Food found in Tyrannosaurus stomach for the first time: Young T-Rex loved drumsticks

For the first time in history, remains of prey have been found in the stomach of a tyrannosaurus. Scientists write this down a new studywhich reveals that the mighty dinosaurs “craved for drumsticks” in their younger years.

The skeleton of a Gorgosaurus, a member of the tyrannosaurus family that also includes the T-Rex, tells us more about how these dinosaurs grew up. The young animals were quite slender in build, but slowly but surely turned into gigantic, bone-crushing apex predators, the researchers said. The Gorgosaurus – loosely translated as ‘terrible lizard’ – was around six years old when it died about 75 million years ago.

Craving baby drumsticks
The fossil was discovered in 2009 in the Dinosaur Provincial Park east of the Canadian city of Calgary. Only when the researchers recently examined the skeleton again in the lab did they see something very special. Lead researcher Francois Therrien of the Royal Tyrrell Museum near Calgary says he was shocked when he “discovered that the remains of this young tyrannosaur’s last meal were preserved inside the fossil.” Most surprisingly, the small bones protruding from the tyrannosaurus’ ribcage turned out to belong to two bird-like dinosaurs. They were the legs of so-called Citipes.

Difficult eater
Paleontologists strongly suspect that the Citipes had feathers and a beak. They walked on two legs, which makes them most resemble modern turkeys: a solidly built, wingless bird. They were much smaller than the enormous herbivorous dinosaurs, which had adult tyrannosaurs on their diet, Therrien explains. In addition, this young Gorgosaurus was a rather ‘picky eater’. “It used its sharp teeth to bite off the legs of two baby Citipes and ate only these ‘drumsticks,’” says researcher Darla Zelenitsky of the University of Calgary.

Transformation of the T-Rex
The discovery gives us a rare glimpse into how tyrannosaurs evolved. They were about 1 meter long at birth and grew to be one of the largest predators to ever walk the Earth. “This fossil is the first tangible evidence that tyrannosaurs dramatically changed their diet as they aged,” Zelenitsky said. Young tyrannosaurs had slender heads and legs, and sharp blade-like teeth for tearing apart carcasses. They were probably able to run quite fast so they could catch their turkey-like prey. “These young animals probably looked more like the velociraptors seen in the movie ‘Jurassic Park’ than the giant T-Rex,” says the paleontologist.

‘Bloodthirsty bananas’
Around the age of eleven, the tyrannosaurus had reached middle age. His size had now increased almost ten times and the scales tipped over 3000 kilos. They got a broader head in relative and absolute terms, while their teeth also became thicker. Therrien calls them ‘bloodthirsty bananas’ that were able to bite through enormous bones. This transformation was accompanied by a change in diet: the childhood craving for drumsticks disappeared and in return came the hunt for gigantic herbivorous dinosaurs. “These types of drastic dietary changes are much more common in the animal kingdom. Crocodiles and Komodo dragons, for example, feed on insects as babies, after which they switch to rodents and eventually eat large mammals,” Therrien explains.

From meso to apex predator
The scientists say the Gorgosaurus fossil is strong evidence for the theory that young tyrannosaurs – including the T-Rex – took on the role of ‘mesopredator’ in the food pyramid. Later they evolved into apex predators. “This adaptation is likely why tyrannosaurs were so successful and dominated their ecosystems at the end of the Cretaceous in North America and Asia,” concludes Therrien.