Rodolfo Coria and Phillip Currie have excavated four or five Giganotosaurus fossils of different sizes in the Patagonian plains of Argentina. Two of the specimens are very large, the others are smaller. They date from 90 million years ago, during the Cretaceous period. The site was discovered by a local goat-herd. Coria, a paleontologist from the Carmen Funes Museum in Neuquen, Argentina, described the original Giganotosaurus in 1993. Currie is the curator of the Royal Tyrrell Museum of Paleontology in Drumheller, Alberta, Canada.
Giganotosaurus was a carnivorous dinosaur that was even larger than T. rex. Because of its very small brain case, it had been thought that Giganotosaurus was a relatively dumb dinosaur, exhibiting few complex behaviors. The existence of a pack of these dinosaurs shows that these assumptions may have been too simplistic. Social behavior on the part of Giganotosaurus (suggested by finding individuals of different sizes in the group) means that it was smarter than previously thought, perhaps cooperating while hunting and/or protecting the young. On the other hand, they may have simply been gathering at a waterhole at the time of their demise.
Giganotosaurus was a 47-foot long meat-eating dinosaur which weighed about 8 tons and stood 12 feet tall (at the hips). It walked on two legs, had a brain the size of a banana, and had enormous jaws with 8-inch long, knife-like, serrated teeth in a 6 feet (1.8 m) long skull. Giganotosaurus was a theropod from the mid-Cretaceous period, living about 100-95 million years ago, toward the end of the Mesozoic Era, the "Age of Reptiles".
Although some news sources (like Reuters, ABC News, and the Boston Globe) reported that Giganotosaurus kept T. rex from venturing into South America, this is wrong, wrong, wrong.
Giganotosaurus lived and died millions of years before T. rex evolved. Also, a sea separated North and South America during the Cretaceous. These two titans could never have met.
Giga-noto-saurus means "giant southern reptile". Giganotosaurus was originally found by a local auto mechanic whose hobby is hunting dinosaur bones. In honor of the discoverer, Ruben Carolini, the huge dinosaur has been named Giganotosaurus carolinii. Its fossil was unearthed in the Patagonia region of southeastern Argentina (near the town of El Chocon) in 1993. 70 percent of the skeleton has been found. Near the Giganotosaurus, fossils were found of a 75-foot-long sauropods (plant eaters), Argentinosaurus, presumably a victim of Giganotosaurus.
Giganotosaurus was probably bigger than Tyrannosaurus rex, who was about 40 feet long, about 5 tons in weight and about 10 feet tall at the hips. Giganotosaurus, however, was more lightly built and had a much smaller brain case. Giganotosaurus lived about 30 million years before Tyrannosaurus rex, which was among the last of the dinosaur species alive before the Cretaceous-Tertiary extinction 65 million years ago.