Giganotosaurus did not die out in the famous asteroid strike that ended the age of dinosaurs. It vanished roughly 30 million years before that event, disappearing from the fossil record around 93 million years ago during a period of extreme environmental upheaval known as the Cenomanian-Turonian extinction. This was a separate mass extinction driven by climate chaos, rising seas, and collapsing ecosystems, and it wiped out not just Giganotosaurus but its entire family of giant predators across the Southern Hemisphere.
Giganotosaurus Lived and Died in the Mid-Cretaceous
Giganotosaurus roamed what is now Patagonia, Argentina, during the Cenomanian stage of the Cretaceous period, roughly 98 to 93 million years ago. Its fossils come from the Candeleros Formation, a geological layer representing ancient floodplains and river systems in a warm, semi-arid landscape. The first fossils were discovered in 1987 near Lake Ezequiel in Patagonia, though the species wasn’t formally named until 1995 after amateur paleontologist Rubén D. Carolini found a leg bone in 1993.
Giganotosaurus belonged to a family called the carcharodontosaurids, a group of massive meat-eating dinosaurs that thrived across the Southern Hemisphere (and parts of the Northern Hemisphere) during the Early to mid-Cretaceous. Its close relatives included Mapusaurus in South America and Carcharodontosaurus in North Africa. No confirmed fossils of any carcharodontosaurid have been found in Southern Hemisphere rocks younger than the Cenomanian, meaning this entire lineage of apex predators vanished within a relatively narrow window of time.
The Cenomanian-Turonian Extinction
The event that likely killed off Giganotosaurus was the Cenomanian-Turonian mass extinction, one of the most significant die-offs of the Cretaceous period. It struck during a time of extreme greenhouse conditions. Atmospheric carbon dioxide levels were at least four times higher than today’s. Sea levels had risen nearly 300 meters above the present stand, flooding vast stretches of continental land. Global temperatures were elevated, and the temperature difference between the poles and the equator was far smaller than it is now.
The oceans became especially unstable. A massive oceanic anoxic event (a period when large portions of the sea lost their dissolved oxygen) disrupted marine chemistry on a global scale. This oxygen depletion didn’t just kill sea life. It triggered cascading changes in carbon cycling, nutrient availability, and atmospheric chemistry that rippled onto land. Researchers have identified multiple discrete pulses of extinction during this interval, each linked to large-scale swings in ocean temperature and chemistry that compounded over time. Two likely catalysts were the expansion of oxygen-depleted ocean zones into shallower continental waters, and a shower of meteorite or comet impacts during the late Cenomanian.
For land animals like Giganotosaurus, these shifts would have disrupted food webs from the bottom up. Changes in plant communities, driven by altered rainfall patterns and temperatures, would have affected herbivorous dinosaurs, which in turn would have starved out the giant predators that depended on them.
A Global Collapse of Giant Predators
Giganotosaurus didn’t disappear in isolation. The Cenomanian-Turonian boundary saw the extinction of carcharodontosaurids across all of the Southern Hemisphere. Spinosaurids, another major group of large predators, also vanished during this same interval. Among plant-eating dinosaurs, the rebbachisaurids (a group of long-necked sauropods) went extinct and were replaced by titanosaurs, which went on to dominate until the final extinction 66 million years ago.
In the Northern Hemisphere, carcharodontosaurids may have held on slightly longer. One species from China dates to the Turonian, the stage immediately following the Cenomanian. But eventually, they disappeared there too, replaced as top predators by tyrannosaurs in North America and Asia. The pattern is consistent: the Cenomanian-Turonian transition reshuffled predator communities worldwide.
What Replaced Giganotosaurus
The ecological role Giganotosaurus had filled didn’t stay empty for long. After the Cenomanian-Turonian turnover, abelisaurids and megaraptorans became the dominant predatory dinosaurs in South America. Abelisaurids like Carnotaurus, Skorpiovenator, and Aucasaurus were stocky, powerful predators with distinctively short arms and deep skulls. They weren’t as large as Giganotosaurus, but they diversified rapidly and produced a remarkable number of species across Patagonia and the rest of the Southern Hemisphere from the late Turonian all the way to the end of the Cretaceous, 66 million years ago.
This kind of replacement is a common pattern in evolution. When one dominant group is removed by environmental catastrophe, other lineages that were previously smaller or less diverse can expand to fill the vacant roles. The abelisaurids were already present alongside Giganotosaurus during the Cenomanian, but they were less prominent. Once the carcharodontosaurids and spinosaurids were gone, abelisaurids had the ecological space to become apex predators themselves.
Why People Confuse It With the Asteroid
The popular image of dinosaur extinction centers on the asteroid impact at the end of the Cretaceous, 66 million years ago. That event did wipe out all remaining non-bird dinosaurs, but Giganotosaurus had already been gone for roughly 27 million years by that point. The confusion is understandable because “dinosaur extinction” is typically taught as a single event, but the Cretaceous period lasted over 80 million years and included several significant extinction pulses along the way.
Giganotosaurus lived in a very different world from the one that existed at the end of the Cretaceous. The continents were in different positions, the oceans were configured differently, and the dinosaur communities bore little resemblance to the Tyrannosaurus-era fauna most people picture. By the time the asteroid hit what is now Mexico’s Yucatán Peninsula, the entire lineage of giant carcharodontosaurid predators had been a distant memory for tens of millions of years.