The young Gorgosaurus I knew what I liked for dinner. About 75 million years ago, in the province of Alberta, Canada, this fearsome cousin of Tyrannosaurus rex began hunting turkey-sized chicks of a feathered herbivorous dinosaur called cities.
With so much prey available, the Gorgosaurus I could be picky about what I ate. He dismembered the defenseless cities and swallowed its fleshy legs whole, ignoring the rest of the corpse.
Scientists said this Friday (8) that they have unearthed fossilized remains of a Gorgosaurus juvenile that was 5 to 7 years old and about 4.5 meters long. Surprisingly, the fossil contained the contents of the animal’s stomach, revealing its last meals.
Gorgosaurus and the famous Tyrannosauruswhich lived several million years later, are members of a group of carnivorous dinosaurs called tyrannosaurs.
The new fossil provided insight into the ecology of this group, showing that the feeding strategy and diet of tyrannosaurs changed drastically throughout their lives.
This is the first tyrannosaur skeleton with prey items preserved inside its stomach.
Based on tooth marks left on the bones, it is known that adults hunted large herbivorous dinosaurs.
“Adult tyrannosaurs were well equipped to capture and kill large prey, such as duck-billed dinosaurs and horned dinosaurs. Their skulls and teeth were able to withstand the major stresses associated with biting and holding large prey,” said François Therrien , curator of dinosaur paleoecology at the Royal Tyrrell Museum in Alberta and co-leader of the study published in the journal Science Advances.
“Already, juveniles’ weaker bites and teeth were ideal for cutting bites, not for holding prey. They would have been well equipped to hunt smaller dinosaur species and young dinosaurs,” Therrien added.
The study indicates that tyrannosaurs occupied different ecological niches throughout their lives: “mesopredators” —medium-sized predators— when young, becoming top predators in adolescence and adulthood. This means that juvenile tyrannosaurs did not compete with older ones for the same prey.
“Young tyrannosaurs had blade-shaped teeth, lightly built skulls, relatively weak bites, long legs, and appeared more ‘athletic’ than adult tyrannosaurs, which were very robust, had massive skulls, thicker teeth—often described as ‘ killer bananas’ because of their shape—and powerful bites that allowed them to crush bones,” Therrien said.
Gorgosaurusslightly smaller than the Tyrannosaurus, dominated its ecosystem. It walked on two legs, had short arms with two-fingered hands, a massive one-meter-long skull, reached 9 to 10 meters in length and weighed 2 to 3 tons. O Gorgosaurus Juvenile weighed approximately 330 kg, with a skull approximately 50 cm long.
The fossil was discovered in Dinosaur Provincial Park in southern Alberta. During the Cretaceous Period, the region was a forested coastal plain and was near the west coast of an inland sea that divided North America into two parts.
The stomach contents, found between the ribs and hip bones, included the leg and foot bones of two baby birds. cities.
O cities it was a small dinosaur that looked like a bird, walked on two legs and had a head similar to a parrot.
“Once the cities would have had large clutches, laying about 30 eggs in a nest, their young would have been abundant in the ecosystem and ready to be captured by young tyrannosaurs,” said Darla Zelenitsky, a dinosaur paleontologist at the University of Calgary and co-leader of the study.
Based on the different damage caused by stomach acid to the bones of citiesthe fry were eaten at different times, and the Gorgosaurus died of unknown causes hours or days after his last meal.
“The bones found in the stomach are entire legs. Perhaps a cities complete was too big to pass through a young man’s throat Gorgosaurus, so the predator selected the meatiest parts of the corpse. That Gorgosaurus I liked chicken legs,” Zelenitsky said.
“While the adults devoured every part of a large herbivore — often pulverizing and swallowing bones in the process — the young were much more surgical in their feeding,” Zelenitsky added.