The last meal of a 75-million-year-old tyrannosaurus was two baby dinosaurs, shedding new light on how these predators lived, scientists say
It is "strong evidence that tyrannosaurs drastically changed their diet as they grew up," said Dr. Darla Zelenicki from the University of Calgary, reports the BBC.
The specimen found is a young gorgosaurus, a close relative of the giant T-rex.
This gorgosaurus was about seven years old, which is equivalent to a teenager in terms of its development. When it died, it weighed about 330 kg, about a tenth of the weight of an adult Gorgosaurus. In his body, where his stomach had been, were found the bones of two baby bird-like dinosaurs called citipes.
"We now know that these teenage tyrannosaurs were preying on small, young dinosaurs ," said Dr. Zelenicki, one of the lead scientists on the study, which was published in the journal Science Advances.
A range of early fossil evidence, including tyrannosaurid bite marks on the bones of larger dinosaurs, has allowed scientists to build a picture of how gorgosaurs attacked and ate large herbivores that lived in herds.
Dr Francois Therrien of the Royal Tyrrell Museum of Palaeontology described these adult tyrannosaurids as animals that fed "indiscriminately" .
"They were probably attacking large herbivores, gnawing through the bones and tearing off the flesh," he told the BBC. But Dr. Zelenicki argues that the smaller, immature tyrannosaurids were unwilling to jump into a herd of several-ton horned dinosaurs.
When it comes to this particular fossil, Dr. Zelenicki and her team found the legs of small dinosaurs in the place where the stomach of the gorgosaurus was, which means that this predator "loved drumsticks" , as the meatiest part.
Gorgosaurus, a slightly smaller and older species than T-rex, were muscular and slender when young, and as they grew, they turned into giants that walked more slowly, but were much stronger.
Commenting on the depiction of a T-rex in the 1993 film Jurassic Park , where a giant dinosaur chases a car through a fictional theme park, Professor Steve Brusate, a palaeontologist at the University of Edinburgh and the National Museum of Scotland, stated that a large, full-grown T-rex would not have chased after the car if they existed then, because his body was too big and he couldn't move that fast.