Giganotosaurus carolinii was one of the largest carnivorous dinosaurs to have ever walked the earth. Discovered in the region of Argentina known as Patagonia in 1993, this theropod dinosaur was larger than Tyrannosaurus rex. Unlike T. rex, it had relatively long arms with three claws on each hand. Giganotosaurus lived in the late Cretaceous period approximately 97 million years ago. Paleontologists believe it had a well-developed sense of smell and was probably quick for its size, although its brain was only about half as large as its Tyrannosaur cousins.