
Like Carcharodontosaurus, Giganotosaurus’s teeth were serrated and laterally compressed – wide in profile but narrow when viewed from the front – making them ideal tools to deliver a series of injurious slices to the body of its prey, which would eventually keel over from exhaustion and blood loss.